Merge pull request #5 from PaulKlinger/master

Some simple functions for manipulating display buffer/partial updates

lcd.c

@@ -155,8 +155,11 @@ void lcd_init(uint8_t dispAttr){
     lcd_clrscr();
 }
 void lcd_gotoxy(uint8_t x, uint8_t y){
-    if( x > (DISPLAY_WIDTH/sizeof(FONT[0])) || y > (DISPLAY_HEIGHT/8-1)) return;// out of display
     x = x * sizeof(FONT[0]);
+    lcd_goto_xpix_y(x,y);
+}
+void lcd_goto_xpix_y(uint8_t x, uint8_t y){
+    if( x > (DISPLAY_WIDTH) || y > (DISPLAY_HEIGHT/8-1)) return;// out of display
     cursorPosition.x=x;
     cursorPosition.y=y;
 #if defined (SSD1306) || defined (SSD1309)
@@ -488,4 +491,21 @@ void lcd_display() {
     }
 #endif
 }
+void lcd_clear_buffer() {
+    for (uint8_t i = 0; i < DISPLAY_HEIGHT/8; i++){
+        memset(displayBuffer[i], 0x00, sizeof(displayBuffer[i]));
+    }
+}
+uint8_t lcd_check_buffer(uint8_t x, uint8_t y) {
+    if( x > DISPLAY_WIDTH-1 || y > (DISPLAY_HEIGHT-1)) return 0; // out of Display
+    return displayBuffer[(y / (DISPLAY_HEIGHT/8))][x] & (1 << (y % (DISPLAY_HEIGHT/8)));
+}
+void lcd_display_block(uint8_t x, uint8_t line, uint8_t width) {
+    if (line > (DISPLAY_HEIGHT/8-1) || x > DISPLAY_WIDTH - 1){return;}
+    if (x + width > DISPLAY_WIDTH) { // no -1 here, x alone is width 1
+        width = DISPLAY_WIDTH - x;
+    }
+    lcd_goto_xpix_y(x,line);
+    lcd_data(&displayBuffer[line][x], width);
+}
 #endif

lcd.h

@@ -124,6 +124,8 @@ extern "C" {
     void lcd_clrscr(void);                // clear screen (and buffer at GRFAICMODE)
     void lcd_gotoxy(uint8_t x, uint8_t y);        // set curser at pos x, y. x means character,
     // y means line (page, refer lcd manual)
+    void lcd_goto_xpix_y(uint8_t x, uint8_t y); // set curser at pos x, y. x means pixel,
+    // y means line (page, refer lcd manual)
     void lcd_putc(char c);                // print character on screen at TEXTMODE
     // at GRAPHICMODE print character to buffer
     void lcd_charMode(uint8_t mode);            // set size of chars
@@ -136,6 +138,9 @@ extern "C" {
     void 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);
     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
+    void lcd_display_block(uint8_t x, uint8_t line, uint8_t width); // display (part of) a display line
 #endif
     
 #ifdef __cplusplus