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      1 /*
      2     Copyright 2011 Google Inc.
      3 
      4     Licensed under the Apache License, Version 2.0 (the "License");
      5     you may not use this file except in compliance with the License.
      6     You may obtain a copy of the License at
      7 
      8     http://www.apache.org/licenses/LICENSE-2.0
      9 
     10     Unless required by applicable law or agreed to in writing, software
     11     distributed under the License is distributed on an "AS IS" BASIS,
     12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13     See the License for the specific language governing permissions and
     14     limitations under the License.
     15  */
     16 
     17 
     18 #ifndef SkGPipe_DEFINED
     19 #define SkGPipe_DEFINED
     20 
     21 #include "SkWriter32.h"
     22 #include "SkFlattenable.h"
     23 
     24 class SkCanvas;
     25 
     26 class SkGPipeReader {
     27 public:
     28     SkGPipeReader(SkCanvas* target);
     29     ~SkGPipeReader();
     30 
     31     enum Status {
     32         kDone_Status,   //!< no more data expected from reader
     33         kEOF_Status,    //!< need more data from reader
     34         kError_Status   //!< encountered error
     35     };
     36 
     37     // data must be 4-byte aligned
     38     // length must be a multiple of 4
     39     Status playback(const void* data, size_t length, size_t* bytesRead = NULL);
     40 
     41 private:
     42     SkCanvas*           fCanvas;
     43     class SkGPipeState* fState;
     44 };
     45 
     46 ///////////////////////////////////////////////////////////////////////////////
     47 
     48 class SkGPipeController {
     49 public:
     50     /**
     51      *  Called periodically by the writer, to get a working buffer of RAM to
     52      *  write into. The actual size of the block is also returned, and must be
     53      *  actual >= minRequest. If NULL is returned, then actual is ignored and
     54      *  writing will stop.
     55      *
     56      *  The returned block must be 4-byte aligned, and actual must be a
     57      *  multiple of 4.
     58      *  minRequest will always be a multiple of 4.
     59      */
     60     virtual void* requestBlock(size_t minRequest, size_t* actual) = 0;
     61 
     62     /**
     63      *  This is called each time some atomic portion of the data has been
     64      *  written to the block (most recently returned by requestBlock()).
     65      *  If bytes == 0, then the writer has finished.
     66      *
     67      *  bytes will always be a multiple of 4.
     68      */
     69     virtual void notifyWritten(size_t bytes) = 0;
     70 };
     71 
     72 class SkGPipeWriter {
     73 public:
     74     SkGPipeWriter();
     75     ~SkGPipeWriter();
     76 
     77     bool isRecording() const { return NULL != fCanvas; }
     78 
     79     enum Flags {
     80         kCrossProcess_Flag = 1 << 0,
     81     };
     82 
     83     SkCanvas* startRecording(SkGPipeController*, uint32_t flags = 0);
     84 
     85     // called in destructor, but can be called sooner once you know there
     86     // should be no more drawing calls made into the recording canvas.
     87     void endRecording();
     88 
     89 private:
     90     class SkGPipeCanvas* fCanvas;
     91     SkGPipeController*   fController;
     92     SkFactorySet         fFactorySet;
     93     SkWriter32 fWriter;
     94 };
     95 
     96 #endif
     97