IO: Invert OLED example

gohai · gohai · commit 5ff162e20a86 · 2017-04-05T14:52:22.000+02:00
This makes bright pixels be illuminated on the display.
diff --git a/java/libraries/io/examples/I2CScreen/I2CScreen.pde b/java/libraries/io/examples/I2CScreen/I2CScreen.pde
@@ -14,7 +14,8 @@ void setup() {
 }
 
 void draw() {
-  background(255);
+  background(0);
+  stroke(255);
   line(0, 0, 127, 63);
   line(0, 63, 127, 0);
   oled.sendImage(get());
diff --git a/java/libraries/io/examples/I2CScreen/SSD1306.pde b/java/libraries/io/examples/I2CScreen/SSD1306.pde
@@ -61,7 +61,7 @@ class SSD1306 extends I2C {
     img.loadPixels();
     for (int y=startY; y < height && y-startY < 64; y++) {
       for (int x=startX; x < width && x-startX < 128; x++) {
-        if (brightness(img.pixels[y*img.width+x]) < 128) {
+        if (128 <= brightness(img.pixels[y*img.width+x])) {
           // this isn't the normal (scanline) mapping, but 8 pixels below each other at a time
           // white pixels have their bit turned on
           frame[x + (y/8)*128] |= (1 << (y % 8));
