gfx/2d/BorrowedContext.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef _MOZILLA_GFX_BORROWED_CONTEXT_H
   8 #define _MOZILLA_GFX_BORROWED_CONTEXT_H
   9
  10 #include "2D.h"
  11
  12 #ifdef MOZ_X11
  13 #  include <X11/extensions/Xrender.h>
  14 #  include <X11/Xlib.h>
  15 #  include "X11UndefineNone.h"
  16 #endif
  17
  18 struct _cairo;
  19 typedef struct _cairo cairo_t;
  20
  21 namespace mozilla {
  22
  23 namespace gfx {
  24
  25 /* This is a helper class that let's you borrow a cairo_t from a
  26  * DrawTargetCairo. This is used for drawing themed widgets.
  27  *
  28  * Callers should check the cr member after constructing the object
  29  * to see if it succeeded. The DrawTarget should not be used while
  30  * the context is borrowed. */
  31 class BorrowedCairoContext {
  32  public:
  33   BorrowedCairoContext() : mCairo(nullptr), mDT(nullptr) {}
  34
  35   explicit BorrowedCairoContext(DrawTarget* aDT) : mDT(aDT) {
  36     mCairo = BorrowCairoContextFromDrawTarget(aDT);
  37   }
  38
  39   // We can optionally Init after construction in
  40   // case we don't know what the DT will be at construction
  41   // time.
  42   cairo_t* Init(DrawTarget* aDT) {
  43     MOZ_ASSERT(!mDT, "Can't initialize twice!");
  44     mDT = aDT;
  45     return mCairo = BorrowCairoContextFromDrawTarget(aDT);
  46   }
  47
  48   // The caller needs to call Finish if cr is non-null when
  49   // they are done with the context. This is currently explicit
  50   // instead of happening implicitly in the destructor to make
  51   // what's happening in the caller more clear. It also
  52   // let's you resume using the DrawTarget in the same scope.
  53   void Finish() {
  54     if (mCairo) {
  55       ReturnCairoContextToDrawTarget(mDT, mCairo);
  56       mCairo = nullptr;
  57     }
  58   }
  59
  60   ~BorrowedCairoContext() { MOZ_ASSERT(!mCairo); }
  61
  62   cairo_t* mCairo;
  63
  64  private:
  65   static cairo_t* BorrowCairoContextFromDrawTarget(DrawTarget* aDT);
  66   static void ReturnCairoContextToDrawTarget(DrawTarget* aDT, cairo_t* aCairo);
  67   DrawTarget* mDT;
  68 };
  69
  70 #ifdef MOZ_X11
  71 /* This is a helper class that let's you borrow an Xlib drawable from
  72  * a DrawTarget. This is used for drawing themed widgets.
  73  *
  74  * Callers should check the Xlib drawable after constructing the object
  75  * to see if it succeeded. The DrawTarget should not be used while
  76  * the drawable is borrowed. */
  77 class BorrowedXlibDrawable {
  78  public:
  79   BorrowedXlibDrawable()
  80       : mDT(nullptr),
  81         mDisplay(nullptr),
  82         mDrawable(X11None),
  83         mScreen(nullptr),
  84         mVisual(nullptr),
  85         mXRenderFormat(nullptr) {}
  86
  87   explicit BorrowedXlibDrawable(DrawTarget* aDT)
  88       : mDT(nullptr),
  89         mDisplay(nullptr),
  90         mDrawable(X11None),
  91         mScreen(nullptr),
  92         mVisual(nullptr),
  93         mXRenderFormat(nullptr) {
  94     Init(aDT);
  95   }
  96
  97   // We can optionally Init after construction in
  98   // case we don't know what the DT will be at construction
  99   // time.
 100   bool Init(DrawTarget* aDT);
 101
 102   // The caller needs to call Finish if drawable is non-zero when
 103   // they are done with the context. This is currently explicit
 104   // instead of happening implicitly in the destructor to make
 105   // what's happening in the caller more clear. It also
 106   // let's you resume using the DrawTarget in the same scope.
 107   void Finish();
 108
 109   ~BorrowedXlibDrawable() { MOZ_ASSERT(!mDrawable); }
 110
 111   Display* GetDisplay() const { return mDisplay; }
 112   Drawable GetDrawable() const { return mDrawable; }
 113   Screen* GetScreen() const { return mScreen; }
 114   Visual* GetVisual() const { return mVisual; }
 115   IntSize GetSize() const { return mSize; }
 116   Point GetOffset() const { return mOffset; }
 117
 118   XRenderPictFormat* GetXRenderFormat() const { return mXRenderFormat; }
 119
 120  private:
 121   DrawTarget* mDT;
 122   Display* mDisplay;
 123   Drawable mDrawable;
 124   Screen* mScreen;
 125   Visual* mVisual;
 126   XRenderPictFormat* mXRenderFormat;
 127   IntSize mSize;
 128   Point mOffset;
 129 };
 130 #endif
 131
 132 #ifdef XP_DARWIN
 133 /* This is a helper class that let's you borrow a CGContextRef from a
 134  * DrawTargetCG. This is used for drawing themed widgets.
 135  *
 136  * Callers should check the cg member after constructing the object
 137  * to see if it succeeded. The DrawTarget should not be used while
 138  * the context is borrowed. */
 139 class BorrowedCGContext {
 140  public:
 141   BorrowedCGContext() : cg(nullptr), mDT(nullptr) {}
 142
 143   explicit BorrowedCGContext(DrawTarget* aDT) : mDT(aDT) {
 144     MOZ_ASSERT(aDT, "Caller should check for nullptr");
 145     cg = BorrowCGContextFromDrawTarget(aDT);
 146   }
 147
 148   // We can optionally Init after construction in
 149   // case we don't know what the DT will be at construction
 150   // time.
 151   CGContextRef Init(DrawTarget* aDT) {
 152     MOZ_ASSERT(aDT, "Caller should check for nullptr");
 153     MOZ_ASSERT(!mDT, "Can't initialize twice!");
 154     mDT = aDT;
 155     cg = BorrowCGContextFromDrawTarget(aDT);
 156     return cg;
 157   }
 158
 159   // The caller needs to call Finish if cg is non-null when
 160   // they are done with the context. This is currently explicit
 161   // instead of happening implicitly in the destructor to make
 162   // what's happening in the caller more clear. It also
 163   // let's you resume using the DrawTarget in the same scope.
 164   void Finish() {
 165     if (cg) {
 166       ReturnCGContextToDrawTarget(mDT, cg);
 167       cg = nullptr;
 168     }
 169   }
 170
 171   ~BorrowedCGContext() { MOZ_ASSERT(!cg); }
 172
 173   CGContextRef cg;
 174
 175  private:
 176 #  ifdef USE_SKIA
 177   static CGContextRef BorrowCGContextFromDrawTarget(DrawTarget* aDT);
 178   static void ReturnCGContextToDrawTarget(DrawTarget* aDT, CGContextRef cg);
 179 #  else
 180   static CGContextRef BorrowCGContextFromDrawTarget(DrawTarget* aDT) {
 181     MOZ_CRASH("Not supported without Skia");
 182   }
 183
 184   static void ReturnCGContextToDrawTarget(DrawTarget* aDT, CGContextRef cg) {
 185     MOZ_CRASH("not supported without Skia");
 186   }
 187 #  endif
 188   DrawTarget* mDT;
 189 };
 190 #endif
 191
 192 }  // namespace gfx
 193 }  // namespace mozilla
 194
 195 #endif  // _MOZILLA_GFX_BORROWED_CONTEXT_H