зеркало из https://github.com/mozilla/gecko-dev.git
108 строки
3.3 KiB
C++
108 строки
3.3 KiB
C++
/* -*- Mode: C++; tab-width: 2; 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_WIDGET_WINDOWSEMF_H
|
|
#define MOZILLA_WIDGET_WINDOWSEMF_H
|
|
|
|
/* include windows.h for the HDC definitions that we need. */
|
|
#include <windows.h>
|
|
|
|
namespace mozilla {
|
|
namespace widget {
|
|
|
|
/**
|
|
* Windows Enhance Metafile: https://en.wikipedia.org/wiki/Windows_Metafile
|
|
* A metafile, also called a vector image, is an image that is stored as a
|
|
* sequence of drawing commands and settings. The commands and settings
|
|
* recorded in a Metafile object can be stored in memory or saved to a file.
|
|
*
|
|
* The metafile device context is used for all drawing operations required to
|
|
* create the picture. When the system processes a GDI function associated with
|
|
* a metafile DC, it converts the function into the appropriate data and stores
|
|
* this data in a record appended to the metafile.
|
|
*/
|
|
class WindowsEMF
|
|
{
|
|
public:
|
|
WindowsEMF();
|
|
~WindowsEMF();
|
|
|
|
/**
|
|
* Initializes the object with the path of a file where the EMF data stream
|
|
* should be stored. Callers are then expected to call GetDC() to draw output
|
|
* before going on to call Playback() or SaveToFile() to generate the EMF
|
|
* output.
|
|
*/
|
|
bool InitForDrawing(const wchar_t* aMetafilePath = nullptr);
|
|
|
|
/**
|
|
* Initializes the object with an existing EMF file. Consumers cannot use
|
|
* GetDC() to obtain an HDC to modify the file. They can only use Playback().
|
|
*/
|
|
bool InitFromFileContents(const wchar_t* aMetafilePath);
|
|
|
|
/**
|
|
* Creates the EMF from the specified data
|
|
*
|
|
* @param aByte Pointer to a buffer that contains EMF data.
|
|
* @param aSize Specifies the size, in bytes, of aByte.
|
|
*/
|
|
bool InitFromFileContents(PBYTE aBytes, UINT aSize);
|
|
|
|
/**
|
|
* If this object was initiaziled using InitForDrawing() then this function
|
|
* returns an HDC that can be drawn to generate the EMF output. Otherwise it
|
|
* returns null. After finishing with the HDC, consumers could call Playback()
|
|
* to draw EMF onto the given DC or call SaveToFile() to finish writing the
|
|
* EMF file.
|
|
*/
|
|
HDC GetDC() const
|
|
{
|
|
MOZ_ASSERT(mDC, "GetDC can be used only after "
|
|
"InitForDrawing/ InitFromFileContents and before"
|
|
"Playback/ SaveToFile");
|
|
return mDC;
|
|
}
|
|
|
|
/**
|
|
* Play the EMF's drawing commands onto the given DC.
|
|
*/
|
|
bool Playback(HDC aDeviceContext, const RECT& aRect);
|
|
|
|
/**
|
|
* Called to generate the EMF file once a consumer has finished drawing to
|
|
* the HDC returned by GetDC(), if initializes the object with the path of a
|
|
* file.
|
|
*/
|
|
bool SaveToFile();
|
|
|
|
/**
|
|
* Return the size of the enhanced metafile, in bytes.
|
|
*/
|
|
UINT GetEMFContentSize();
|
|
|
|
/**
|
|
* Retrieves the contents of the EMF and copies them into a buffer.
|
|
*
|
|
* @param aByte the buffer to receive the data.
|
|
*/
|
|
bool GetEMFContentBits(PBYTE aBytes);
|
|
|
|
private:
|
|
|
|
WindowsEMF(const WindowsEMF& aEMF) = delete;
|
|
bool FinishDocument();
|
|
void ReleaseEMFHandle();
|
|
void ReleaseAllResource();
|
|
|
|
/* Compiled EMF data handle. */
|
|
HENHMETAFILE mEmf;
|
|
HDC mDC;
|
|
};
|
|
|
|
} // namespace widget
|
|
} // namespace mozilla
|
|
|
|
#endif /* MOZILLA_WIDGET_WINDOWSEMF_H */ |