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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef _MOZILLA_GFX_BORROWED_CONTEXT_H
#define _MOZILLA_GFX_BORROWED_CONTEXT_H
#include "2D.h"
struct _cairo;
typedef struct _cairo cairo_t;
namespace mozilla {
namespace gfx {
/* This is a helper class that let's you borrow a cairo_t from a
* DrawTargetCairo. This is used for drawing themed widgets.
*
* Callers should check the cr member after constructing the object
* to see if it succeeded. The DrawTarget should not be used while
* the context is borrowed. */
class BorrowedCairoContext
{
public:
BorrowedCairoContext()
: mCairo(nullptr)
, mDT(nullptr)
{ }
explicit BorrowedCairoContext(DrawTarget *aDT)
: mDT(aDT)
{
mCairo = BorrowCairoContextFromDrawTarget(aDT);
}
// We can optionally Init after construction in
// case we don't know what the DT will be at construction
// time.
cairo_t *Init(DrawTarget *aDT)
{
MOZ_ASSERT(!mDT, "Can't initialize twice!");
mDT = aDT;
return mCairo = BorrowCairoContextFromDrawTarget(aDT);
}
// The caller needs to call Finish if cr is non-null when
// they are done with the context. This is currently explicit
// instead of happening implicitly in the destructor to make
// what's happening in the caller more clear. It also
// let's you resume using the DrawTarget in the same scope.
void Finish()
{
if (mCairo) {
ReturnCairoContextToDrawTarget(mDT, mCairo);
mCairo = nullptr;
}
}
~BorrowedCairoContext() {
MOZ_ASSERT(!mCairo);
}
cairo_t *mCairo;
private:
static cairo_t* BorrowCairoContextFromDrawTarget(DrawTarget *aDT);
static void ReturnCairoContextToDrawTarget(DrawTarget *aDT, cairo_t *aCairo);
DrawTarget *mDT;
};
#ifdef XP_MACOSX
/* This is a helper class that let's you borrow a CGContextRef from a
* DrawTargetCG. This is used for drawing themed widgets.
*
* Callers should check the cg member after constructing the object
* to see if it succeeded. The DrawTarget should not be used while
* the context is borrowed. */
class BorrowedCGContext
{
public:
BorrowedCGContext()
: cg(nullptr)
, mDT(nullptr)
{ }
explicit BorrowedCGContext(DrawTarget *aDT)
: mDT(aDT)
{
MOZ_ASSERT(aDT, "Caller should check for nullptr");
cg = BorrowCGContextFromDrawTarget(aDT);
}
// We can optionally Init after construction in
// case we don't know what the DT will be at construction
// time.
CGContextRef Init(DrawTarget *aDT)
{
MOZ_ASSERT(aDT, "Caller should check for nullptr");
MOZ_ASSERT(!mDT, "Can't initialize twice!");
mDT = aDT;
cg = BorrowCGContextFromDrawTarget(aDT);
return cg;
}
// The caller needs to call Finish if cg is non-null when
// they are done with the context. This is currently explicit
// instead of happening implicitly in the destructor to make
// what's happening in the caller more clear. It also
// let's you resume using the DrawTarget in the same scope.
void Finish()
{
if (cg) {
ReturnCGContextToDrawTarget(mDT, cg);
cg = nullptr;
}
}
~BorrowedCGContext() {
MOZ_ASSERT(!cg);
}
CGContextRef cg;
private:
static CGContextRef BorrowCGContextFromDrawTarget(DrawTarget *aDT);
static void ReturnCGContextToDrawTarget(DrawTarget *aDT, CGContextRef cg);
DrawTarget *mDT;
};
#endif
}
}
#endif // _MOZILLA_GFX_BORROWED_CONTEXT_H
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