/* -*- 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 */