tek/crates/tek_layout/src/measure.rs

use crate::*;

/// A widget that tracks its render width and height
pub struct Measure<E: Engine>(PhantomData<E>, AtomicUsize, AtomicUsize);

impl<E: Engine> Clone for Measure<E> {
    fn clone (&self) -> Self {
        Self(
            Default::default(),
            AtomicUsize::from(self.1.load(Ordering::Relaxed)),
            AtomicUsize::from(self.2.load(Ordering::Relaxed)),
        )
    }
}

impl<E: Engine> std::fmt::Debug for Measure<E> {
    fn fmt (&self, f: &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
        f.debug_struct("Measure")
            .field("width",  &self.0)
            .field("height", &self.1)
            .finish()
    }
}

impl<E: Engine> Measure<E> {
    pub fn w (&self) -> usize { self.1.load(Ordering::Relaxed) }
    pub fn h (&self) -> usize { self.2.load(Ordering::Relaxed) }
    pub fn wh (&self) -> [usize;2] { [self.w(), self.h()] }
    pub fn set_w (&self, w: impl Into<usize>) { self.1.store(w.into(), Ordering::Relaxed) }
    pub fn set_h (&self, h: impl Into<usize>) { self.2.store(h.into(), Ordering::Relaxed) }
    pub fn set_wh (&self, w: impl Into<usize>, h: impl Into<usize>) { self.set_w(w); self.set_h(h); }
    pub fn new () -> Self { Self(PhantomData::default(), 0.into(), 0.into()) }
    pub fn format (&self) -> String { format!("{}x{}", self.w(), self.h()) }
}

impl<E: Engine> Render<E> for Measure<E> {
    fn min_size (&self, _: E::Size) -> Perhaps<E::Size> {
        Ok(Some([0u16.into(), 0u16.into()].into()))
    }
    fn render (&self, to: &mut E::Output) -> Usually<()> {
        self.set_w(to.area().w());
        self.set_h(to.area().h());
        Ok(())
    }
}