nsDeviceContext.h
/* -*- Mode: C++; 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 _NS_DEVICECONTEXT_H_
#define _NS_DEVICECONTEXT_H_
#include "nsCOMPtr.h"
#include "nsIDeviceContextSpec.h"
#include "nsIScreenManager.h"
#include "nsIWidget.h"
#include "nsCoord.h"
#include "gfxContext.h"
class nsIAtom;
class nsFontCache;
class gfxUserFontSet;
class nsDeviceContext
{
public:
nsDeviceContext();
~nsDeviceContext();
NS_INLINE_DECL_REFCOUNTING(nsDeviceContext)
/**
* Initialize the device context from a widget
* @param aWidget a widget to initialize the device context from
* @return error status
*/
nsresult Init(nsIWidget *aWidget);
/**
* Initialize the device context from a device context spec
* @param aDevSpec the specification of the printing device
* @return error status
*/
nsresult InitForPrinting(nsIDeviceContextSpec *aDevSpec);
/**
* Create a rendering context and initialize it. Only call this
* method on device contexts that were initialized for printing.
* @param aContext out parameter for new rendering context
* @return error status
*/
nsresult CreateRenderingContext(nsRenderingContext *&aContext);
/**
* Gets the number of app units in one CSS pixel; this number is global,
* not unique to each device context.
*/
static int32_t AppUnitsPerCSSPixel() { return 60; }
/**
* Gets the number of app units in one device pixel; this number
* is usually a factor of AppUnitsPerCSSPixel(), although that is
* not guaranteed.
*/
uint32_t AppUnitsPerDevPixel() const { return mAppUnitsPerDevPixel; }
/**
* Convert device pixels which is used for gfx/thebes to nearest
* (rounded) app units
*/
nscoord GfxUnitsToAppUnits(gfxFloat aGfxUnits) const
{ return nscoord(NS_round(aGfxUnits * AppUnitsPerDevPixel())); }
/**
* Convert app units to device pixels which is used for gfx/thebes.
*/
gfxFloat AppUnitsToGfxUnits(nscoord aAppUnits) const
{ return gfxFloat(aAppUnits) / AppUnitsPerDevPixel(); }
/**
* Gets the number of app units in one physical inch; this is the
* device's DPI times AppUnitsPerDevPixel().
*/
int32_t AppUnitsPerPhysicalInch() const
{ return mAppUnitsPerPhysicalInch; }
/**
* Gets the number of app units in one CSS inch; this is
* 96 times AppUnitsPerCSSPixel.
*/
static int32_t AppUnitsPerCSSInch() { return 96 * AppUnitsPerCSSPixel(); }
/**
* Get the unscaled ratio of app units to dev pixels; useful if something
* needs to be converted from to unscaled pixels
*/
int32_t UnscaledAppUnitsPerDevPixel() const
{ return mAppUnitsPerDevNotScaledPixel; }
/**
* Get the nsFontMetrics that describe the properties of
* an nsFont.
* @param aFont font description to obtain metrics for
* @param aLanguage the language of the document
* @param aMetrics out parameter for font metrics
* @param aUserFontSet user font set
* @return error status
*/
nsresult GetMetricsFor(const nsFont& aFont, nsIAtom* aLanguage,
gfxUserFontSet* aUserFontSet,
nsFontMetrics*& aMetrics);
/**
* Notification when a font metrics instance created for this device is
* about to be deleted
*/
nsresult FontMetricsDeleted(const nsFontMetrics* aFontMetrics);
/**
* Attempt to free up resources by flushing out any fonts no longer
* referenced by anything other than the font cache itself.
* @return error status
*/
nsresult FlushFontCache();
/**
* Return the bit depth of the device.
*/
nsresult GetDepth(uint32_t& aDepth);
/**
* Get the size of the displayable area of the output device
* in app units.
