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nothings-stb/stb_image_resize.h

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/* stb_image_resize - v0.50 - public domain image resampling
no warranty implied; use at your own risk
Do this:
#define STB_IMAGE_RESIZE_IMPLEMENTATION
before you include this file in *one* C or C++ file to create the implementation.
#define STBIR_ASSERT(x) to avoid using assert.h.
#define STBIR_MALLOC(size,context) and STBIR_FREE(ptr,context) to avoid using stdlib.h malloc.
Each function makes exactly one call to malloc/free, so to avoid allocations,
pass in a temp memory block as context and return that from MALLOC.
QUICK NOTES:
Written with emphasis on usage and speed. Only the resize operation is
currently supported, no rotations or translations.
Supports arbitrary resize for separable filters. For a list of
supported filters see the stbir_filter enum. To add a new filter,
write a filter function and add it to stbir__filter_info_table.
Revisions:
0.50 (2014-??-??) first released version
TODO:
Installable filters
Resize that respects alpha test coverage
(Reference code: FloatImage::alphaTestCoverage and FloatImage::scaleAlphaToCoverage:
https://code.google.com/p/nvidia-texture-tools/source/browse/trunk/src/nvimage/FloatImage.cpp )
Initial implementation by Jorge L Rodriguez, @VinoBS
*/
#ifndef STBIR_INCLUDE_STB_IMAGE_RESIZE_H
#define STBIR_INCLUDE_STB_IMAGE_RESIZE_H
typedef unsigned char stbir_uint8;
#ifdef _MSC_VER
typedef unsigned short stbir_uint16;
typedef unsigned int stbir_uint32;
#else
#include <stdint.h>
typedef uint16_t stbir_uint16;
typedef uint32_t stbir_uint32;
#endif
#ifdef STB_IMAGE_RESIZE_STATIC
#define STBIRDEF static
#else
#ifdef __cplusplus
#define STBIRDEF extern "C"
#else
#define STBIRDEF extern
#endif
#endif
//////////////////////////////////////////////////////////////////////////////
//
// Easy-to-use API:
//
// * "input pixels" points to an array of image data with 'num_channels' channels (e.g. RGB=3, RGBA=4)
// * input_w is input image width (x-axis), input_h is input image height (y-axis)
// * stride is the offset between successive rows of image data in memory, in bytes. you can
// specify 0 to mean packed continuously in memory
// * alpha channel is treated identically to other channels.
// * colorspace is linear or sRGB as specified by function name
// * returned result is 1 for success or 0 in case of an error.
// #define STBIR_ASSERT() to trigger an assert on parameter validation errors.
// * Memory required grows approximately linearly with input and output size, but with
// discontinuities at input_w == output_w and input_h == output_h.
// * These functions use a "default" resampling filter defined at compile time. To change the filter,
// you can change the compile-time defaults by #defining STBIR_DEFAULT_FILTER_UPSAMPLE
// and STBIR_DEFAULT_FILTER_DOWNSAMPLE, or you can use the medium-complexity API.
STBIRDEF int stbir_resize_uint8( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
int num_channels);
STBIRDEF int stbir_resize_float( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
float *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
int num_channels);
// The following functions interpret image data as gamma-corrected sRGB.
// Specify STBIR_ALPHA_CHANNEL_NONE if you have no alpha channel,
// or otherwise provide the index of the alpha channel. Flags value
// of 0 will probably do the right thing if you're not sure what
// the flags mean.
#define STBIR_ALPHA_CHANNEL_NONE -1
// Set this flag if your texture has premultiplied alpha. Otherwise, stbir will
// use alpha-correct resampling by multiplying the the specified alpha channel
// into all other channels before resampling, then dividing back out after.
#define STBIR_FLAG_PREMULTIPLIED_ALPHA (1 << 0)
// The specified alpha channel should be handled as gamma-corrected value even
// when doing sRGB operations.
#define STBIR_FLAG_ALPHA_USES_COLORSPACE (1 << 1)
STBIRDEF int stbir_resize_uint8_srgb(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
int num_channels, int alpha_channel, int flags);
typedef enum
{
STBIR_EDGE_CLAMP = 1,
STBIR_EDGE_REFLECT = 2,
STBIR_EDGE_WRAP = 3,
STBIR_EDGE_ZERO = 4,
} stbir_edge;
// This function adds the ability to specify how requests to sample off the edge of the image are handled.
STBIRDEF int stbir_resize_uint8_srgb_edgemode(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_wrap_mode);
//////////////////////////////////////////////////////////////////////////////
//
// Medium-complexity API
//
// This extends the easy-to-use API as follows:
//
// * Alpha-channel can be processed separately
// * If alpha_channel is not STBIR_ALPHA_CHANNEL_NONE
// * Alpha channel will not be gamma corrected (unless flags&STBIR_FLAG_GAMMA_CORRECT)
// * Filters will be weighted by alpha channel (unless flags&STBIR_FLAG_PREMULTIPLIED_ALPHA)
// * Filter can be selected explicitly
// * uint16 image type
// * sRGB colorspace available for all types
// * context parameter for passing to STBIR_MALLOC
typedef enum
{
STBIR_FILTER_DEFAULT = 0, // use same filter type that easy-to-use API chooses
STBIR_FILTER_BOX = 1, // Is actually a trapezoid. See https://developer.nvidia.com/content/non-power-two-mipmapping
STBIR_FILTER_BILINEAR = 2,
STBIR_FILTER_BICUBIC = 3, // A cubic b spline
STBIR_FILTER_CATMULLROM = 4,
STBIR_FILTER_MITCHELL = 5,
} stbir_filter;
typedef enum
{
STBIR_COLORSPACE_LINEAR,
STBIR_COLORSPACE_SRGB,
STBIR_MAX_COLORSPACES,
} stbir_colorspace;
// The following functions are all identical except for the type of the image data
STBIRDEF int stbir_resize_uint8_generic( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
void *alloc_context);
STBIRDEF int stbir_resize_uint16_generic(const stbir_uint16 *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
stbir_uint16 *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
void *alloc_context);
STBIRDEF int stbir_resize_float_generic( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
float *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
void *alloc_context);
//////////////////////////////////////////////////////////////////////////////
//
// Full-complexity API
//
// This extends the medium API as follows:
//
// * uint32 image type
// * not typesafe
// * separate filter types for each axis
// * separate edge modes for each axis
// * can specify scale explicitly for subpixel correctness
// * can specify image source tile using texture coordinates
typedef enum
{
STBIR_TYPE_UINT8 ,
STBIR_TYPE_UINT16,
STBIR_TYPE_UINT32,
STBIR_TYPE_FLOAT ,
STBIR_MAX_TYPES
} stbir_datatype;
STBIRDEF int stbir_resize( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
stbir_datatype datatype,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
stbir_filter filter_horizontal, stbir_filter filter_vertical,
stbir_colorspace space, void *alloc_context);
STBIRDEF int stbir_resize_subpixel(const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
stbir_datatype datatype,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
stbir_filter filter_horizontal, stbir_filter filter_vertical,
stbir_colorspace space, void *alloc_context,
float x_scale, float y_scale,
float x_offset, float y_offset);
STBIRDEF int stbir_resize_region( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
stbir_datatype datatype,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
stbir_filter filter_horizontal, stbir_filter filter_vertical,
stbir_colorspace space, void *alloc_context,
float s0, float t0, float s1, float t1);
// (s0, t0) & (s1, t1) are the top-left and bottom right corner (uv addressing style: [0, 1]x[0, 1]) of a region of the input image to use.
// Define this if you want a progress report.
// Example:
// void my_progress_report(float progress)
// {
// printf("Progress: %f%%\n", progress*100);
// }
//
// #define STBIR_PROGRESS_REPORT my_progress_report
#ifndef STBIR_PROGRESS_REPORT
#define STBIR_PROGRESS_REPORT(float_0_to_1)
#endif
// This value is added to alpha just before premultiplication to avoid
// zeroing out color values. It is equivalent to 2^-80. If you don't want
// that behavior (it may interfere if you have floating point images with
// very small alpha values) then you can define STBIR_NO_ALPHA_EPSILON to
// disable it.
#ifndef STBIR_ALPHA_EPSILON
#define STBIR_ALPHA_EPSILON ((float)1 / (1 << 20) / (1 << 20) / (1 << 20) / (1 << 20))
#endif
//
//
//// end header file /////////////////////////////////////////////////////
#endif // STBIR_INCLUDE_STB_IMAGE_RESIZE_H
#ifdef STB_IMAGE_RESIZE_IMPLEMENTATION
#ifndef STBIR_ASSERT
#include <assert.h>
#define STBIR_ASSERT(x) assert(x)
#endif
#ifdef STBIR_DEBUG
#define STBIR__DEBUG_ASSERT STBIR_ASSERT
#else
#define STBIR__DEBUG_ASSERT
#endif
// If you hit this it means I haven't done it yet.
