QtQuick DragHandler Lag
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With the QtQuick DragHandler there is a noticeable lag between the pointer motion and the target item translation. A rapid drag results in the drag target sliding across the screen to "catch up" with the pointer. A simple test of this is below. The lag is apparent on Windows and Android.
Is there a way to adjust this behaviour to reduce the lag? Or is this an unavoidable feature of QML?
import QtQuick 2 Window { id: window width: 640 height: 480 visible: true Rectangle { id: x width: 100 height: 100 color: "blue" } DragHandler { id: dragHandler target: x } } -
With the QtQuick DragHandler there is a noticeable lag between the pointer motion and the target item translation. A rapid drag results in the drag target sliding across the screen to "catch up" with the pointer. A simple test of this is below. The lag is apparent on Windows and Android.
Is there a way to adjust this behaviour to reduce the lag? Or is this an unavoidable feature of QML?
import QtQuick 2 Window { id: window width: 640 height: 480 visible: true Rectangle { id: x width: 100 height: 100 color: "blue" } DragHandler { id: dragHandler target: x } }@KenAppleby-0 Having the same issue as you have. Have you found a solution?
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@KenAppleby-0 Having the same issue as you have. Have you found a solution?
@StudentScripter No, I haven't. But I think it must be possible to improve the performance. If you try the Qt positioning examples that use the QtQuick Map element the responsiveness to drag gestures is good. The Qt documentation states that Map uses OpenGL (ES) but I have not found a way to match the responsiveness of QtQuick Map even using OpenGL.
However, I find that a QGraphicsView with a QOpenGLWidget viewport performs really well on mobile platforms, even though some people in this forum claim that you can't use QWidgets on them.
