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 #include "mozilla/StaticPrefs_widget.h"
  11
  12 using namespace mozilla;
  13 using namespace mozilla::widget;
  14
  15 LayoutDeviceIntSize ScrollbarDrawingAndroid::GetMinimumWidgetSize(
  16     nsPresContext* aPresContext, StyleAppearance aAppearance,
  17     nsIFrame* aFrame) {
  18   MOZ_ASSERT(nsNativeTheme::IsWidgetScrollbarPart(aAppearance));
  19   auto size =
  20       GetScrollbarSize(aPresContext, StyleScrollbarWidth::Auto, Overlay::Yes);
  21   return LayoutDeviceIntSize{size, size};
  22 }
  23
  24 template <typename PaintBackendData>
  25 void ScrollbarDrawingAndroid::DoPaintScrollbarThumb(
  26     PaintBackendData& aPaintData, const LayoutDeviceRect& aRect,
  27     ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
  28     const ElementState& aElementState, const DocumentState& aDocumentState,
  29     const Colors& aColors, const DPIRatio& aDpiRatio) {
  30   // TODO(emilio): Maybe do like macOS and draw a stroke?
  31   const auto color = ComputeScrollbarThumbColor(aFrame, aStyle, aElementState,
  32                                                 aDocumentState, aColors);
  33   const bool horizontal = aScrollbarKind == ScrollbarKind::Horizontal;
  34
  35   // Draw the thumb rect centered in the scrollbar.
  36   LayoutDeviceRect thumbRect(aRect);
  37   if (horizontal) {
  38     thumbRect.height *= 0.5f;
  39     thumbRect.y += thumbRect.height * 0.5f;
  40   } else {
  41     thumbRect.width *= 0.5f;
  42     thumbRect.x += thumbRect.width * 0.5f;
  43   }
  44
  45   const LayoutDeviceCoord radius =
  46       (horizontal ? thumbRect.height : thumbRect.width) / 2.0f;
  47   ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, thumbRect, color,
  48                                            sRGBColor::White(0.0f), 0.0f,
  49                                            radius / aDpiRatio, aDpiRatio);
  50 }
  51
  52 bool ScrollbarDrawingAndroid::PaintScrollbarThumb(
  53     DrawTarget& aDt, const LayoutDeviceRect& aRect,
  54     ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
  55     const ElementState& aElementState, const DocumentState& aDocumentState,
  56     const Colors& aColors, const DPIRatio& aDpiRatio) {
  57   DoPaintScrollbarThumb(aDt, aRect, aScrollbarKind, aFrame, aStyle,
  58                         aElementState, aDocumentState, aColors, aDpiRatio);
  59   return true;
  60 }
  61
  62 bool ScrollbarDrawingAndroid::PaintScrollbarThumb(
  63     WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
  64     ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
  65     const ElementState& aElementState, const DocumentState& aDocumentState,
  66     const Colors& aColors, const DPIRatio& aDpiRatio) {
  67   DoPaintScrollbarThumb(aWrData, aRect, aScrollbarKind, aFrame, aStyle,
  68                         aElementState, aDocumentState, aColors, aDpiRatio);
  69   return true;
  70 }
  71
  72 void ScrollbarDrawingAndroid::RecomputeScrollbarParams() {
  73   uint32_t defaultSize = 6;
  74   uint32_t overrideSize =
  75       StaticPrefs::widget_non_native_theme_scrollbar_size_override();
  76   if (overrideSize > 0) {
  77     defaultSize = overrideSize;
  78   }
  79   ConfigureScrollbarSize(defaultSize);
  80   // We make thin scrollbars as wide as auto ones because auto scrollbars on
  81   // android are already thin enough.
  82   ConfigureScrollbarSize(StyleScrollbarWidth::Thin, Overlay::Yes, defaultSize);
  83   ConfigureScrollbarSize(StyleScrollbarWidth::Thin, Overlay::No, defaultSize);
  84 }