#define STBIR__UNIMPLEMENTED(x) STBIR_ASSERT(!(x))
// For memset
#include <string.h>
#include <math.h>
#ifndef STBIR_MALLOC
#include <stdlib.h>
#define STBIR_MALLOC(x,c) malloc(x)
#define STBIR_FREE(x,c) free(x)
#endif
#ifndef _MSC_VER
#ifdef __cplusplus
#define stbir__inline inline
#else
#define stbir__inline
#endif
#else
#define stbir__inline __forceinline
#endif
// should produce compiler error if size is wrong
typedef unsigned char stbir__validate_uint32[sizeof(stbir_uint32) == 4 ? 1 : -1];
#ifdef _MSC_VER
#define STBIR__NOTUSED(v) (void)(v)
#else
#define STBIR__NOTUSED(v) (void)sizeof(v)
#endif
#define STBIR__ARRAY_SIZE(a) (sizeof((a))/sizeof((a)[0]))
#ifndef STBIR_DEFAULT_FILTER_UPSAMPLE
#define STBIR_DEFAULT_FILTER_UPSAMPLE STBIR_FILTER_CATMULLROM
#endif
#ifndef STBIR_DEFAULT_FILTER_DOWNSAMPLE
#define STBIR_DEFAULT_FILTER_DOWNSAMPLE STBIR_FILTER_MITCHELL
#endif
#define STBIR__UNUSED_PARAM(s) s=s;
// must match stbir_datatype
static unsigned char stbir__type_size[] = {
1, // STBIR_TYPE_UINT8
2, // STBIR_TYPE_UINT16
4, // STBIR_TYPE_UINT32
4, // STBIR_TYPE_FLOAT
};
// Kernel function centered at 0
typedef float (stbir__kernel_fn)(float x, float scale);
typedef float (stbir__support_fn)(float scale);
typedef struct
{
stbir__kernel_fn* kernel;
stbir__support_fn* support;
} stbir__filter_info;
// When upsampling, the contributors are which source pixels contribute.
// When downsampling, the contributors are which destination pixels are contributed to.
typedef struct
{
int n0; // First contributing pixel
int n1; // Last contributing pixel
} stbir__contributors;
typedef struct
{
const void* input_data;
int input_w;
int input_h;
int input_stride_bytes;
void* output_data;
int output_w;
int output_h;
int output_stride_bytes;
float s0, t0, s1, t1;
float horizontal_shift; // Units: output pixels
float vertical_shift; // Units: output pixels
float horizontal_scale;
float vertical_scale;
int channels;
int alpha_channel;
stbir_uint32 flags;
stbir_datatype type;
stbir_filter horizontal_filter;
stbir_filter vertical_filter;
stbir_edge edge_horizontal;
stbir_edge edge_vertical;
stbir_colorspace colorspace;
stbir__contributors* horizontal_contributors;
float* horizontal_coefficients;
stbir__contributors vertical_contributors;
float* vertical_coefficients;
int decode_buffer_pixels;
float* decode_buffer;
float* horizontal_buffer;
int ring_buffer_length_bytes; // The length of an individual entry in the ring buffer. The total number of ring buffers is stbir__get_filter_pixel_width(filter)
int ring_buffer_first_scanline;
int ring_buffer_last_scanline;
int ring_buffer_begin_index;
float* ring_buffer;
float* encode_buffer; // A temporary buffer to store floats so we don't lose precision while we do multiply-adds.
int horizontal_contributors_size;
int horizontal_coefficients_size;
int vertical_coefficients_size;
int decode_buffer_size;
int horizontal_buffer_size;
int ring_buffer_size;
int encode_buffer_size;
} stbir__info;
static stbir__inline int stbir__min(int a, int b)
{
return a < b ? a : b;
}
static stbir__inline int stbir__max(int a, int b)
{
return a > b ? a : b;
}
static stbir__inline float stbir__saturate(float x)
{
if (x < 0)
return 0;
if (x > 1)
return 1;
return x;
}
static float stbir__srgb_uchar_to_linear_float[256] = {
0.000000f, 0.000304f, 0.000607f, 0.000911f, 0.001214f, 0.001518f, 0.001821f, 0.002125f, 0.002428f, 0.002732f, 0.003035f,
0.003347f, 0.003677f, 0.004025f, 0.004391f, 0.004777f, 0.005182f, 0.005605f, 0.006049f, 0.006512f, 0.006995f, 0.007499f,
0.008023f, 0.008568f, 0.009134f, 0.009721f, 0.010330f, 0.010960f, 0.011612f, 0.012286f, 0.012983f, 0.013702f, 0.014444f,
0.015209f, 0.015996f, 0.016807f, 0.017642f, 0.018500f, 0.019382f, 0.020289f, 0.021219f, 0.022174f, 0.023153f, 0.024158f,
0.025187f, 0.026241f, 0.027321f, 0.028426f, 0.029557f, 0.030713f, 0.031896f, 0.033105f, 0.034340f, 0.035601f, 0.036889f,
0.038204f, 0.039546f, 0.040915f, 0.042311f, 0.043735f, 0.045186f, 0.046665f, 0.048172f, 0.049707f, 0.051269f, 0.052861f,
0.054480f, 0.056128f, 0.057805f, 0.059511f, 0.061246f, 0.063010f, 0.064803f, 0.066626f, 0.068478f, 0.070360f, 0.072272f,
0.074214f, 0.076185f, 0.078187f, 0.080220f, 0.082283f, 0.084376f, 0.086500f, 0.088656f, 0.090842f, 0.093059f, 0.095307f,
0.097587f, 0.099899f, 0.102242f, 0.104616f, 0.107023f, 0.109462f, 0.111932f, 0.114435f, 0.116971f, 0.119538f, 0.122139f,
0.124772f, 0.127438f, 0.130136f, 0.132868f, 0.135633f, 0.138432f, 0.141263f, 0.144128f, 0.147027f, 0.149960f, 0.152926f,
0.155926f, 0.158961f, 0.162029f, 0.165132f, 0.168269f, 0.171441f, 0.174647f, 0.177888f, 0.181164f, 0.184475f, 0.187821f,
0.191202f, 0.194618f, 0.198069f, 0.201556f, 0.205079f, 0.208637f, 0.212231f, 0.215861f, 0.219526f, 0.223228f, 0.226966f,
0.230740f, 0.234551f, 0.238398f, 0.242281f, 0.246201f, 0.250158f, 0.254152f, 0.258183f, 0.262251f, 0.266356f, 0.270498f,
0.274677f, 0.278894f, 0.283149f, 0.287441f, 0.291771f, 0.296138f, 0.300544f, 0.304987f, 0.309469f, 0.313989f, 0.318547f,
0.323143f, 0.327778f, 0.332452f, 0.337164f, 0.341914f, 0.346704f, 0.351533f, 0.356400f, 0.361307f, 0.366253f, 0.371238f,
0.376262f, 0.381326f, 0.386430f, 0.391573f, 0.396755f, 0.401978f, 0.407240f, 0.412543f, 0.417885f, 0.423268f, 0.428691f,
0.434154f, 0.439657f, 0.445201f, 0.450786f, 0.456411f, 0.462077f, 0.467784f, 0.473532f, 0.479320f, 0.485150f, 0.491021f,
0.496933f, 0.502887f, 0.508881f, 0.514918f, 0.520996f, 0.527115f, 0.533276f, 0.539480f, 0.545725f, 0.552011f, 0.558340f,
0.564712f, 0.571125f, 0.577581f, 0.584078f, 0.590619f, 0.597202f, 0.603827f, 0.610496f, 0.617207f, 0.623960f, 0.630757f,
0.637597f, 0.644480f, 0.651406f, 0.658375f, 0.665387f, 0.672443f, 0.679543f, 0.686685f, 0.693872f, 0.701102f, 0.708376f,
0.715694f, 0.723055f, 0.730461f, 0.737911f, 0.745404f, 0.752942f, 0.760525f, 0.768151f, 0.775822f, 0.783538f, 0.791298f,
0.799103f, 0.806952f, 0.814847f, 0.822786f, 0.830770f, 0.838799f, 0.846873f, 0.854993f, 0.863157f, 0.871367f, 0.879622f,
0.887923f, 0.896269f, 0.904661f, 0.913099f, 0.921582f, 0.930111f, 0.938686f, 0.947307f, 0.955974f, 0.964686f, 0.973445f,
0.982251f, 0.991102f, 1.0f
};
// sRGB transition values, scaled by 1<<28
static int stbir__srgb_offset_to_linear_scaled[256] =
{
0, 40738, 122216, 203693, 285170, 366648, 448125, 529603,
611080, 692557, 774035, 855852, 942009, 1033024, 1128971, 1229926,
1335959, 1447142, 1563542, 1685229, 1812268, 1944725, 2082664, 2226148,
2375238, 2529996, 2690481, 2856753, 3028870, 3206888, 3390865, 3580856,
3776916, 3979100, 4187460, 4402049, 4622919, 4850123, 5083710, 5323731,
5570236, 5823273, 6082892, 6349140, 6622065, 6901714, 7188133, 7481369,
7781466, 8088471, 8402427, 8723380, 9051372, 9386448, 9728650, 10078021,
10434603, 10798439, 11169569, 11548036, 11933879, 12327139, 12727857, 13136073,
13551826, 13975156, 14406100, 14844697, 15290987, 15745007, 16206795, 16676389,
17153826, 17639142, 18132374, 18633560, 19142734, 19659934, 20185196, 20718552,
21260042, 21809696, 22367554, 22933648, 23508010, 24090680, 24681686, 25281066,
25888850, 26505076, 27129772, 27762974, 28404716, 29055026, 29713942, 30381490,
31057708, 31742624, 32436272, 33138682, 33849884, 34569912, 35298800, 36036568,
36783260, 37538896, 38303512, 39077136, 39859796, 40651528, 41452360, 42262316,
43081432, 43909732, 44747252, 45594016, 46450052, 47315392, 48190064, 49074096,
49967516, 50870356, 51782636, 52704392, 53635648, 54576432, 55526772, 56486700,
57456236, 58435408, 59424248, 60422780, 61431036, 62449032, 63476804, 64514376,
65561776, 66619028, 67686160, 68763192, 69850160, 70947088, 72053992, 73170912,
74297864, 75434880, 76581976, 77739184, 78906536, 80084040, 81271736, 82469648,
83677792, 84896192, 86124888, 87363888, 88613232, 89872928, 91143016, 92423512,
93714432, 95015816, 96327688, 97650056, 98982952, 100326408, 101680440, 103045072,
104420320, 105806224, 107202800, 108610064, 110028048, 111456776, 112896264, 114346544,
115807632, 117279552, 118762328, 120255976, 121760536, 123276016, 124802440, 126339832,
127888216, 129447616, 131018048, 132599544, 134192112, 135795792, 137410592, 139036528,
