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 static constexpr gfx::sRGBColor sScrollbarColor(
  21     gfx::sRGBColor::UnusualFromARGB(0xfff0f0f0));
  22 static constexpr gfx::sRGBColor sScrollbarThumbColor(
  23     gfx::sRGBColor::UnusualFromARGB(0xffcdcdcd));
  24
  25 class ScrollbarDrawing {
  26  protected:
  27   using DPIRatio = mozilla::CSSToLayoutDeviceScale;
  28   using EventStates = mozilla::EventStates;
  29   using DrawTarget = mozilla::gfx::DrawTarget;
  30   using sRGBColor = mozilla::gfx::sRGBColor;
  31   using Colors = ThemeColors;
  32   using ScrollbarSizes = nsITheme::ScrollbarSizes;
  33   using Overlay = nsITheme::Overlay;
  34   using WebRenderBackendData = mozilla::widget::WebRenderBackendData;
  35
  36  public:
  37   ScrollbarDrawing() = default;
  38   virtual ~ScrollbarDrawing() = default;
  39
  40   struct ScrollbarParams {
  41     bool isOverlay = false;
  42     bool isRolledOver = false;
  43     bool isSmall = false;
  44     bool isHorizontal = false;
  45     bool isRtl = false;
  46     bool isOnDarkBackground = false;
  47     bool isCustom = false;
  48     // Two colors only used when custom is true.
  49     nscolor trackColor = NS_RGBA(0, 0, 0, 0);
  50     nscolor faceColor = NS_RGBA(0, 0, 0, 0);
  51   };
  52
  53   static DPIRatio GetDPIRatioForScrollbarPart(nsPresContext*);
  54
  55   static nsIFrame* GetParentScrollbarFrame(nsIFrame* aFrame);
  56   static bool IsParentScrollbarRolledOver(nsIFrame* aFrame);
  57   static bool IsParentScrollbarHoveredOrActive(nsIFrame* aFrame);
  58
  59   static bool IsScrollbarWidthThin(const ComputedStyle& aStyle);
  60   static bool IsScrollbarWidthThin(nsIFrame* aFrame);
  61
  62   virtual ScrollbarSizes GetScrollbarSizes(nsPresContext*, StyleScrollbarWidth,
  63                                            Overlay);
  64   virtual LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*,
  65                                                    StyleAppearance aAppearance,
  66                                                    nsIFrame* aFrame) = 0;
  67   virtual Maybe<nsITheme::Transparency> GetScrollbarPartTransparency(
  68       nsIFrame* aFrame, StyleAppearance aAppearance) {
  69     return Nothing();
  70   }
  71
  72   bool IsScrollbarTrackOpaque(nsIFrame*);
  73   virtual sRGBColor ComputeScrollbarTrackColor(
  74       nsIFrame*, const ComputedStyle&, const EventStates& aDocumentState,
  75       const Colors&);
  76   virtual sRGBColor ComputeScrollbarThumbColor(
  77       nsIFrame*, const ComputedStyle&, const EventStates& aElementState,
  78       const EventStates& aDocumentState, const Colors&);
  79
  80   static ScrollbarParams ComputeScrollbarParams(nsIFrame* aFrame,
  81                                                 const ComputedStyle& aStyle,
  82                                                 bool aIsHorizontal);
  83   static bool ShouldUseDarkScrollbar(nsIFrame*, const ComputedStyle&);
  84
  85   nscolor GetScrollbarButtonColor(nscolor aTrackColor, EventStates);
  86   Maybe<nscolor> GetScrollbarArrowColor(nscolor aButtonColor);
  87
  88   // Returned colors are button, arrow.
