Some improvements

Add return-values for some graphic function for error handling.
Improved some graphic functions to reduce needed flash.
Update readme for flash size values

lcd.c

@@ -384,42 +384,47 @@ void lcd_puts_p(const char* progmem_s){
 #ifdef GRAPHICMODE
 #pragma mark -
 #pragma mark GRAPHIC FUNCTIONS
-void lcd_drawPixel(uint8_t x, uint8_t y, uint8_t color){
+uint8_t lcd_drawPixel(uint8_t x, uint8_t y, uint8_t color){
-    if( x > DISPLAY_WIDTH-1 || y > (DISPLAY_HEIGHT-1)) return; // out of Display
+    if( x > DISPLAY_WIDTH-1 || y > (DISPLAY_HEIGHT-1)) return 1; // out of Display
+    
     if( color == WHITE){
         displayBuffer[(y / 8)][x] |= (1 << (y % 8));
     } else {
         displayBuffer[(y / 8)][x] &= ~(1 << (y % 8));
     }
+    
+    return 0;
 }
-void lcd_drawLine(uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2, uint8_t color){
+uint8_t lcd_drawLine(uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2, uint8_t color){
-    if( x1 > DISPLAY_WIDTH-1 ||
+	uint8_t result;
-       x2 > DISPLAY_WIDTH-1 ||
+	
-       y1 > DISPLAY_HEIGHT-1 ||
-       y2 > DISPLAY_HEIGHT-1) return;
     int dx =  abs(x2-x1), sx = x1<x2 ? 1 : -1;
     int dy = -abs(y2-y1), sy = y1<y2 ? 1 : -1;
     int err = dx+dy, e2; /* error value e_xy */
     
     while(1){
-        lcd_drawPixel(x1, y1, color);
+        result = lcd_drawPixel(x1, y1, color);
         if (x1==x2 && y1==y2) break;
         e2 = 2*err;
         if (e2 > dy) { err += dy; x1 += sx; } /* e_xy+e_x > 0 */
         if (e2 < dx) { err += dx; y1 += sy; } /* e_xy+e_y < 0 */
     }
+    
+    return result;
 }
-void lcd_drawRect(uint8_t px1, uint8_t py1, uint8_t px2, uint8_t py2, uint8_t color){
+uint8_t lcd_drawRect(uint8_t px1, uint8_t py1, uint8_t px2, uint8_t py2, uint8_t color){
-    if( px1 > DISPLAY_WIDTH-1 ||
+    uint8_t result;
-       px2 > DISPLAY_WIDTH-1 ||
+    
-       py1 > DISPLAY_HEIGHT-1 ||
+    result = lcd_drawLine(px1, py1, px2, py1, color);
-       py2 > DISPLAY_HEIGHT-1) return;
+    result = lcd_drawLine(px2, py1, px2, py2, color);
-    lcd_drawLine(px1, py1, px2, py1, color);
+    result = lcd_drawLine(px2, py2, px1, py2, color);
-    lcd_drawLine(px2, py1, px2, py2, color);
+    result = lcd_drawLine(px1, py2, px1, py1, color);
-    lcd_drawLine(px2, py2, px1, py2, color);
+    
-    lcd_drawLine(px1, py2, px1, py1, color);
+    return result;
 }
-void lcd_fillRect(uint8_t px1, uint8_t py1, uint8_t px2, uint8_t py2, uint8_t color){
+uint8_t lcd_fillRect(uint8_t px1, uint8_t py1, uint8_t px2, uint8_t py2, uint8_t color){
+    uint8_t result;
+    
     if( px1 > px2){
         uint8_t temp = px1;
         px1 = px2;
@@ -429,24 +434,24 @@ void lcd_fillRect(uint8_t px1, uint8_t py1, uint8_t px2, uint8_t py2, uint8_t co
         py2 = temp;
     }
     for (uint8_t i=0; i<=(py2-py1); i++){
-        lcd_drawLine(px1, py1+i, px2, py1+i, color);
+        result = lcd_drawLine(px1, py1+i, px2, py1+i, color);
     }
+    
+    return result;
 }
-void lcd_drawCircle(uint8_t center_x, uint8_t center_y, uint8_t radius, uint8_t color){
+uint8_t lcd_drawCircle(uint8_t center_x, uint8_t center_y, uint8_t radius, uint8_t color){
-    if( ((center_x + radius) > DISPLAY_WIDTH-1) ||
+    uint8_t result;
-       ((center_y + radius) > DISPLAY_HEIGHT-1) ||
+    
-       center_x < radius ||
-       center_y < radius) return;
     int16_t f = 1 - radius;
     int16_t ddF_x = 1;
     int16_t ddF_y = -2 * radius;
     int16_t x = 0;
     int16_t y = radius;
     
