fixed bitmap n tested

examples/bmp/bmp.ino

@@ -77,7 +77,7 @@ void setup(void) {
 
   if (!SD.begin(SD_CS)) {
     Serial.println("failed!");
-    return;
+    while(1);
   }
   Serial.println("SD OK!");
 
@@ -87,6 +87,7 @@ void setup(void) {
 void loop() {
 }
 
+
 // This function opens a Windows Bitmap (BMP) file and
 // displays it at the given coordinates.  It's sped up
 // by reading many pixels worth of data at a time
@@ -97,7 +98,7 @@ void loop() {
 
 #define BUFFPIXEL 20
 
-void bmpDraw(char *filename, uint8_t x, uint8_t y) {
+void bmpDraw(char *filename, int16_t x, int16_t y) {
 
   File     bmpFile;
   int      bmpWidth, bmpHeight;   // W+H in pixels
@@ -108,40 +109,40 @@ void bmpDraw(char *filename, uint8_t x, uint8_t y) {
   uint8_t  buffidx = sizeof(sdbuffer); // Current position in sdbuffer
   boolean  goodBmp = false;       // Set to true on valid header parse
   boolean  flip    = true;        // BMP is stored bottom-to-top
-  int      w, h, row, col;
+  int      w, h, row, col, x2, y2, bx1, by1;
   uint8_t  r, g, b;
   uint32_t pos = 0, startTime = millis();
 
   if((x >= tft.width()) || (y >= tft.height())) return;
 
   Serial.println();
-  Serial.print("Loading image '");
+  Serial.print(F("Loading image '"));
   Serial.print(filename);
   Serial.println('\'');
 
   // Open requested file on SD card
   if ((bmpFile = SD.open(filename)) == NULL) {
-    Serial.print("File not found");
+    Serial.print(F("File not found"));
     return;
   }
 
   // Parse BMP header
   if(read16(bmpFile) == 0x4D42) { // BMP signature
-    Serial.print("File size: "); Serial.println(read32(bmpFile));
+    Serial.print(F("File size: ")); Serial.println(read32(bmpFile));
     (void)read32(bmpFile); // Read & ignore creator bytes
     bmpImageoffset = read32(bmpFile); // Start of image data
-    Serial.print("Image Offset: "); Serial.println(bmpImageoffset, DEC);
+    Serial.print(F("Image Offset: ")); Serial.println(bmpImageoffset, DEC);
     // Read DIB header
-    Serial.print("Header size: "); Serial.println(read32(bmpFile));
+    Serial.print(F("Header size: ")); Serial.println(read32(bmpFile));
     bmpWidth  = read32(bmpFile);
     bmpHeight = read32(bmpFile);
     if(read16(bmpFile) == 1) { // # planes -- must be '1'
       bmpDepth = read16(bmpFile); // bits per pixel
-      Serial.print("Bit Depth: "); Serial.println(bmpDepth);
+      Serial.print(F("Bit Depth: ")); Serial.println(bmpDepth);
       if((bmpDepth == 24) && (read32(bmpFile) == 0)) { // 0 = uncompressed
 
         goodBmp = true; // Supported BMP format -- proceed!
-        Serial.print("Image size: ");
+        Serial.print(F("Image size: "));
         Serial.print(bmpWidth);
         Serial.print('x');
         Serial.println(bmpHeight);
@@ -157,13 +158,30 @@ void bmpDraw(char *filename, uint8_t x, uint8_t y) {
         }
 
