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add support for quad-color eInk displays

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Liz 2025-07-31 18:34:34 -04:00
parent 12d776a358
commit 923a861821
2 changed files with 101 additions and 45 deletions
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127
Adafruit_ImageReader_EPD.cpp
View file

@ -6,6 +6,87 @@
#define BUFPIXELS 200 ///< 200 * 5 = 1000 bytes
#endif
/*!
@brief Maps RGB color values to EPD display colors based on display mode.
@param r
Red component of the color (0-255).
@param g
Green component of the color (0-255).
@param b
Blue component of the color (0-255).
@param mode
The display mode (THINKINK_MONO, THINKINK_TRICOLOR,
THINKINK_GRAYSCALE4, THINKINK_QUADCOLOR, etc.) that
determines the available colors and mapping strategy.
@return EPD color constant (EPD_BLACK, EPD_WHITE, EPD_RED, EPD_YELLOW,
EPD_DARK, EPD_LIGHT) appropriate for the display mode.
@note Color mapping thresholds:
- Monochrome: Simple average threshold at 128
- Tricolor: Black < 0x60, Red >= 0x80 (red only), White otherwise
- Grayscale: Black < 0x40, Dark < 0x80, Light < 0xC0, White >= 0xC0
- Quadcolor: Black < 0x60, White >= 0xE0 (all channels),
Yellow >= 0xC0 red + >= 0x80 green, Red >= 0xC0 red + < 0x80
green
*/
uint8_t Adafruit_ImageReader_EPD::mapColorForDisplay(uint8_t r, uint8_t g,
uint8_t b,
thinkinkmode_t mode) {
uint8_t result;
switch (mode) {
case THINKINK_MONO:
case THINKINK_MONO_PARTIAL:
if ((r + g + b) / 3 < 128) {
return EPD_BLACK;
} else {
return EPD_WHITE;
}
case THINKINK_TRICOLOR:
if ((r < 0x60) && (g < 0x60) && (b < 0x60)) {
return EPD_BLACK;
} else if ((r >= 0x80) && (g < 0x80) && (b < 0x80)) {
return EPD_RED;
} else {
return EPD_WHITE;
}
case THINKINK_GRAYSCALE4: {
uint8_t gray = (r + g + b) / 3;
if (gray < 0x40) {
return EPD_BLACK;
} else if (gray < 0x80) {
return EPD_DARK;
} else if (gray < 0xC0) {
return EPD_LIGHT;
} else {
return EPD_WHITE;
}
}
case THINKINK_QUADCOLOR:
if ((r < 0x60) && (g < 0x60) && (b < 0x60)) {
return EPD_BLACK;
} else if ((r >= 0xE0) && (g >= 0xE0) && (b >= 0xE0)) {
return EPD_WHITE;
} else if ((r >= 0xC0) && (g >= 0x80) && (b < 0x40)) {
return EPD_YELLOW;
} else if ((r >= 0xC0) && (g < 0x80) && (b < 0x40)) {
return EPD_RED;
} else {
return EPD_WHITE;
}
default:
if ((r < 0x60) && (g < 0x60) && (b < 0x60)) {
return EPD_BLACK;
} else if ((r >= 0x80) && (g < 0x80) && (b < 0x80)) {
return EPD_RED;
} else {
return EPD_WHITE;
}
}
}
/*!
@brief Draw image to an Adafruit ePaper-type display.
@param epd
@ -43,24 +124,16 @@ void Adafruit_Image_EPD::draw(Adafruit_EPD &epd, int16_t x, int16_t y) {
} else if (format == IMAGE_8) {
} else if (format == IMAGE_16) {
uint16_t *buffer = canvas.canvas16->getBuffer();
thinkinkmode_t displayMode = epd.getMode();
while (row < y + canvas.canvas16->height()) {
// RGB in 565 format
uint8_t r = (*buffer & 0xf800) >> 8;
uint8_t g = (*buffer & 0x07e0) >> 3;
uint8_t b = (*buffer & 0x001f) << 3;