-    lcd_drawPixel(center_x  , center_y+radius, color);
+    result = lcd_drawPixel(center_x  , center_y+radius, color);
-    lcd_drawPixel(center_x  , center_y-radius, color);
+    result = lcd_drawPixel(center_x  , center_y-radius, color);
-    lcd_drawPixel(center_x+radius, center_y  , color);
+    result = lcd_drawPixel(center_x+radius, center_y  , color);
-    lcd_drawPixel(center_x-radius, center_y  , color);
+    result = lcd_drawPixel(center_x-radius, center_y  , color);
     
     while (x<y) {
         if (f >= 0) {
@@ -458,32 +463,36 @@ void lcd_drawCircle(uint8_t center_x, uint8_t center_y, uint8_t radius, uint8_t
         ddF_x += 2;
         f += ddF_x;
         
-        lcd_drawPixel(center_x + x, center_y + y, color);
+        result = lcd_drawPixel(center_x + x, center_y + y, color);
-        lcd_drawPixel(center_x - x, center_y + y, color);
+        result = lcd_drawPixel(center_x - x, center_y + y, color);
-        lcd_drawPixel(center_x + x, center_y - y, color);
+        result = lcd_drawPixel(center_x + x, center_y - y, color);
-        lcd_drawPixel(center_x - x, center_y - y, color);
+        result = lcd_drawPixel(center_x - x, center_y - y, color);
-        lcd_drawPixel(center_x + y, center_y + x, color);
+        result = lcd_drawPixel(center_x + y, center_y + x, color);
-        lcd_drawPixel(center_x - y, center_y + x, color);
+        result = lcd_drawPixel(center_x - y, center_y + x, color);
-        lcd_drawPixel(center_x + y, center_y - x, color);
+        result = lcd_drawPixel(center_x + y, center_y - x, color);
-        lcd_drawPixel(center_x - y, center_y - x, color);
+        result = lcd_drawPixel(center_x - y, center_y - x, color);
     }
+    return result;
 }
-void lcd_fillCircle(uint8_t center_x, uint8_t center_y, uint8_t radius, uint8_t color) {
+uint8_t lcd_fillCircle(uint8_t center_x, uint8_t center_y, uint8_t radius, uint8_t color) {
+    uint8_t result;
     for(uint8_t i=0; i<= radius;i++){
-        lcd_drawCircle(center_x, center_y, i, color);
+        result = lcd_drawCircle(center_x, center_y, i, color);
     }
+    return result;
 }
-void lcd_drawBitmap(uint8_t x, uint8_t y, const uint8_t *picture, uint8_t width, uint8_t height, uint8_t color){
+uint8_t lcd_drawBitmap(uint8_t x, uint8_t y, const uint8_t *picture, uint8_t width, uint8_t height, uint8_t color){
-    uint8_t i,j, byteWidth = (width+7)/8;
+    uint8_t result,i,j, byteWidth = (width+7)/8;
     for (j = 0; j < height; j++) {
         for(i=0; i < width;i++){
             if(pgm_read_byte(picture + j * byteWidth + i / 8) & (128 >> (i & 7))){
-                lcd_drawPixel(x+i, y+j, color);
+                result = lcd_drawPixel(x+i, y+j, color);
             } else {
-                lcd_drawPixel(x+i, y+j, !color);
+                result = lcd_drawPixel(x+i, y+j, !color);
             }
         }
     }
+    return result;
 }
 void lcd_display() {
 #if defined (SSD1306) || defined (SSD1309)

