src/third_party/skia/src/image/SkSurface.cpp

   1 /*
   2  * Copyright 2012 Google Inc.
   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 #include "SkSurface_Base.h"
   9 #include "SkImagePriv.h"
  10 #include "SkCanvas.h"
  11
  12 SK_DEFINE_INST_COUNT(SkSurface)
  13
  14 ///////////////////////////////////////////////////////////////////////////////
  15
  16 SkSurface_Base::SkSurface_Base(int width, int height) : INHERITED(width, height) {
  17     fCachedCanvas = NULL;
  18     fCachedImage = NULL;
  19 }
  20
  21 SkSurface_Base::~SkSurface_Base() {
  22     // in case the canvas outsurvives us, we null the callback
  23     if (fCachedCanvas) {
  24         fCachedCanvas->setSurfaceBase(NULL);
  25     }
  26
  27     SkSafeUnref(fCachedImage);
  28     SkSafeUnref(fCachedCanvas);
  29 }
  30
  31 void SkSurface_Base::onDraw(SkCanvas* canvas, SkScalar x, SkScalar y,
  32                             const SkPaint* paint) {
  33     SkImage* image = this->newImageSnapshot();
  34     if (image) {
  35         image->draw(canvas, x, y, paint);
  36         image->unref();
  37     }
  38 }
  39
  40 void SkSurface_Base::aboutToDraw(ContentChangeMode mode) {
  41     this->dirtyGenerationID();
  42
  43     if (NULL != fCachedCanvas) {
  44         SkASSERT(fCachedCanvas->getSurfaceBase() == this || \
  45                  NULL == fCachedCanvas->getSurfaceBase());
  46         fCachedCanvas->setSurfaceBase(NULL);
  47     }
  48
  49     if (NULL != fCachedImage) {
  50         // the surface may need to fork its backend, if its sharing it with
  51         // the cached image. Note: we only call if there is an outstanding owner
  52         // on the image (besides us).
  53         if (!fCachedImage->unique()) {
  54             this->onCopyOnWrite(mode);
  55         }
  56
  57         // regardless of copy-on-write, we must drop our cached image now, so
  58         // that the next request will get our new contents.
  59         fCachedImage->unref();
  60         fCachedImage = NULL;
  61     }
  62 }
  63
  64 uint32_t SkSurface_Base::newGenerationID() {
  65     this->installIntoCanvasForDirtyNotification();
  66
  67     static int32_t gID;
  68     return sk_atomic_inc(&gID) + 1;
  69 }
  70
  71 static SkSurface_Base* asSB(SkSurface* surface) {
  72     return static_cast<SkSurface_Base*>(surface);
  73 }
  74
  75 ///////////////////////////////////////////////////////////////////////////////
  76
  77 SkSurface::SkSurface(int width, int height) : fWidth(width), fHeight(height) {
  78     SkASSERT(width >= 0);
  79     SkASSERT(height >= 0);
  80     fGenerationID = 0;
  81 }
  82
  83 uint32_t SkSurface::generationID() {
  84     if (0 == fGenerationID) {
  85         fGenerationID = asSB(this)->newGenerationID();
  86     }
  87     return fGenerationID;
  88 }
  89
  90 void SkSurface::notifyContentWillChange(ContentChangeMode mode) {
  91     asSB(this)->aboutToDraw(mode);
  92 }
  93
  94 SkCanvas* SkSurface::getCanvas() {
  95     return asSB(this)->getCachedCanvas();
  96 }
  97
  98 SkImage* SkSurface::newImageSnapshot() {
  99     SkImage* image = asSB(this)->getCachedImage();
 100     SkSafeRef(image);   // the caller will call unref() to balance this
 101     return image;
 102 }
 103
 104 SkSurface* SkSurface::newSurface(const SkImageInfo& info) {
 105     return asSB(this)->onNewSurface(info);
 106 }
 107
 108 void SkSurface::draw(SkCanvas* canvas, SkScalar x, SkScalar y,
 109                      const SkPaint* paint) {
 110     return asSB(this)->onDraw(canvas, x, y, paint);
 111 }