140673648, 142321952, 143981456, 145652208, 147334208, 149027488, 150732064, 152447968,
154175200, 155913792, 157663776, 159425168, 161197984, 162982240, 164777968, 166585184,
168403904, 170234160, 172075968, 173929344, 175794320, 177670896, 179559120, 181458992,
183370528, 185293776, 187228736, 189175424, 191133888, 193104112, 195086128, 197079968,
199085648, 201103184, 203132592, 205173888, 207227120, 209292272, 211369392, 213458480,
215559568, 217672656, 219797792, 221934976, 224084240, 226245600, 228419056, 230604656,
232802400, 235012320, 237234432, 239468736, 241715280, 243974080, 246245120, 248528464,
250824112, 253132064, 255452368, 257785040, 260130080, 262487520, 264857376, 267239664,
};
static float stbir__srgb_to_linear(float f)
{
if (f <= 0.04045f)
return f / 12.92f;
else
return (float)pow((f + 0.055f) / 1.055f, 2.4f);
}
static float stbir__linear_to_srgb(float f)
{
if (f <= 0.0031308f)
return f * 12.92f;
else
return 1.055f * (float)pow(f, 1 / 2.4f) - 0.055f;
}
static unsigned char stbir__linear_to_srgb_uchar(float f)
{
int x = (int) (f * (1 << 28)); // has headroom so you don't need to clamp
int v = 0;
int i;
i = v + 128; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
i = v + 64; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
i = v + 32; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
i = v + 16; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
i = v + 8; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
i = v + 4; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
i = v + 2; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
i = v + 1; if (x >= stbir__srgb_offset_to_linear_scaled[i]) v = i;
return (unsigned char) v;
}
static float stbir__filter_trapezoid(float x, float scale)
{
float halfscale = scale / 2;
float t = 0.5f + halfscale;
STBIR__DEBUG_ASSERT(scale <= 1);
x = (float)fabs(x);
if (x >= t)
return 0;
else
{
float r = 0.5f - halfscale;
if (x <= r)
return 1;
else
return (t - x) / scale;
}
}
static float stbir__support_trapezoid(float scale)
{
STBIR__DEBUG_ASSERT(scale <= 1);
return 0.5f + scale / 2;
}
static float stbir__filter_bilinear(float x, float s)
{
STBIR__UNUSED_PARAM(s)
x = (float)fabs(x);
if (x <= 1.0f)
return 1 - x;
else
return 0;
}
static float stbir__filter_bicubic(float x, float s)
{
STBIR__UNUSED_PARAM(s)
x = (float)fabs(x);
if (x < 1.0f)
return (4 + x*x*(3*x - 6))/6;
else if (x < 2.0f)
return (8 + x*(-12 + x*(6 - x)))/6;
return (0.0f);
}
static float stbir__filter_catmullrom(float x, float s)
{
STBIR__UNUSED_PARAM(s)
x = (float)fabs(x);
if (x < 1.0f)
return 1 - x*x*(2.5f - 1.5f*x);
else if (x < 2.0f)
return 2 - x*(4 + x*(0.5f*x - 2.5f));
return (0.0f);
}
static float stbir__filter_mitchell(float x, float s)
{
STBIR__UNUSED_PARAM(s)
x = (float)fabs(x);
if (x < 1.0f)
return (16 + x*x*(21 * x - 36))/18;
else if (x < 2.0f)
return (32 + x*(-60 + x*(36 - 7*x)))/18;
return (0.0f);
}
static float stbir__support_zero(float s)
{
STBIR__UNUSED_PARAM(s)
return 0;
}
static float stbir__support_one(float s)
{
STBIR__UNUSED_PARAM(s)
return 1;
}
static float stbir__support_two(float s)
{
STBIR__UNUSED_PARAM(s)
return 2;
}
static stbir__filter_info stbir__filter_info_table[] = {
{ NULL, stbir__support_zero },
{ stbir__filter_trapezoid, stbir__support_trapezoid },
{ stbir__filter_bilinear, stbir__support_one },
{ stbir__filter_bicubic, stbir__support_two },
{ stbir__filter_catmullrom, stbir__support_two },
{ stbir__filter_mitchell, stbir__support_two },
};
stbir__inline static int stbir__use_upsampling(float ratio)
{
return ratio > 1;
}
stbir__inline static int stbir__use_width_upsampling(stbir__info* stbir_info)
{
return stbir__use_upsampling(stbir_info->horizontal_scale);
}
stbir__inline static int stbir__use_height_upsampling(stbir__info* stbir_info)
{
return stbir__use_upsampling(stbir_info->vertical_scale);
}
// This is the maximum number of input samples that can affect an output sample
// with the given filter
stbir__inline static int stbir__get_filter_pixel_width(stbir_filter filter, float scale)
{
STBIR_ASSERT(filter != 0);
STBIR_ASSERT(filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
if (stbir__use_upsampling(scale))
return (int)ceil(stbir__filter_info_table[filter].support(1/scale) * 2);
else
return (int)ceil(stbir__filter_info_table[filter].support(scale) * 2 / scale);
}
stbir__inline static int stbir__get_filter_pixel_width_horizontal(stbir__info* stbir_info)
{
return stbir__get_filter_pixel_width(stbir_info->horizontal_filter, stbir_info->horizontal_scale);
}
stbir__inline static int stbir__get_filter_pixel_width_vertical(stbir__info* stbir_info)
{
return stbir__get_filter_pixel_width(stbir_info->vertical_filter, stbir_info->vertical_scale);
}
// This is how much to expand buffers to account for filters seeking outside
// the image boundaries.
stbir__inline static int stbir__get_filter_pixel_margin(stbir_filter filter, float scale)
{
return stbir__get_filter_pixel_width(filter, scale) / 2;
}
stbir__inline static int stbir__get_filter_pixel_margin_horizontal(stbir__info* stbir_info)
{
return stbir__get_filter_pixel_width(stbir_info->horizontal_filter, stbir_info->horizontal_scale) / 2;
}
stbir__inline static int stbir__get_filter_pixel_margin_vertical(stbir__info* stbir_info)
{
return stbir__get_filter_pixel_width(stbir_info->vertical_filter, stbir_info->vertical_scale) / 2;
}
stbir__inline static int stbir__get_horizontal_contributors(stbir__info* info)
{
if (stbir__use_upsampling(info->horizontal_scale))
return info->output_w;
else
return (info->input_w + stbir__get_filter_pixel_margin(info->horizontal_filter, info->horizontal_scale) * 2);
}
stbir__inline static int stbir__get_total_coefficients(stbir__info* info)
{
return stbir__get_horizontal_contributors(info)
* stbir__get_filter_pixel_width (info->horizontal_filter, info->horizontal_scale);
}
stbir__inline static stbir__contributors* stbir__get_contributor(stbir__info* stbir_info, int n)
{
STBIR__DEBUG_ASSERT(n >= 0 && n < stbir__get_horizontal_contributors(stbir_info));
return &stbir_info->horizontal_contributors[n];
}
stbir__inline static float* stbir__get_coefficient(stbir__info* stbir_info, int n, int c)
{
int width = stbir__get_filter_pixel_width(stbir_info->horizontal_filter, stbir_info->horizontal_scale);
return &stbir_info->horizontal_coefficients[width*n + c];
}
static int stbir__edge_wrap_slow(stbir_edge edge, int n, int max)
{
switch (edge)
{
case STBIR_EDGE_ZERO:
return 0; // we'll decode the wrong pixel here, and then overwrite with 0s later
case STBIR_EDGE_CLAMP:
if (n < 0)
return 0;
if (n >= max)
return max - 1;
return n; // NOTREACHED
case STBIR_EDGE_REFLECT:
{
if (n < 0)
{
if (n < max)
return -n;
else
return max - 1;
}
if (n >= max)
{
int max2 = max * 2;
if (n >= max2)
return 0;
else
return max2 - n - 1;
}
return n; // NOTREACHED
}
case STBIR_EDGE_WRAP:
if (n >= 0)
return (n % max);
else
{
int m = (-n) % max;
if (m != 0)
m = max - m;
return (m);
}
return n; // NOTREACHED
default:
STBIR__UNIMPLEMENTED("Unimplemented edge type");
return 0;
}
}
stbir__inline static int stbir__edge_wrap(stbir_edge edge, int n, int max)
{
// avoid per-pixel switch
if (n >= 0 && n < max)
return n;
return stbir__edge_wrap_slow(edge, n, max);
}
// What input pixels contribute to this output pixel?
static void stbir__calculate_sample_range_upsample(int n, float out_filter_radius, float scale_ratio, float out_shift, int* in_first_pixel, int* in_last_pixel, float* in_center_of_out)
{
float out_pixel_center = (float)n + 0.5f;
float out_pixel_influence_lowerbound = out_pixel_center - out_filter_radius;
float out_pixel_influence_upperbound = out_pixel_center + out_filter_radius;
float in_pixel_influence_lowerbound = (out_pixel_influence_lowerbound + out_shift) / scale_ratio;
float in_pixel_influence_upperbound = (out_pixel_influence_upperbound + out_shift) / scale_ratio;
*in_center_of_out = (out_pixel_center + out_shift) / scale_ratio;
*in_first_pixel = (int)(floor(in_pixel_influence_lowerbound + 0.5));
*in_last_pixel = (int)(floor(in_pixel_influence_upperbound - 0.5));
}
// What output pixels does this input pixel contribute to?