  89   virtual std::pair<sRGBColor, sRGBColor> ComputeScrollbarButtonColors(
  90       nsIFrame*, StyleAppearance, const ComputedStyle&,
  91       const EventStates& aElementState, const EventStates& aDocumentState,
  92       const Colors&);
  93
  94   virtual bool PaintScrollbarButton(DrawTarget&, StyleAppearance,
  95                                     const LayoutDeviceRect&, nsIFrame*,
  96                                     const ComputedStyle&,
  97                                     const EventStates& aElementState,
  98                                     const EventStates& aDocumentState,
  99                                     const Colors&);
 100
 101   virtual bool PaintScrollbarThumb(DrawTarget&, const LayoutDeviceRect&,
 102                                    bool aHorizontal, nsIFrame*,
 103                                    const ComputedStyle&,
 104                                    const EventStates& aElementState,
 105                                    const EventStates& aDocumentState,
 106                                    const Colors&, const DPIRatio&) = 0;
 107   virtual bool PaintScrollbarThumb(WebRenderBackendData&,
 108                                    const LayoutDeviceRect&, bool aHorizontal,
 109                                    nsIFrame*, const ComputedStyle&,
 110                                    const EventStates& aElementState,
 111                                    const EventStates& aDocumentState,
 112                                    const Colors&, const DPIRatio&) = 0;
 113
 114   template <typename PaintBackendData>
 115   bool DoPaintDefaultScrollbar(PaintBackendData&, const LayoutDeviceRect&,
 116                                bool aHorizontal, nsIFrame*,
 117                                const ComputedStyle&,
 118                                const EventStates& aElementState,
 119                                const EventStates& aDocumentState, const Colors&,
 120                                const DPIRatio&);
 121   virtual bool PaintScrollbar(DrawTarget&, const LayoutDeviceRect&,
 122                               bool aHorizontal, nsIFrame*, const ComputedStyle&,
 123                               const EventStates& aElementState,
 124                               const EventStates& aDocumentState, const Colors&,
 125                               const DPIRatio&);
 126   virtual bool PaintScrollbar(WebRenderBackendData&, const LayoutDeviceRect&,
 127                               bool aHorizontal, nsIFrame*, const ComputedStyle&,
 128                               const EventStates& aElementState,
 129                               const EventStates& aDocumentState, const Colors&,
 130                               const DPIRatio&);
 131
 132   virtual bool PaintScrollbarTrack(DrawTarget&, const LayoutDeviceRect&,
 133                                    bool aHorizontal, nsIFrame*,
 134                                    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   virtual bool PaintScrollbarTrack(WebRenderBackendData&,
 141                                    const LayoutDeviceRect&, bool aHorizontal,
 142                                    nsIFrame*, const ComputedStyle&,
 143                                    const EventStates& aDocumentState,
 144                                    const Colors&, const DPIRatio&) {
 145     // Draw nothing by default. Subclasses can override this.
 146     return true;
 147   }
 148
 149   template <typename PaintBackendData>
 150   bool DoPaintDefaultScrollCorner(PaintBackendData&, const LayoutDeviceRect&,
 151                                   nsIFrame*, const ComputedStyle&,
 152                                   const EventStates& aDocumentState,
 153                                   const Colors&, const DPIRatio&);
 154   virtual bool PaintScrollCorner(DrawTarget&, const LayoutDeviceRect&,
 155                                  nsIFrame*, const ComputedStyle&,
 156                                  const EventStates& aDocumentState,
 157                                  const Colors&, const DPIRatio&);
 158   virtual bool PaintScrollCorner(WebRenderBackendData&, const LayoutDeviceRect&,
 159                                  nsIFrame*, const ComputedStyle&,
 160                                  const EventStates& aDocumentState,
 161                                  const Colors&, const DPIRatio&);
 162
 163   virtual void RecomputeScrollbarParams() = 0;
 164
 165   virtual bool ShouldDrawScrollbarButtons() { return true; }
 166
 167   uint32_t GetHorizontalScrollbarHeight() const {
 168     return mHorizontalScrollbarHeight;
 169   }
 170   uint32_t GetVerticalScrollbarWidth() const { return mVerticalScrollbarWidth; }
 171
 172  protected:
 173   uint32_t mHorizontalScrollbarHeight = 0;
 174   uint32_t mVerticalScrollbarWidth = 0;
 175 };
 176
 177 }  // namespace mozilla::widget
 178
 179 #endif