Add pixman_color_space_t

This differentiates pixel data from just having a format code to having
a pixel layout - pixman_format_code_t - and color space -
pixman_color_space_t.
No new formats were added, only the option to create unmultiplied ARGB
images exists now.

In the future the general code path will look like this:
Each colorspace provides a "canonical" format. pixman-access.c will
provide accessors to read/write data from/to the image representation to
the canonical format. Additional functions that convert between
different color spaces will be added. These will be called from the
generic store/fetch paths, so the accessors do not need to care about
the color space.

As a first step, compositing will still be done in ARGB, so the general
path will look like this:
 src => fetch => convert \
                          > combine => convert => store => dest
dest => fetch => convert /

Benefits of this approach for adding more formats:
- Minimal changes required to current code.
  With a simple check of the color space, all optimizations can continue
  working with a minimal performance impact. Even in the general case
  optimized store/fetch functions can be used.
- Ease of optimization for common paths
  Common cases can be optimized easily. For example, Pixel-aligned
  rectangular fills with PIXMAN_OP_SRC and the same color space can
  be done with:
  src => fetch => store => dest
  and not a lot of code is required to do this.
- Extensibility
  More color spaces can easily be added later, possibly even making use
  of the same accessors for data storage, i.e. linear RGB, more color
  matrices for YCbCr or even CMYK.

1 files changed, 9 insertions, 0 deletions

diff --git a/pixman/pixman.h b/pixman/pixman.h
index 89ce899..f483163 100644
--- a/pixman/pixman.h
+++ b/pixman/pixman.h
@@ -709,6 +709,14 @@ typedef enum {
     PIXMAN_yv12 =	 PIXMAN_FORMAT(12,PIXMAN_TYPE_YV12,0,0,0,0)
 } pixman_format_code_t;
 
+typedef enum {
+    PIXMAN_COLOR_SPACE_ARGB,
+    PIXMAN_COLOR_SPACE_ARGB_UNMULTIPLIED,
+    PIXMAN_COLOR_SPACE_YCBCR_HD,
+    PIXMAN_COLOR_SPACE_YCBCR_SD,
+    PIXMAN_COLOR_SPACE_YCBCR_JPEG
+} pixman_color_space_t;
+
 /* Querying supported format values. */
 pixman_bool_t pixman_format_supported_destination (pixman_format_code_t format);
 pixman_bool_t pixman_format_supported_source      (pixman_format_code_t format);
@@ -736,6 +744,7 @@ pixman_image_t *pixman_image_create_bits             (pixman_format_code_t
 						      uint32_t                     *bits,
 						      int                           rowstride_bytes);
 pixman_image_t *pixman_image_create_planar           (pixman_format_code_t          format,
+                                                      pixman_color_space_t         color_space,
 						      int                           width,
 						      int                           height,
                                                       unsigned int                  num_planes,