static void stbir__calculate_sample_range_downsample(int n, float in_pixels_radius, float scale_ratio, float out_shift, int* out_first_pixel, int* out_last_pixel, float* out_center_of_in)
{
float in_pixel_center = (float)n + 0.5f;
float in_pixel_influence_lowerbound = in_pixel_center - in_pixels_radius;
float in_pixel_influence_upperbound = in_pixel_center + in_pixels_radius;
float out_pixel_influence_lowerbound = in_pixel_influence_lowerbound * scale_ratio - out_shift;
float out_pixel_influence_upperbound = in_pixel_influence_upperbound * scale_ratio - out_shift;
*out_center_of_in = in_pixel_center * scale_ratio - out_shift;
*out_first_pixel = (int)(floor(out_pixel_influence_lowerbound + 0.5));
*out_last_pixel = (int)(floor(out_pixel_influence_upperbound - 0.5));
}
static void stbir__calculate_coefficients_upsample(stbir__info* stbir_info, stbir_filter filter, float scale, int in_first_pixel, int in_last_pixel, float in_center_of_out, stbir__contributors* contributor, float* coefficient_group)
{
int i;
float total_filter = 0;
float filter_scale;
STBIR__DEBUG_ASSERT(in_last_pixel - in_first_pixel <= (int)ceil(stbir__filter_info_table[filter].support(1/scale) * 2)); // Taken directly from stbir__get_filter_pixel_width() which we can't call because we don't know if we're horizontal or vertical.
contributor->n0 = in_first_pixel;
contributor->n1 = in_last_pixel;
STBIR__DEBUG_ASSERT(contributor->n1 >= contributor->n0);
for (i = 0; i <= in_last_pixel - in_first_pixel; i++)
{
float in_pixel_center = (float)(i + in_first_pixel) + 0.5f;
total_filter += coefficient_group[i] = stbir__filter_info_table[filter].kernel(in_center_of_out - in_pixel_center, 1 / scale);
}
STBIR__DEBUG_ASSERT(total_filter > 0.9);
STBIR__DEBUG_ASSERT(total_filter < 1.1f); // Make sure it's not way off.
// Make sure the sum of all coefficients is 1.
filter_scale = 1 / total_filter;
for (i = 0; i <= in_last_pixel - in_first_pixel; i++)
coefficient_group[i] *= filter_scale;
}
static void stbir__calculate_coefficients_downsample(stbir__info* stbir_info, stbir_filter filter, float scale_ratio, int out_first_pixel, int out_last_pixel, float out_center_of_in, stbir__contributors* contributor, float* coefficient_group)
{
int i;
STBIR__DEBUG_ASSERT(out_last_pixel - out_first_pixel <= (int)ceil(stbir__filter_info_table[filter].support(scale_ratio) * 2 / scale_ratio)); // Taken directly from stbir__get_filter_pixel_width() which we can't call because we don't know if we're horizontal or vertical.
contributor->n0 = out_first_pixel;
contributor->n1 = out_last_pixel;
STBIR__DEBUG_ASSERT(contributor->n1 >= contributor->n0);
for (i = 0; i <= out_last_pixel - out_first_pixel; i++)
{
float out_pixel_center = (float)(i + out_first_pixel) + 0.5f;
float x = out_pixel_center - out_center_of_in;
coefficient_group[i] = stbir__filter_info_table[filter].kernel(x, scale_ratio) * scale_ratio;
}
}
static void stbir__normalize_downsample_coefficients(stbir__info* stbir_info)
{
int num_contributors = stbir__get_horizontal_contributors(stbir_info);
int i;
for (i = 0; i < stbir_info->output_w; i++)
{
float scale;
float total = 0;
int j;
for (j = 0; j < num_contributors; j++)
{
if (i >= stbir_info->horizontal_contributors[j].n0 && i <= stbir_info->horizontal_contributors[j].n1)
{
float coefficient = *stbir__get_coefficient(stbir_info, j, i - stbir_info->horizontal_contributors[j].n0);
total += coefficient;
}
else if (i < stbir_info->horizontal_contributors[j].n0)
break;
}
STBIR__DEBUG_ASSERT(total > 0.9f);
STBIR__DEBUG_ASSERT(total < 1.1f);
scale = 1 / total;
for (j = 0; j < num_contributors; j++)
{
if (i >= stbir_info->horizontal_contributors[j].n0 && i <= stbir_info->horizontal_contributors[j].n1)
*stbir__get_coefficient(stbir_info, j, i - stbir_info->horizontal_contributors[j].n0) *= scale;
else if (i < stbir_info->horizontal_contributors[j].n0)
break;
}
}
// Using min to avoid writing into invalid pixels.
for (i = 0; i < num_contributors; i++)
{
stbir__contributors* contributors = &stbir_info->horizontal_contributors[i];
STBIR__DEBUG_ASSERT(contributors->n1 >= contributors->n0);
contributors->n1 = stbir__min(contributors->n1, stbir_info->output_w - 1);
}
}
// Each scan line uses the same kernel values so we should calculate the kernel
// values once and then we can use them for every scan line.
static void stbir__calculate_horizontal_filters(stbir__info* stbir_info)
{
int n;
float scale_ratio = stbir_info->horizontal_scale;
int total_contributors = stbir__get_horizontal_contributors(stbir_info);
if (stbir__use_width_upsampling(stbir_info))
{
float out_pixels_radius = stbir__filter_info_table[stbir_info->horizontal_filter].support(1/scale_ratio) * scale_ratio;
// Looping through out pixels
for (n = 0; n < total_contributors; n++)
{
float in_center_of_out; // Center of the current out pixel in the in pixel space
int in_first_pixel, in_last_pixel;
stbir__calculate_sample_range_upsample(n, out_pixels_radius, scale_ratio, stbir_info->horizontal_shift, &in_first_pixel, &in_last_pixel, &in_center_of_out);
stbir__calculate_coefficients_upsample(stbir_info, stbir_info->horizontal_filter, scale_ratio, in_first_pixel, in_last_pixel, in_center_of_out, stbir__get_contributor(stbir_info, n), stbir__get_coefficient(stbir_info, n, 0));
}
}
else
{
float in_pixels_radius = stbir__filter_info_table[stbir_info->horizontal_filter].support(scale_ratio) / scale_ratio;
// Looping through in pixels
for (n = 0; n < total_contributors; n++)
{
float out_center_of_in; // Center of the current out pixel in the in pixel space
int out_first_pixel, out_last_pixel;
int n_adjusted = n - stbir__get_filter_pixel_margin_horizontal(stbir_info);
stbir__calculate_sample_range_downsample(n_adjusted, in_pixels_radius, scale_ratio, stbir_info->horizontal_shift, &out_first_pixel, &out_last_pixel, &out_center_of_in);
stbir__calculate_coefficients_downsample(stbir_info, stbir_info->horizontal_filter, scale_ratio, out_first_pixel, out_last_pixel, out_center_of_in, stbir__get_contributor(stbir_info, n), stbir__get_coefficient(stbir_info, n, 0));
}
stbir__normalize_downsample_coefficients(stbir_info);
}
}
static float* stbir__get_decode_buffer(stbir__info* stbir_info)
{
// The 0 index of the decode buffer starts after the margin. This makes
// it okay to use negative indexes on the decode buffer.
return &stbir_info->decode_buffer[stbir__get_filter_pixel_margin_horizontal(stbir_info) * stbir_info->channels];
}
#define STBIR__DECODE(type, colorspace) ((type) * (STBIR_MAX_COLORSPACES) + (colorspace))
static void stbir__decode_scanline(stbir__info* stbir_info, int n)
{
int c;
int channels = stbir_info->channels;
int alpha_channel = stbir_info->alpha_channel;
int type = stbir_info->type;
int colorspace = stbir_info->colorspace;
int input_w = stbir_info->input_w;
int input_stride_bytes = stbir_info->input_stride_bytes;
float* decode_buffer = stbir__get_decode_buffer(stbir_info);
stbir_edge edge_horizontal = stbir_info->edge_horizontal;
stbir_edge edge_vertical = stbir_info->edge_vertical;
int in_buffer_row_offset = stbir__edge_wrap(edge_vertical, n, stbir_info->input_h) * input_stride_bytes;
const void* input_data = (char *) stbir_info->input_data + in_buffer_row_offset;
int max_x = input_w + stbir__get_filter_pixel_margin_horizontal(stbir_info);
int decode = STBIR__DECODE(type, colorspace);
int x = -stbir__get_filter_pixel_margin_horizontal(stbir_info);
// special handling for STBIR_EDGE_ZERO because it needs to return an item that doesn't appear in the input,
// and we want to avoid paying overhead on every pixel if not STBIR_EDGE_ZERO
if (edge_vertical == STBIR_EDGE_ZERO && (n < 0 || n >= stbir_info->input_h))
{
for (; x < max_x; x++)
for (c = 0; c < channels; c++)
decode_buffer[x*channels + c] = 0;
return;
}
switch (decode)
{
case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR):
for (; x < max_x; x++)
{
int decode_pixel_index = x * channels;
int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
for (c = 0; c < channels; c++)
decode_buffer[decode_pixel_index + c] = ((float)((const unsigned char*)input_data)[input_pixel_index + c]) / 255;
}
break;
case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB):
for (; x < max_x; x++)
{
int decode_pixel_index = x * channels;
int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
for (c = 0; c < channels; c++)
decode_buffer[decode_pixel_index + c] = stbir__srgb_uchar_to_linear_float[((const unsigned char*)input_data)[input_pixel_index + c]];
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
decode_buffer[decode_pixel_index + alpha_channel] = ((float)((const unsigned char*)input_data)[input_pixel_index + alpha_channel]) / 255;
}
break;
case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR):
for (; x < max_x; x++)
{
int decode_pixel_index = x * channels;
int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
for (c = 0; c < channels; c++)
decode_buffer[decode_pixel_index + c] = ((float)((const unsigned short*)input_data)[input_pixel_index + c]) / 65535;
}
break;
case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB):
for (; x < max_x; x++)
{
int decode_pixel_index = x * channels;
int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
for (c = 0; c < channels; c++)
decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear(((float)((const unsigned short*)input_data)[input_pixel_index + c]) / 65535);
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
decode_buffer[decode_pixel_index + alpha_channel] = ((float)((const unsigned short*)input_data)[input_pixel_index + alpha_channel]) / 65535;
}
break;
case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR):
for (; x < max_x; x++)
{
int decode_pixel_index = x * channels;
int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
for (c = 0; c < channels; c++)
decode_buffer[decode_pixel_index + c] = (float)(((double)((const unsigned int*)input_data)[input_pixel_index + c]) / 4294967295);
}
break;
case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB):
for (; x < max_x; x++)
{
int decode_pixel_index = x * channels;
int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
for (c = 0; c < channels; c++)
decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear((float)(((double)((const unsigned int*)input_data)[input_pixel_index + c]) / 4294967295));
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
decode_buffer[decode_pixel_index + alpha_channel] = (float)(((double)((const unsigned int*)input_data)[input_pixel_index + alpha_channel]) / 4294967295);
}
break;
case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR):
for (; x < max_x; x++)
{
int decode_pixel_index = x * channels;
int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
for (c = 0; c < channels; c++)
decode_buffer[decode_pixel_index + c] = ((const float*)input_data)[input_pixel_index + c];
}
break;
case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB):
for (; x < max_x; x++)
{
int decode_pixel_index = x * channels;
int input_pixel_index = stbir__edge_wrap(edge_horizontal, x, input_w) * channels;
for (c = 0; c < channels; c++)
decode_buffer[decode_pixel_index + c] = stbir__srgb_to_linear(((const float*)input_data)[input_pixel_index + c]);
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
decode_buffer[decode_pixel_index + alpha_channel] = ((const float*)input_data)[input_pixel_index + alpha_channel];
}
break;
default:
STBIR__UNIMPLEMENTED("Unknown type/colorspace/channels combination.");
break;
}
#ifndef STBIR_NO_ALPHA_EPSILON
if (!(stbir_info->flags & STBIR_FLAG_PREMULTIPLIED_ALPHA))
{
for (x = -stbir__get_filter_pixel_margin_horizontal(stbir_info); x < max_x; x++)
{
int decode_pixel_index = x * channels;
// If the alpha value is 0 it will clobber the color values. Make sure it's not.
