ResizeStrip

A thin invisible widget that forwards a window resize gesture to the platform host when the user presses the primary button inside it. Used to build a 6-px resize frame around a borderless window on Wayland.

Public functions

ResizeStrip

Detailed description

This is the frame complement to crate::title_bar::DragRegion: drag moves the window, resize strips drag the window edges. On platforms that don't expose Window::drag_resize_window (notably winit's macOS backend), PlatformTitleBarHost::begin_resize returns PlatformError::Unsupported and the strip becomes a silent no-op — macOS handles edge resize via its own native chrome.

Reaching a 6 dp edge with a finger

The strip's thickness is fixed at every density — it is an overlay drawn over the window's own edge, so widening it would eat into content rather than into empty space, and the frame would start swallowing presses meant for the app.

The grab is Widget::hit_outset instead: for a direct pointer the strip is offered the press against bounds inflated inward to the density's target size (24 dp Compact, 44 dp Touch), and the arena's outset pre-pass runs before the ordinary reverse-sibling walk, so the widened band beats the content underneath. An edge strip inflates only across its thickness; a corner cell inflates on all four sides, since both of its axes are the diagonal grab. For a precise pointer the outset is zero and a mouse press resolves exactly where it always did.

Two strips whose bands overlap are settled by distance to their own uninflated rectangles, not by sibling order, so the midpoint between two adjacent edges belongs to the nearer one.

One resize per gesture

PlatformTitleBarHost::begin_resize hands the window to the compositor for the rest of the gesture, so it must be asked once. The press that asks is gated on the pointer being the primary one: a second finger landing on the frame while a resize is already running would ask for a second interactive resize of the same window, which on Wayland means a second xdg_toplevel::resize against a live one. A mouse is always primary, so the gate never fires for one.

API reference

📖 Full rustdoc API for this module

pub struct ResizeStrip

Import: use teksilo::widgets::ResizeStrip;

A single edge of a resize frame. Construct one per side and lay them out around your content (HStack of left + content + right inside a VStack of top + middle + bottom is the conventional shape — see the title bar demo for an example).

#![allow(unused)]
fn main() {
pub struct ResizeStrip { /* fields */ }
}

Methods

pub fn horizontal( host: Rc<dyn PlatformTitleBarHost>, edge: ResizeEdge, thickness: f32, ) -> Self

Build a horizontal (top / bottom) strip of the given height. The width is unconstrained — the strip claims whatever its parent container offers, so it can stretch across the full window width.

pub fn vertical(host: Rc<dyn PlatformTitleBarHost>, edge: ResizeEdge, thickness: f32) -> Self

Build a vertical (left / right) strip of the given width. The height is unconstrained.

pub fn corner(host: Rc<dyn PlatformTitleBarHost>, edge: ResizeEdge, size: f32) -> Self

Build a square corner cell of the given size. The corner handles a diagonal resize gesture (e.g. TopLeft does NW/SE resize). Should be placed on top of the edge strips at the four corners so the framework's hit-test routes the click to the corner rather than the adjacent edge.