SkMultiPictureDocument & SkMultiPictureDocumentReader

src/utils/SkMultiPictureDocumentReader.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef SkMultiPictureDocumentReader_DEFINED
+#define SkMultiPictureDocumentReader_DEFINED
+
+#include "../private/SkTArray.h"
+#include "SkPicture.h"
+#include "SkSize.h"
+#include "SkStream.h"
+
+/** A lightweight helper class for reading a Skia MultiPictureDocument. */
+class SkMultiPictureDocumentReader {
+public:
+    /** Initialize the MultiPictureDocument.  Does not take ownership
+        of the SkStreamSeekable. */
+    bool init(SkStreamSeekable*);
+
+    /** Return to factory settings. */
+    void reset() {
+        fSizes.reset();
+        fOffsets.reset();
+    }
+
+    /** Call this after calling init() */
+    int pageCount() const { return fSizes.count(); }
+
+    /** Deserialize a page from the stream.  Call init() first.  The
+        SkStreamSeekable doesn't need to be the same object, but
+        should point to the same information as before. */
+    sk_sp<SkPicture> readPage(SkStreamSeekable*, int) const;
+
+    /** Fetch the size of the given page, without deserializing the
+        entire page. */
+    SkSize pageSize(int i) const { return fSizes[i]; }
+
+private:
+    SkTArray<SkSize> fSizes;
+    SkTArray<size_t> fOffsets;
+};
+
+#endif  // SkMultiPictureDocumentReader_DEFINED