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    * Return the bit depth of the device.
 112    */
 113   uint32_t GetDepth();
 114
 115   /**
 116    * Get the size of the displayable area of the output device
 117    * in app units.
 118    * @param aWidth out parameter for width
 119    * @param aHeight out parameter for height
 120    * @return error status
 121    */
 122   nsresult GetDeviceSurfaceDimensions(nscoord& aWidth, nscoord& aHeight);
 123
 124   /**
 125    * Get the size of the content area of the output device in app
 126    * units.  This corresponds on a screen device, for instance, to
 127    * the entire screen.
 128    * @param aRect out parameter for full rect. Position (x,y) will
 129    *              be (0,0) or relative to the primary monitor if
 130    *              this is not the primary.
 131    * @return error status
 132    */
 133   nsresult GetRect(nsRect& aRect);
 134
 135   /**
 136    * Get the size of the content area of the output device in app
 137    * units.  This corresponds on a screen device, for instance, to
 138    * the area reported by GetDeviceSurfaceDimensions, minus the
 139    * taskbar (Windows) or menubar (Macintosh).
 140    * @param aRect out parameter for client rect. Position (x,y) will
 141    *              be (0,0) adjusted for any upper/left non-client
 142    *              space if present or relative to the primary
 143    *              monitor if this is not the primary.
 144    * @return error status
 145    */
 146   nsresult GetClientRect(nsRect& aRect);
 147
 148   /**
 149    * Returns true if we're currently between BeginDocument() and
 150    * EndDocument() calls.
 151    */
 152   bool IsCurrentlyPrintingDocument() const { return mIsCurrentlyPrintingDoc; }
 153
 154   /**
 155    * Inform the output device that output of a document is beginning
 156    * Used for print related device contexts. Must be matched 1:1 with
 157    * EndDocument() or AbortDocument().
 158    *
 159    * @param aTitle - title of Document
 160    * @param aPrintToFileName - name of file to print to, if empty then don't
 161    *                           print to file
 162    * @param aStartPage - starting page number (must be greater than zero)
 163    * @param aEndPage - ending page number (must be less than or
 164    * equal to number of pages)
 165    *
 166    * @return error status
 167    */
 168   nsresult BeginDocument(const nsAString& aTitle,
 169                          const nsAString& aPrintToFileName, int32_t aStartPage,
 170                          int32_t aEndPage);
 171
 172   /**
 173    * Inform the output device that output of a document is ending.
 174    * Used for print related device contexts. Must be matched 1:1 with
 175    * BeginDocument()
 176    * @return error status
 177    */
 178   nsresult EndDocument();
 179
 180   /**
 181    * Inform the output device that output of a document is being aborted.
 182    * Must be matched 1:1 with BeginDocument()
 183    * @return error status
 184    */
 185   nsresult AbortDocument();
 186
 187   /**
 188    * Inform the output device that output of a page is beginning
 189    * Used for print related device contexts. Must be matched 1:1 with
 190    * EndPage() and within a BeginDocument()/EndDocument() pair.
 191    * @return error status
 192    */
 193   nsresult BeginPage();
 194
 195   /**
 196    * Inform the output device that output of a page is ending
 197    * Used for print related device contexts. Must be matched 1:1 with
 198    * BeginPage() and within a BeginDocument()/EndDocument() pair.
 199    * @return error status
 200    */
 201   nsresult EndPage();
 202
 203   /**
 204    * Check to see if the DPI has changed, or impose a new DPI scale value.
 205    * @return whether there was actually a change in the DPI (whether
 206    *         AppUnitsPerDevPixel() or AppUnitsPerPhysicalInch()
 207    *         changed)
 208    */
 209   bool CheckDPIChange();
 210
 211   /**
 212    * Set the full zoom factor: all lengths are multiplied by this factor
 213    * when we convert them to device pixels. Returns whether the ratio of
 214    * app units to dev pixels changed because of the zoom factor.
 215    */
 216   bool SetFullZoom(float aScale);
 217
 218   /**
 219    * Returns the page full zoom factor applied.
 220    */
 221   float GetFullZoom() const { return mFullZoom; }
 222
 223   /**
 224    * True if this device context was created for printing.
 225    */
 226   bool IsPrinterContext() const { return !!mPrintTarget; }
 227
 228   mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale();
 229
 230  private:
 231   // Private destructor, to discourage deletion outside of Release():
 232   ~nsDeviceContext();
 233
 234   /**
 235    * Implementation shared by CreateRenderingContext and
 236    * CreateReferenceRenderingContext.
 237    */
 238   already_AddRefed<gfxContext> CreateRenderingContextCommon(
 239       bool aWantReferenceContext);
 240
 241   void SetDPI();
 242   void ComputeClientRectUsingScreen(nsRect* outRect);
 243   void ComputeFullAreaUsingScreen(nsRect* outRect);
 244   void FindScreen(nsIScreen** outScreen);
 245
 246   // Return false if the surface is not right
 247   bool CalcPrintingSize();
 248   void UpdateAppUnitsForFullZoom();
 249
 250   nscoord mWidth;
 251   nscoord mHeight;
 252   int32_t mAppUnitsPerDevPixel;
 253   int32_t mAppUnitsPerDevPixelAtUnitFullZoom;
 254   int32_t mAppUnitsPerPhysicalInch;
 255   float mFullZoom;
 256   float mPrintingScale;
 257   gfxPoint mPrintingTranslate;
 258
 259   nsCOMPtr<nsIWidget> mWidget;
 260   nsCOMPtr<nsIScreenManager> mScreenManager;
 261   nsCOMPtr<nsIDeviceContextSpec> mDeviceContextSpec;
 262   RefPtr<PrintTarget> mPrintTarget;
 263   bool mIsCurrentlyPrintingDoc;
 264 #ifdef DEBUG
 265   bool mIsInitialized;
 266 #endif
 267 };
 268
 269 #endif /* _NS_DEVICECONTEXT_H_ */