PinchHandler QML Type▲
-
Import Statement: import QtQuick 2.13
-
Inherits: MultiPointHandler
-
Group: PinchHandler is part of qtquick-input-handlers
Detailed Description▲
PinchHandler is a handler that interprets a multi-finger gesture to interactively rotate, zoom, and drag an Item. Like other Input Handlers, by default it is fully functional, and manipulates its target, which is the Item within which it is declared.
import
QtQuick 2.12
Rectangle
{
width
:
400
height
:
300
color
:
"lightsteelblue"
PinchHandler {
}
}
It has properties to restrict the range of dragging, rotation, and zoom.
If it is declared within one Item but is assigned a different target, it handles events within the bounds of the outer Item but manipulates the target Item instead:
import
QtQuick 2.12
Item
{
width
:
640
height
:
480
Rectangle
{
id
:
map
color
:
"aqua"
width
:
400
height
:
300
}
PinchHandler {
target
:
map
}
}
A third way to use it is to set target to null and react to property changes in some other way:
import
QtQuick 2.12
Item
{
width
:
640
height
:
480
PinchHandler {
id
:
handler
target
:
null
}
Text
{
color
:
handler.active ? "darkgreen"
:
"black"
text
:
handler.rotation.toFixed(1
) +
" degrees\n"
+
handler.translation.x.toFixed(1
) +
", "
+
handler.translation.y.toFixed(1
) +
"\n"
+
(handler.scale *
100
).toFixed(1
) +
"%"
}
}
See Also▲
See also PinchArea
Property Documentation▲
acceptedButtons : flags▲
The mouse buttons which can activate this Pointer Handler.
By default, this property is set to Qt.LeftButton. It can be set to an OR combination of mouse buttons, and will ignore events from other buttons.
For example, a control could be made to respond to left and right clicks in different ways, with two handlers:
Item
{
TapHandler {
onTapped
:
console.log("left clicked"
)
}
TapHandler {
acceptedButtons
:
Qt.RightButton
onTapped
:
console.log("right clicked"
)
}
}
Tapping on a touchscreen or tapping the stylus on a graphics tablet emulates clicking the left mouse button. This behavior can be altered via acceptedDevices or acceptedPointerTypes.
acceptedDevices : flags▲
The types of pointing devices that can activate this Pointer Handler.
By default, this property is set to PointerDevice.AllDevices. If you set it to an OR combination of device types, it will ignore events from non-matching devices.
For example, a control could be made to respond to mouse and stylus clicks in one way, and touchscreen taps in another way, with two handlers:
Item
{
TapHandler {
acceptedDevices
:
PointerDevice.Mouse |
PointerDevice.Stylus
onTapped
:
console.log("clicked"
)
}
TapHandler {
acceptedDevices
:
PointerDevice.TouchScreen
onTapped
:
console.log("tapped"
)
}
}
acceptedModifiers : flags▲
If this property is set, it will require the given keyboard modifiers to be pressed in order to react to pointer events, and otherwise ignore them.
If this property is set to Qt.KeyboardModifierMask (the default value), then the PointerHandler ignores the modifier keys.
For example, an Item could have two handlers of the same type, one of which is enabled only if the required keyboard modifiers are pressed:
Item
{
TapHandler {
acceptedModifiers
:
Qt.ControlModifier
onTapped
:
console.log("control-tapped"
)
}
TapHandler {
acceptedModifiers
:
Qt.NoModifier
onTapped
:
console.log("tapped"
)
}
}
If you set acceptedModifiers to an OR combination of modifier keys, it means all of those modifiers must be pressed to activate the handler:
Item
{
TapHandler {
acceptedModifiers
:
Qt.ControlModifier |
Qt.AltModifier |
Qt.ShiftModifier
onTapped
:
console.log("control-alt-shift-tapped"
)
}
}
The available modifiers are as follows:
Constant |
Description |
---|---|
NoModifier |