pimoroni-pico/libraries/pico_graphics/pico_graphics_pen_p4.cpp

156 wiersze
5.4 KiB
C++

#include "pico_graphics.hpp"
namespace pimoroni {
PicoGraphics_PenP4::PicoGraphics_PenP4(uint16_t width, uint16_t height, void *frame_buffer)
: PicoGraphics(width, height, frame_buffer) {
this->pen_type = PEN_P4;
if(this->frame_buffer == nullptr) {
this->frame_buffer = (void *)(new uint8_t[buffer_size(width, height)]);
}
for(auto i = 0u; i < palette_size; i++) {
palette[i] = {
uint8_t(i << 4),
uint8_t(i << 4),
uint8_t(i << 4)
};
used[i] = false;
}
cache_built = false;
}
void PicoGraphics_PenP4::set_pen(uint c) {
color = c & 0xf;
}
void PicoGraphics_PenP4::set_pen(uint8_t r, uint8_t g, uint8_t b) {
int pen = RGB(r, g, b).closest(palette, palette_size);
if(pen != -1) color = pen;
}
int PicoGraphics_PenP4::update_pen(uint8_t i, uint8_t r, uint8_t g, uint8_t b) {
i &= 0xf;
used[i] = true;
palette[i] = {r, g, b};
cache_built = false;
return i;
}
int PicoGraphics_PenP4::create_pen(uint8_t r, uint8_t g, uint8_t b) {
// Create a colour and place it in the palette if there's space
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_PenP4::reset_pen(uint8_t i) {
palette[i] = {0, 0, 0};
used[i] = false;
cache_built = false;
return i;
}
void PicoGraphics_PenP4::set_pixel(const Point &p) {
auto i = (p.x + p.y * bounds.w);
// pointer to byte in framebuffer that contains this pixel
uint8_t *buf = (uint8_t *)frame_buffer;
uint8_t *f = &buf[i / 2];
uint8_t o = (~i & 0b1) * 4; // bit offset within byte
uint8_t m = ~(0b1111 << o); // bit mask for byte
uint8_t b = color << o; // bit value shifted to position
*f &= m; // clear bits
*f |= b; // set value
}
void PicoGraphics_PenP4::set_pixel_span(const Point &p, uint l) {
auto i = (p.x + p.y * bounds.w);
// pointer to byte in framebuffer that contains this pixel
uint8_t *buf = (uint8_t *)frame_buffer;
uint8_t *f = &buf[i / 2];
// doubled up color value, so the color is stored in both nibbles
uint8_t cc = color | (color << 4);
// handle the first pixel if not byte aligned
if(i & 0b1) {*f &= 0b11110000; *f |= (cc & 0b00001111); f++; l--;}
// write any double nibble pixels
while(l > 1) {*f++ = cc; l -= 2;}
// handle the last pixel if not byte aligned
if(l) {*f &= 0b00001111; *f |= (cc & 0b11110000);}
}
void PicoGraphics_PenP4::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_PenP4::set_pixel_dither(const Point &p, const RGB &c) {
if(!bounds.contains(p)) return;
uint used_palette_entries = 0;
for(auto i = 0u; i < palette_size; i++) {
if(!used[i]) break;
used_palette_entries++;
}
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, used_palette_entries, 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]];
set_pixel(p);
}
void PicoGraphics_PenP4::frame_convert(PenType type, conversion_callback_func callback) {
if(type == PEN_RGB565) {
// Cache the RGB888 palette as RGB565
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;
uint8_t o = 4;
frame_convert_rgb565(callback, [&]() {
uint8_t c = *src;
uint8_t b = (c >> o) & 0xf; // bit value shifted to position
// Increment to next 4-bit entry
o ^= 4;
if (o != 0) ++src;
return cache[b];
});
}
}
}