lcd.h

@@ -69,7 +69,7 @@ extern "C" {
     
     // using 7-bit-adress for lcd-library
     // if you use your own library for twi check I2C-adress-handle
-#define LCD_I2C_ADR         (0x7a >> 1)    // 7 bit slave-adress without r/w-bit
+#define LCD_I2C_ADR         (0x78 >> 1)    // 7 bit slave-adress without r/w-bit
     // r/w-bit are set/unset by library
     // e.g. 8 bit slave-adress:
     // 0x78 = adress 0x3C with cleared r/w-bit (write-mode)
@@ -130,13 +130,13 @@ extern "C" {
     // at GRAPHICMODE print character to buffer
     void lcd_charMode(uint8_t mode);            // set size of chars
 #if defined GRAPHICMODE
-    void lcd_drawPixel(uint8_t x, uint8_t y, uint8_t color);
+    uint8_t lcd_drawPixel(uint8_t x, uint8_t y, uint8_t color);
-    void lcd_drawLine(uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2, uint8_t color);
+    uint8_t lcd_drawLine(uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2, uint8_t color);
-    void lcd_drawRect(uint8_t px1, uint8_t py1, uint8_t px2, uint8_t py2, uint8_t color);
+    uint8_t lcd_drawRect(uint8_t px1, uint8_t py1, uint8_t px2, uint8_t py2, uint8_t color);
-    void lcd_fillRect(uint8_t px1, uint8_t py1, uint8_t px2, uint8_t py2, uint8_t color);
+    uint8_t lcd_fillRect(uint8_t px1, uint8_t py1, uint8_t px2, uint8_t py2, uint8_t color);
-    void lcd_drawCircle(uint8_t center_x, uint8_t center_y, uint8_t radius, uint8_t color);
+    uint8_t lcd_drawCircle(uint8_t center_x, uint8_t center_y, uint8_t radius, uint8_t color);
-    void lcd_fillCircle(uint8_t center_x, uint8_t center_y, uint8_t radius, uint8_t color);
+    uint8_t lcd_fillCircle(uint8_t center_x, uint8_t center_y, uint8_t radius, uint8_t color);
-    void lcd_drawBitmap(uint8_t x, uint8_t y, const uint8_t picture[], uint8_t width, uint8_t height, uint8_t color);
+    uint8_t lcd_drawBitmap(uint8_t x, uint8_t y, const uint8_t picture[], uint8_t width, uint8_t height, uint8_t color);
     void lcd_display(void);                // copy buffer to display RAM
     void lcd_clear_buffer(void); // clear display buffer
     uint8_t lcd_check_buffer(uint8_t x, uint8_t y); // read a pixel value from the display buffer

readme.md

@@ -24,7 +24,7 @@ Memory:
   </tr>
   <tr>
     <td>I2C-Core</td>
-    <td>234 Bytes</td>
+    <td>220 Bytes</td>
     <td>0 Bytes</td>
   </tr>
   <tr>
@@ -34,12 +34,12 @@ Memory:
   </tr>
   <tr>
     <td>OLED (Text-Mode)</td>
-    <td>1449 Bytes</td>
+    <td>1395 Bytes</td>
     <td>3 Bytes</td>
   </tr>
   <tr>
     <td>OLED (Graphic-Mode)</td>
-    <td>2403 Bytes</td>
+    <td>2541 Bytes</td>
     <td>1027 Bytes</td>
   </tr>
  </table>