float alpha = decode_buffer[decode_pixel_index + alpha_channel];
if (stbir_info->type != STBIR_TYPE_FLOAT) {
alpha += STBIR_ALPHA_EPSILON;
decode_buffer[decode_pixel_index + alpha_channel] = alpha;
}
for (c = 0; c < channels; c++)
{
if (c == alpha_channel)
continue;
decode_buffer[decode_pixel_index + c] *= alpha;
}
}
}
#endif
if (edge_horizontal == STBIR_EDGE_ZERO)
{
for (x = -stbir__get_filter_pixel_margin_horizontal(stbir_info); x < 0; x++)
{
for (c = 0; c < channels; c++)
decode_buffer[x*channels + c] = 0;
}
for (x = input_w; x < max_x; x++)
{
for (c = 0; c < channels; c++)
decode_buffer[x*channels + c] = 0;
}
}
}
static float* stbir__get_ring_buffer_entry(float* ring_buffer, int index, int ring_buffer_length)
{
return &ring_buffer[index * ring_buffer_length];
}
static float* stbir__add_empty_ring_buffer_entry(stbir__info* stbir_info, int n)
{
int ring_buffer_index;
float* ring_buffer;
if (stbir_info->ring_buffer_begin_index < 0)
{
ring_buffer_index = stbir_info->ring_buffer_begin_index = 0;
stbir_info->ring_buffer_first_scanline = n;
}
else
{
ring_buffer_index = (stbir_info->ring_buffer_begin_index + (stbir_info->ring_buffer_last_scanline - stbir_info->ring_buffer_first_scanline) + 1) % stbir__get_filter_pixel_width_vertical(stbir_info);
STBIR__DEBUG_ASSERT(ring_buffer_index != stbir_info->ring_buffer_begin_index);
}
ring_buffer = stbir__get_ring_buffer_entry(stbir_info->ring_buffer, ring_buffer_index, stbir_info->ring_buffer_length_bytes / sizeof(float));
memset(ring_buffer, 0, stbir_info->ring_buffer_length_bytes);
stbir_info->ring_buffer_last_scanline = n;
return ring_buffer;
}
static void stbir__resample_horizontal_upsample(stbir__info* stbir_info, int n, float* output_buffer)
{
int x, k;
int output_w = stbir_info->output_w;
int kernel_pixel_width = stbir__get_filter_pixel_width_horizontal(stbir_info);
int channels = stbir_info->channels;
float* decode_buffer = stbir__get_decode_buffer(stbir_info);
stbir__contributors* horizontal_contributors = stbir_info->horizontal_contributors;
float* horizontal_coefficients = stbir_info->horizontal_coefficients;
for (x = 0; x < output_w; x++)
{
int n0 = horizontal_contributors[x].n0;
int n1 = horizontal_contributors[x].n1;
int out_pixel_index = x * channels;
int coefficient_group_index = x * kernel_pixel_width;
int coefficient_counter = 0;
STBIR__DEBUG_ASSERT(n1 >= n0);
STBIR__DEBUG_ASSERT(n0 >= -stbir__get_filter_pixel_margin_horizontal(stbir_info));
STBIR__DEBUG_ASSERT(n1 >= -stbir__get_filter_pixel_margin_horizontal(stbir_info));
STBIR__DEBUG_ASSERT(n0 < stbir_info->input_w + stbir__get_filter_pixel_margin_horizontal(stbir_info));
STBIR__DEBUG_ASSERT(n1 < stbir_info->input_w + stbir__get_filter_pixel_margin_horizontal(stbir_info));
for (k = n0; k <= n1; k++)
{
int coefficient_index = coefficient_group_index + (coefficient_counter++);
int in_pixel_index = k * channels;
float coefficient = horizontal_coefficients[coefficient_index];
int c;
for (c = 0; c < channels; c++)
output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient;
}
}
}
static void stbir__resample_horizontal_downsample(stbir__info* stbir_info, int n, float* output_buffer)
{
int x, k;
int input_w = stbir_info->input_w;
int output_w = stbir_info->output_w;
int kernel_pixel_width = stbir__get_filter_pixel_width_horizontal(stbir_info);
int channels = stbir_info->channels;
float* decode_buffer = stbir__get_decode_buffer(stbir_info);
stbir__contributors* horizontal_contributors = stbir_info->horizontal_contributors;
float* horizontal_coefficients = stbir_info->horizontal_coefficients;
int filter_pixel_margin = stbir__get_filter_pixel_margin_horizontal(stbir_info);
int max_x = input_w + filter_pixel_margin * 2;
STBIR__DEBUG_ASSERT(!stbir__use_width_upsampling(stbir_info));
for (x = 0; x < max_x; x++)
{
int n0 = horizontal_contributors[x].n0;
int n1 = horizontal_contributors[x].n1;
int in_x = x - filter_pixel_margin;
int in_pixel_index = in_x * channels;
int max_n = n1;
int coefficient_group = x*kernel_pixel_width;
// Using max to avoid writing into invalid pixels.
for (k = stbir__max(n0, 0); k <= max_n; k++)
{
int coefficient_index = (k - n0) + coefficient_group;
int out_pixel_index = k * channels;
float coefficient = horizontal_coefficients[coefficient_index];
int c;
for (c = 0; c < channels; c++)
output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient;
}
}
}
static void stbir__decode_and_resample_upsample(stbir__info* stbir_info, int n)
{
// Decode the nth scanline from the source image into the decode buffer.
stbir__decode_scanline(stbir_info, n);
// Now resample it into the ring buffer.
if (stbir__use_width_upsampling(stbir_info))
stbir__resample_horizontal_upsample(stbir_info, n, stbir__add_empty_ring_buffer_entry(stbir_info, n));
else
stbir__resample_horizontal_downsample(stbir_info, n, stbir__add_empty_ring_buffer_entry(stbir_info, n));
// Now it's sitting in the ring buffer ready to be used as source for the vertical sampling.
}
static void stbir__decode_and_resample_downsample(stbir__info* stbir_info, int n)
{
// Decode the nth scanline from the source image into the decode buffer.
stbir__decode_scanline(stbir_info, n);
memset(stbir_info->horizontal_buffer, 0, stbir_info->output_w * stbir_info->channels * sizeof(float));
// Now resample it into the horizontal buffer.
if (stbir__use_width_upsampling(stbir_info))
stbir__resample_horizontal_upsample(stbir_info, n, stbir_info->horizontal_buffer);
else
stbir__resample_horizontal_downsample(stbir_info, n, stbir_info->horizontal_buffer);
// Now it's sitting in the horizontal buffer ready to be distributed into the ring buffers.
}
// Get the specified scan line from the ring buffer.
static float* stbir__get_ring_buffer_scanline(int get_scanline, float* ring_buffer, int begin_index, int first_scanline, int ring_buffer_size, int ring_buffer_length)
{
int ring_buffer_index = (begin_index + (get_scanline - first_scanline)) % ring_buffer_size;
return stbir__get_ring_buffer_entry(ring_buffer, ring_buffer_index, ring_buffer_length);
}
static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void *output_buffer, float *encode_buffer, int channels, int alpha_channel, int decode)
{
int x;
int n;
#ifndef STBIR_NO_ALPHA_EPSILON
if (!(stbir_info->flags&STBIR_FLAG_PREMULTIPLIED_ALPHA))
{
for (x=0; x < num_pixels; ++x)
{
int pixel_index = x*channels;
float alpha = encode_buffer[pixel_index + alpha_channel];
float reciprocal_alpha = alpha ? 1.0f / alpha : 0;
for (n = 0; n < channels; n++)
if (n != alpha_channel)
encode_buffer[pixel_index + n] *= reciprocal_alpha;
// We added in a small epsilon to prevent the color channel from being deleted with zero alpha.
