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     ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
  40     const ElementState& aElementState, const DocumentState& 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   const bool horizontal = aScrollbarKind == ScrollbarKind::Horizontal;
  46
  47   // Draw the thumb rect centered in the scrollbar.
  48   LayoutDeviceRect thumbRect(aRect);
  49   if (horizontal) {
  50     thumbRect.height *= 0.5f;
  51     thumbRect.y += thumbRect.height * 0.5f;
  52   } else {
  53     thumbRect.width *= 0.5f;
  54     thumbRect.x += thumbRect.width * 0.5f;
  55   }
  56
  57   const LayoutDeviceCoord radius =
  58       (horizontal ? thumbRect.height : thumbRect.width) / 2.0f;
  59   ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, thumbRect, color,
  60                                            sRGBColor::White(0.0f), 0.0f,
  61                                            radius / aDpiRatio, aDpiRatio);
  62 }
  63
  64 bool ScrollbarDrawingAndroid::PaintScrollbarThumb(
  65     DrawTarget& aDt, const LayoutDeviceRect& aRect,
  66     ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
  67     const ElementState& aElementState, const DocumentState& aDocumentState,
  68     const Colors& aColors, const DPIRatio& aDpiRatio) {
  69   DoPaintScrollbarThumb(aDt, aRect, aScrollbarKind, aFrame, aStyle,
  70                         aElementState, aDocumentState, aColors, aDpiRatio);
  71   return true;
  72 }
  73
  74 bool ScrollbarDrawingAndroid::PaintScrollbarThumb(
  75     WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
  76     ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
  77     const ElementState& aElementState, const DocumentState& aDocumentState,
  78     const Colors& aColors, const DPIRatio& aDpiRatio) {
  79   DoPaintScrollbarThumb(aWrData, aRect, aScrollbarKind, aFrame, aStyle,
  80                         aElementState, aDocumentState, aColors, aDpiRatio);
  81   return true;
  82 }
  83
  84 void ScrollbarDrawingAndroid::RecomputeScrollbarParams() {
  85   uint32_t defaultSize = 6;
  86   uint32_t overrideSize =
  87       StaticPrefs::widget_non_native_theme_scrollbar_size_override();
  88   if (overrideSize > 0) {
  89     defaultSize = overrideSize;
  90   }
  91   mHorizontalScrollbarHeight = mVerticalScrollbarWidth = defaultSize;
  92 }