2 * Copyright 2017 Google Inc.
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
8 #ifndef SkPngPriv_DEFINED
9 #define SkPngPriv_DEFINED
11 #include "include/core/SkTypes.h"
13 // We store kAlpha_8 images as GrayAlpha in png. Our private signal is significant bits for gray.
14 // If that is set to 1, we assume the gray channel can be ignored, and we output just alpha.
15 // We tried 0 at first, but png doesn't like a 0 sigbit for a channel it expects, hence we chose 1.
17 static constexpr int kGraySigBit_GrayAlphaIsJustAlpha = 1;