gfx/src/nsDeviceContext.h

   1 /* -*- Mode: C++; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef _NS_DEVICECONTEXT_H_
   7 #define _NS_DEVICECONTEXT_H_
   8
   9 #include <stdint.h>                     // for uint32_t
  10 #include <sys/types.h>                  // for int32_t
  11 #include "gfxTypes.h"                   // for gfxFloat
  12 #include "mozilla/Assertions.h"         // for MOZ_ASSERT_HELPER2
  13 #include "nsAutoPtr.h"                  // for nsRefPtr
  14 #include "nsCOMPtr.h"                   // for nsCOMPtr
  15 #include "nsCoord.h"                    // for nscoord
  16 #include "nsError.h"                    // for nsresult
  17 #include "nsISupports.h"                // for NS_INLINE_DECL_REFCOUNTING
  18 #include "nsMathUtils.h"                // for NS_round
  19 #include "nscore.h"                     // for char16_t, nsAString
  20 #include "mozilla/AppUnits.h"           // for AppUnits
  21
  22 class gfxASurface;
  23 class gfxTextPerfMetrics;
  24 class gfxUserFontSet;
  25 struct nsFont;
  26 class nsFontCache;
  27 class nsFontMetrics;
  28 class nsIAtom;
  29 class nsIDeviceContextSpec;
  30 class nsIScreen;
  31 class nsIScreenManager;
  32 class nsIWidget;
  33 struct nsRect;
  34 class nsRenderingContext;
  35
  36 class nsDeviceContext MOZ_FINAL
  37 {
  38 public:
  39     nsDeviceContext();
  40
  41     NS_INLINE_DECL_REFCOUNTING(nsDeviceContext)
  42
  43     /**
  44      * Initialize the device context from a widget
  45      * @param aWidget a widget to initialize the device context from
  46      * @return error status
  47      */
  48     nsresult Init(nsIWidget *aWidget);
  49
  50     /**
  51      * Initialize the device context from a device context spec
  52      * @param aDevSpec the specification of the printing device
  53      * @return error status
  54      */
  55     nsresult InitForPrinting(nsIDeviceContextSpec *aDevSpec);
  56
  57     /**
  58      * Create a rendering context and initialize it.  Only call this
  59      * method on device contexts that were initialized for printing.
  60      *
  61      * @return the new rendering context (guaranteed to be non-null)
  62      */
  63     already_AddRefed<nsRenderingContext> CreateRenderingContext();
  64
  65     /**
  66      * Gets the number of app units in one CSS pixel; this number is global,
  67      * not unique to each device context.
  68      */
  69     static int32_t AppUnitsPerCSSPixel() { return mozilla::AppUnitsPerCSSPixel(); }
  70
  71     /**
  72      * Gets the number of app units in one device pixel; this number
  73      * is usually a factor of AppUnitsPerCSSPixel(), although that is
  74      * not guaranteed.
  75      */
  76     int32_t AppUnitsPerDevPixel() const { return mAppUnitsPerDevPixel; }
  77
  78     /**
  79      * Convert device pixels which is used for gfx/thebes to nearest
  80      * (rounded) app units
  81      */
  82     nscoord GfxUnitsToAppUnits(gfxFloat aGfxUnits) const
  83     { return nscoord(NS_round(aGfxUnits * AppUnitsPerDevPixel())); }
  84
  85     /**
  86      * Convert app units to device pixels which is used for gfx/thebes.
  87      */
  88     gfxFloat AppUnitsToGfxUnits(nscoord aAppUnits) const
  89     { return gfxFloat(aAppUnits) / AppUnitsPerDevPixel(); }
  90
  91     /**
  92      * Gets the number of app units in one physical inch; this is the
  93      * device's DPI times AppUnitsPerDevPixel().
  94      */
  95     int32_t AppUnitsPerPhysicalInch() const
  96     { return mAppUnitsPerPhysicalInch; }
  97
  98     /**
  99      * Gets the number of app units in one CSS inch; this is
 100      * 96 times AppUnitsPerCSSPixel.
 101      */
 102     static int32_t AppUnitsPerCSSInch() { return mozilla::AppUnitsPerCSSInch(); }
 103
 104     /**
 105      * Get the unscaled ratio of app units to dev pixels; useful if something
 106      * needs to be converted from to unscaled pixels
 107      */
 108     int32_t UnscaledAppUnitsPerDevPixel() const
 109     { return mAppUnitsPerDevNotScaledPixel; }
 110
 111     /**
 112      * Get the nsFontMetrics that describe the properties of
 113      * an nsFont.
 114      * @param aFont font description to obtain metrics for
 115      * @param aLanguage the language of the document
 116      * @param aMetrics out parameter for font metrics
 117      * @param aUserFontSet user font set
 118      * @return error status
 119      */
 120     nsresult GetMetricsFor(const nsFont& aFont, nsIAtom* aLanguage,
 121                            gfxUserFontSet* aUserFontSet,
 122                            gfxTextPerfMetrics* aTextPerf,
 123                            nsFontMetrics*& aMetrics);
 124
 125     /**
 126      * Notification when a font metrics instance created for this device is
 127      * about to be deleted
 128      */
 129     nsresult FontMetricsDeleted(const nsFontMetrics* aFontMetrics);
 130
 131     /**
 132      * Attempt to free up resources by flushing out any fonts no longer
 133      * referenced by anything other than the font cache itself.
