/* 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_layers_AutoDirWheelDeltaAdjuster_h_
#define _mozilla_layers_AutoDirWheelDeltaAdjuster_h_
#include "Axis.h" // for AxisX, AxisY, Side
#include "mozilla/WheelHandlingHelper.h" // for AutoDirWheelDeltaAdjuster
namespace mozilla {
namespace layers {
/**
* About AutoDirWheelDeltaAdjuster:
* For an AutoDir wheel scroll, there's some situations where we should adjust a
* wheel event's delta values. AutoDirWheelDeltaAdjuster converts delta values
* for AutoDir scrolling. An AutoDir wheel scroll lets the user scroll a frame
* with only one scrollbar, using either a vertical or a horzizontal wheel.
* For more detail about the concept of AutoDir scrolling, see the comments in
* AutoDirWheelDeltaAdjuster.
*
* This is the APZ implementation of AutoDirWheelDeltaAdjuster.
*/
class MOZ_STACK_CLASS APZAutoDirWheelDeltaAdjuster final
:
public AutoDirWheelDeltaAdjuster {
public:
/**
* @param aDeltaX DeltaX for a wheel event whose delta values will
* be adjusted upon calling adjust() when
* ShouldBeAdjusted() returns true.
* @param aDeltaY DeltaY for a wheel event, like DeltaX.
* @param aAxisX The X axis information provider for the current
* frame, such as whether the frame can be scrolled
* horizontally, leftwards or rightwards.
* @param aAxisY The Y axis information provider for the current
* frame, such as whether the frame can be scrolled
* vertically, upwards or downwards.
* @param aIsHorizontalContentRightToLeft
* Indicates whether the horizontal content starts
* at rightside. This value will decide which edge
* the adjusted scroll goes towards, in other words,
* it will decide the sign of the adjusted delta
* values). For detailed information, see
* IsHorizontalContentRightToLeft() in
* the base class AutoDirWheelDeltaAdjuster.
*/
APZAutoDirWheelDeltaAdjuster(
double& aDeltaX,
double& aDeltaY,
const AxisX& aAxisX,
const AxisY& aAxisY,
bool aIsHorizontalContentRightToLeft)
: AutoDirWheelDeltaAdjuster(aDeltaX, aDeltaY),
mAxisX(aAxisX),
mAxisY(aAxisY),
mIsHorizontalContentRightToLeft(aIsHorizontalContentRightToLeft) {}
private:
virtual bool CanScrollAlongXAxis()
const override {
return mAxisX.CanScroll();
}
virtual bool CanScrollAlongYAxis()
const override {
return mAxisY.CanScroll();
}
virtual bool CanScrollUpwards()
const override {
return mAxisY.CanScrollTo(eSideTop);
}
virtual bool CanScrollDownwards()
const override {
return mAxisY.CanScrollTo(eSideBottom);
}
virtual bool CanScrollLeftwards()
const override {
return mAxisX.CanScrollTo(eSideLeft);
}
virtual bool CanScrollRightwards()
const override {
return mAxisX.CanScrollTo(eSideRight);
}
virtual bool IsHorizontalContentRightToLeft()
const override {
return mIsHorizontalContentRightToLeft;
}
const AxisX& mAxisX;
const AxisY& mAxisY;
bool mIsHorizontalContentRightToLeft;
};
}
// namespace layers
}
// namespace mozilla
#endif // _mozilla_layers_AutoDirWheelDeltaAdjuster_h_
