widget/ScrollbarDrawingAndroid.cpp

   1 /* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "ScrollbarDrawingAndroid.h"
   7
   8 #include "nsIFrame.h"
   9 #include "nsNativeTheme.h"
  10
  11 using namespace mozilla;
  12 using namespace mozilla::widget;
  13
  14 LayoutDeviceIntSize ScrollbarDrawingAndroid::GetMinimumWidgetSize(
  15     nsPresContext* aPresContext, StyleAppearance aAppearance,
  16     nsIFrame* aFrame) {
  17   MOZ_ASSERT(nsNativeTheme::IsWidgetScrollbarPart(aAppearance));
  18
  19   auto sizes =
  20       GetScrollbarSizes(aPresContext, StyleScrollbarWidth::Auto, Overlay::Yes);
  21   MOZ_ASSERT(sizes.mHorizontal == sizes.mVertical);
  22
  23   return LayoutDeviceIntSize{sizes.mHorizontal, sizes.mVertical};
  24 }
  25
  26 auto ScrollbarDrawingAndroid::GetScrollbarSizes(nsPresContext* aPresContext,
  27                                                 StyleScrollbarWidth aWidth,
  28                                                 Overlay aOverlay)
  29     -> ScrollbarSizes {
  30   // We force auto-width scrollbars because scrollbars on android are already
  31   // thin enough.
  32   return ScrollbarDrawing::GetScrollbarSizes(
  33       aPresContext, StyleScrollbarWidth::Auto, aOverlay);
  34 }
  35
  36 template <typename PaintBackendData>
  37 void ScrollbarDrawingAndroid::DoPaintScrollbarThumb(
  38     PaintBackendData& aPaintData, const LayoutDeviceRect& aRect,
  39     bool aHorizontal, nsIFrame* aFrame, const ComputedStyle& aStyle,
  40     const EventStates& aElementState, const EventStates& aDocumentState,
  41     const Colors& aColors, const DPIRatio& aDpiRatio) {
  42   // TODO(emilio): Maybe do like macOS and draw a stroke?
  43   const auto color = ComputeScrollbarThumbColor(aFrame, aStyle, aElementState,
  44                                                 aDocumentState, aColors);
  45
  46   // Draw the thumb rect centered in the scrollbar.
  47   LayoutDeviceRect thumbRect(aRect);
  48   if (aHorizontal) {
  49     thumbRect.height *= 0.5f;
  50     thumbRect.y += thumbRect.height * 0.5f;
  51   } else {
  52     thumbRect.width *= 0.5f;
  53     thumbRect.x += thumbRect.width * 0.5f;
  54   }
  55
  56   const LayoutDeviceCoord radius =
  57       (aHorizontal ? thumbRect.height : thumbRect.width) / 2.0f;
  58   ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, thumbRect, color,
  59                                            sRGBColor::White(0.0f), 0.0f,
  60                                            radius / aDpiRatio, aDpiRatio);
  61 }
  62
  63 bool ScrollbarDrawingAndroid::PaintScrollbarThumb(
  64     DrawTarget& aDt, const LayoutDeviceRect& aRect, bool aHorizontal,
  65     nsIFrame* aFrame, const ComputedStyle& aStyle,
  66     const EventStates& aElementState, const EventStates& aDocumentState,
  67     const Colors& aColors, const DPIRatio& aDpiRatio) {
  68   DoPaintScrollbarThumb(aDt, aRect, aHorizontal, aFrame, aStyle, aElementState,
  69                         aDocumentState, aColors, aDpiRatio);
  70   return true;
  71 }
  72
  73 bool ScrollbarDrawingAndroid::PaintScrollbarThumb(
  74     WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
  75     bool aHorizontal, nsIFrame* aFrame, const ComputedStyle& aStyle,
  76     const EventStates& aElementState, const EventStates& aDocumentState,
  77     const Colors& aColors, const DPIRatio& aDpiRatio) {
  78   DoPaintScrollbarThumb(aWrData, aRect, aHorizontal, aFrame, aStyle,
  79                         aElementState, aDocumentState, aColors, aDpiRatio);
  80   return true;
  81 }
  82
  83 void ScrollbarDrawingAndroid::RecomputeScrollbarParams() {
  84   uint32_t defaultSize = 6;
  85   uint32_t overrideSize =
  86       StaticPrefs::widget_non_native_theme_scrollbar_size_override();
  87   if (overrideSize > 0) {
  88     defaultSize = overrideSize;
  89   }
  90   mHorizontalScrollbarHeight = mVerticalScrollbarWidth = defaultSize;
  91 }