Reland "Hide SkEncodedInfo"

This partially reverts commit
1793e7bb46c1f9d430c1a699a1c3d3168159b659.

Hide SkEncodedInfo

Bug: skia:7353
Bug: skia:6839

This contains information that is not necessary for clients to know. The
Color enum tells the number of components in the input, but this is only
interesting internally (to the SkSwizzler).

Similarly, the Alpha enum differs from SkAlphaType in that it has
kBinary instead of kPremul. This is useful information only internally
for determining whether the SkColorSpaceXform needs to premultiply.

The bitsPerComponent is potentially useful for a client; Android (in
SkAndroidCodec) uses it to determine the SkColorType. Rather than
exposing bitsPerComponent, make SkAndroidCodec a friend so it can
access the SkEncodedInfo. A future change will change SkCodec to
recommend F16 for bitsPerComponent > 8, but that will be more involved;
it was the reason for the revert of this CL.

Switch conversionSupported to use an SkColorType, which is enough info.

Replace the SkEncodedInfo::Alpha field on SkCodec::FrameInfo with an
SkAlphaType.

SkCodec still needs an SkEncodedInfo, so move its header (which is
already not SK_API) to include/private.

TBR=mtklein@chromium.org,reed@google.com
Change-Id: I928b1f55317602cb37d29da63b53026c8d139cee
Reviewed-on: https://skia-review.googlesource.com/80860
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>

2 files changed, 5 insertions, 4 deletions

diff --git a/third_party/gif/SkGifImageReader.cpp b/third_party/gif/SkGifImageReader.cpp
index a54fb59d3b..a04f8e11d0 100644
--- a/third_party/gif/SkGifImageReader.cpp
+++ b/third_party/gif/SkGifImageReader.cpp
@@ -879,15 +879,16 @@ static bool restore_bg(const SkFrame& frame) {
     return frame.getDisposalMethod() == SkCodecAnimation::DisposalMethod::kRestoreBGColor;
 }
 
-bool SkGIFFrameContext::onReportsAlpha() const {
+SkEncodedInfo::Alpha SkGIFFrameContext::onReportedAlpha() const {
     // Note: We could correct these after decoding - i.e. some frames may turn out to be
     // independent and opaque if they do not use the transparent pixel, but that would require
     // checking whether each pixel used the transparent index.
-    return is_palette_index_valid(this->transparentPixel());
+    return is_palette_index_valid(this->transparentPixel()) ? SkEncodedInfo::kBinary_Alpha
+                                                            : SkEncodedInfo::kOpaque_Alpha;
 }
 
 void SkFrameHolder::setAlphaAndRequiredFrame(SkFrame* frame) {
-    const bool reportsAlpha = frame->reportsAlpha();
+    const bool reportsAlpha = frame->reportedAlpha() != SkEncodedInfo::kOpaque_Alpha;
     const auto screenRect = SkIRect::MakeWH(fScreenWidth, fScreenHeight);
     const auto frameRect = frame_rect_on_screen(frame->frameRect(), screenRect);
 
diff --git a/third_party/gif/SkGifImageReader.h b/third_party/gif/SkGifImageReader.h
index b5eca10dfb..5d8597fccf 100644
--- a/third_party/gif/SkGifImageReader.h
+++ b/third_party/gif/SkGifImageReader.h
@@ -247,7 +247,7 @@ public:
     SkGIFColorMap& localColorMap() { return m_localColorMap; }
 
 protected:
-    bool onReportsAlpha() const override;
+    SkEncodedInfo::Alpha onReportedAlpha() const override;
 
 private:
     int m_transparentPixel; // Index of transparent pixel. Value is kNotFound if there is no transparent pixel.