// Because we only add it for integer types, it will automatically be discarded on integer
// conversion.
}
}
#endif
switch (decode)
{
case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR):
for (x=0; x < num_pixels; ++x)
{
int pixel_index = x*channels;
for (n = 0; n < channels; n++)
{
int index = pixel_index + n;
((unsigned char*)output_buffer)[index] = (unsigned char)(floor(stbir__saturate(encode_buffer[index]) * 255 + 0.5f));
}
}
break;
case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB):
for (x=0; x < num_pixels; ++x)
{
int pixel_index = x*channels;
for (n = 0; n < channels; n++)
{
int index = pixel_index + n;
((unsigned char*)output_buffer)[index] = stbir__linear_to_srgb_uchar(encode_buffer[index]);
}
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
((unsigned char*)output_buffer)[pixel_index + alpha_channel] = (unsigned char)(floor(stbir__saturate(encode_buffer[pixel_index + alpha_channel]) * 255+0.5f));
}
break;
case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR):
for (x=0; x < num_pixels; ++x)
{
int pixel_index = x*channels;
for (n = 0; n < channels; n++)
{
int index = pixel_index + n;
((unsigned short*)output_buffer)[index] = (unsigned short)(floor(stbir__saturate(encode_buffer[index]) * 65535+0.5f));
}
}
break;
case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB):
for (x=0; x < num_pixels; ++x)
{
int pixel_index = x*channels;
for (n = 0; n < channels; n++)
{
int index = pixel_index + n;
((unsigned short*)output_buffer)[index] = (unsigned short)(floor(stbir__linear_to_srgb(stbir__saturate(encode_buffer[index])) * 65535 + 0.5f));
}
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
((unsigned short*)output_buffer)[pixel_index + alpha_channel] = (unsigned short)(floor(stbir__saturate(encode_buffer[pixel_index + alpha_channel]) * 65535 + 0.5f));
}
break;
case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR):
for (x=0; x < num_pixels; ++x)
{
int pixel_index = x*channels;
for (n = 0; n < channels; n++)
{
int index = pixel_index + n;
((unsigned int*)output_buffer)[index] = (unsigned int)(floor(((double)stbir__saturate(encode_buffer[index])) * 4294967295 + 0.5f));
}
}
break;
case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB):
for (x=0; x < num_pixels; ++x)
{
int pixel_index = x*channels;
for (n = 0; n < channels; n++)
{
int index = pixel_index + n;
((unsigned int*)output_buffer)[index] = (unsigned int)(floor(((double)stbir__linear_to_srgb(stbir__saturate(encode_buffer[index]))) * 4294967295 + 0.5f));
}
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
((unsigned int*)output_buffer)[pixel_index + alpha_channel] = (unsigned int)(floor(((double)stbir__saturate(encode_buffer[pixel_index + alpha_channel])) * 4294967295 + 0.5f));
}
break;
case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR):
for (x=0; x < num_pixels; ++x)
{
int pixel_index = x*channels;
for (n = 0; n < channels; n++)
{
int index = pixel_index + n;
((float*)output_buffer)[index] = encode_buffer[index];
}
}
break;
case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB):
for (x=0; x < num_pixels; ++x)
{
int pixel_index = x*channels;
for (n = 0; n < channels; n++)
{
int index = pixel_index + n;
((float*)output_buffer)[index] = stbir__linear_to_srgb(encode_buffer[index]);
}
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
((float*)output_buffer)[pixel_index + alpha_channel] = encode_buffer[pixel_index + alpha_channel];
}
break;
default:
STBIR__UNIMPLEMENTED("Unknown type/colorspace/channels combination.");
break;
}
}
static void stbir__resample_vertical_upsample(stbir__info* stbir_info, int n, int in_first_scanline, int in_last_scanline, float in_center_of_out)
{
int x, k;
int output_w = stbir_info->output_w;
stbir__contributors* vertical_contributors = &stbir_info->vertical_contributors;
float* vertical_coefficients = stbir_info->vertical_coefficients;
int channels = stbir_info->channels;
int alpha_channel = stbir_info->alpha_channel;
int type = stbir_info->type;
int colorspace = stbir_info->colorspace;
int kernel_pixel_width = stbir__get_filter_pixel_width_vertical(stbir_info);
void* output_data = stbir_info->output_data;
float* encode_buffer = stbir_info->encode_buffer;
int decode = STBIR__DECODE(type, colorspace);
float* ring_buffer = stbir_info->ring_buffer;
int ring_buffer_begin_index = stbir_info->ring_buffer_begin_index;
int ring_buffer_first_scanline = stbir_info->ring_buffer_first_scanline;
int ring_buffer_last_scanline = stbir_info->ring_buffer_last_scanline;
int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
int n0,n1, output_row_start;
stbir__calculate_coefficients_upsample(stbir_info, stbir_info->vertical_filter, stbir_info->vertical_scale, in_first_scanline, in_last_scanline, in_center_of_out, vertical_contributors, vertical_coefficients);
n0 = vertical_contributors->n0;
n1 = vertical_contributors->n1;
output_row_start = n * stbir_info->output_stride_bytes;
STBIR__DEBUG_ASSERT(stbir__use_height_upsampling(stbir_info));
STBIR__DEBUG_ASSERT(n0 >= in_first_scanline);
STBIR__DEBUG_ASSERT(n1 <= in_last_scanline);
memset(encode_buffer, 0, output_w * sizeof(float) * channels);
for (x = 0; x < output_w; x++)
{
int in_pixel_index = x * channels;
int coefficient_counter = 0;
STBIR__DEBUG_ASSERT(n1 >= n0);
for (k = n0; k <= n1; k++)
{
int coefficient_index = coefficient_counter++;
float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, kernel_pixel_width, ring_buffer_length);
float coefficient = vertical_coefficients[coefficient_index];
int c;
for (c = 0; c < channels; c++)
encode_buffer[in_pixel_index + c] += ring_buffer_entry[in_pixel_index + c] * coefficient;
}
}
stbir__encode_scanline(stbir_info, output_w, (char *) output_data + output_row_start, encode_buffer, channels, alpha_channel, decode);
}
static void stbir__resample_vertical_downsample(stbir__info* stbir_info, int n, int in_first_scanline, int in_last_scanline, float in_center_of_out)
{
int x, k;
int output_w = stbir_info->output_w;
int output_h = stbir_info->output_h;
stbir__contributors* vertical_contributors = &stbir_info->vertical_contributors;
float* vertical_coefficients = stbir_info->vertical_coefficients;
int channels = stbir_info->channels;
int kernel_pixel_width = stbir__get_filter_pixel_width_vertical(stbir_info);
void* output_data = stbir_info->output_data;
float* horizontal_buffer = stbir_info->horizontal_buffer;
float* ring_buffer = stbir_info->ring_buffer;
int ring_buffer_begin_index = stbir_info->ring_buffer_begin_index;
int ring_buffer_first_scanline = stbir_info->ring_buffer_first_scanline;
int ring_buffer_last_scanline = stbir_info->ring_buffer_last_scanline;
int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
int n0,n1,max_n;
stbir__calculate_coefficients_downsample(stbir_info, stbir_info->vertical_filter, stbir_info->vertical_scale, in_first_scanline, in_last_scanline, in_center_of_out, vertical_contributors, vertical_coefficients);
n0 = vertical_contributors->n0;
n1 = vertical_contributors->n1;
max_n = stbir__min(n1, output_h - 1);
STBIR__DEBUG_ASSERT(!stbir__use_height_upsampling(stbir_info));
STBIR__DEBUG_ASSERT(n0 >= in_first_scanline);
STBIR__DEBUG_ASSERT(n1 <= in_last_scanline);
STBIR__DEBUG_ASSERT(n1 >= n0);
// Using min and max to avoid writing into ring buffers that will be thrown out.
for (k = stbir__max(n0, 0); k <= max_n; k++)
{
int coefficient_index = k - n0;
float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, kernel_pixel_width, ring_buffer_length);
float coefficient = vertical_coefficients[coefficient_index];
for (x = 0; x < output_w; x++)
{
int in_pixel_index = x * channels;
int c;
for (c = 0; c < channels; c++)
ring_buffer_entry[in_pixel_index + c] += horizontal_buffer[in_pixel_index + c] * coefficient;
}
}
}
static void stbir__buffer_loop_upsample(stbir__info* stbir_info)
{
int y;
float scale_ratio = stbir_info->vertical_scale;
float out_scanlines_radius = stbir__filter_info_table[stbir_info->vertical_filter].support(1/scale_ratio) * scale_ratio;
STBIR__DEBUG_ASSERT(stbir__use_height_upsampling(stbir_info));
for (y = 0; y < stbir_info->output_h; y++)
{
float in_center_of_out = 0; // Center of the current out scanline in the in scanline space
int in_first_scanline = 0, in_last_scanline = 0;
stbir__calculate_sample_range_upsample(y, out_scanlines_radius, scale_ratio, stbir_info->vertical_shift, &in_first_scanline, &in_last_scanline, &in_center_of_out);
STBIR__DEBUG_ASSERT(in_last_scanline - in_first_scanline <= stbir__get_filter_pixel_width_vertical(stbir_info));
if (stbir_info->ring_buffer_begin_index >= 0)
{
// Get rid of whatever we don't need anymore.
while (in_first_scanline > stbir_info->ring_buffer_first_scanline)
{
if (stbir_info->ring_buffer_first_scanline == stbir_info->ring_buffer_last_scanline)
{
// We just popped the last scanline off the ring buffer.
