Merge pull request #110 from recallmenot/SSD1306_drawimage

SSD1306 drawImage

examples/i2c_oled/bomb.h

+/*
+The bomb illustration has been drawn and provided by [DoubleWaffleCakes](https://www.reddit.com/user/DoubleWaffleCakes/).  
+*/
+const unsigned char bomb_i_stripped[] = {
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x00,
+  0x00, 0x00, 0x12, 0x00, 0x00, 0x00, 0x24, 0x00, 0x00, 0x00, 0x48, 0x00,
+  0x00, 0x00, 0x50, 0x00, 0x00, 0x00, 0xf8, 0x00, 0x00, 0x03, 0xfe, 0x00,
+  0x00, 0x0f, 0xff, 0x80, 0x00, 0x1f, 0xff, 0xc0, 0x00, 0x1f, 0xff, 0xc0,
+  0x00, 0x3f, 0xff, 0xe0, 0x00, 0x3f, 0xff, 0xe0, 0x00, 0x73, 0x9f, 0xf0,
+  0x00, 0x73, 0x9f, 0xf0, 0x00, 0x73, 0x9f, 0xf0, 0x00, 0x73, 0x9f, 0xf0,
+  0x00, 0x73, 0x9f, 0xf0, 0x00, 0x3f, 0xff, 0xe0, 0x00, 0x3f, 0xff, 0xe0,
+  0x00, 0x1f, 0xff, 0xc0, 0x00, 0x1f, 0xff, 0xc0, 0x00, 0x0f, 0xff, 0x80,
+  0x00, 0x13, 0xe0, 0x40, 0x00, 0x20, 0xc0, 0x20, 0x00, 0x7f, 0xff, 0xe0,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+};
+const unsigned int bomb_i_stripped_len = 128;

examples/i2c_oled/i2c_oled.c

@@ -17,6 +17,8 @@
 #include "ssd1306_i2c.h"
 #include "ssd1306.h"
 
+#include "bomb.h"
+
 int main()
 {
 	// 48MHz internal clock
@@ -42,7 +44,7 @@ int main()
 		printf("Looping on test modes...");
 		while(1)
 		{
-			for(uint8_t mode=0;mode<(SSD1306_H>32?8:7);mode++)
+			for(uint8_t mode=0;mode<(SSD1306_H>32?9:8);mode++)
 			{
 				// clear buffer for next mode
 				ssd1306_setbuf(0);
@@ -85,8 +87,11 @@ int main()
 							else
 								ssd1306_fillCircle(x, SSD1306_H/2, 15, 1);
 						break;
-					
 					case 4:
+						printf("Image\n\r");
+						ssd1306_drawImage(0, 0, bomb_i_stripped, 32, 32, 0);
+						break;
+					case 5:
 						printf("Unscaled Text\n\r");
 						ssd1306_drawstr(0,0, "This is a test", 1);
 						ssd1306_drawstr(0,8, "of the emergency", 1);
@@ -102,19 +107,19 @@ int main()
 						ssd1306_xorrect(SSD1306_W/2, 0, SSD1306_W/2, SSD1306_W);
 						break;
 						
-					case 5:
+					case 6:
 						printf("Scaled Text 1, 2\n\r");
 						ssd1306_drawstr_sz(0,0, "sz 8x8", 1, fontsize_8x8);
 						ssd1306_drawstr_sz(0,16, "16x16", 1, fontsize_16x16);
 						break;
 					
-					case 6:
+					case 7:
 						printf("Scaled Text 4\n\r");
 						ssd1306_drawstr_sz(0,0, "32x32", 1, fontsize_32x32);
 						break;
 					
 					
-					case 7:
+					case 8:
 						printf("Scaled Text 8\n\r");
 						ssd1306_drawstr_sz(0,0, "64", 1, fontsize_64x64);
 						break;

examples/i2c_oled/ssd1306.h

@@ -240,6 +240,77 @@ void ssd1306_xorPixel(uint8_t x, uint8_t y)
 	ssd1306_buffer[addr] ^= (1<<(y&7));
 }
 
+/*
+ * draw a an image from an array, directly into to the display buffer
+ * the color modes allow for overwriting and even layering (sprites!)
+ */
+void ssd1306_drawImage(uint8_t x, uint8_t y, const unsigned char* input, uint8_t width, uint8_t height, uint8_t color_mode) {
+	uint8_t x_absolute;
+	uint8_t y_absolute;
+	uint8_t pixel;
+	uint8_t bytes_to_draw = width / 8;
+	uint16_t buffer_addr;
+
+	for (uint8_t line = 0; line < height; line++) {
+		y_absolute = y + line;
+		if (y_absolute >= SSD1306_H) {
+			break;
+		}
+
+		// SSD1306 is in vertical mode, yet we want to draw horizontally, which necessitates assembling the output bytes from the input data
+		// bitmask for current pixel in vertical (output) byte
+		uint8_t v_mask = 1 << (y_absolute & 7);
+
+		for (uint8_t byte = 0; byte < bytes_to_draw; byte++) {
+			uint8_t input_byte = input[byte + line * bytes_to_draw];
+
+			for (pixel = 0; pixel < 8; pixel++) {
+				x_absolute = x + 8 * (bytes_to_draw - byte) + pixel;
+				if (x_absolute >= SSD1306_W) {
+					break;
+				}
+				// looking at the horizontal display, we're drawing bytes bottom to top, not left to right, hence y / 8
+				buffer_addr = x_absolute + SSD1306_W * (y_absolute / 8);
+				// state of current pixel
+				uint8_t input_pixel = input_byte & (1 << pixel);
+
+				switch (color_mode) {
+					case 0:
+						// write pixels as they are
+						ssd1306_buffer[buffer_addr] = (ssd1306_buffer[buffer_addr] & ~v_mask) | (input_pixel ? v_mask : 0);
+						break;
+					case 1:
+						// write pixels after inversion
+						ssd1306_buffer[buffer_addr] = (ssd1306_buffer[buffer_addr] & ~v_mask) | (!input_pixel ? v_mask : 0);
+						break;
+					case 2:
+						// 0 clears pixel
+						ssd1306_buffer[buffer_addr] &= input_pixel ? 0xFF : ~v_mask;
+						break;
+					case 3:
+						// 1 sets pixel
+						ssd1306_buffer[buffer_addr] |= input_pixel ? v_mask : 0;
+						break;
+					case 4:
+						// 0 sets pixel
+						ssd1306_buffer[buffer_addr] |= !input_pixel ? v_mask : 0;
+						break;
+					case 5:
+						// 1 clears pixel
+						ssd1306_buffer[buffer_addr] &= input_pixel ? ~v_mask : 0xFF;
+						break;
+				}
+			}
+			#if SSD1306_LOG_IMAGE == 1
+			printf("%02x ", input_byte);
+			#endif
+		}
+		#if SSD1306_LOG_IMAGE == 1
+		printf("\n\r");
+		#endif
+	}
+}
+
 /*
  *  fast vert line
  */