1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/2d/BorrowedContext.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,132 @@
1.4 +/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + * This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef _MOZILLA_GFX_BORROWED_CONTEXT_H
1.10 +#define _MOZILLA_GFX_BORROWED_CONTEXT_H
1.11 +
1.12 +#include "2D.h"
1.13 +
1.14 +struct _cairo;
1.15 +typedef struct _cairo cairo_t;
1.16 +
1.17 +namespace mozilla {
1.18 +
1.19 +namespace gfx {
1.20 +
1.21 +/* This is a helper class that let's you borrow a cairo_t from a
1.22 + * DrawTargetCairo. This is used for drawing themed widgets.
1.23 + *
1.24 + * Callers should check the cr member after constructing the object
1.25 + * to see if it succeeded. The DrawTarget should not be used while
1.26 + * the context is borrowed. */
1.27 +class BorrowedCairoContext
1.28 +{
1.29 +public:
1.30 + BorrowedCairoContext()
1.31 + : mCairo(nullptr)
1.32 + , mDT(nullptr)
1.33 + { }
1.34 +
1.35 + BorrowedCairoContext(DrawTarget *aDT)
1.36 + : mDT(aDT)
1.37 + {
1.38 + mCairo = BorrowCairoContextFromDrawTarget(aDT);
1.39 + }
1.40 +
1.41 + // We can optionally Init after construction in
1.42 + // case we don't know what the DT will be at construction
1.43 + // time.
1.44 + cairo_t *Init(DrawTarget *aDT)
1.45 + {
1.46 + MOZ_ASSERT(!mDT, "Can't initialize twice!");
1.47 + mDT = aDT;
1.48 + return mCairo = BorrowCairoContextFromDrawTarget(aDT);
1.49 + }
1.50 +
1.51 + // The caller needs to call Finish if cr is non-null when
1.52 + // they are done with the context. This is currently explicit
1.53 + // instead of happening implicitly in the destructor to make
1.54 + // what's happening in the caller more clear. It also
1.55 + // let's you resume using the DrawTarget in the same scope.
1.56 + void Finish()
1.57 + {
1.58 + if (mCairo) {
1.59 + ReturnCairoContextToDrawTarget(mDT, mCairo);
1.60 + mCairo = nullptr;
1.61 + }
1.62 + }
1.63 +
1.64 + ~BorrowedCairoContext() {
1.65 + MOZ_ASSERT(!mCairo);
1.66 + }
1.67 +
1.68 + cairo_t *mCairo;
1.69 +private:
1.70 + static cairo_t* BorrowCairoContextFromDrawTarget(DrawTarget *aDT);
1.71 + static void ReturnCairoContextToDrawTarget(DrawTarget *aDT, cairo_t *aCairo);
1.72 + DrawTarget *mDT;
1.73 +};
1.74 +
1.75 +#ifdef XP_MACOSX
1.76 +/* This is a helper class that let's you borrow a CGContextRef from a
1.77 + * DrawTargetCG. This is used for drawing themed widgets.
1.78 + *
1.79 + * Callers should check the cg member after constructing the object
1.80 + * to see if it succeeded. The DrawTarget should not be used while
1.81 + * the context is borrowed. */
1.82 +class BorrowedCGContext
1.83 +{
1.84 +public:
1.85 + BorrowedCGContext()
1.86 + : cg(nullptr)
1.87 + , mDT(nullptr)
1.88 + { }
1.89 +
1.90 + BorrowedCGContext(DrawTarget *aDT)
1.91 + : mDT(aDT)
1.92 + {
1.93 + cg = BorrowCGContextFromDrawTarget(aDT);
1.94 + }
1.95 +
1.96 + // We can optionally Init after construction in
1.97 + // case we don't know what the DT will be at construction
1.98 + // time.
1.99 + CGContextRef Init(DrawTarget *aDT)
1.100 + {
1.101 + MOZ_ASSERT(!mDT, "Can't initialize twice!");
1.102 + mDT = aDT;
1.103 + cg = BorrowCGContextFromDrawTarget(aDT);
1.104 + return cg;
1.105 + }
1.106 +
1.107 + // The caller needs to call Finish if cg is non-null when
1.108 + // they are done with the context. This is currently explicit
1.109 + // instead of happening implicitly in the destructor to make
1.110 + // what's happening in the caller more clear. It also
1.111 + // let's you resume using the DrawTarget in the same scope.
1.112 + void Finish()
1.113 + {
1.114 + if (cg) {
1.115 + ReturnCGContextToDrawTarget(mDT, cg);
1.116 + cg = nullptr;
1.117 + }
1.118 + }
1.119 +
1.120 + ~BorrowedCGContext() {
1.121 + MOZ_ASSERT(!cg);
1.122 + }
1.123 +
1.124 + CGContextRef cg;
1.125 +private:
1.126 + static CGContextRef BorrowCGContextFromDrawTarget(DrawTarget *aDT);
1.127 + static void ReturnCGContextToDrawTarget(DrawTarget *aDT, CGContextRef cg);
1.128 + DrawTarget *mDT;
1.129 +};
1.130 +#endif
1.131 +
1.132 +}
1.133 +}
1.134 +
1.135 +#endif // _MOZILLA_GFX_BORROWED_CONTEXT_H
