gfx/thebes/gfxCachedTempSurface.cpp

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "gfxCachedTempSurface.h"
   7 #include "gfxContext.h"
   8 #include "mozilla/Attributes.h"
   9
  10 class CachedSurfaceExpirationTracker MOZ_FINAL :
  11   public nsExpirationTracker<gfxCachedTempSurface,2> {
  12
  13 public:
  14   // With K = 2, this means that surfaces will be released when they are not
  15   // used for 1-2 seconds.
  16   enum { TIMEOUT_MS = 1000 };
  17   CachedSurfaceExpirationTracker()
  18     : nsExpirationTracker<gfxCachedTempSurface,2>(TIMEOUT_MS) {}
  19
  20   ~CachedSurfaceExpirationTracker() {
  21     AgeAllGenerations();
  22   }
  23
  24   virtual void NotifyExpired(gfxCachedTempSurface* aSurface) {
  25     RemoveObject(aSurface);
  26     aSurface->Expire();
  27   }
  28
  29   static void MarkSurfaceUsed(gfxCachedTempSurface* aSurface)
  30   {
  31     if (aSurface->GetExpirationState()->IsTracked()) {
  32       sExpirationTracker->MarkUsed(aSurface);
  33       return;
  34     }
  35
  36     if (!sExpirationTracker) {
  37       sExpirationTracker = new CachedSurfaceExpirationTracker();
  38     }
  39     sExpirationTracker->AddObject(aSurface);
  40   }
  41
  42   static void RemoveSurface(gfxCachedTempSurface* aSurface)
  43   {
  44     if (!sExpirationTracker)
  45       return;
  46
  47     if (aSurface->GetExpirationState()->IsTracked()) {
  48       sExpirationTracker->RemoveObject(aSurface);
  49     }
  50     if (sExpirationTracker->IsEmpty()) {
  51       delete sExpirationTracker;
  52       sExpirationTracker = nullptr;
  53     }
  54   }
  55
  56 private:
  57   static CachedSurfaceExpirationTracker* sExpirationTracker;
  58 };
  59
  60 CachedSurfaceExpirationTracker*
  61 CachedSurfaceExpirationTracker::sExpirationTracker = nullptr;
  62
  63 gfxCachedTempSurface::~gfxCachedTempSurface()
  64 {
  65   CachedSurfaceExpirationTracker::RemoveSurface(this);
  66 }
  67
  68 already_AddRefed<gfxContext>
  69 gfxCachedTempSurface::Get(gfxASurface::gfxContentType aContentType,
  70                           const gfxRect& aRect,
  71                           gfxASurface* aSimilarTo)
  72 {
  73   if (mSurface) {
  74     /* Verify the current buffer is valid for this purpose */
  75     if (mSize.width < aRect.width || mSize.height < aRect.height
  76         || mSurface->GetContentType() != aContentType) {
  77       mSurface = nullptr;
  78     } else {
  79       NS_ASSERTION(mType == aSimilarTo->GetType(),
  80                    "Unexpected surface type change");
  81     }
  82   }
  83
  84   bool cleared = false;
  85   if (!mSurface) {
  86     mSize = gfxIntSize(int32_t(ceil(aRect.width)), int32_t(ceil(aRect.height)));
  87     mSurface = aSimilarTo->CreateSimilarSurface(aContentType, mSize);
  88     if (!mSurface)
  89       return nullptr;
  90
  91     cleared = true;
  92 #ifdef DEBUG
  93     mType = aSimilarTo->GetType();
  94 #endif
  95   }
  96   mSurface->SetDeviceOffset(-aRect.TopLeft());
  97
  98   nsRefPtr<gfxContext> ctx = new gfxContext(mSurface);
  99   ctx->Rectangle(aRect);
 100   ctx->Clip();
 101   if (!cleared && aContentType != gfxASurface::CONTENT_COLOR) {
 102     ctx->SetOperator(gfxContext::OPERATOR_CLEAR);
 103     ctx->Paint();
 104     ctx->SetOperator(gfxContext::OPERATOR_OVER);
 105   }
 106
 107   CachedSurfaceExpirationTracker::MarkSurfaceUsed(this);
 108
 109   return ctx.forget();
 110 }