Add SkCodec methods for individual frames

Add a version of getFrameInfo that returns information about a single
frame, allowing a client to skip creating the entire vector.

Add getFrameCount, for determining the number of frames in the image.

Reimplement std::vector<FrameInfo> getFrameInfo with the new methods.

Updates to the test:
- getFrameInfo(size_t, FrameInfo*) fails before parsing
- Test both versions of getFrameInfo
- Recreate the codec between tests, to test parsing

Change-Id: I77c19087f2f8dcf2c536d80167b18ad1ca96ae94
Reviewed-on: https://skia-review.googlesource.com/13190
Reviewed-by: Matt Sarett <msarett@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Chris Blume <cblume@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/src/codec/SkCodec.cpp b/src/codec/SkCodec.cpp
index 5bdb3e2b59..6a6fdc78c9 100644
--- a/src/codec/SkCodec.cpp
+++ b/src/codec/SkCodec.cpp
@@ -489,3 +489,24 @@ bool SkCodec::initializeColorXform(const SkImageInfo& dstInfo,
 
     return true;
 }
+
+std::vector<SkCodec::FrameInfo> SkCodec::getFrameInfo() {
+    const size_t frameCount = this->getFrameCount();
+    switch (frameCount) {
+        case 0:
+            return std::vector<FrameInfo>{};
+        case 1:
+            if (!this->onGetFrameInfo(0, nullptr)) {
+                // Not animated.
+                return std::vector<FrameInfo>{};
+            }
+            // fall through
+        default: {
+            std::vector<FrameInfo> result(frameCount);
+            for (size_t i = 0; i < frameCount; ++i) {
+                SkAssertResult(this->onGetFrameInfo(i, &result[i]));
+            }
+            return result;
+        }
+    }
+}