gfx/src/nsDeviceContext.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   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 "gfxFont.h"                  // for gfxFont::Orientation
  13 #include "mozilla/Assertions.h"       // for MOZ_ASSERT_HELPER2
  14 #include "mozilla/RefPtr.h"           // for RefPtr
  15 #include "nsCOMPtr.h"                 // for nsCOMPtr
  16 #include "nsCoord.h"                  // for nscoord
  17 #include "nsError.h"                  // for nsresult
  18 #include "nsISupports.h"              // for NS_INLINE_DECL_REFCOUNTING
  19 #include "nsMathUtils.h"              // for NS_round
  20 #include "nscore.h"                   // for char16_t, nsAString
  21 #include "mozilla/AppUnits.h"         // for AppUnits
  22 #include "nsFontMetrics.h"            // for nsFontMetrics::Params
  23 #include "mozilla/gfx/PrintTarget.h"  // for PrintTarget::PageDoneCallback
  24
  25 class gfxContext;
  26 class gfxTextPerfMetrics;
  27 class gfxUserFontSet;
  28 struct nsFont;
  29 class nsAtom;
  30 class nsIDeviceContextSpec;
  31 class nsIScreen;
  32 class nsIScreenManager;
  33 class nsIWidget;
  34 struct nsRect;
  35
  36 class nsDeviceContext final {
  37  public:
  38   typedef mozilla::gfx::PrintTarget PrintTarget;
  39
  40   nsDeviceContext();
  41
  42   NS_INLINE_DECL_REFCOUNTING(nsDeviceContext)
  43
  44   /**
  45    * Initialize the device context from a widget
  46    * @param aWidget a widget to initialize the device context from
  47    * @return error status
  48    */
  49   nsresult Init(nsIWidget* aWidget);
  50
  51   /**
  52    * Initialize the device context from a device context spec
  53    * @param aDevSpec the specification of the printing device
  54    * @return error status
  55    */
  56   nsresult InitForPrinting(nsIDeviceContextSpec* aDevSpec);
  57
  58   /**
  59    * Create a rendering context and initialize it.  Only call this
  60    * method on device contexts that were initialized for printing.
  61    *
  62    * @return the new rendering context (guaranteed to be non-null)
  63    */
  64   already_AddRefed<gfxContext> CreateRenderingContext();
  65
  66   /**
  67    * Create a reference rendering context and initialize it.  Only call this
  68    * method on device contexts that were initialized for printing.
  69    *
  70    * @return the new rendering context.
  71    */
  72   already_AddRefed<gfxContext> CreateReferenceRenderingContext();
  73
  74   /**
  75    * Gets the number of app units in one device pixel; this number
  76    * is usually a factor of AppUnitsPerCSSPixel(), although that is
  77    * not guaranteed.
  78    */
  79   int32_t AppUnitsPerDevPixel() const { return mAppUnitsPerDevPixel; }
  80
  81   /**
  82    * Convert device pixels which is used for gfx/thebes to nearest
  83    * (rounded) app units
  84    */
  85   nscoord GfxUnitsToAppUnits(gfxFloat aGfxUnits) const {
  86     return nscoord(NS_round(aGfxUnits * AppUnitsPerDevPixel()));
  87   }
  88
  89   /**
  90    * Convert app units to device pixels which is used for gfx/thebes.
  91    */
  92   gfxFloat AppUnitsToGfxUnits(nscoord aAppUnits) const {
  93     return gfxFloat(aAppUnits) / AppUnitsPerDevPixel();
  94   }
  95
  96   /**
  97    * Gets the number of app units in one physical inch; this is the
  98    * device's DPI times AppUnitsPerDevPixel().
  99    */
 100   int32_t AppUnitsPerPhysicalInch() const { return mAppUnitsPerPhysicalInch; }
 101
 102   /**
 103    * Get the ratio of app units to dev pixels that would be used at unit
 104    * (100%) full zoom.
 105    */
 106   int32_t AppUnitsPerDevPixelAtUnitFullZoom() const {
 107     return mAppUnitsPerDevPixelAtUnitFullZoom;
 108   }
 109
 110   /**
 111    * Get the ratio of app units to dev pixels that would be used in a top-level
 112    * chrome page such as browser.xhtml.
 113    */
 114   int32_t AppUnitsPerDevPixelInTopLevelChromePage() const;
 115
 116   /**
 117    * Return the bit depth of the device.
 118    */
 119   uint32_t GetDepth();
 120
 121   /**
 122    * Get the size of the displayable area of the output device
 123    * in app units.
 124    * @param aWidth out parameter for width
 125    * @param aHeight out parameter for height
 126    * @return error status
 127    */
 128   nsresult GetDeviceSurfaceDimensions(nscoord& aWidth, nscoord& aHeight);
 129
 130   /**
 131    * Get the size of the content area of the output device in app
 132    * units.  This corresponds on a screen device, for instance, to
 133    * the entire screen.
 134    * @param aRect out parameter for full rect. Position (x,y) will
 135    *              be (0,0) or relative to the primary monitor if
 136    *              this is not the primary.
