Call initializeColorXform inside SkCodec

Make initializeColorXform private, and only call in the base class.
Add virtual method to skip initializeColorXform, for classes that do
not need one.

Change SkCodec::FrameInfo's SkAlphaType to an SkEncodedInfo::Alpha.
This allows proper checking internally whether SkCodec needs to do a
color correct premultiply.

Depends on https://chromium-review.googlesource.com/c/620947, for this
API change.

(Separated from review.skia.org/25746)

Bug: skia:5609
Bug: skia:6839
Change-Id: Icb0d46659c546060c34d32eaf792c86708726c7a
Reviewed-on: https://skia-review.googlesource.com/35880
Reviewed-by: Chris Blume <cblume@chromium.org>
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/src/codec/SkPngCodec.cpp b/src/codec/SkPngCodec.cpp
index c5dae3ed4a..08f23dddea 100644
--- a/src/codec/SkPngCodec.cpp
+++ b/src/codec/SkPngCodec.cpp
@@ -263,7 +263,8 @@ bool SkPngCodec::createColorTable(const SkImageInfo& dstInfo) {
     if (png_get_tRNS(fPng_ptr, fInfo_ptr, &alphas, &numColorsWithAlpha, nullptr)) {
         // If we are performing a color xform, it will handle the premultiply.  Otherwise,
         // we'll do it here.
-        bool premultiply = !this->colorXform() && needs_premul(dstInfo, this->getEncodedInfo());
+        bool premultiply = !this->colorXform() && needs_premul(dstInfo.alphaType(),
+                                                               this->getEncodedInfo().alpha());
 
         // Choose which function to use to create the color table. If the final destination's
         // colortype is unpremultiplied, the color table will store unpremultiplied colors.
@@ -980,10 +981,6 @@ SkCodec::Result SkPngCodec::initializeXforms(const SkImageInfo& dstInfo, const O
     // interlaced scanline decoder may need to rewind.
     fSwizzler.reset(nullptr);
 
-    if (!this->initializeColorXform(dstInfo, options.fPremulBehavior)) {
-        return kInvalidConversion;
-    }
-
     // If SkColorSpaceXform directly supports the encoded PNG format, we should skip format
     // conversion in the swizzler (or skip swizzling altogether).
     bool skipFormatConversion = false;