iris/src/widget/text/mod.rs

mod build;
mod edit;

pub use build::*;
pub use edit::*;
use iris_core::util::MutDetect;

use crate::prelude::*;
use std::ops::{Deref, DerefMut};

pub struct Text {
    pub content: MutDetect<String>,
    view: TextView,
}

pub struct TextView {
    pub attrs: TextAttrs,
    pub buf: TextBuffer,
    pub hint: Option<StrongWidget>,
}

impl TextView {
    fn is_empty(&self) -> bool {
        self.buf.is_empty()
    }

    pub fn wrap_width(&self) -> Option<f32> {
        self.buf.wrap_width()
    }
}

impl TextView {
    pub fn new(buf: TextBuffer, attrs: TextAttrs, hint: Option<StrongWidget>) -> Self {
        Self { attrs, buf, hint }
    }

    /// region where the text should be draw
    /// does not include extra height or width from weird unicode
    pub fn region(&self) -> UiRegion {
        self.tex()
            .map(|t| t.size)
            .unwrap_or(Vec2::ZERO)
            .align(self.align)
    }

    /// The text shaped for the width it is drawn in. The buffer keeps its
    /// answers under the attrs too, so changing those asks a new question
    /// rather than invalidating anything.
    fn render(&mut self, painter: &mut Painter) -> &RenderedText {
        let width = self.attrs.wrap.then(|| painter.px_len(Axis::X));
        // The shaper measures in floats, which is where a glyph advance comes
        // from; what it answers goes back on the grid.
        let text = painter.render_text(&mut self.buf, &self.attrs, width.map(Px::to_f32));
        // A greedy break is the same break at every width from its longest
        // line up to the one it was made at: each line still fits, and none
        // could take a word that did not fit in the wider box. A line too
        // long to fit at all says nothing about narrower boxes.
        //
        // The step at or above that longest line rather than the nearest
        // one, since the shaper measures in floats: the nearest step is
        // under the line half the time, and a range starting there admits a
        // box the line does not fit in, where the break is not this one.
        if let Some(width) = width {
            painter.holds(Axis::X, Px::ceil_from_f32(text.size.x).min(width)..=width);
        }
        text
    }

    pub fn tex(&self) -> Option<&RenderedText> {
        self.buf.rendered()
    }
    /// Draws the text, and says where the glyphs went and what they use.
    pub fn draw(&mut self, painter: &mut Painter) -> (UiRegion, Size) {
        let align = self.align;
        if self.is_empty() && self.hint.is_some() {
            let region = self.render(painter).size.align(align);
            let size = match &self.hint {
                Some(hint) => painter.widget(hint).size(),
                None => Size::ZERO,
            };
            return (region, size);
        }

        let tex = self.render(painter);
        let region = tex.size.align(align);
        // The step at or above what the shaper measured, so a parent that
        // hands back the length this reports hands back a box the longest
        // line fits in. Rounded to the nearest step it is half the time a
        // hair under that line, and the break made in it is not the break a
        // cold layout makes there.
        let size = Size::from_px(PxVec2::ceil_from_f32(tex.size));
        let within = region.within(&painter.region());
        painter.glyphs(tex, within);
        (region, size)
    }

    pub fn content(&self) -> String {
        self.buf.text().to_string()
    }
}

impl Text {
    pub fn new(content: impl Into<String>) -> Self {
        let content: String = content.into();
        Self {
            view: TextView::new(TextBuffer::new(&content), TextAttrs::default(), None),
            content: content.into(),
        }
    }
    fn update_buf(&mut self) {
        if self.content.changed {
            self.content.changed = false;
            self.view.buf.set_text(self.content.as_str());
        }
    }
}

impl Widget for Text {
    fn draw(&mut self, painter: &mut Painter) -> Size {
        self.update_buf();
        self.view.draw(painter).1
    }
}

impl Deref for Text {
    type Target = TextAttrs;

    fn deref(&self) -> &Self::Target {
        &self.view
    }
}

impl DerefMut for Text {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.view
    }
}

impl Deref for TextView {
    type Target = TextAttrs;

    fn deref(&self) -> &Self::Target {
        &self.attrs
    }
}

impl DerefMut for TextView {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.attrs
    }
}