C API: add sk_xfermode.h, impl, test
Review URL: https://codereview.chromium.org/1242403005
diff --git a/tests/CTest.cpp b/tests/CTest.cpp
index 413f629..acab4bb 100644
--- a/tests/CTest.cpp
+++ b/tests/CTest.cpp
@@ -32,6 +32,11 @@
sk_canvas_draw_paint(canvas, paint);
REPORTER_ASSERT(reporter, 0xFFFFFFFF == pixel[0]);
+ sk_paint_set_xfermode_mode(paint, SRC_SK_XFERMODE_MODE);
+ sk_paint_set_color(paint, sk_color_set_argb(0x80, 0x80, 0x80, 0x80));
+ sk_canvas_draw_paint(canvas, paint);
+ REPORTER_ASSERT(reporter, 0x80404040 == pixel[0]);
+
sk_paint_delete(paint);
sk_surface_unref(surface);
}