add sRGB pixel formats to the HALs
Change-Id: I1d5f9dd14a6485dd3a29fb5960edfa79aa86da42
diff --git a/include/system/graphics.h b/include/system/graphics.h
index ed493f5..2ddcc08 100644
--- a/include/system/graphics.h
+++ b/include/system/graphics.h
@@ -42,6 +42,13 @@
*/
enum {
+ /*
+ * "linear" color pixel formats:
+ *
+ * The pixel formats below contain sRGB data but are otherwise treated
+ * as linear formats, i.e.: no special operation is performed when
+ * reading or writing into a buffer in one of these formats
+ */
HAL_PIXEL_FORMAT_RGBA_8888 = 1,
HAL_PIXEL_FORMAT_RGBX_8888 = 2,
HAL_PIXEL_FORMAT_RGB_888 = 3,
@@ -50,7 +57,27 @@
HAL_PIXEL_FORMAT_RGBA_5551 = 6,
HAL_PIXEL_FORMAT_RGBA_4444 = 7,
- /* 0x8 - 0xFF range unavailable */
+ /*
+ * sRGB color pixel formats:
+ *
+ * The red, green and blue components are stored in sRGB space, and converted
+ * to linear space when read, using the standard sRGB to linear equation:
+ *
+ * Clinear = Csrgb / 12.92 for Csrgb <= 0.04045
+ * = (Csrgb + 0.055 / 1.055)^2.4 for Csrgb > 0.04045
+ *
+ * When written the inverse transformation is performed:
+ *
+ * Csrgb = 12.92 * Clinear for Clinear <= 0.0031308
+ * = 1.055 * Clinear^(1/2.4) - 0.055 for Clinear > 0.0031308
+ *
+ *
+ * The alpha component, if present, is always stored in linear space and
+ * is left unmodified when read or written.
+ *
+ */
+ HAL_PIXEL_FORMAT_sRGB_A_8888 = 0xC,
+ HAL_PIXEL_FORMAT_sRGB_888 = 0xD,
/*
* 0x100 - 0x1FF