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      1 /*
      2  * Copyright 2007 The Android Open Source Project
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #ifndef SkPicture_DEFINED
      9 #define SkPicture_DEFINED
     10 
     11 #include "SkRefCnt.h"
     12 #include "SkRect.h"
     13 #include "SkTypes.h"
     14 
     15 class GrContext;
     16 class SkBigPicture;
     17 class SkBitmap;
     18 class SkCanvas;
     19 class SkData;
     20 class SkImage;
     21 class SkImageDeserializer;
     22 class SkPath;
     23 class SkPictureData;
     24 class SkPixelSerializer;
     25 class SkReadBuffer;
     26 class SkRefCntSet;
     27 class SkStream;
     28 class SkTypefacePlayback;
     29 class SkWStream;
     30 class SkWriteBuffer;
     31 struct SkPictInfo;
     32 
     33 /** \class SkPicture
     34 
     35     An SkPicture records drawing commands made to a canvas to be played back at a later time.
     36     This base class handles serialization and a few other miscellany.
     37 */
     38 class SK_API SkPicture : public SkRefCnt {
     39 public:
     40     /**
     41      *  Function signature defining a function that sets up an SkBitmap from encoded data. On
     42      *  success, the SkBitmap should have its Config, width, height, rowBytes and pixelref set.
     43      *  If the installed pixelref has decoded the data into pixels, then the src buffer need not be
     44      *  copied. If the pixelref defers the actual decode until its lockPixels() is called, then it
     45      *  must make a copy of the src buffer.
     46      *  @param src Encoded data.
     47      *  @param length Size of the encoded data, in bytes.
     48      *  @param dst SkBitmap to install the pixel ref on.
     49      *  @param bool Whether or not a pixel ref was successfully installed.
     50      */
     51     typedef bool (*InstallPixelRefProc)(const void* src, size_t length, SkBitmap* dst);
     52 
     53     /**
     54      *  Recreate a picture that was serialized into a stream.
     55      *
     56      *  Any serialized images in the stream will be passed the image-deserializer, or if that is
     57      *  null, to the default deserializer that will call SkImage::MakeFromEncoded().
     58      */
     59     static sk_sp<SkPicture> MakeFromStream(SkStream*, SkImageDeserializer*);
     60     static sk_sp<SkPicture> MakeFromStream(SkStream*);
     61     static sk_sp<SkPicture> MakeFromData(const void* data, size_t size,
     62                                          SkImageDeserializer* = nullptr);
     63     static sk_sp<SkPicture> MakeFromData(const SkData* data, SkImageDeserializer* = nullptr);
     64 
     65     /**
     66      *  Recreate a picture that was serialized into a buffer. If the creation requires bitmap
     67      *  decoding, the decoder must be set on the SkReadBuffer parameter by calling
     68      *  SkReadBuffer::setBitmapDecoder() before calling SkPicture::CreateFromBuffer().
     69      *  @param SkReadBuffer Serialized picture data.
     70      *  @return A new SkPicture representing the serialized data, or NULL if the buffer is
     71      *          invalid.
     72      */
     73     static sk_sp<SkPicture> MakeFromBuffer(SkReadBuffer&);
     74 
     75     /**
     76     *  Subclasses of this can be passed to playback(). During the playback
     77     *  of the picture, this callback will periodically be invoked. If its
     78     *  abort() returns true, then picture playback will be interrupted.
     79     *
     80     *  The resulting drawing is undefined, as there is no guarantee how often the
     81     *  callback will be invoked. If the abort happens inside some level of nested
     82     *  calls to save(), restore will automatically be called to return the state
     83     *  to the same level it was before the playback call was made.
     84     */
     85     class SK_API AbortCallback {
     86     public:
     87         AbortCallback() {}
     88         virtual ~AbortCallback() {}
     89         virtual bool abort() = 0;
     90     };
     91 
     92     /** Replays the drawing commands on the specified canvas. Note that
     93         this has the effect of unfurling this picture into the destination
     94         canvas. Using the SkCanvas::drawPicture entry point gives the destination
     95         canvas the option of just taking a ref.
     96         @param canvas the canvas receiving the drawing commands.
     97         @param callback a callback that allows interruption of playback
     98     */
     99     virtual void playback(SkCanvas*, AbortCallback* = NULL) const = 0;
    100 
    101     /** Return a cull rect for this picture.
    102         Ops recorded into this picture that attempt to draw outside the cull might not be drawn.
    103      */
    104     virtual SkRect cullRect() const = 0;
    105 
    106     /** Returns a non-zero value unique among all pictures. */
    107     uint32_t uniqueID() const;
    108 
    109     /**
    110      *  Serialize the picture to SkData. If non nullptr, pixel-serializer will be used to
    111      *  customize how images reference by the picture are serialized/compressed.
    112      */
    113     sk_sp<SkData> serialize(SkPixelSerializer* = nullptr) const;
    114 
    115     /**
    116      *  Serialize to a stream. If non nullptr, pixel-serializer will be used to
    117      *  customize how images reference by the picture are serialized/compressed.
