Change behavior of custom image serial/deserial

New behavior is to *always* call the client's deserial image proc for all data.
This allows the client to make decisions even on "std" image data like PNG.

The change also means that if there is no client deserial image proc, Skia will
still attempt to create an image from the data, even if it was written by a
custom serial proc.

Bug: skia:7706
Change-Id: Ia58bdd10b86d497f02187082c6373c029e9c8293
Reviewed-on: https://skia-review.googlesource.com/113302
Reviewed-by: Florin Malita <fmalita@chromium.org>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Mike Reed <reed@google.com>

2 files changed, 18 insertions, 6 deletions

diff --git a/include/core/SkPicture.h b/include/core/SkPicture.h
index b2beb56b86..1a5ecb360b 100644
--- a/include/core/SkPicture.h
+++ b/include/core/SkPicture.h
@@ -168,10 +168,11 @@ private:
     // V59: No more LocalSpace option on PictureImageFilter
     // V60: Remove flags in picture header
     // V61: Change SkDrawPictureRec to take two colors rather than two alphas
+    // V62: Don't negate size of custom encoded images (don't write origin x,y either)
 
     // Only SKPs within the min/current picture version range (inclusive) can be read.
     static const uint32_t     MIN_PICTURE_VERSION = 56;     // august 2017
-    static const uint32_t CURRENT_PICTURE_VERSION = 61;
+    static const uint32_t CURRENT_PICTURE_VERSION = 62;
 
     static bool IsValidPictInfo(const SkPictInfo& info);
     static sk_sp<SkPicture> Forwardport(const SkPictInfo&,
diff --git a/include/core/SkSerialProcs.h b/include/core/SkSerialProcs.h
index 0c20f08b5c..e5a886a332 100644
--- a/include/core/SkSerialProcs.h
+++ b/include/core/SkSerialProcs.h
@@ -18,7 +18,7 @@
  *  If null is returned, then Skia will take its default action.
  *
  *  The default action for pictures is to use Skia's internal format.
- *  The default action for images is to encode using PNG.
+ *  The default action for images is to encode either in its native format or PNG.
  *  The default action for typefaces is to use Skia's internal format.
  */
 
@@ -27,13 +27,24 @@ typedef sk_sp<SkData> (*SkSerialImageProc)(SkImage*, void* ctx);
 typedef sk_sp<SkData> (*SkSerialTypefaceProc)(SkTypeface*, void* ctx);
 
 /**
- *  A deserial-proc is given the serialized form previously returned by the corresponding
- *  serial-proc, and should return the re-constituted object. In case of an error, the proc
- *  can return nullptr.
+ *  Called with the encoded form of a picture (previously written with a custom
+ *  SkSerialPictureProc proc). Return a picture object, or nullptr indicating failure.
  */
-
 typedef sk_sp<SkPicture> (*SkDeserialPictureProc)(const void* data, size_t length, void* ctx);
+
+/**
+ *  Called with the encoded from of an image. The proc can return an image object, or if it
+ *  returns nullptr, then Skia will take its default action to try to create an image from the data.
+ *
+ *  Note that unlike SkDeserialPictureProc and SkDeserialTypefaceProc, return nullptr from this
+ *  does not indicate failure, but is a signal for Skia to take its default action.
+ */
 typedef sk_sp<SkImage> (*SkDeserialImageProc)(const void* data, size_t length, void* ctx);
+
+/**
+ *  Called with the encoded form of a typeface (previously written with a custom
+ *  SkSerialTypefaceProc proc). Return a typeface object, or nullptr indicating failure.
+ */
 typedef sk_sp<SkTypeface> (*SkDeserialTypefaceProc)(const void* data, size_t length, void* ctx);
 
 struct SK_API SkSerialProcs {