TouchArea reacts differently on Mac than on Linux and Windows

[oswald2]

Hi,

I have a TouchArea for handling events on a chart with the Rust plotters library. I want to differentiate between click and click and drag, so I did the following:

                            touch1_p := TouchArea {
                                property <bool> touching: false;
                                property <bool> is_drag: false;
                                property <KeyboardModifiers> keys;
                                pointer-event(event) => {
                                    if self.enabled {
                                        if event.kind == PointerEventKind.down {
                                            if event.button == PointerEventButton.left {
                                                debug("touching");
                                                touching = true;
                                                keys = event.modifiers;
                                            } 
                                        } else if event.kind == PointerEventKind.up {
                                            if event.button == PointerEventButton.left {
                                                debug("touching done");
                                                touching = false;
                                                if is_drag {
                                                    debug("drag end");
                                                    Logic.p_plot_drag_end();
                                                    is_drag = false;
                                                }
                                            } 
                                        } else if event.kind == PointerEventKind.move {
                                            if touching {
                                                debug("Drag start");
                                                is_drag = true;
                                                Logic.p_plot_click_drag(touch1_p.pressed-x, touch1_p.pressed-y, touch1_p.mouse-x, touch1_p.mouse-y, event.modifiers);
                                            }
                                        }
                                    }
                                }
                                clicked => {
                                    debug("Clicked ");
                                    if (self.enabled) {
                                        if !is_drag {
                                            Logic.p_plot_clicked(touch1_p.pressed-x, touch1_p.pressed-y, keys);
                                        }
                                    }
                                }

On Linux and Windows this works perfectly fine, I can click and click-and-drag (and click-drag with modifiers like CTRL).

On Mac, the PointerEventKind.move comes immediately after "touching", no matter how brief I try to click without movement, and then afterwards the clicked() callback is called, and since it checks for dragging with the is_drag flag, it does never call the p_plot_clicked function.

Am I doing something wrong?

This is slint 1.13.1 with Rust 1.90.

Thank you!

[ogoffart]

We just forward the event as they come from winit, so i believe in this case it is winit which has a difference and the difference may be caused by how the platform itself sends the events.

I think you may be able to work around this issue if you check for the distance from the pressed position before claiming it is a drag.

[oswald2]

Ok, thank you, this was exactly what I was doing.