gecko-dev/gfx/thebes/PrintTarget.h
2016-06-16 17:28:50 +01:00

135 lines
4.6 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* 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_PRINTTARGET_H
#define MOZILLA_GFX_PRINTTARGET_H
#include "mozilla/RefPtr.h"
#include "mozilla/gfx/2D.h"
#include "nsISupportsImpl.h"
namespace mozilla {
namespace gfx {
class DrawEventRecorder;
/**
* A class that is used to draw output that is to be sent to a printer or print
* preview.
*
* This class wraps a cairo_surface_t* and provides access to it via a
* DrawTarget. The various checkpointing methods manage the state of the
* platform specific cairo_surface_t*.
*/
class PrintTarget {
public:
NS_INLINE_DECL_REFCOUNTING(PrintTarget);
/// Must be matched 1:1 by an EndPrinting/AbortPrinting call.
virtual nsresult BeginPrinting(const nsAString& aTitle,
const nsAString& aPrintToFileName) {
return NS_OK;
}
virtual nsresult EndPrinting() {
return NS_OK;
}
virtual nsresult AbortPrinting() {
return NS_OK;
}
virtual nsresult BeginPage() {
return NS_OK;
}
virtual nsresult EndPage() {
return NS_OK;
}
/**
* Releases the resources used by this PrintTarget. Typically this should be
* called after calling EndPrinting(). Calling this more than once is
* allowed, but subsequent calls are a no-op.
*
* Note that any DrawTarget obtained from this PrintTarget will no longer be
* useful after this method has been called.
*/
virtual void Finish();
/**
* Returns true if to print landscape our consumers must apply a 90 degrees
* rotation to our DrawTarget.
*/
virtual bool RotateNeededForLandscape() const {
return false;
}
const IntSize& GetSize() const {
return mSize;
}
/**
* Makes a DrawTarget to draw the printer output to, or returns null on
* failure.
*
* If aRecorder is passed a recording DrawTarget will be created instead of
* the type of DrawTarget that would normally be returned for a particular
* subclass of this class. This argument is only intended to be used in
* the e10s content process if printing output can't otherwise be transfered
* over to the parent process using the normal DrawTarget type.
*
* XXX For consistency with the old code this takes a size parameter even
* though we already have the size passed to our subclass's CreateOrNull
* factory methods. The size passed to the factory method comes from
* nsIDeviceContextSpec::MakePrintTarget overrides, whereas the size
* passed to us comes from nsDeviceContext::CreateRenderingContext. In at
* least one case (nsDeviceContextSpecAndroid::MakePrintTarget) these are
* different. At some point we should align the two sources and get rid of
* this method's size parameter.
*
* XXX For consistency with the old code this returns a new DrawTarget for
* each call. Perhaps we can create and cache a DrawTarget in our subclass's
* CreateOrNull factory methods and return that on each call? Currently that
* seems to cause Mochitest failures on Windows though, which coincidentally
* is the only platform where we get passed an aRecorder. Probably the
* issue is that we get called more than once with a different aRecorder, so
* storing one recording DrawTarget for our lifetime doesn't currently work.
*
* XXX Could we pass aRecorder to our subclass's CreateOrNull factory methods?
* We'd need to check that our consumers always pass the same aRecorder for
* our entire lifetime.
*
* XXX Once PrintTargetThebes is removed this can become non-virtual.
*
* XXX In the long run, this class and its sub-classes should be converted to
* use STL classes and mozilla::RefCounted<> so the can be moved to Moz2D.
*
* TODO: Consider adding a SetDPI method that calls
* cairo_surface_set_fallback_resolution.
*/
virtual already_AddRefed<DrawTarget>
MakeDrawTarget(const IntSize& aSize,
DrawEventRecorder* aRecorder = nullptr);
protected:
// Only created via subclass's constructors
explicit PrintTarget(cairo_surface_t* aCairoSurface, const IntSize& aSize);
// Protected because we're refcounted
virtual ~PrintTarget();
already_AddRefed<DrawTarget>
CreateRecordingDrawTarget(DrawEventRecorder* aRecorder,
DrawTarget* aDrawTarget);
cairo_surface_t* mCairoSurface;
IntSize mSize;
bool mIsFinished;
};
} // namespace gfx
} // namespace mozilla
#endif /* MOZILLA_GFX_PRINTTARGET_H */