add arbitrary rect drawing from bitmaps/canvases (RGB 565, RAM only)

Adafruit_GFX.cpp

@@ -1009,6 +1009,37 @@ void Adafruit_GFX::drawRGBBitmap(int16_t x, int16_t y, const uint16_t bitmap[],
   endWrite();
 }
 
+/**************************************************************************/
+/*!
+   @brief   Draw a RAM-resident 16-bit image (RGB 5/6/5) or sub-section thereof
+   at the specified (x,y) position, from the specified (src_x,src_y) position.
+   For 16-bit display devices; no color reduction performed.
+    @param    x   Top left corner x coordinate to draw at
+    @param    y   Top left corner y coordinate to draw at
+    @param    bitmap  byte array with 16-bit color bitmap
+    @param    w   Width of the area in the bitmap to draw, in pixels
+    @param    h   Height of the area in the bitmap to draw, in pixels
+    @param    src_x Top left corner x coordinate in the bitmap to read from
+    @param    src_y Top left corner y coordinate in the bitmap to read from
+    @param    src_w Width of the bitmap in pixels. Set to zero if w already
+    contains the bitmap's width.
+*/
+/**************************************************************************/
+void Adafruit_GFX::drawRGBBitmap(int16_t x, int16_t y, uint16_t *bitmap,
+                                 int16_t w, int16_t h, int16_t src_x,
+                                 int16_t src_y, int16_t src_w) {
+  if (src_w == 0)
+    src_w = w;
+
+  startWrite();
+  for (int16_t j = 0; j < h; j++, y++) {
+    for (int16_t i = 0; i < w; i++) {
+      writePixel(x + i, y, bitmap[((j + src_y) * src_w) + src_x + i]);
+    }
+  }
+  endWrite();
+}
+
 /**************************************************************************/
 /*!
    @brief   Draw a RAM-resident 16-bit image (RGB 5/6/5) at the specified (x,y)
@@ -1022,13 +1053,7 @@ void Adafruit_GFX::drawRGBBitmap(int16_t x, int16_t y, const uint16_t bitmap[],
 /**************************************************************************/
 void Adafruit_GFX::drawRGBBitmap(int16_t x, int16_t y, uint16_t *bitmap,
                                  int16_t w, int16_t h) {
-  startWrite();
-  for (int16_t j = 0; j < h; j++, y++) {
-    for (int16_t i = 0; i < w; i++) {
-      writePixel(x + i, y, bitmap[j * w + i]);
-    }
-  }
-  endWrite();
+  drawRGBBitmap(x, y, bitmap, w, h, 0, 0, 0);
 }
 
 /**************************************************************************/

Adafruit_GFX.h

@@ -101,6 +101,8 @@ class Adafruit_GFX : public Print {
                            int16_t w, int16_t h);
   void drawRGBBitmap(int16_t x, int16_t y, const uint16_t bitmap[], int16_t w,
                      int16_t h);
+  void drawRGBBitmap(int16_t x, int16_t y, uint16_t *bitmap, int16_t w,
+                     int16_t h, int16_t src_x, int16_t src_y, int16_t src_w);
   void drawRGBBitmap(int16_t x, int16_t y, uint16_t *bitmap, int16_t w,
                      int16_t h);
   void drawRGBBitmap(int16_t x, int16_t y, const uint16_t bitmap[],

