Add support for querying the absolute x/y coordinates of elements

[tronical]

Sometimes it's useful to know the absolute x or y coordinate of an element within the entire window, not just the x/y coordinate relative to the parent.

This could be implemented in the compiler by providing synthetic absolute-x and absolute-y coordinates that, when used, are associated with a (generated) binding that walks up the chain of parent elements - like we do for popups.

[threefoldo]

Hi, how to get the relative x,y coordinate? I'm new to slint, don't find much information about it.

[ogoffart]

@threefoldo you can get the relative x, y coodinate using x and y property.

I am not quite sure what you are trying to do, but maybe this example helps? https://slint-ui.com/releases/0.3.1/editor/?snippet=import+%7B+Button%2C+VerticalBox+%7D+from+%22std-widgets.slint%22%3B%0Aexport+Demo+%3A%3D+Window+%7B%0A++++VerticalBox+%7B%0A++++++++alignment%3A+start%3B%0A++++++++Text+%7B%0A++++++++++++text%3A+%22Hello+World%21%22%3B%0A++++++++++++font-size%3A+24px%3B%0A++++++++++++horizontal-alignment%3A+center%3B%0A++++++++%7D%0A++++++++rect+%3A%3D+Rectangle+%7B%0A++++++++++++Text+%7B%0A++++++++++++++++text%3A+%22Rect+is+at+%28%5C%7Brect.x+%2F+1px%7D%2C%5C%7Brect.y+%2F+1px%7D%29%22%3B+%0A++++++++++++%7D%0A++++++++%7D%0A++++%7D%0A%7D%0A%0A

[threefoldo]

We want to generate UI automatically. In the example above, how to find the x,y,w,h of the previous Text component? And how to locate the rect object from the Window handle? I tried this, but didn't work:

slint::slint!(import {App} from "app.slint";);

pub fn main() {
    let app = App::new();
    app.show();
    let w = app.window();
    let pos = w.position();
    let size = w.size();

    println!("position: {},{}", pos.x, pos.y);
    println!("size: {},{}", size.width, size.height);
}

I can get the position and size of the window, but don't know how to enumerate all sub-components and get their properties.

[flukejones]

I'm finding I need this so that I can do bounds checking of PopupWindow and a few other items I'm setting with absolute coordinates (relative to parent).

[flukejones]

I should mention this is also highly desired for a root window popover that needs to display an overlay with components at the precise locations of the nested child components it is covering - for example a widget leftmost at 600px screen coords, I need this info to pass to the popover to show a ring/glow/dropdown/help-text etc. This info is also required to more precisely place a PopupWindow widget if called by deeply nested components.

[flukejones]

Example of why I need the absolute coords: