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   enum class Kind : uint8_t {
  32     Android,
  33     Cocoa,
  34     Gtk,
  35     Win10,
  36     Win11,
  37   };
  38
  39   explicit ScrollbarDrawing(Kind aKind) : mKind(aKind) {}
  40
  41  public:
  42   virtual ~ScrollbarDrawing() = default;
  43
  44   enum class ScrollbarKind : uint8_t {
  45     Horizontal,
  46     VerticalLeft,
  47     VerticalRight,
  48   };
  49
  50   static DPIRatio GetDPIRatioForScrollbarPart(nsPresContext*);
  51
  52   static nsIFrame* GetParentScrollbarFrame(nsIFrame* aFrame);
  53   static bool IsParentScrollbarRolledOver(nsIFrame* aFrame);
  54   static bool IsParentScrollbarHoveredOrActive(nsIFrame* aFrame);
  55
  56   static bool IsScrollbarWidthThin(const ComputedStyle& aStyle);
  57   static bool IsScrollbarWidthThin(nsIFrame* aFrame);
  58
  59   virtual ScrollbarSizes GetScrollbarSizes(nsPresContext*, StyleScrollbarWidth,
  60                                            Overlay);
  61   ScrollbarSizes GetScrollbarSizes(nsPresContext*, nsIFrame*);
  62   virtual LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*,
  63                                                    StyleAppearance aAppearance,
  64                                                    nsIFrame* aFrame) = 0;
  65   virtual Maybe<nsITheme::Transparency> GetScrollbarPartTransparency(
  66       nsIFrame* aFrame, StyleAppearance aAppearance) {
  67     return Nothing();
  68   }
  69
  70   bool IsScrollbarTrackOpaque(nsIFrame*);
  71   virtual sRGBColor ComputeScrollbarTrackColor(
  72       nsIFrame*, const ComputedStyle&, const EventStates& aDocumentState,
  73       const Colors&);
  74   virtual sRGBColor ComputeScrollbarThumbColor(
  75       nsIFrame*, const ComputedStyle&, const EventStates& aElementState,
  76       const EventStates& aDocumentState, const Colors&);
  77
  78   nscolor GetScrollbarButtonColor(nscolor aTrackColor, EventStates);
  79   Maybe<nscolor> GetScrollbarArrowColor(nscolor aButtonColor);
  80
  81   // Returned colors are button, arrow.
  82   virtual std::pair<sRGBColor, sRGBColor> ComputeScrollbarButtonColors(
  83       nsIFrame*, StyleAppearance, const ComputedStyle&,
  84       const EventStates& aElementState, const EventStates& aDocumentState,
  85       const Colors&);
  86
  87   virtual bool PaintScrollbarButton(DrawTarget&, StyleAppearance,
  88                                     const LayoutDeviceRect&, ScrollbarKind,
  89                                     nsIFrame*, const ComputedStyle&,
  90                                     const EventStates& aElementState,
  91                                     const EventStates& aDocumentState,
  92                                     const Colors&, const DPIRatio&);
  93
  94   virtual bool PaintScrollbarThumb(DrawTarget&, const LayoutDeviceRect&,
  95                                    ScrollbarKind, nsIFrame*,
  96                                    const ComputedStyle&,
  97                                    const EventStates& aElementState,
  98                                    const EventStates& aDocumentState,
  99                                    const Colors&, const DPIRatio&) = 0;
 100   virtual bool PaintScrollbarThumb(WebRenderBackendData&,
 101                                    const LayoutDeviceRect&, ScrollbarKind,
 102                                    nsIFrame*, const ComputedStyle&,
 103                                    const EventStates& aElementState,
 104                                    const EventStates& aDocumentState,
 105                                    const Colors&, const DPIRatio&) = 0;
 106
 107   template <typename PaintBackendData>
 108   bool DoPaintDefaultScrollbar(PaintBackendData&, const LayoutDeviceRect&,
 109                                ScrollbarKind, nsIFrame*, const ComputedStyle&,
 110                                const EventStates& aElementState,
 111                                const EventStates& aDocumentState, const Colors&,
 112                                const DPIRatio&);
 113   bool PaintScrollbar(DrawTarget&, const LayoutDeviceRect&, ScrollbarKind,
 114                       nsIFrame*, const ComputedStyle&,
 115                       const EventStates& aElementState,
 116                       const EventStates& aDocumentState, const Colors&,
 117                       const DPIRatio&);
 118   bool PaintScrollbar(WebRenderBackendData&, const LayoutDeviceRect&,
 119                       ScrollbarKind, nsIFrame*, const ComputedStyle&,
 120                       const EventStates& aElementState,
 121                       const EventStates& aDocumentState, const Colors&,
 122                       const DPIRatio&);
 123
 124   virtual bool PaintScrollbarTrack(DrawTarget&, const LayoutDeviceRect&,
 125                                    ScrollbarKind, nsIFrame*,
 126                                    const ComputedStyle&,
 127                                    const EventStates& aDocumentState,
 128                                    const Colors&, const DPIRatio&) {
 129     // Draw nothing by default. Subclasses can override this.
 130     return true;
 131   }
 132   virtual bool PaintScrollbarTrack(WebRenderBackendData&,
 133                                    const LayoutDeviceRect&, ScrollbarKind,
 134                                    nsIFrame*, const ComputedStyle&,
 135                                    const EventStates& aDocumentState,
 136                                    const Colors&, const DPIRatio&) {
 137     // Draw nothing by default. Subclasses can override this.
 138     return true;
 139   }
 140
 141   template <typename PaintBackendData>
 142   bool DoPaintDefaultScrollCorner(PaintBackendData&, const LayoutDeviceRect&,
 143                                   ScrollbarKind, nsIFrame*,
 144                                   const ComputedStyle&,
 145                                   const EventStates& aDocumentState,
 146                                   const Colors&, const DPIRatio&);
 147   virtual bool PaintScrollCorner(DrawTarget&, const LayoutDeviceRect&,
 148                                  ScrollbarKind, nsIFrame*, const ComputedStyle&,
 149                                  const EventStates& aDocumentState,
 150                                  const Colors&, const DPIRatio&);
 151   virtual bool PaintScrollCorner(WebRenderBackendData&, const LayoutDeviceRect&,
 152                                  ScrollbarKind, nsIFrame*, const ComputedStyle&,
 153                                  const EventStates& aDocumentState,
 154                                  const Colors&, const DPIRatio&);
 155
 156   virtual void RecomputeScrollbarParams() = 0;
 157
 158   virtual bool ShouldDrawScrollbarButtons() { return true; }
 159
 160   uint32_t GetHorizontalScrollbarHeight() const {
 161     return mHorizontalScrollbarHeight;
 162   }
 163   uint32_t GetVerticalScrollbarWidth() const { return mVerticalScrollbarWidth; }
 164
 165  protected:
 166   // For some kind of style differences a full virtual method is overkill, so we
 167   // store the kind here so we can branch on it if necessary.
 168   Kind mKind;
 169   uint32_t mHorizontalScrollbarHeight = 0;
 170   uint32_t mVerticalScrollbarWidth = 0;
 171 };
 172
 173 }  // namespace mozilla::widget
 174
 175 #endif