uint8_t c = 0;
if ((r < 0x60) && (g < 0x60) && (b < 0x60)) {
c = EPD_BLACK; // try to infer black
} else if ((r < 0x80) && (g < 0x80) && (b < 0x80)) {
c = EPD_DARK; // try to infer dark gray
} else if ((r < 0xD0) && (g < 0xD0) && (b < 0xD0)) {
c = EPD_LIGHT; // try to infer light gray
} else if ((r >= 0x80) && (g >= 0x80) && (b >= 0x80)) {
c = EPD_WHITE;
} else if (r >= 0x80) {
c = EPD_RED; // try to infer red color
}
uint8_t c =
Adafruit_ImageReader_EPD::mapColorForDisplay(r, g, b, displayMode);
epd.writePixel(col, row, c);
col++;
@ -157,7 +230,7 @@ ImageReturnCode Adafruit_ImageReader_EPD::coreBMP(
int16_t y,
Adafruit_Image_EPD *img, // NULL if load-to-screen
boolean transact) { // SD & EPD sharing bus, use transactions
thinkinkmode_t displayMode = epd ? epd->getMode() : THINKINK_TRICOLOR;
ImageReturnCode status = IMAGE_ERR_FORMAT; // IMAGE_SUCCESS on valid file
uint32_t offset; // Start of image data in file
uint32_t headerSize; // Indicates BMP version
@ -297,23 +370,14 @@ ImageReturnCode Adafruit_ImageReader_EPD::coreBMP(
(quantized = (uint16_t *)malloc(colors * sizeof(uint16_t)))) {
if (depth < 16) {
// Load and quantize color table
thinkinkmode_t displayMode =
epd ? epd->getMode() : THINKINK_TRICOLOR;
for (uint16_t c = 0; c < colors; c++) {
b = file.read();
g = file.read();
r = file.read();
(void)file.read(); // Ignore 4th byte
color = 0;
if ((r < 0x60) && (g < 0x60) && (b < 0x60)) {
color = EPD_BLACK; // try to infer black
} else if ((r < 0x80) && (g < 0x80) && (b < 0x80)) {
color = EPD_DARK; // try to infer dark gray
} else if ((r < 0xD0) && (g < 0xD0) && (b < 0xD0)) {
color = EPD_LIGHT; // try to infer light gray
} else if ((r >= 0x80) && (g >= 0x80) && (b >= 0x80)) {
color = EPD_WHITE;
} else if (r >= 0x80) {
color = EPD_RED; // try to infer red color
}
color = mapColorForDisplay(r, g, b, displayMode);
quantized[c] = color;
}
}
@ -400,18 +464,7 @@ ImageReturnCode Adafruit_ImageReader_EPD::coreBMP(
g = sdbuf[srcidx++];
r = sdbuf[srcidx++];
color = 0;
if ((r < 0x60) && (g < 0x60) && (b < 0x60)) {
color = EPD_BLACK; // try to infer black
} else if ((r < 0x80) && (g < 0x80) && (b < 0x80)) {
color = EPD_DARK; // try to infer dark gray
} else if ((r < 0xD0) && (g < 0xD0) && (b < 0xD0)) {
color = EPD_LIGHT; // try to infer light gray
} else if ((r >= 0x80) && (g >= 0x80) && (b >= 0x80)) {
color = EPD_WHITE;
} else if (r >= 0x80) {
color = EPD_RED; // try to infer red color
}
color = mapColorForDisplay(r, g, b, displayMode);
dest[destidx++] = color;
} else {
// Extract 1-bit color index

3
Adafruit_ImageReader_EPD.h
View file

@ -48,6 +48,9 @@ public:
ImageReturnCode drawBMP(char *filename, Adafruit_EPD &epd, int16_t x,
int16_t y, boolean transact = true);
static uint8_t mapColorForDisplay(uint8_t r, uint8_t g, uint8_t b,
thinkinkmode_t mode);
private:
ImageReturnCode coreBMP(char *filename, Adafruit_EPD *epd, uint16_t *dest,
int16_t x, int16_t y, Adafruit_Image_EPD *img,