    118      */
    119     void serialize(SkWStream*, SkPixelSerializer* = nullptr) const;
    120 
    121     /**
    122      *  Serialize to a buffer.
    123      */
    124     void flatten(SkWriteBuffer&) const;
    125 
    126     /**
    127      * Returns true if any bitmaps may be produced when this SkPicture
    128      * is replayed.
    129      */
    130     virtual bool willPlayBackBitmaps() const = 0;
    131 
    132     /** Return the approximate number of operations in this picture.  This
    133      *  number may be greater or less than the number of SkCanvas calls
    134      *  recorded: some calls may be recorded as more than one operation, or some
    135      *  calls may be optimized away.
    136      */
    137     virtual int approximateOpCount() const = 0;
    138 
    139     /** Returns the approximate byte size of this picture, not including large ref'd objects. */
    140     virtual size_t approximateBytesUsed() const = 0;
    141 
    142     /** Return true if the SkStream/Buffer represents a serialized picture, and
    143         fills out SkPictInfo. After this function returns, the data source is not
    144         rewound so it will have to be manually reset before passing to
    145         CreateFromStream or CreateFromBuffer. Note, CreateFromStream and
    146         CreateFromBuffer perform this check internally so these entry points are
    147         intended for stand alone tools.
    148         If false is returned, SkPictInfo is unmodified.
    149     */
    150     static bool InternalOnly_StreamIsSKP(SkStream*, SkPictInfo*);
    151     static bool InternalOnly_BufferIsSKP(SkReadBuffer*, SkPictInfo*);
    152 
    153 #ifdef SK_SUPPORT_LEGACY_PICTURE_GPUVETO
    154     /** Return true if the picture is suitable for rendering on the GPU.  */
    155     bool suitableForGpuRasterization(GrContext*, const char** whyNot = NULL) const;
    156 #endif
    157 
    158     // Returns NULL if this is not an SkBigPicture.
    159     virtual const SkBigPicture* asSkBigPicture() const { return NULL; }
    160 
    161     // Global setting to enable or disable security precautions for serialization.
    162     static void SetPictureIOSecurityPrecautionsEnabled_Dangerous(bool set);
    163     static bool PictureIOSecurityPrecautionsEnabled();
    164 
    165 private:
    166     // Subclass whitelist.
    167     SkPicture();
    168     friend class SkBigPicture;
    169     friend class SkEmptyPicture;
    170     template <typename> friend class SkMiniPicture;
    171 
    172     void serialize(SkWStream*, SkPixelSerializer*, SkRefCntSet* typefaces) const;
    173     static sk_sp<SkPicture> MakeFromStream(SkStream*, SkImageDeserializer*, SkTypefacePlayback*);
    174     friend class SkPictureData;
    175 
    176     virtual int numSlowPaths() const = 0;
    177     friend class SkPictureGpuAnalyzer;
    178     friend struct SkPathCounter;
    179 
    180     // V35: Store SkRect (rather then width & height) in header
    181     // V36: Remove (obsolete) alphatype from SkColorTable
    182     // V37: Added shadow only option to SkDropShadowImageFilter (last version to record CLEAR)
    183     // V38: Added PictureResolution option to SkPictureImageFilter
    184     // V39: Added FilterLevel option to SkPictureImageFilter
    185     // V40: Remove UniqueID serialization from SkImageFilter.
    186     // V41: Added serialization of SkBitmapSource's filterQuality parameter
    187     // V42: Added a bool to SkPictureShader serialization to indicate did-we-serialize-a-picture?
    188     // V43: Added DRAW_IMAGE and DRAW_IMAGE_RECT opt codes to serialized data
    189     // V44: Move annotations from paint to drawAnnotation
    190     // V45: Add invNormRotation to SkLightingShader.
    191     // V46: Add drawTextRSXform
    192     // V47: Add occluder rect to SkBlurMaskFilter
    193     // V48: Read and write extended SkTextBlobs.
    194     // V49: Gradients serialized as SkColor4f + SkColorSpace
    195     // V50: SkXfermode -> SkBlendMode
    196     // V51: more SkXfermode -> SkBlendMode
    197     // V52: Remove SkTextBlob::fRunCount
    198     // V53: SaveLayerRec clip mask
    199     // V54: ComposeShader can use a Mode or a Lerp
    200     // V55: Drop blendmode[] from MergeImageFilter
    201     // V56: Add TileMode in SkBlurImageFilter.
    202 
    203     // Only SKPs within the min/current picture version range (inclusive) can be read.
    204     static const uint32_t     MIN_PICTURE_VERSION = 51;     // Produced by Chrome ~M56.
    205     static const uint32_t CURRENT_PICTURE_VERSION = 56;
    206 
    207     static bool IsValidPictInfo(const SkPictInfo& info);
    208     static sk_sp<SkPicture> Forwardport(const SkPictInfo&,
    209                                         const SkPictureData*,
    210                                         SkReadBuffer* buffer);
    211 
    212     SkPictInfo createHeader() const;
    213     SkPictureData* backport() const;
    214 
    215     mutable uint32_t fUniqueID;
    216 };
    217 
    218 #endif
    219