Adafruit_SPITFT.cpp

@@ -1811,58 +1811,78 @@ void Adafruit_SPITFT::pushColor(uint16_t color) {
 }
 
 /*!
-    @brief  Draw a 16-bit image (565 RGB) at the specified (x,y) position.
-            For 16-bit display devices; no color reduction performed.
+    @brief  Draw a 16-bit image (565 RGB) at the specified (x,y) position from
+            the specified (src_x,src_y). For 16-bit display devices; no color
+            reduction performed.
             Adapted from https://github.com/PaulStoffregen/ILI9341_t3
             by Marc MERLIN. See examples/pictureEmbed to use this.
             5/6/2017: function name and arguments have changed for
             compatibility with current GFX library and to avoid naming
             problems in prior implementation.  Formerly drawBitmap() with
             arguments in different order. Handles its own transaction and
             edge clipping/rejection.
-    @param  x        Top left corner horizontal coordinate.
-    @param  y        Top left corner vertical coordinate.
+    @param  x        Top left corner horizontal coordinate to draw at.
+    @param  y        Top left corner vertical coordinate to draw at.
     @param  pcolors  Pointer to 16-bit array of pixel values.
-    @param  w        Width of bitmap in pixels.
-    @param  h        Height of bitmap in pixels.
+    @param  w        Width of the area of the bitmap to draw, in pixels.
+    @param  h        Height of the area of the bitmap to draw, in pixels.
+    @param  src_x    Top left corner horizontal coordinate to read from.
+    @param  src_y    Top left corner vertical coordinate to read from.
+    @param  src_w    Width of the source bitmap in pixels.
 */
 void Adafruit_SPITFT::drawRGBBitmap(int16_t x, int16_t y, uint16_t *pcolors,
-                                    int16_t w, int16_t h) {
-
-  int16_t x2, y2;                 // Lower-right coord
-  if ((x >= _width) ||            // Off-edge right
-      (y >= _height) ||           // " top
-      ((x2 = (x + w - 1)) < 0) || // " left
-      ((y2 = (y + h - 1)) < 0))
-    return; // " bottom
-
-  int16_t bx1 = 0, by1 = 0, // Clipped top-left within bitmap
-      saveW = w;            // Save original bitmap width value
-  if (x < 0) {              // Clip left
+                                    int16_t w, int16_t h, int16_t src_x,
+                                    int16_t src_y, int16_t src_w) {
+  int16_t x2, y2;                                          // Lower-right coord
+  if ((x >= _width) ||                                     // Off-edge right
+      (src_x >= src_w) || (y >= _height) ||                // " bottom
+      ((x2 = (x + w - 1)) < 0) ||                          // " left
+      (src_x + src_w - 1 < 0) || ((y2 = (y + h - 1)) < 0)) // " top
+    return;                                                // " bottom
+
+  if (x < 0) { // Clip left
     w += x;
-    bx1 = -x;
     x = 0;
   }
   if (y < 0) { // Clip top
     h += y;
-    by1 = -y;
     y = 0;
   }
+  if (src_x < 0) {
+    src_w += src_x;
+    src_x = -src_x;
+  }
+  if (src_y < 0)
+    src_y = -src_y;
   if (x2 >= _width)
     w = _width - x; // Clip right
   if (y2 >= _height)
     h = _height - y; // Clip bottom
 
-  pcolors += by1 * saveW + bx1; // Offset bitmap ptr to clipped top-left
+  pcolors += (src_y * src_w) + src_x; // Offset bitmap ptr to clipped top-left
   startWrite();
   setAddrWindow(x, y, w, h); // Clipped area
   while (h--) {              // For each (clipped) scanline...
     writePixels(pcolors, w); // Push one (clipped) row
-    pcolors += saveW;        // Advance pointer by one full (unclipped) line
+    pcolors += src_w;        // Advance pointer by one full (unclipped) line
   }
   endWrite();
 }
 
+/*!
+    @brief  Draw a 16-bit image (565 RGB) at the specified (x,y) position.
+            For 16-bit display devices; no color reduction performed.
+    @param  x        Top left corner horizontal coordinate.
+    @param  y        Top left corner vertical coordinate.
+    @param  pcolors  Pointer to 16-bit array of pixel values.
+    @param  w        Width of bitmap in pixels.
+    @param  h        Height of bitmap in pixels.
+ */
+void Adafruit_SPITFT::drawRGBBitmap(int16_t x, int16_t y, uint16_t *pcolors,
+                                    int16_t w, int16_t h) {
+  drawRGBBitmap(x, y, pcolors, w, h, 0, 0, w);
+}
+
 // -------------------------------------------------------------------------
 // Miscellaneous class member functions that don't draw anything.
 

Adafruit_SPITFT.h

@@ -251,6 +251,8 @@ class Adafruit_SPITFT : public Adafruit_GFX {
   void pushColor(uint16_t color);
 
   using Adafruit_GFX::drawRGBBitmap; // Check base class first
+  void drawRGBBitmap(int16_t x, int16_t y, uint16_t *bitmap, int16_t w,
+                     int16_t h, int16_t src_x, int16_t src_y, int16_t src_w);
   void drawRGBBitmap(int16_t x, int16_t y, uint16_t *pcolors, int16_t w,
                      int16_t h);