// Reset it to the empty state.
stbir_info->ring_buffer_begin_index = -1;
stbir_info->ring_buffer_first_scanline = 0;
stbir_info->ring_buffer_last_scanline = 0;
break;
}
else
{
stbir_info->ring_buffer_first_scanline++;
stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir__get_filter_pixel_width_vertical(stbir_info);
}
}
}
// Load in new ones.
if (stbir_info->ring_buffer_begin_index < 0)
stbir__decode_and_resample_upsample(stbir_info, in_first_scanline);
while (in_last_scanline > stbir_info->ring_buffer_last_scanline)
stbir__decode_and_resample_upsample(stbir_info, stbir_info->ring_buffer_last_scanline + 1);
// Now all buffers should be ready to write a row of vertical sampling.
stbir__resample_vertical_upsample(stbir_info, y, in_first_scanline, in_last_scanline, in_center_of_out);
STBIR_PROGRESS_REPORT((float)y / stbir_info->output_h);
}
}
static void stbir__empty_ring_buffer(stbir__info* stbir_info, int first_necessary_scanline)
{
int output_stride_bytes = stbir_info->output_stride_bytes;
int channels = stbir_info->channels;
int alpha_channel = stbir_info->alpha_channel;
int type = stbir_info->type;
int colorspace = stbir_info->colorspace;
int output_w = stbir_info->output_w;
void* output_data = stbir_info->output_data;
int decode = STBIR__DECODE(type, colorspace);
float* ring_buffer = stbir_info->ring_buffer;
int ring_buffer_length = stbir_info->ring_buffer_length_bytes/sizeof(float);
if (stbir_info->ring_buffer_begin_index >= 0)
{
// Get rid of whatever we don't need anymore.
while (first_necessary_scanline > stbir_info->ring_buffer_first_scanline)
{
if (stbir_info->ring_buffer_first_scanline >= 0 && stbir_info->ring_buffer_first_scanline < stbir_info->output_h)
{
int output_row_start = stbir_info->ring_buffer_first_scanline * output_stride_bytes;
float* ring_buffer_entry = stbir__get_ring_buffer_entry(ring_buffer, stbir_info->ring_buffer_begin_index, ring_buffer_length);
stbir__encode_scanline(stbir_info, output_w, (char *) output_data + output_row_start, ring_buffer_entry, channels, alpha_channel, decode);
STBIR_PROGRESS_REPORT((float)stbir_info->ring_buffer_first_scanline / stbir_info->output_h);
}
if (stbir_info->ring_buffer_first_scanline == stbir_info->ring_buffer_last_scanline)
{
// We just popped the last scanline off the ring buffer.
// Reset it to the empty state.
stbir_info->ring_buffer_begin_index = -1;
stbir_info->ring_buffer_first_scanline = 0;
stbir_info->ring_buffer_last_scanline = 0;
break;
}
else
{
stbir_info->ring_buffer_first_scanline++;
stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir__get_filter_pixel_width_vertical(stbir_info);
}
}
}
}
static void stbir__buffer_loop_downsample(stbir__info* stbir_info)
{
int y;
float scale_ratio = stbir_info->vertical_scale;
int output_h = stbir_info->output_h;
float in_pixels_radius = stbir__filter_info_table[stbir_info->vertical_filter].support(scale_ratio) / scale_ratio;
int pixel_margin = stbir__get_filter_pixel_margin_vertical(stbir_info);
int max_y = stbir_info->input_h + pixel_margin;
STBIR__DEBUG_ASSERT(!stbir__use_height_upsampling(stbir_info));
for (y = -pixel_margin; y < max_y; y++)
{
float out_center_of_in; // Center of the current out scanline in the in scanline space
int out_first_scanline, out_last_scanline;
stbir__calculate_sample_range_downsample(y, in_pixels_radius, scale_ratio, stbir_info->vertical_shift, &out_first_scanline, &out_last_scanline, &out_center_of_in);
STBIR__DEBUG_ASSERT(out_last_scanline - out_first_scanline <= stbir__get_filter_pixel_width_vertical(stbir_info));
if (out_last_scanline < 0 || out_first_scanline >= output_h)
continue;
stbir__empty_ring_buffer(stbir_info, out_first_scanline);
stbir__decode_and_resample_downsample(stbir_info, y);
// Load in new ones.
if (stbir_info->ring_buffer_begin_index < 0)
stbir__add_empty_ring_buffer_entry(stbir_info, out_first_scanline);
while (out_last_scanline > stbir_info->ring_buffer_last_scanline)
stbir__add_empty_ring_buffer_entry(stbir_info, stbir_info->ring_buffer_last_scanline + 1);
// Now the horizontal buffer is ready to write to all ring buffer rows.
stbir__resample_vertical_downsample(stbir_info, y, out_first_scanline, out_last_scanline, out_center_of_in);
}
stbir__empty_ring_buffer(stbir_info, stbir_info->output_h);
}
static void stbir__setup(stbir__info *info, int input_w, int input_h, int output_w, int output_h, int channels)
{
info->input_w = input_w;
info->input_h = input_h;
info->output_w = output_w;
info->output_h = output_h;
info->channels = channels;
}
static void stbir__calculate_transform(stbir__info *info, float s0, float t0, float s1, float t1, float *transform)
{
info->s0 = s0;
info->t0 = t0;
info->s1 = s1;
info->t1 = t1;
if (transform)
{
info->horizontal_scale = transform[0];
info->vertical_scale = transform[1];
info->horizontal_shift = transform[2];
info->vertical_shift = transform[3];
}
else
{
info->horizontal_scale = ((float)info->output_w / info->input_w) / (s1 - s0);
info->vertical_scale = ((float)info->output_h / info->input_h) / (t1 - t0);
info->horizontal_shift = s0 * info->input_w / (s1 - s0);
info->vertical_shift = t0 * info->input_h / (t1 - t0);
}
}
static void stbir__choose_filter(stbir__info *info, stbir_filter h_filter, stbir_filter v_filter)
{
if (h_filter == 0)
h_filter = stbir__use_upsampling(info->horizontal_scale) ? STBIR_DEFAULT_FILTER_UPSAMPLE : STBIR_DEFAULT_FILTER_DOWNSAMPLE;
if (v_filter == 0)
v_filter = stbir__use_upsampling(info->vertical_scale) ? STBIR_DEFAULT_FILTER_UPSAMPLE : STBIR_DEFAULT_FILTER_DOWNSAMPLE;
info->horizontal_filter = h_filter;
info->vertical_filter = v_filter;
}
static stbir_uint32 stbir__calculate_memory(stbir__info *info)
{
int pixel_margin = stbir__get_filter_pixel_margin(info->horizontal_filter, info->horizontal_scale);
int filter_height = stbir__get_filter_pixel_width(info->vertical_filter, info->vertical_scale);
info->horizontal_contributors_size = stbir__get_horizontal_contributors(info) * sizeof(stbir__contributors);
info->horizontal_coefficients_size = stbir__get_total_coefficients(info) * sizeof(float);
info->vertical_coefficients_size = filter_height * sizeof(float);
info->decode_buffer_size = (info->input_w + pixel_margin * 2) * info->channels * sizeof(float);
info->horizontal_buffer_size = info->output_w * info->channels * sizeof(float);
info->ring_buffer_size = info->output_w * info->channels * filter_height * sizeof(float);
info->encode_buffer_size = info->output_w * info->channels * sizeof(float);
STBIR_ASSERT(info->horizontal_filter != 0);
STBIR_ASSERT(info->horizontal_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table)); // this now happens too late
STBIR_ASSERT(info->vertical_filter != 0);
STBIR_ASSERT(info->vertical_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table)); // this now happens too late
if (stbir__use_height_upsampling(info))
// The horizontal buffer is for when we're downsampling the height and we
// can't output the result of sampling the decode buffer directly into the
// ring buffers.
info->horizontal_buffer_size = 0;
else
// The encode buffer is to retain precision in the height upsampling method
// and isn't used when height downsampling.
