gfx/public/nsITheme.h

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  38
  39 /* service providing platform-specific native rendering for widgets */
  40
  41 #ifndef nsITheme_h_
  42 #define nsITheme_h_
  43
  44 #include "nsISupports.h"
  45 #include "nsCOMPtr.h"
  46 #include "nsColor.h"
  47
  48 struct nsRect;
  49 struct nsSize;
  50 struct nsFont;
  51 struct nsMargin;
  52 class nsPresContext;
  53 class nsIRenderingContext;
  54 class nsIDeviceContext;
  55 class nsIFrame;
  56 class nsIContent;
  57 class nsIAtom;
  58
  59 // IID for the nsITheme interface
  60 // {df8baf21-5ea7-49eb-a2bc-f2fd4a9fd896}
  61 #define NS_ITHEME_IID     \
  62 { 0xdf8baf21, 0x5ea7, 0x49eb, { 0xa2, 0xbc, 0xf2, 0xfd, 0x4a, 0x9f, 0xd8, 0x96 } }
  63
  64 // {D930E29B-6909-44e5-AB4B-AF10D6923705}
  65 #define NS_THEMERENDERER_CID \
  66 { 0xd930e29b, 0x6909, 0x44e5, { 0xab, 0x4b, 0xaf, 0x10, 0xd6, 0x92, 0x37, 0x5 } }
  67
  68 /**
  69  * nsITheme is a service that provides platform-specific native
  70  * rendering for widgets.  In other words, it provides the necessary
  71  * operations to draw a rendering object (an nsIFrame) as a native
  72  * widget.
  73  *
  74  * All the methods on nsITheme take a rendering context or device
  75  * context, a frame (the rendering object), and a widget type (one of
  76  * the constants in nsThemeConstants.h).
  77  */
  78 class nsITheme: public nsISupports {
  79 public:
  80   NS_DECLARE_STATIC_IID_ACCESSOR(NS_ITHEME_IID)
  81
  82   NS_IMETHOD DrawWidgetBackground(nsIRenderingContext* aContext,
  83                                   nsIFrame* aFrame,
  84                                   PRUint8 aWidgetType,
  85                                   const nsRect& aRect,
  86                                   const nsRect& aDirtyRect)=0;
  87
  88   /**
  89    * Get the computed CSS border for the widget, in pixels.
  90    */
  91   NS_IMETHOD GetWidgetBorder(nsIDeviceContext* aContext,
  92                              nsIFrame* aFrame,
  93                              PRUint8 aWidgetType,
  94                              nsMargin* aResult)=0;
  95
  96   /**
  97    * This method can return PR_FALSE to indicate that the CSS padding
  98    * value should be used.  Otherwise, it will fill in aResult with the
  99    * computed padding, in pixels, and return PR_TRUE.
 100    *
 101    * XXXldb This ought to be required to return true for non-containers
 102    * so that we don't let specified padding that has no effect change
 103    * the computed padding and potentially the size.
 104    */
 105   virtual PRBool GetWidgetPadding(nsIDeviceContext* aContext,
 106                                   nsIFrame* aFrame,
 107                                   PRUint8 aWidgetType,
 108                                   nsMargin* aResult) = 0;
 109
 110   /**
 111    * On entry, *aResult is positioned at 0,0 and sized to the new size
 112    * of aFrame (aFrame->GetSize() may be stale and should not be used).
 113    * This method can return PR_FALSE to indicate that no special
 114    * overflow area is required by the native widget. Otherwise it will
 115    * fill in aResult with the desired overflow area, in appunits, relative
 116    * to the frame origin, and return PR_TRUE.
 117    */
 118   virtual PRBool GetWidgetOverflow(nsIDeviceContext* aContext,
 119                                    nsIFrame* aFrame,
 120                                    PRUint8 aWidgetType,
 121                                    /*INOUT*/ nsRect* aOverflowRect)
 122   { return PR_FALSE; }
 123
 124   /**
 125    * Get the minimum border-box size of a widget, in *pixels* (in
 126    * |aResult|).  If |aIsOverridable| is set to true, this size is a
 127    * minimum size; if false, this size is the only valid size for the
 128    * widget.
 129    */
 130   NS_IMETHOD GetMinimumWidgetSize(nsIRenderingContext* aContext,
 131                                   nsIFrame* aFrame,
 132                                   PRUint8 aWidgetType,
 133                                   nsSize* aResult,
 134                                   PRBool* aIsOverridable)=0;
 135
 136   NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, PRUint8 aWidgetType,
 137                                 nsIAtom* aAttribute, PRBool* aShouldRepaint)=0;
 138
 139   NS_IMETHOD ThemeChanged()=0;
 140
 141   /**
 142    * Can the nsITheme implementation handle this widget?
 143    */
 144   virtual PRBool ThemeSupportsWidget(nsPresContext* aPresContext,
 145                                      nsIFrame* aFrame,
 146                                      PRUint8 aWidgetType)=0;
 147
 148   virtual PRBool WidgetIsContainer(PRUint8 aWidgetType)=0;
 149
 150   /**
 151    * Does the nsITheme implementation draw its own focus ring for this widget?
 152    */
 153   virtual PRBool ThemeDrawsFocusForWidget(nsPresContext* aPresContext,
 154                                           nsIFrame* aFrame,
 155                                           PRUint8 aWidgetType)=0;
 156
 157   /**
 158     * Should we insert a dropmarker inside of combobox button?
 159    */
 160   virtual PRBool ThemeNeedsComboboxDropmarker()=0;
 161 };
 162
 163 NS_DEFINE_STATIC_IID_ACCESSOR(nsITheme, NS_ITHEME_IID)
 164
 165 // Creator function
 166 extern NS_METHOD NS_NewNativeTheme(nsISupports *aOuter, REFNSIID aIID, void **aResult);
 167
 168 #endif