add tool_util to compare images

Bug: skia:
Change-Id: I826190aa15cf42a3ca7f3c7d5271ead5b514c116
Reviewed-on: https://skia-review.googlesource.com/32220
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/tools/sk_tool_utils.h b/tools/sk_tool_utils.h
index ea06c119e7..dc8c8c10a0 100644
--- a/tools/sk_tool_utils.h
+++ b/tools/sk_tool_utils.h
@@ -91,6 +91,17 @@ namespace sk_tool_utils {
      */
     void write_pixels(SkCanvas*, const SkBitmap&, int x, int y, SkColorType, SkAlphaType);
 
+    /**
+     *  Returns true iff all of the pixels between the two images differ by <= the maxDiff value
+     *  per component.
+     *
+     *  If the configs differ, return false.
+     *
+     *  If the colorType is half-float, then maxDiff is interpreted as 0..255 --> 0..1
+     */
+    bool equal_pixels(const SkPixmap&, const SkPixmap&, unsigned maxDiff = 0);
+    bool equal_pixels(const SkBitmap&, const SkBitmap&, unsigned maxDiff = 0);
+
     // private to sk_tool_utils
     sk_sp<SkTypeface> create_font(const char* name, SkFontStyle);