Greetings, premise: I love QML and Qt Quick, and whenever I attempt a Component design exercise like this, I strive for doing things in the spirit of the framework, i.e. simple, and declarative.
I tried (not for the first time during my life of Qt Quick user) to make a (mouse-)interactive component where some item can be resized by mouse. Inevitably I end up putting a MouseArea as children of an Item that changes position and/or size, and this will break things, e.g. the mouse interaction and the dragged items become jittery. I tried various approaches, e.g. using a MouseArea, a DragHandler, the Drag attached property. Those all work well when the ancestors are static, but those all break when any ancestor is interactively moved by mouse. In hindsight, this probably makes sense, as we are trying to measure something (e.g. the relative mouse position) while things all around are moving... it's like building a table during a earthquake :D I wonder how Qt Quick pros would design a solution to this problem (i.e. it would be nice to have such a demo amongst the Qt Quick demos ;-) ). This is how I did it: https://github.com/fferri/qt-quick-events-timeline/tree/d98b33830291ce9b85670b6bcc41952d513e610b and if it looks bad to you, consider I tried to solve this or a very similar problem another 2-3 times in the past 5 years, and this is a great improvement with respect to my past iterations :-) In a gist: - have a "global" MouseArea and a "global" Item used as drag target (global in the sense their reference frame is never moved interactively by the mouse) - have a "local" MouseArea (3 in this case for the 3 regions of an item: start, middle, end; as dragging over each region has a different function, i.e.: resizing from left, moving, resizing from right respectively) that only serves for showing a specific cursorShape, and intercepting the pressed event (discarding it) to set up the drag target for the global MouseArea; - as the global drag target Item moves, the actual item to be moved/resized watches the changes an computes the adjustments. It may look extremely hacky and low-level, but it is the only way I could achieve smooth resizing without the issues mentioned above. Which makes me wonder if I overlooked something way more obvious to achieve the same result.... Thanks for any feedback. Best Regards, Federico Ferri
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