samples: drivers: display: Add support for AL_88 color

Renders three different shades of gray in each corner, with one corner
continually changing color.

Signed-off-by: Martin Stumpf <[email protected]>

Author: Finomnis

samples/drivers/display/src/main.c

@@ -165,6 +165,34 @@ static inline void fill_buffer_l_8(enum corner corner, uint8_t grey, uint8_t *bu
 	}
 }
 
+static void fill_buffer_al_88(enum corner corner, uint8_t grey, uint8_t *buf,
+				 size_t buf_size)
+{
+	uint16_t color;
+
+	switch (corner) {
+	case TOP_LEFT:
+		color = 0xFF00u;
+		break;
+	case TOP_RIGHT:
+		color = 0xFFFFu;
+		break;
+	case BOTTOM_RIGHT:
+		color = 0xFF88u;
+		break;
+	case BOTTOM_LEFT:
+		color = 0xFF00u | grey;
+		break;
+	default:
+		color = 0;
+		break;
+	}
+
+	for (size_t idx = 0; idx < buf_size; idx += 2) {
+		*((uint16_t *)(buf + idx)) = color;
+	}
+}
+
 static inline void fill_buffer_mono01(enum corner corner, uint8_t grey,
 				      uint8_t *buf, size_t buf_size)
 {
@@ -273,6 +301,11 @@ int main(void)
 		bg_color = 0xFFu;
 		fill_buffer_fnc = fill_buffer_l_8;
 		break;
+	case PIXEL_FORMAT_AL_88:
+		bg_color = 0x00u;
+		fill_buffer_fnc = fill_buffer_al_88;
+		buf_size *= 2;
+		break;
 	case PIXEL_FORMAT_MONO01:
 		bg_color = 0xFFu;
 		fill_buffer_fnc = fill_buffer_mono01;