 134      * @return error status
 135      */
 136     nsresult FlushFontCache();
 137
 138     /**
 139      * Return the bit depth of the device.
 140      */
 141     nsresult GetDepth(uint32_t& aDepth);
 142
 143     /**
 144      * Get the size of the displayable area of the output device
 145      * in app units.
 146      * @param aWidth out parameter for width
 147      * @param aHeight out parameter for height
 148      * @return error status
 149      */
 150     nsresult GetDeviceSurfaceDimensions(nscoord& aWidth, nscoord& aHeight);
 151
 152     /**
 153      * Get the size of the content area of the output device in app
 154      * units.  This corresponds on a screen device, for instance, to
 155      * the entire screen.
 156      * @param aRect out parameter for full rect. Position (x,y) will
 157      *              be (0,0) or relative to the primary monitor if
 158      *              this is not the primary.
 159      * @return error status
 160      */
 161     nsresult GetRect(nsRect& aRect);
 162
 163     /**
 164      * Get the size of the content area of the output device in app
 165      * units.  This corresponds on a screen device, for instance, to
 166      * the area reported by GetDeviceSurfaceDimensions, minus the
 167      * taskbar (Windows) or menubar (Macintosh).
 168      * @param aRect out parameter for client rect. Position (x,y) will
 169      *              be (0,0) adjusted for any upper/left non-client
 170      *              space if present or relative to the primary
 171      *              monitor if this is not the primary.
 172      * @return error status
 173      */
 174     nsresult GetClientRect(nsRect& aRect);
 175
 176     /**
 177      * Inform the output device that output of a document is beginning
 178      * Used for print related device contexts. Must be matched 1:1 with
 179      * EndDocument() or AbortDocument().
 180      *
 181      * @param aTitle - title of Document
 182      * @param aPrintToFileName - name of file to print to, if nullptr
 183      * then don't print to file
 184      * @param aStartPage - starting page number (must be greater than zero)
 185      * @param aEndPage - ending page number (must be less than or
 186      * equal to number of pages)
 187      *
 188      * @return error status
 189      */
 190     nsresult BeginDocument(const nsAString& aTitle,
 191                            char16_t*       aPrintToFileName,
 192                            int32_t          aStartPage,
 193                            int32_t          aEndPage);
 194
 195     /**
 196      * Inform the output device that output of a document is ending.
 197      * Used for print related device contexts. Must be matched 1:1 with
 198      * BeginDocument()
 199      * @return error status
 200      */
 201     nsresult EndDocument();
 202
 203     /**
 204      * Inform the output device that output of a document is being aborted.
 205      * Must be matched 1:1 with BeginDocument()
 206      * @return error status
 207      */
 208     nsresult AbortDocument();
 209
 210     /**
 211      * Inform the output device that output of a page is beginning
 212      * Used for print related device contexts. Must be matched 1:1 with
 213      * EndPage() and within a BeginDocument()/EndDocument() pair.
 214      * @return error status
 215      */
 216     nsresult BeginPage();
 217
 218     /**
 219      * Inform the output device that output of a page is ending
 220      * Used for print related device contexts. Must be matched 1:1 with
 221      * BeginPage() and within a BeginDocument()/EndDocument() pair.
 222      * @return error status
 223      */
 224     nsresult EndPage();
 225
 226     /**
 227      * Check to see if the DPI has changed
 228      * @return whether there was actually a change in the DPI (whether
 229      *         AppUnitsPerDevPixel() or AppUnitsPerPhysicalInch()
 230      *         changed)
 231      */
 232     bool CheckDPIChange();
 233
 234     /**
 235      * Set the pixel scaling factor: all lengths are multiplied by this factor
 236      * when we convert them to device pixels. Returns whether the ratio of
 237      * app units to dev pixels changed because of the scale factor.
 238      */
 239     bool SetPixelScale(float aScale);
 240
 241     /**
 242      * Returns the pixel scaling factor (page zoom factor) applied.
 243      */
 244     float GetPixelScale() const { return mPixelScale; }
 245
 246     /**
 247      * True if this device context was created for printing.
 248      */
 249     bool IsPrinterSurface();
 250
 251 private:
 252     // Private destructor, to discourage deletion outside of Release():
 253     ~nsDeviceContext();
 254
 255     void SetDPI();
 256     void ComputeClientRectUsingScreen(nsRect *outRect);
 257     void ComputeFullAreaUsingScreen(nsRect *outRect);
 258     void FindScreen(nsIScreen **outScreen);
 259     void CalcPrintingSize();
 260     void UpdateScaledAppUnits();
 261
 262     nscoord  mWidth;
 263     nscoord  mHeight;
 264     uint32_t mDepth;
 265     int32_t  mAppUnitsPerDevPixel;
 266     int32_t  mAppUnitsPerDevNotScaledPixel;
 267     int32_t  mAppUnitsPerPhysicalInch;
 268     float    mPixelScale;
 269     float    mPrintingScale;
 270
 271     nsFontCache*                   mFontCache;
 272     nsCOMPtr<nsIWidget>            mWidget;
 273     nsCOMPtr<nsIScreenManager>     mScreenManager;
 274     nsCOMPtr<nsIDeviceContextSpec> mDeviceContextSpec;
 275     nsRefPtr<gfxASurface>          mPrintingSurface;
 276 #ifdef XP_MACOSX
 277     nsRefPtr<gfxASurface>          mCachedPrintingSurface;
 278 #endif
 279 };
 280
 281 #endif /* _NS_DEVICECONTEXT_H_ */