gfx/src/nsITheme.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /* service providing platform-specific native rendering for widgets */
   8
   9 #ifndef nsITheme_h_
  10 #define nsITheme_h_
  11
  12 #include "nsISupports.h"
  13 #include "nsCOMPtr.h"
  14 #include "nsColor.h"
  15
  16 struct nsRect;
  17 struct nsIntRect;
  18 struct nsIntSize;
  19 struct nsFont;
  20 struct nsIntMargin;
  21 class nsPresContext;
  22 class nsRenderingContext;
  23 class nsDeviceContext;
  24 class nsIFrame;
  25 class nsIContent;
  26 class nsIAtom;
  27 class nsIWidget;
  28
  29 // IID for the nsITheme interface
  30 // {b0f3efe9-0bd4-4f6b-8daa-0ec7f6006822}
  31  #define NS_ITHEME_IID     \
  32 { 0xb0f3efe9, 0x0bd4, 0x4f6b, { 0x8d, 0xaa, 0x0e, 0xc7, 0xf6, 0x00, 0x68, 0x22 } }
  33 // {D930E29B-6909-44e5-AB4B-AF10D6923705}
  34 #define NS_THEMERENDERER_CID \
  35 { 0xd930e29b, 0x6909, 0x44e5, { 0xab, 0x4b, 0xaf, 0x10, 0xd6, 0x92, 0x37, 0x5 } }
  36
  37 enum nsTransparencyMode {
  38   eTransparencyOpaque = 0,  // Fully opaque
  39   eTransparencyTransparent, // Parts of the window may be transparent
  40   eTransparencyGlass,       // Transparent parts of the window have Vista AeroGlass effect applied
  41   eTransparencyBorderlessGlass // As above, but without a border around the opaque areas when there would otherwise be one with eTransparencyGlass
  42 };
  43
  44 /**
  45  * nsITheme is a service that provides platform-specific native
  46  * rendering for widgets.  In other words, it provides the necessary
  47  * operations to draw a rendering object (an nsIFrame) as a native
  48  * widget.
  49  *
  50  * All the methods on nsITheme take a rendering context or device
  51  * context, a frame (the rendering object), and a widget type (one of
  52  * the constants in nsThemeConstants.h).
  53  */
  54 class nsITheme: public nsISupports {
  55 public:
  56   NS_DECLARE_STATIC_IID_ACCESSOR(NS_ITHEME_IID)
  57
  58   /**
  59    * Draw the actual theme background.
  60    * @param aContext the context to draw into
  61    * @param aFrame the frame for the widget that we're drawing
  62    * @param aWidgetType the -moz-appearance value to draw
  63    * @param aRect the rectangle defining the area occupied by the widget
  64    * @param aDirtyRect the rectangle that needs to be drawn
  65    */
  66   NS_IMETHOD DrawWidgetBackground(nsRenderingContext* aContext,
  67                                   nsIFrame* aFrame,
  68                                   uint8_t aWidgetType,
  69                                   const nsRect& aRect,
  70                                   const nsRect& aDirtyRect) = 0;
  71
  72   /**
  73    * Get the computed CSS border for the widget, in pixels.
  74    */
  75   NS_IMETHOD GetWidgetBorder(nsDeviceContext* aContext,
  76                              nsIFrame* aFrame,
  77                              uint8_t aWidgetType,
  78                              nsIntMargin* aResult)=0;
  79
  80   /**
  81    * This method can return false to indicate that the CSS padding
  82    * value should be used.  Otherwise, it will fill in aResult with the
  83    * computed padding, in pixels, and return true.
  84    *
  85    * XXXldb This ought to be required to return true for non-containers
  86    * so that we don't let specified padding that has no effect change
  87    * the computed padding and potentially the size.
  88    */
  89   virtual bool GetWidgetPadding(nsDeviceContext* aContext,
  90                                   nsIFrame* aFrame,
  91                                   uint8_t aWidgetType,
  92                                   nsIntMargin* aResult) = 0;
  93
  94   /**
  95    * On entry, *aResult is positioned at 0,0 and sized to the new size
  96    * of aFrame (aFrame->GetSize() may be stale and should not be used).
  97    * This method can return false to indicate that no special
  98    * overflow area is required by the native widget. Otherwise it will
  99    * fill in aResult with the desired overflow area, in appunits, relative
 100    * to the frame origin, and return true.
 101    *
 102    * This overflow area is used to determine what area needs to be
 103    * repainted when the widget changes.  However, it does not affect the
 104    * widget's size or what area is reachable by scrollbars.  (In other
 105    * words, in layout terms, it affects visual overflow but not
 106    * scrollable overflow.)
 107    */
 108   virtual bool GetWidgetOverflow(nsDeviceContext* aContext,
 109                                    nsIFrame* aFrame,
 110                                    uint8_t aWidgetType,
 111                                    /*INOUT*/ nsRect* aOverflowRect)
 112   { return false; }
 113
 114   /**
 115    * Get the minimum border-box size of a widget, in *pixels* (in
 116    * |aResult|).  If |aIsOverridable| is set to true, this size is a
 117    * minimum size; if false, this size is the only valid size for the
 118    * widget.
 119    */
 120   NS_IMETHOD GetMinimumWidgetSize(nsRenderingContext* aContext,
 121                                   nsIFrame* aFrame,
 122                                   uint8_t aWidgetType,
 123                                   nsIntSize* aResult,
 124                                   bool* aIsOverridable)=0;
 125
 126
 127   enum Transparency {
 128     eOpaque = 0,
 129     eTransparent,
 130     eUnknownTransparency
 131   };
 132
 133   /**
 134    * Returns what we know about the transparency of the widget.
 135    */
 136   virtual Transparency GetWidgetTransparency(nsIFrame* aFrame, uint8_t aWidgetType)
 137   { return eUnknownTransparency; }
 138
 139   NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, uint8_t aWidgetType,
 140                                 nsIAtom* aAttribute, bool* aShouldRepaint)=0;
 141
 142   NS_IMETHOD ThemeChanged()=0;
 143
 144   /**
 145    * Can the nsITheme implementation handle this widget?
 146    */
 147   virtual bool ThemeSupportsWidget(nsPresContext* aPresContext,
 148                                      nsIFrame* aFrame,
 149                                      uint8_t aWidgetType)=0;
 150
 151   virtual bool WidgetIsContainer(uint8_t aWidgetType)=0;
 152
 153   /**
 154    * Does the nsITheme implementation draw its own focus ring for this widget?
 155    */
 156   virtual bool ThemeDrawsFocusForWidget(uint8_t aWidgetType)=0;
 157
 158   /**
 159     * Should we insert a dropmarker inside of combobox button?
 160    */
 161   virtual bool ThemeNeedsComboboxDropmarker()=0;
 162 };
 163
 164 NS_DEFINE_STATIC_IID_ACCESSOR(nsITheme, NS_ITHEME_IID)
 165
 166 // Creator function
 167 extern nsresult NS_NewNativeTheme(nsISupports *aOuter, REFNSIID aIID, void **aResult);
 168
 169 #endif