pimoroni-pico/libraries/pico_graphics/pico_graphics_pen_p8.cpp

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#include "pico_graphics.hpp"
namespace pimoroni {
PicoGraphics_PenP8::PicoGraphics_PenP8(uint16_t width, uint16_t height, void *frame_buffer)
: PicoGraphics(width, height, frame_buffer) {
this->pen_type = PEN_P8;
if(this->frame_buffer == nullptr) {
this->frame_buffer = (void *)(new uint8_t[buffer_size(width, height)]);
}
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for(auto i = 0u; i < palette_size; i++) {
palette[i] = {uint8_t(i), uint8_t(i), uint8_t(i)};
used[i] = false;
}
cache_built = false;
}
void PicoGraphics_PenP8::set_pen(uint c) {
color = c;
}
void PicoGraphics_PenP8::set_pen(uint8_t r, uint8_t g, uint8_t b) {
int pen = RGB(r, g, b).closest(palette, 16);
if(pen != -1) color = pen;
}
int PicoGraphics_PenP8::update_pen(uint8_t i, uint8_t r, uint8_t g, uint8_t b) {
i &= 0xff;
used[i] = true;
palette[i] = {r, g, b};
cache_built = false;
return i;
}
int PicoGraphics_PenP8::create_pen(uint8_t r, uint8_t g, uint8_t b) {
// Create a colour and place it in the palette if there's space
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for(auto i = 0u; i < palette_size; i++) {
if(!used[i]) {
palette[i] = {r, g, b};
used[i] = true;
cache_built = false;
return i;
}
}
return -1;
}
int PicoGraphics_PenP8::reset_pen(uint8_t i) {
palette[i] = {0, 0, 0};
used[i] = false;
cache_built = false;
return i;
}
void PicoGraphics_PenP8::set_pixel(const Point &p) {
uint8_t *buf = (uint8_t *)frame_buffer;
buf[p.y * bounds.w + p.x] = color;
}
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void PicoGraphics_PenP8::set_pixel_span(const Point &p, uint l) {
// pointer to byte in framebuffer that contains this pixel
uint8_t *buf = (uint8_t *)frame_buffer;
buf = &buf[p.y * bounds.w + p.x];
while(l--) {
*buf++ = color;
}
}
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void PicoGraphics_PenP8::get_dither_candidates(const RGB &col, const RGB *palette, size_t len, std::array<uint8_t, 16> &candidates) {
RGB error;
for(size_t i = 0; i < candidates.size(); i++) {
candidates[i] = (col + error).closest(palette, len);
error += (col - palette[candidates[i]]);
}
// sort by a rough approximation of luminance, this ensures that neighbouring
// pixels in the dither matrix are at extreme opposites of luminence
// giving a more balanced output
std::sort(candidates.begin(), candidates.end(), [palette](int a, int b) {
return palette[a].luminance() > palette[b].luminance();
});
}
void PicoGraphics_PenP8::set_pixel_dither(const Point &p, const RGB &c) {
if(!bounds.contains(p)) return;
if(!cache_built) {
for(uint i = 0; i < 512; i++) {
RGB cache_col((i & 0x1C0) >> 1, (i & 0x38) << 2, (i & 0x7) << 5);
get_dither_candidates(cache_col, palette, palette_size, candidate_cache[i]);
}
cache_built = true;
}
uint cache_key = ((c.r & 0xE0) << 1) | ((c.g & 0xE0) >> 2) | ((c.b & 0xE0) >> 5);
//get_dither_candidates(c, palette, 256, candidates);
// find the pattern coordinate offset
uint pattern_index = (p.x & 0b11) | ((p.y & 0b11) << 2);
// set the pixel
//color = candidates[pattern[pattern_index]];
color = candidate_cache[cache_key][dither16_pattern[pattern_index]];
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set_pixel(p);
}
void PicoGraphics_PenP8::frame_convert(PenType type, conversion_callback_func callback) {
if(type == PEN_RGB565) {
// Cache the RGB888 palette as RGB565
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RGB565 cache[palette_size];
for(auto i = 0u; i < palette_size; i++) {
cache[i] = palette[i].to_rgb565();
}
// Treat our void* frame_buffer as uint8_t
uint8_t *src = (uint8_t *)frame_buffer;
frame_convert_rgb565(callback, [&]() {
return cache[*src++];
});
}
}
}