widget/ScrollbarDrawing.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   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 #ifndef mozilla_widget_ScrollbarDrawing_h
   8 #define mozilla_widget_ScrollbarDrawing_h
   9
  10 #include "mozilla/EventStates.h"
  11 #include "mozilla/gfx/2D.h"
  12 #include "nsColor.h"
  13 #include "nsITheme.h"
  14 #include "ThemeColors.h"
  15 #include "ThemeDrawing.h"
  16 #include "Units.h"
  17
  18 namespace mozilla::widget {
  19
  20 class ScrollbarDrawing {
  21  protected:
  22   using DPIRatio = mozilla::CSSToLayoutDeviceScale;
  23   using EventStates = mozilla::EventStates;
  24   using DrawTarget = mozilla::gfx::DrawTarget;
  25   using sRGBColor = mozilla::gfx::sRGBColor;
  26   using Colors = ThemeColors;
  27   using ScrollbarSizes = nsITheme::ScrollbarSizes;
  28   using Overlay = nsITheme::Overlay;
  29   using WebRenderBackendData = mozilla::widget::WebRenderBackendData;
  30
  31  public:
  32   ScrollbarDrawing() = default;
  33   virtual ~ScrollbarDrawing() = default;
  34
  35   static DPIRatio GetDPIRatioForScrollbarPart(nsPresContext*);
  36
  37   static nsIFrame* GetParentScrollbarFrame(nsIFrame* aFrame);
  38   static bool IsParentScrollbarRolledOver(nsIFrame* aFrame);
  39   static bool IsParentScrollbarHoveredOrActive(nsIFrame* aFrame);
  40
  41   static bool IsScrollbarWidthThin(const ComputedStyle& aStyle);
  42   static bool IsScrollbarWidthThin(nsIFrame* aFrame);
  43
  44   virtual ScrollbarSizes GetScrollbarSizes(nsPresContext*, StyleScrollbarWidth,
  45                                            Overlay);
  46   ScrollbarSizes GetScrollbarSizes(nsPresContext*, nsIFrame*);
  47   virtual LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*,
  48                                                    StyleAppearance aAppearance,
  49                                                    nsIFrame* aFrame) = 0;
  50   virtual Maybe<nsITheme::Transparency> GetScrollbarPartTransparency(
  51       nsIFrame* aFrame, StyleAppearance aAppearance) {
  52     return Nothing();
  53   }
  54
  55   bool IsScrollbarTrackOpaque(nsIFrame*);
  56   virtual sRGBColor ComputeScrollbarTrackColor(
  57       nsIFrame*, const ComputedStyle&, const EventStates& aDocumentState,
  58       const Colors&);
  59   virtual sRGBColor ComputeScrollbarThumbColor(
  60       nsIFrame*, const ComputedStyle&, const EventStates& aElementState,
  61       const EventStates& aDocumentState, const Colors&);
  62
  63   nscolor GetScrollbarButtonColor(nscolor aTrackColor, EventStates);
  64   Maybe<nscolor> GetScrollbarArrowColor(nscolor aButtonColor);
  65
  66   // Returned colors are button, arrow.