         // Crop area to be loaded
-        w = bmpWidth;
+        x2 = x + bmpWidth  - 1; // Lower-right corner
+        y2 = y + bmpHeight - 1;
+        if((x2 >= 0) && (y2 >= 0)) { // On screen?
+          w = bmpWidth; // Width/height of section to load/display
           h = bmpHeight;
-        if((x+w-1) >= tft.width())  w = tft.width()  - x;
+          bx1 = by1 = 0; // UL coordinate in BMP file
-        if((y+h-1) >= tft.height()) h = tft.height() - y;
+          if(x < 0) { // Clip left
+            bx1 = -x;
+            x   = 0;
+            w   = x2 + 1;
+          }
+          if(y < 0) { // Clip top
+            by1 = -y;
+            y   = 0;
+            h   = y2 + 1;
+          }
+          if(x2 >= tft.width())  w = tft.width()  - x; // Clip right
+          if(y2 >= tft.height()) h = tft.height() - y; // Clip bottom
+  
+          // Set TFT address window to clipped image bounds
+          tft.startWrite(); // Requires start/end transaction now
+          tft.setAddrWindow(x, y, w, h);
   
           for (row=0; row<h; row++) { // For each scanline...
-          tft.goTo(x, y+row);
   
             // Seek to start of scan line.  It might seem labor-
             // intensive to be doing this on every line, but this
@@ -172,33 +190,34 @@ void bmpDraw(char *filename, uint8_t x, uint8_t y) {
             // place if the file position actually needs to change
             // (avoids a lot of cluster math in SD library).
             if(flip) // Bitmap is stored bottom-to-top order (normal BMP)
-            pos = bmpImageoffset + (bmpHeight - 1 - row) * rowSize;
+              pos = bmpImageoffset + (bmpHeight - 1 - (row + by1)) * rowSize;
             else     // Bitmap is stored top-to-bottom
-            pos = bmpImageoffset + row * rowSize;
+              pos = bmpImageoffset + (row + by1) * rowSize;
+            pos += bx1 * 3; // Factor in starting column (bx1)
             if(bmpFile.position() != pos) { // Need seek?
+              tft.endWrite(); // End TFT transaction
               bmpFile.seek(pos);
               buffidx = sizeof(sdbuffer); // Force buffer reload
+              tft.startWrite(); // Start new TFT transaction
             }
-
-          // optimize by setting pins now
             for (col=0; col<w; col++) { // For each pixel...
               // Time to read more pixel data?
               if (buffidx >= sizeof(sdbuffer)) { // Indeed
+                tft.endWrite(); // End TFT transaction
                 bmpFile.read(sdbuffer, sizeof(sdbuffer));
                 buffidx = 0; // Set index to beginning
+                tft.startWrite(); // Start new TFT transaction
               }
-
               // Convert pixel from BMP to TFT format, push to display
               b = sdbuffer[buffidx++];
               g = sdbuffer[buffidx++];
               r = sdbuffer[buffidx++];
-
+              tft.writePixel(tft.color565(r,g,b));
-            //tft.drawPixel(x+col, y+row, tft.Color565(r,g,b));
-            // optimized!
-            tft.pushColor(tft.Color565(r,g,b));
             } // end pixel
           } // end scanline
-        Serial.print("Loaded in ");
+          tft.endWrite(); // End last TFT transaction
+        } // end onscreen
+        Serial.print(F("Loaded in "));
         Serial.print(millis() - startTime);
         Serial.println(" ms");
       } // end goodBmp
@@ -206,21 +225,21 @@ void bmpDraw(char *filename, uint8_t x, uint8_t y) {
   }
 
   bmpFile.close();
-  if(!goodBmp) Serial.println("BMP format not recognized.");
+  if(!goodBmp) Serial.println(F("BMP format not recognized."));
 }
 
 // These read 16- and 32-bit types from the SD card file.
 // BMP data is stored little-endian, Arduino is little-endian too.
 // May need to reverse subscript order if porting elsewhere.
 
-uint16_t read16(File f) {
+uint16_t read16(File &f) {
   uint16_t result;
   ((uint8_t *)&result)[0] = f.read(); // LSB
   ((uint8_t *)&result)[1] = f.read(); // MSB
   return result;
 }
 
-uint32_t read32(File f) {
+uint32_t read32(File &f) {
   uint32_t result;
   ((uint8_t *)&result)[0] = f.read(); // LSB
   ((uint8_t *)&result)[1] = f.read();