WheelEvent QML Type

Provides information about a mouse wheel event. 更多...

import 语句：

import QtQuick 2.12

所有成员列表，包括继承成员

特性

accepted : bool
angleDelta : point
buttons : int
inverted : int
modifiers : int
pixelDelta : point
x : real
y : real

详细描述

The position of the mouse can be found via the x and y 特性。

另请参阅 MouseArea .

特性文档编制

accepted : bool

设置 accepted to true prevents the wheel event from being propagated to items below this item.

Generally, if the item acts on the wheel event then it should be accepted so that items lower in the stacking order do not also respond to the same event.

angleDelta : point

This property holds the distance that the wheel is rotated in wheel degrees. The x and y cordinate of this property holds the delta in horizontal and vertical orientation.

A positive value indicates that the wheel was rotated up/right; a negative value indicates that the wheel was rotated down/left.

大多数鼠标类型以 15 度步幅为单位工作，在这种情况下，增量值是 120 的倍增 (即：120 单位 *1/8 = 15 度)。

buttons : int

This property holds the mouse buttons pressed when the wheel event was generated.

It contains a bitwise combination of:

inverted : int

返回随事件交付的增量值是否反转。

通常，垂直滚轮会产生 WheelEvent 具有正增量值若滚轮顶部旋转离开操作它的手。同样，水平滚轮运动会产生 QWheelEvent 具有正增量值若滚轮顶部向左移动。

However, on some platforms this is configurable, so that the same operations described above will produce negative delta values (but with the same magnitude). For instance, in a QML component (such as a tumbler or a slider) where it is appropriate to synchronize the movement or rotation of an item with the direction of the wheel, regardless of the system settings, the wheel event handler can use the inverted property to decide whether to negate the angleDelta or pixelDelta 值。

注意： 很多平台不提供这样的信息。在这种平台，inverted 始终返回 false。

modifiers : int

This property holds the keyboard modifier flags that existed immediately before the event occurred.

It contains a bitwise combination of:

Qt.NoModifier - No modifier key is pressed.
Qt.ShiftModifier - A Shift key on the keyboard is pressed.
Qt.ControlModifier - A Ctrl key on the keyboard is pressed.
Qt.AltModifier - An Alt key on the keyboard is pressed.
Qt.MetaModifier - A Meta key on the keyboard is pressed.
Qt.KeypadModifier - A keypad button is pressed.

For example, to react to a Control key pressed during the wheel event:

MouseArea {
    onWheel: {
        if (wheel.modifiers & Qt.ControlModifier) {
            adjustZoom(wheel.angleDelta.y / 120);
        }
    }
}

pixelDelta : point

This property holds the delta in screen pixels and is available in platforms that have high-resolution trackpads, such as macOS . The x and y cordinate of this property holds the delta in horizontal and vertical orientation. The value should be used directly to scroll content on screen.

For platforms without high-resolution trackpad support, pixelDelta will always be (0,0), and angleDelta 应该被使用以取而代之。

x : real

These properties hold the coordinates of the position supplied by the wheel event.

y : real

These properties hold the coordinates of the position supplied by the wheel event.