  67   virtual std::pair<sRGBColor, sRGBColor> ComputeScrollbarButtonColors(
  68       nsIFrame*, StyleAppearance, const ComputedStyle&,
  69       const EventStates& aElementState, const EventStates& aDocumentState,
  70       const Colors&);
  71
  72   virtual bool PaintScrollbarButton(DrawTarget&, StyleAppearance,
  73                                     const LayoutDeviceRect&, nsIFrame*,
  74                                     const ComputedStyle&,
  75                                     const EventStates& aElementState,
  76                                     const EventStates& aDocumentState,
  77                                     const Colors&, const DPIRatio&);
  78
  79   virtual bool PaintScrollbarThumb(DrawTarget&, const LayoutDeviceRect&,
  80                                    bool aHorizontal, nsIFrame*,
  81                                    const ComputedStyle&,
  82                                    const EventStates& aElementState,
  83                                    const EventStates& aDocumentState,
  84                                    const Colors&, const DPIRatio&) = 0;
  85   virtual bool PaintScrollbarThumb(WebRenderBackendData&,
  86                                    const LayoutDeviceRect&, bool aHorizontal,
  87                                    nsIFrame*, const ComputedStyle&,
  88                                    const EventStates& aElementState,
  89                                    const EventStates& aDocumentState,
  90                                    const Colors&, const DPIRatio&) = 0;
  91
  92   template <typename PaintBackendData>
  93   bool DoPaintDefaultScrollbar(PaintBackendData&, const LayoutDeviceRect&,
  94                                bool aHorizontal, nsIFrame*,
  95                                const ComputedStyle&,
  96                                const EventStates& aElementState,
  97                                const EventStates& aDocumentState, const Colors&,
  98                                const DPIRatio&);
  99   virtual bool PaintScrollbar(DrawTarget&, const LayoutDeviceRect&,
 100                               bool aHorizontal, nsIFrame*, const ComputedStyle&,
 101                               const EventStates& aElementState,
 102                               const EventStates& aDocumentState, const Colors&,
 103                               const DPIRatio&);
 104   virtual bool PaintScrollbar(WebRenderBackendData&, const LayoutDeviceRect&,
 105                               bool aHorizontal, nsIFrame*, const ComputedStyle&,
 106                               const EventStates& aElementState,
 107                               const EventStates& aDocumentState, const Colors&,
 108                               const DPIRatio&);
 109
 110   virtual bool PaintScrollbarTrack(DrawTarget&, const LayoutDeviceRect&,
 111                                    bool aHorizontal, nsIFrame*,
 112                                    const ComputedStyle&,
 113                                    const EventStates& aDocumentState,
 114                                    const Colors&, const DPIRatio&) {
 115     // Draw nothing by default. Subclasses can override this.
 116     return true;
 117   }
 118   virtual bool PaintScrollbarTrack(WebRenderBackendData&,
 119                                    const LayoutDeviceRect&, bool aHorizontal,
 120                                    nsIFrame*, const ComputedStyle&,
 121                                    const EventStates& aDocumentState,
 122                                    const Colors&, const DPIRatio&) {
 123     // Draw nothing by default. Subclasses can override this.
 124     return true;
 125   }
 126
 127   template <typename PaintBackendData>
 128   bool DoPaintDefaultScrollCorner(PaintBackendData&, const LayoutDeviceRect&,
 129                                   nsIFrame*, const ComputedStyle&,
 130                                   const EventStates& aDocumentState,
 131                                   const Colors&, const DPIRatio&);
 132   virtual bool PaintScrollCorner(DrawTarget&, const LayoutDeviceRect&,
 133                                  nsIFrame*, const ComputedStyle&,
 134                                  const EventStates& aDocumentState,
 135                                  const Colors&, const DPIRatio&);
 136   virtual bool PaintScrollCorner(WebRenderBackendData&, const LayoutDeviceRect&,
 137                                  nsIFrame*, const ComputedStyle&,
 138                                  const EventStates& aDocumentState,
 139                                  const Colors&, const DPIRatio&);
 140
 141   virtual void RecomputeScrollbarParams() = 0;
 142
 143   virtual bool ShouldDrawScrollbarButtons() { return true; }
 144
 145   uint32_t GetHorizontalScrollbarHeight() const {
 146     return mHorizontalScrollbarHeight;
 147   }
 148   uint32_t GetVerticalScrollbarWidth() const { return mVerticalScrollbarWidth; }
 149
 150  protected:
 151   uint32_t mHorizontalScrollbarHeight = 0;
 152   uint32_t mVerticalScrollbarWidth = 0;
 153 };
 154
 155 }  // namespace mozilla::widget
 156
 157 #endif