ScrollbarDrawing.h

Enable keyboard shortcuts

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_widget_ScrollbarDrawing_h

#define mozilla_widget_ScrollbarDrawing_h

#include "mozilla/dom/RustTypes.h"

#include "mozilla/gfx/2D.h"

#include "nsColor.h"

#include "nsITheme.h"

#include "ThemeColors.h"

#include "ThemeDrawing.h"

#include "Units.h"

namespace mozilla::widget {

class ScrollbarDrawing {

 protected:

  using DPIRatio = mozilla::CSSToLayoutDeviceScale;

  using ElementState = dom::ElementState;

  using DocumentState = dom::DocumentState;

  using DrawTarget = mozilla::gfx::DrawTarget;

  using sRGBColor = mozilla::gfx::sRGBColor;

  using Colors = ThemeColors;

  using Overlay = nsITheme::Overlay;

  using WebRenderBackendData = mozilla::widget::WebRenderBackendData;

  enum class Kind : uint8_t {

    Android,

    Cocoa,

    Gtk,

    Win10,

    Win11,

};

  explicit ScrollbarDrawing(Kind aKind) : mKind(aKind) {}

 public:

  virtual ~ScrollbarDrawing() = default;

  enum class ScrollbarKind : uint8_t {

    Horizontal,

    VerticalLeft,

    VerticalRight,

};

  DPIRatio GetDPIRatioForScrollbarPart(const nsPresContext*);

  static nsIFrame* GetParentScrollbarFrame(nsIFrame* aFrame);

  static bool IsParentScrollbarRolledOver(nsIFrame* aFrame);

  static bool IsParentScrollbarHoveredOrActive(nsIFrame* aFrame);

  static bool IsScrollbarWidthThin(const ComputedStyle& aStyle);

  static bool IsScrollbarWidthThin(nsIFrame* aFrame);

  CSSIntCoord GetCSSScrollbarSize(StyleScrollbarWidth, Overlay) const;

  LayoutDeviceIntCoord GetScrollbarSize(const nsPresContext*,

                                        StyleScrollbarWidth, Overlay);

  LayoutDeviceIntCoord GetScrollbarSize(const nsPresContext*, nsIFrame*);

  virtual LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*,

                                                   StyleAppearance aAppearance,

                                                   nsIFrame* aFrame) = 0;

  virtual Maybe<nsITheme::Transparency> GetScrollbarPartTransparency(

      nsIFrame* aFrame, StyleAppearance aAppearance) {

    return Nothing();

  bool IsScrollbarTrackOpaque(nsIFrame*);

  virtual sRGBColor ComputeScrollbarTrackColor(nsIFrame*, const ComputedStyle&,

                                               const DocumentState&,

                                               const Colors&);

  virtual sRGBColor ComputeScrollbarThumbColor(nsIFrame*, const ComputedStyle&,

                                               const ElementState&,

                                               const DocumentState&,

                                               const Colors&);

  nscolor GetScrollbarButtonColor(nscolor aTrackColor, ElementState);

  Maybe<nscolor> GetScrollbarArrowColor(nscolor aButtonColor);

  // Returned colors are button, arrow.

  virtual std::pair<sRGBColor, sRGBColor> ComputeScrollbarButtonColors(

      nsIFrame*, StyleAppearance, const ComputedStyle&, const ElementState&,

      const DocumentState&, const Colors&);

  virtual bool PaintScrollbarButton(DrawTarget&, StyleAppearance,

                                    const LayoutDeviceRect&, ScrollbarKind,

                                    nsIFrame*, const ComputedStyle&,

                                    const ElementState&, const DocumentState&,

                                    const Colors&, const DPIRatio&);

  virtual bool PaintScrollbarThumb(DrawTarget&, const LayoutDeviceRect&,

                                   ScrollbarKind, nsIFrame*,

                                   const ComputedStyle&, const ElementState&,

                                   const DocumentState&, const Colors&,

                                   const DPIRatio&) = 0;

  virtual bool PaintScrollbarThumb(WebRenderBackendData&,

                                   const LayoutDeviceRect&, ScrollbarKind,

                                   nsIFrame*, const ComputedStyle&,

                                   const ElementState&, const DocumentState&,

                                   const Colors&, const DPIRatio&) = 0;

  template <typename PaintBackendData>

  bool DoPaintDefaultScrollbar(PaintBackendData&, const LayoutDeviceRect&,

                               ScrollbarKind, nsIFrame*, const ComputedStyle&,

                               const ElementState&, const DocumentState&,

                               const Colors&, const DPIRatio&);

  bool PaintScrollbar(DrawTarget&, const LayoutDeviceRect&, ScrollbarKind,

                      nsIFrame*, const ComputedStyle&, const ElementState&,

                      const DocumentState&, const Colors&, const DPIRatio&);

  bool PaintScrollbar(WebRenderBackendData&, const LayoutDeviceRect&,

                      ScrollbarKind, nsIFrame*, const ComputedStyle&,

                      const ElementState&, const DocumentState&, const Colors&,

                      const DPIRatio&);

  virtual bool PaintScrollbarTrack(DrawTarget&, const LayoutDeviceRect&,

                                   ScrollbarKind, nsIFrame*,

                                   const ComputedStyle&, const DocumentState&,

                                   const Colors&, const DPIRatio&) {

    // Draw nothing by default. Subclasses can override this.

    return true;

  virtual bool PaintScrollbarTrack(WebRenderBackendData&,

                                   const LayoutDeviceRect&, ScrollbarKind,

                                   nsIFrame*, const ComputedStyle&,

                                   const DocumentState&, const Colors&,

                                   const DPIRatio&) {

    // Draw nothing by default. Subclasses can override this.

    return true;

  template <typename PaintBackendData>

  bool DoPaintDefaultScrollCorner(PaintBackendData&, const LayoutDeviceRect&,

                                  ScrollbarKind, nsIFrame*,

                                  const ComputedStyle&, const DocumentState&,

                                  const Colors&, const DPIRatio&);

  virtual bool PaintScrollCorner(DrawTarget&, const LayoutDeviceRect&,

                                 ScrollbarKind, nsIFrame*, const ComputedStyle&,

                                 const DocumentState&, const Colors&,

                                 const DPIRatio&);

  virtual bool PaintScrollCorner(WebRenderBackendData&, const LayoutDeviceRect&,

                                 ScrollbarKind, nsIFrame*, const ComputedStyle&,

                                 const DocumentState&, const Colors&,

                                 const DPIRatio&);

  virtual void RecomputeScrollbarParams() = 0;

  virtual bool ShouldDrawScrollbarButtons() { return true; }

 private:

  // The scrollbar sizes for all our scrollbars. Indices are overlay or not,

  // then thin or not. Should be configured via ConfigureScrollbarSize.

  CSSIntCoord mScrollbarSize[2][2]{};

 protected:

  // For some kind of style differences a full virtual method is overkill, so we

  // store the kind here so we can branch on it if necessary.

  Kind mKind;

  // Configures the scrollbar sizes based on a single size.

  void ConfigureScrollbarSize(CSSIntCoord);

  // Configures a particular scrollbar size.

  void ConfigureScrollbarSize(StyleScrollbarWidth, Overlay, CSSIntCoord);

};

}  // namespace mozilla::widget

#endif