info->encode_buffer_size = 0;
return info->horizontal_contributors_size + info->horizontal_coefficients_size
+ info->vertical_coefficients_size + info->decode_buffer_size
+ info->horizontal_buffer_size + info->ring_buffer_size
+ info->encode_buffer_size;
}
static int stbir__resize_allocated(stbir__info *info,
const void* input_data, int input_stride_in_bytes,
void* output_data, int output_stride_in_bytes,
int alpha_channel, stbir_uint32 flags, stbir_datatype type,
stbir_edge edge_horizontal, stbir_edge edge_vertical, stbir_colorspace colorspace,
void* tempmem, size_t tempmem_size_in_bytes)
{
size_t memory_required = stbir__calculate_memory(info);
int width_stride_input = input_stride_in_bytes ? input_stride_in_bytes : info->channels * info->input_w * stbir__type_size[type];
int width_stride_output = output_stride_in_bytes ? output_stride_in_bytes : info->channels * info->output_w * stbir__type_size[type];
#ifdef STBIR_DEBUG_OVERWRITE_TEST
#define OVERWRITE_ARRAY_SIZE 8
unsigned char overwrite_output_before_pre[OVERWRITE_ARRAY_SIZE];
unsigned char overwrite_tempmem_before_pre[OVERWRITE_ARRAY_SIZE];
unsigned char overwrite_output_after_pre[OVERWRITE_ARRAY_SIZE];
unsigned char overwrite_tempmem_after_pre[OVERWRITE_ARRAY_SIZE];
size_t begin_forbidden = width_stride_output * (info->output_h - 1) + info->output_w * info->channels * stbir__type_size[type];
memcpy(overwrite_output_before_pre, &((unsigned char*)output_data)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE);
memcpy(overwrite_output_after_pre, &((unsigned char*)output_data)[begin_forbidden], OVERWRITE_ARRAY_SIZE);
memcpy(overwrite_tempmem_before_pre, &((unsigned char*)tempmem)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE);
memcpy(overwrite_tempmem_after_pre, &((unsigned char*)tempmem)[tempmem_size_in_bytes], OVERWRITE_ARRAY_SIZE);
#endif
STBIR_ASSERT(info->channels >= 0);
if (info->channels < 0)
return 0;
STBIR_ASSERT(info->horizontal_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
STBIR_ASSERT(info->vertical_filter < STBIR__ARRAY_SIZE(stbir__filter_info_table));
if (info->horizontal_filter >= STBIR__ARRAY_SIZE(stbir__filter_info_table))
return 0;
if (info->vertical_filter >= STBIR__ARRAY_SIZE(stbir__filter_info_table))
return 0;
if (alpha_channel < 0)
flags |= STBIR_FLAG_ALPHA_USES_COLORSPACE | STBIR_FLAG_PREMULTIPLIED_ALPHA;
if (!(flags&STBIR_FLAG_ALPHA_USES_COLORSPACE) || !(flags&STBIR_FLAG_PREMULTIPLIED_ALPHA))
STBIR_ASSERT(alpha_channel >= 0 && alpha_channel < info->channels);
if (alpha_channel >= info->channels)
return 0;
STBIR_ASSERT(tempmem);
if (!tempmem)
return 0;
STBIR_ASSERT(tempmem_size_in_bytes >= memory_required);
if (tempmem_size_in_bytes < memory_required)
return 0;
memset(tempmem, 0, tempmem_size_in_bytes);
info->input_data = input_data;
info->input_stride_bytes = width_stride_input;
info->output_data = output_data;
info->output_stride_bytes = width_stride_output;
info->alpha_channel = alpha_channel;
info->flags = flags;
info->type = type;
info->edge_horizontal = edge_horizontal;
info->edge_vertical = edge_vertical;
info->colorspace = colorspace;
info->ring_buffer_length_bytes = info->output_w * info->channels * sizeof(float);
info->decode_buffer_pixels = info->input_w + stbir__get_filter_pixel_margin_horizontal(info) * 2;
#define STBIR__NEXT_MEMPTR(current, newtype) (newtype*)(((unsigned char*)current) + current##_size)
info->horizontal_contributors = (stbir__contributors *) tempmem;
info->horizontal_coefficients = STBIR__NEXT_MEMPTR(info->horizontal_contributors, float);
info->vertical_coefficients = STBIR__NEXT_MEMPTR(info->horizontal_coefficients, float);
info->decode_buffer = STBIR__NEXT_MEMPTR(info->vertical_coefficients, float);
if (stbir__use_height_upsampling(info))
{
info->horizontal_buffer = NULL;
info->ring_buffer = STBIR__NEXT_MEMPTR(info->decode_buffer, float);
info->encode_buffer = STBIR__NEXT_MEMPTR(info->ring_buffer, float);
STBIR__DEBUG_ASSERT((size_t)STBIR__NEXT_MEMPTR(info->encode_buffer, unsigned char) == (size_t)tempmem + tempmem_size_in_bytes);
}
else
{
info->horizontal_buffer = STBIR__NEXT_MEMPTR(info->decode_buffer, float);
info->ring_buffer = STBIR__NEXT_MEMPTR(info->horizontal_buffer, float);
info->encode_buffer = NULL;
STBIR__DEBUG_ASSERT((size_t)STBIR__NEXT_MEMPTR(info->ring_buffer, unsigned char) == (size_t)tempmem + tempmem_size_in_bytes);
}
#undef STBIR__NEXT_MEMPTR
// This signals that the ring buffer is empty
info->ring_buffer_begin_index = -1;
stbir__calculate_horizontal_filters(info);
STBIR_PROGRESS_REPORT(0);
if (stbir__use_height_upsampling(info))
stbir__buffer_loop_upsample(info);
else
stbir__buffer_loop_downsample(info);
STBIR_PROGRESS_REPORT(1);
#ifdef STBIR_DEBUG_OVERWRITE_TEST
STBIR__DEBUG_ASSERT(memcmp(overwrite_output_before_pre, &((unsigned char*)output_data)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE) == 0);
STBIR__DEBUG_ASSERT(memcmp(overwrite_output_after_pre, &((unsigned char*)output_data)[begin_forbidden], OVERWRITE_ARRAY_SIZE) == 0);
STBIR__DEBUG_ASSERT(memcmp(overwrite_tempmem_before_pre, &((unsigned char*)tempmem)[-OVERWRITE_ARRAY_SIZE], OVERWRITE_ARRAY_SIZE) == 0);
STBIR__DEBUG_ASSERT(memcmp(overwrite_tempmem_after_pre, &((unsigned char*)tempmem)[tempmem_size_in_bytes], OVERWRITE_ARRAY_SIZE) == 0);
#endif
return 1;
}
static int stbir__resize_arbitrary(
void *alloc_context,
const void* input_data, int input_w, int input_h, int input_stride_in_bytes,
void* output_data, int output_w, int output_h, int output_stride_in_bytes,
float s0, float t0, float s1, float t1, float *transform,
int channels, int alpha_channel, stbir_uint32 flags, stbir_datatype type,
stbir_filter h_filter, stbir_filter v_filter,
stbir_edge edge_horizontal, stbir_edge edge_vertical, stbir_colorspace colorspace)
{
stbir__info info;
int result;
size_t memory_required;
void* extra_memory;
stbir__setup(&info, input_w, input_h, output_w, output_h, channels);
stbir__calculate_transform(&info, s0,t0,s1,t1,transform);
stbir__choose_filter(&info, h_filter, v_filter);
memory_required = stbir__calculate_memory(&info);
extra_memory = STBIR_MALLOC(memory_required, alloc_context);
if (!extra_memory)
return 0;
result = stbir__resize_allocated(&info, input_data, input_stride_in_bytes,
output_data, output_stride_in_bytes,
alpha_channel, flags, type,
edge_horizontal, edge_vertical,
colorspace, extra_memory, memory_required);
STBIR_FREE(extra_memory, alloc_context);
return result;
}
STBIRDEF int stbir_resize_uint8( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
int num_channels)
{
return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
output_pixels, output_w, output_h, output_stride_in_bytes,
0,0,1,1,NULL,num_channels,-1,0, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_LINEAR);
}
STBIRDEF int stbir_resize_float( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
float *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
int num_channels)
{
return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
output_pixels, output_w, output_h, output_stride_in_bytes,
0,0,1,1,NULL,num_channels,-1,0, STBIR_TYPE_FLOAT, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_LINEAR);
}
STBIRDEF int stbir_resize_uint8_srgb(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
int num_channels, int alpha_channel, int flags)
{
return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
output_pixels, output_w, output_h, output_stride_in_bytes,
0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB);
}
STBIRDEF int stbir_resize_uint8_srgb_edgemode(const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_wrap_mode)
{
return stbir__resize_arbitrary(NULL, input_pixels, input_w, input_h, input_stride_in_bytes,
output_pixels, output_w, output_h, output_stride_in_bytes,
0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, STBIR_FILTER_DEFAULT, STBIR_FILTER_DEFAULT,
edge_wrap_mode, edge_wrap_mode, STBIR_COLORSPACE_SRGB);
}
STBIRDEF int stbir_resize_uint8_generic( const unsigned char *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
unsigned char *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
void *alloc_context)
{
return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
output_pixels, output_w, output_h, output_stride_in_bytes,
0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT8, filter, filter,
edge_wrap_mode, edge_wrap_mode, space);
}
STBIRDEF int stbir_resize_uint16_generic(const stbir_uint16 *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
stbir_uint16 *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
void *alloc_context)
{
return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
output_pixels, output_w, output_h, output_stride_in_bytes,
0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_UINT16, filter, filter,
edge_wrap_mode, edge_wrap_mode, space);
}
STBIRDEF int stbir_resize_float_generic( const float *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
float *output_pixels , int output_w, int output_h, int output_stride_in_bytes,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_wrap_mode, stbir_filter filter, stbir_colorspace space,
void *alloc_context)
{
return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
output_pixels, output_w, output_h, output_stride_in_bytes,
0,0,1,1,NULL,num_channels,alpha_channel,flags, STBIR_TYPE_FLOAT, filter, filter,
edge_wrap_mode, edge_wrap_mode, space);
}
STBIRDEF int stbir_resize( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
stbir_datatype datatype,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
stbir_filter filter_horizontal, stbir_filter filter_vertical,
stbir_colorspace space, void *alloc_context)
{
return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
output_pixels, output_w, output_h, output_stride_in_bytes,
0,0,1,1,NULL,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
edge_mode_horizontal, edge_mode_vertical, space);
}
STBIRDEF int stbir_resize_subpixel(const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
stbir_datatype datatype,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
stbir_filter filter_horizontal, stbir_filter filter_vertical,
stbir_colorspace space, void *alloc_context,
float x_scale, float y_scale,
float x_offset, float y_offset)
{
float transform[4];
transform[0] = x_scale;
transform[1] = y_scale;
transform[2] = x_offset;
transform[3] = y_offset;
return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
output_pixels, output_w, output_h, output_stride_in_bytes,
0,0,1,1,transform,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
edge_mode_horizontal, edge_mode_vertical, space);
}
STBIRDEF int stbir_resize_region( const void *input_pixels , int input_w , int input_h , int input_stride_in_bytes,
void *output_pixels, int output_w, int output_h, int output_stride_in_bytes,
stbir_datatype datatype,
int num_channels, int alpha_channel, int flags,
stbir_edge edge_mode_horizontal, stbir_edge edge_mode_vertical,
stbir_filter filter_horizontal, stbir_filter filter_vertical,
stbir_colorspace space, void *alloc_context,
float s0, float t0, float s1, float t1)
{
return stbir__resize_arbitrary(alloc_context, input_pixels, input_w, input_h, input_stride_in_bytes,
output_pixels, output_w, output_h, output_stride_in_bytes,
s0,t0,s1,t1,NULL,num_channels,alpha_channel,flags, datatype, filter_horizontal, filter_vertical,
edge_mode_horizontal, edge_mode_vertical, space);
}
#endif // STB_IMAGE_RESIZE_IMPLEMENTATION
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