1 files changed, 58 insertions, 0 deletions
diff --git a/img_mono.c b/img_mono.c
new file mode 100644
index 0000000..b711a6b
--- /dev/null
+++ b/img_mono.c
@@ -0,0 +1,58 @@
+#include <math.h>
+#include "libleds.h"
+#include "img_mono.xbm"
+
+static char const PORT = 0;
+static char const PINS = 1<<7;
+
+char const is_active(unsigned int const n)
+{
+	/*
+	 * The first led is in the top left corner.
+	 * After that it goes down the column, then up the next and so on.
+	 *
+	 * This means all columns with an even index count down.
+	 * Those with an odd index count up.
+	 *
+	 *
+	 * With a height of 8 the led numbers would look like this:
+	 *
+	 * 00  0F  10  1F  20  ...
+	 * 01  0E  11  1E  21  ...
+	 * 02  0D  12  1D  ...
+	 * 03  0C  13  1C  ...
+	 * 04  0B  14  1B  ...
+	 * 05  0A  15  1A  ...
+	 * 06  09  16  19  ...
+	 * 07  08  17  18  ...
+	 */
+
+	unsigned int const bytes_per_row = ceil(img_width / 8.0);
+	unsigned int col = n / img_height;
+	unsigned int row = n % img_height;
+	if (col % 2)
+		row = img_height - 1 - row;
+	
+	// calculate byte to access
+	unsigned int byte = row * bytes_per_row;
+	byte += col / 8;
+
+	unsigned char data = img_bits[byte];
+	unsigned char mask = 1<<(col % 8);
+	return data & mask;
+}
+
+void led_main()
+{
+	const int length = img_width * img_height;
+
+	struct led_color pixel[length];
+
+	for (unsigned int i = 0; i < length; i++) {
+		unsigned char out = is_active(i) ? 0xFF : 0x00;
+		pixel[i] = (struct led_color){out, out, out};
+	}
+
+	for (unsigned int i = 0; i < length; i++)
+		led_write_rgb(PORT, PINS, pixel[i]);
+}