add asComponentTable() query (will impl in SkTableColorFilter next)

git-svn-id: http://skia.googlecode.com/svn/trunk@2971 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 18 insertions, 0 deletions

diff --git a/include/core/SkColorFilter.h b/include/core/SkColorFilter.h
index 6328e706cb..97db5cc546 100644
--- a/include/core/SkColorFilter.h
+++ b/include/core/SkColorFilter.h
@@ -30,6 +30,24 @@ public:
      */
     virtual bool asColorMatrix(SkScalar matrix[20]);
 
+    /**
+     *  If the filter can be represented by per-component table, return true,
+     *  and if table is not null, copy the bitmap containing the table into it.
+     *
+     *  The table bitmap will be in SkBitmap::kA8_Config. Each row corresponding
+     *  to each component in ARGB order. e.g. row[0] == alpha, row[1] == red,
+     *  etc. To transform a color, you (logically) perform the following:
+     *
+     *      a' = *table.getAddr8(a, 0);
+     *      r' = *table.getAddr8(r, 1);
+     *      g' = *table.getAddr8(g, 2);
+     *      b' = *table.getAddr8(b, 3);
+     *
+     *  The original component value is the horizontal index for a given row,
+     *  and the stored value at that index is the new value for that component.
+     */
+    virtual bool asComponentTable(SkBitmap* table);
+
     /** Called with a scanline of colors, as if there was a shader installed.
         The implementation writes out its filtered version into result[].
         Note: shader and result may be the same buffer.