Small changes to color dithering algorithm

Author: JosipKuci

src/graphics/ImageColor/ImageDitherColor.cpp

@@ -39,8 +39,8 @@ static uint32_t pallete[] = {0xFFFFFF, 0x0000000, 0xFF0000};
 static unsigned int width = E_INK_WIDTH, height = E_INK_HEIGHT;
 
 #elif defined(ARDUINO_ESP32S3_DEV)
-static uint32_t pallete[] = { 0x424852, 0xA1A8A8, 0xB0AB44, 0x7D4749, 0x4B689A, 0x516A64};
-//static uint32_t pallete[] = { 0x000000, 0xFFFFFF, 0xFFFF00, 0xFF0000, 0x0000FF, 0x00FF00};
+//static uint32_t pallete[] = { 0x424852, 0xA1A8A8, 0xB0AB44, 0x7D4749, 0x4B689A, 0x516A64};
+static uint32_t pallete[] = { 0x000000, 0xFFFFFF, 0xFFFF00, 0xFF0000, 0x0000FF, 0x00FF00};
 static unsigned int width = E_INK_WIDTH, height = E_INK_HEIGHT;
 
 #endif
@@ -117,15 +117,17 @@ uint8_t ImageColor::ditherGetPixelBmp(uint32_t px, int i, int j, int w, bool pal
     int16_t g = GREEN8(px) + ditherBuffer[1][j % 8][i];
     int16_t b = BLUE8(px) + ditherBuffer[2][j % 8][i];
 
-    ditherBuffer[0][j % 8][i] = 0;
-    ditherBuffer[1][j % 8][i] = 0;
-    ditherBuffer[2][j % 8][i] = 0;
+    if (i == w - 1) {
+        int row = j % 8;
+        memset(ditherBuffer[0][row], 0, w * sizeof(int16_t));
+        memset(ditherBuffer[1][row], 0, w * sizeof(int16_t));
+        memset(ditherBuffer[2][row], 0, w * sizeof(int16_t));
+    }
 
     r = max((int16_t)0, min((int16_t)255, r));
     g = max((int16_t)0, min((int16_t)255, g));
     b = max((int16_t)0, min((int16_t)255, b));
 
-
     int closest = findClosestPalette(r, g, b);
 
     int32_t rErr = r - (int32_t)((pallete[closest] >> 16) & 0xFF);

src/graphics/ImageColor/jpegHelpers/ImageJPEG.cpp

@@ -377,9 +377,13 @@ bool ImageColor::drawJpegChunk(int16_t x, int16_t y, uint16_t w, uint16_t h, uin
 
     // Carry global error from previous scanline
     if (dither && y != _imagePtrJpeg->lastY)
-    {
-        _imagePtrJpeg->lastY = y;
-    }
+{
+    // We moved to a new scanline
+    int oldRow = _imagePtrJpeg->lastY & (18 - 1);
+
+    _imagePtrJpeg->lastY = y;
+}
+
 
     // --- Draw the JPEG MCU block ---
     for (int j = 0; j < h; ++j)
@@ -399,7 +403,7 @@ bool ImageColor::drawJpegChunk(int16_t x, int16_t y, uint16_t w, uint16_t h, uin
             if (dither)
             {
                 val = _imagePtrJpeg->ditherGetPixelBmp(((uint32_t)r << 16) | ((uint32_t)g << 8) | ((uint32_t)b), i + x,
-                                                       j + y, E_INK_WIDTH, 0);
+                                                       j + y, E_INK_HEIGHT, 0); // Changed from E_INK_WIDTH
             }
             else
             {

src/graphics/ImageColor/pngHelpers/ImagePNG.cpp

@@ -77,12 +77,16 @@ void pngle_on_draw(pngle_t *pngle, uint32_t x, uint32_t y, uint32_t w, uint32_t
                     g = 255 - g;
                     b = 255 - b;
                 }
-
-                uint8_t px = _imagePtrPng->findClosestPalette(r, g, b);
+                uint8_t px;
 
                 if (_pngDither)
                 {
-                    px = _imagePtrPng->ditherGetPixelBmp((r << 16) | (g << 8) | (b), x + i, y + j, E_INK_WIDTH, 0);
+                    px = _imagePtrPng->ditherGetPixelBmp((r << 16) | (g << 8) | (b), x + i, y + j, pngle_get_width(pngle), 0); // Changed from e_ink_width
+                }
+                else
+                {
+                    px = _imagePtrPng->findClosestPalette(r, g, b);
+
                 }
                 _imagePtrPng->_inkplate->drawPixel(_pngX + x + i, _pngY + y + j, px);
             }