 137    * @return error status
 138    */
 139   nsresult GetRect(nsRect& aRect);
 140
 141   /**
 142    * Get the size of the content area of the output device in app
 143    * units.  This corresponds on a screen device, for instance, to
 144    * the area reported by GetDeviceSurfaceDimensions, minus the
 145    * taskbar (Windows) or menubar (Macintosh).
 146    * @param aRect out parameter for client rect. Position (x,y) will
 147    *              be (0,0) adjusted for any upper/left non-client
 148    *              space if present or relative to the primary
 149    *              monitor if this is not the primary.
 150    * @return error status
 151    */
 152   nsresult GetClientRect(nsRect& aRect);
 153
 154   /**
 155    * Returns true if we're currently between BeginDocument() and
 156    * EndDocument() calls.
 157    */
 158   bool IsCurrentlyPrintingDocument() const { return mIsCurrentlyPrintingDoc; }
 159
 160   /**
 161    * Inform the output device that output of a document is beginning
 162    * Used for print related device contexts. Must be matched 1:1 with
 163    * EndDocument() or AbortDocument().
 164    *
 165    * @param aTitle - title of Document
 166    * @param aPrintToFileName - name of file to print to, if empty then don't
 167    *                           print to file
 168    * @param aStartPage - starting page number (must be greater than zero)
 169    * @param aEndPage - ending page number (must be less than or
 170    * equal to number of pages)
 171    *
 172    * @return error status
 173    */
 174   nsresult BeginDocument(const nsAString& aTitle,
 175                          const nsAString& aPrintToFileName, int32_t aStartPage,
 176                          int32_t aEndPage);
 177
 178   /**
 179    * Inform the output device that output of a document is ending.
 180    * Used for print related device contexts. Must be matched 1:1 with
 181    * BeginDocument()
 182    * @return error status
 183    */
 184   nsresult EndDocument();
 185
 186   /**
 187    * Inform the output device that output of a document is being aborted.
 188    * Must be matched 1:1 with BeginDocument()
 189    * @return error status
 190    */
 191   nsresult AbortDocument();
 192
 193   /**
 194    * Inform the output device that output of a page is beginning
 195    * Used for print related device contexts. Must be matched 1:1 with
 196    * EndPage() and within a BeginDocument()/EndDocument() pair.
 197    * @return error status
 198    */
 199   nsresult BeginPage();
 200
 201   /**
 202    * Inform the output device that output of a page is ending
 203    * Used for print related device contexts. Must be matched 1:1 with
 204    * BeginPage() and within a BeginDocument()/EndDocument() pair.
 205    * @return error status
 206    */
 207   nsresult EndPage();
 208
 209   /**
 210    * Check to see if the DPI has changed, or impose a new DPI scale value.
 211    * @return whether there was actually a change in the DPI (whether
 212    *         AppUnitsPerDevPixel() or AppUnitsPerPhysicalInch()
 213    *         changed)
 214    */
 215   bool CheckDPIChange();
 216
 217   /**
 218    * Set the full zoom factor: all lengths are multiplied by this factor
 219    * when we convert them to device pixels. Returns whether the ratio of
 220    * app units to dev pixels changed because of the zoom factor.
 221    */
 222   bool SetFullZoom(float aScale);
 223
 224   /**
 225    * Returns the page full zoom factor applied.
 226    */
 227   float GetFullZoom() const { return mFullZoom; }
 228
 229   /**
 230    * True if this device context was created for printing.
 231    */
 232   bool IsPrinterContext() const { return !!mPrintTarget; }
 233
 234   mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale();
 235
 236  private:
 237   // Private destructor, to discourage deletion outside of Release():
 238   ~nsDeviceContext();
 239
 240   /**
 241    * Implementation shared by CreateRenderingContext and
 242    * CreateReferenceRenderingContext.
 243    */
 244   already_AddRefed<gfxContext> CreateRenderingContextCommon(
 245       bool aWantReferenceContext);
 246
 247   void SetDPI();
 248   void ComputeClientRectUsingScreen(nsRect* outRect);
 249   void ComputeFullAreaUsingScreen(nsRect* outRect);
 250   void FindScreen(nsIScreen** outScreen);
 251
 252   // Return false if the surface is not right
 253   bool CalcPrintingSize();
 254   void UpdateAppUnitsForFullZoom();
 255
 256   nscoord mWidth;
 257   nscoord mHeight;
 258   int32_t mAppUnitsPerDevPixel;
 259   int32_t mAppUnitsPerDevPixelAtUnitFullZoom;
 260   int32_t mAppUnitsPerPhysicalInch;
 261   float mFullZoom;
 262   float mPrintingScale;
 263   gfxPoint mPrintingTranslate;
 264
 265   nsCOMPtr<nsIWidget> mWidget;
 266   nsCOMPtr<nsIScreenManager> mScreenManager;
 267   nsCOMPtr<nsIDeviceContextSpec> mDeviceContextSpec;
 268   RefPtr<PrintTarget> mPrintTarget;
 269   bool mIsCurrentlyPrintingDoc;
 270 #ifdef DEBUG
 271   bool mIsInitialized;
 272 #endif
 273 };
 274
 275 #endif /* _NS_DEVICECONTEXT_H_ */