Source code

Revision control

Copy as Markdown

Other Tools

/* -*- 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 */
// nsScrollbarFrame
#ifndef nsScrollbarFrame_h__
#define nsScrollbarFrame_h__
#include "mozilla/Attributes.h"
#include "mozilla/ScrollTypes.h"
#include "nsIAnonymousContentCreator.h"
#include "nsBoxFrame.h"
class nsIScrollbarMediator;
namespace mozilla {
class PresShell;
namespace dom {
class Element;
} // namespace mozilla
nsIFrame* NS_NewScrollbarFrame(mozilla::PresShell* aPresShell,
mozilla::ComputedStyle* aStyle);
class nsScrollbarFrame final : public nsBoxFrame,
public nsIAnonymousContentCreator {
using Element = mozilla::dom::Element;
explicit nsScrollbarFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
: nsBoxFrame(aStyle, aPresContext, kClassID),
mDownBottomButton(nullptr) {}
virtual nsresult GetFrameName(nsAString& aResult) const override {
return MakeFrameName(u"ScrollbarFrame"_ns, aResult);
// nsIFrame overrides
virtual nsresult AttributeChanged(int32_t aNameSpaceID, nsAtom* aAttribute,
int32_t aModType) override;
NS_IMETHOD HandlePress(nsPresContext* aPresContext,
mozilla::WidgetGUIEvent* aEvent,
nsEventStatus* aEventStatus) override;
NS_IMETHOD HandleMultiplePress(nsPresContext* aPresContext,
mozilla::WidgetGUIEvent* aEvent,
nsEventStatus* aEventStatus,
bool aControlHeld) override;
NS_IMETHOD HandleDrag(nsPresContext* aPresContext,
mozilla::WidgetGUIEvent* aEvent,
nsEventStatus* aEventStatus) override;
NS_IMETHOD HandleRelease(nsPresContext* aPresContext,
mozilla::WidgetGUIEvent* aEvent,
nsEventStatus* aEventStatus) override;
virtual void DestroyFrom(nsIFrame* aDestructRoot,
PostDestroyData& aPostDestroyData) override;
virtual void Init(nsIContent* aContent, nsContainerFrame* aParent,
nsIFrame* aPrevInFlow) override;
virtual void Reflow(nsPresContext* aPresContext, ReflowOutput& aDesiredSize,
const ReflowInput& aReflowInput,
nsReflowStatus& aStatus) override;
void SetScrollbarMediatorContent(nsIContent* aMediator);
nsIScrollbarMediator* GetScrollbarMediator();
// nsBox methods
* Treat scrollbars as clipping their children; overflowing children
* will not be allowed to set an overflow rect on this
* frame. This means that when the scroll code decides to hide a
* scrollframe by setting its height or width to zero, that will
* hide the children too.
virtual bool DoesClipChildrenInBothAxes() override { return true; }
virtual nsresult GetXULMargin(nsMargin& aMargin) override;
* The following three methods set the value of mIncrement when a
* scrollbar button is pressed.
void SetIncrementToLine(int32_t aDirection);
void SetIncrementToPage(int32_t aDirection);
void SetIncrementToWhole(int32_t aDirection);
* If aImplementsScrollByUnit is Yes then this uses mSmoothScroll,
* mScrollUnit, and mDirection and calls ScrollByUnit on the
* nsIScrollbarMediator. The return value is 0. This is better because it is
* more modern and the scroll frame can perform the scroll via apz for
* example. The old way below is still supported for xul trees. If
* aImplementsScrollByUnit is No this adds mIncrement to the current
* position and updates the curpos attribute obeying mSmoothScroll.
* @returns The new position after clamping, in CSS Pixels
* @note This method might destroy the frame, pres shell, and other objects.
enum class ImplementsScrollByUnit { Yes, No };
int32_t MoveToNewPosition(ImplementsScrollByUnit aImplementsScrollByUnit);
int32_t GetIncrement() { return mIncrement; }
// nsIAnonymousContentCreator
virtual nsresult CreateAnonymousContent(
nsTArray<ContentInfo>& aElements) override;
virtual void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
uint32_t aFilter) override;
void UpdateChildrenAttributeValue(nsAtom* aAttribute, bool aNotify);
bool mSmoothScroll;
mozilla::ScrollUnit mScrollUnit;
// Direction and multiple to scroll
int32_t mDirection;
// Amount to scroll, in CSSPixels
// Ignored in favour of mScrollUnit/mDirection for regular scroll frames.
// Trees use this though.
int32_t mIncrement;
nsCOMPtr<nsIContent> mScrollbarMediator;
nsCOMPtr<Element> mUpTopButton;
nsCOMPtr<Element> mDownTopButton;
nsCOMPtr<Element> mSlider;
nsCOMPtr<Element> mThumb;
nsCOMPtr<Element> mUpBottomButton;
nsCOMPtr<Element> mDownBottomButton;
}; // class nsScrollbarFrame