* @param aWidth out parameter for width
* @param aHeight out parameter for height
* @return error status
*/
nsresult GetDeviceSurfaceDimensions(nscoord& aWidth, nscoord& aHeight);
/**
* Get the size of the content area of the output device in app
* units. This corresponds on a screen device, for instance, to
* the entire screen.
* @param aRect out parameter for full rect. Position (x,y) will
* be (0,0) or relative to the primary monitor if
* this is not the primary.
* @return error status
*/
nsresult GetRect(nsRect& aRect);
/**
* Get the size of the content area of the output device in app
* units. This corresponds on a screen device, for instance, to
* the area reported by GetDeviceSurfaceDimensions, minus the
* taskbar (Windows) or menubar (Macintosh).
* @param aRect out parameter for client rect. Position (x,y) will
* be (0,0) adjusted for any upper/left non-client
* space if present or relative to the primary
* monitor if this is not the primary.
* @return error status
*/
nsresult GetClientRect(nsRect& aRect);
/**
* Inform the output device that output of a document is beginning
* Used for print related device contexts. Must be matched 1:1 with
* EndDocument() or AbortDocument().
*
* @param aTitle - title of Document
* @param aPrintToFileName - name of file to print to, if NULL
* then don't print to file
* @param aStartPage - starting page number (must be greater than zero)
* @param aEndPage - ending page number (must be less than or
* equal to number of pages)
*
* @return error status
*/
nsresult BeginDocument(PRUnichar *aTitle,
PRUnichar *aPrintToFileName,
int32_t aStartPage,
int32_t aEndPage);
/**
* Inform the output device that output of a document is ending.
* Used for print related device contexts. Must be matched 1:1 with
* BeginDocument()
* @return error status
*/
nsresult EndDocument();
/**
* Inform the output device that output of a document is being aborted.
* Must be matched 1:1 with BeginDocument()
* @return error status
*/
nsresult AbortDocument();
/**
* Inform the output device that output of a page is beginning
* Used for print related device contexts. Must be matched 1:1 with
* EndPage() and within a BeginDocument()/EndDocument() pair.
* @return error status
*/
nsresult BeginPage();
/**
* Inform the output device that output of a page is ending
* Used for print related device contexts. Must be matched 1:1 with
* BeginPage() and within a BeginDocument()/EndDocument() pair.
* @return error status
*/
nsresult EndPage();
/**
* Check to see if the DPI has changed
* @return whether there was actually a change in the DPI (whether
* AppUnitsPerDevPixel() or AppUnitsPerPhysicalInch()
* changed)
*/
bool CheckDPIChange();
/**
* Set the pixel scaling factor: all lengths are multiplied by this factor
* when we convert them to device pixels. Returns whether the ratio of
* app units to dev pixels changed because of the scale factor.
*/
bool SetPixelScale(float aScale);
/**
* Returns the pixel scaling factor (page zoom factor) applied.
*/
float GetPixelScale() const { return mPixelScale; }
/**
* True if this device context was created for printing.
*/
bool IsPrinterSurface();
protected:
void SetDPI();
void ComputeClientRectUsingScreen(nsRect *outRect);
void ComputeFullAreaUsingScreen(nsRect *outRect);
void FindScreen(nsIScreen **outScreen);
void CalcPrintingSize();
void UpdateScaledAppUnits();
nscoord mWidth;
nscoord mHeight;
uint32_t mDepth;
uint32_t mAppUnitsPerDevPixel;
int32_t mAppUnitsPerDevNotScaledPixel;
int32_t mAppUnitsPerPhysicalInch;
float mPixelScale;
float mPrintingScale;
nsFontCache* mFontCache;
nsCOMPtr<nsIWidget> mWidget;
nsCOMPtr<nsIScreenManager> mScreenManager;
nsCOMPtr<nsIDeviceContextSpec> mDeviceContextSpec;
nsRefPtr<gfxASurface> mPrintingSurface;
};
#endif /* _NS_DEVICECONTEXT_H_ */