Struct ShapedLine 

pub struct ShapedLine {
    pub text: SharedString,
    /* private fields */
}

A shaped line that is ready to measure and paint.

WindowTextSystem::shape_line does the expensive shaping work. Reuse the result to measure with ShapedLine::width and paint on each frame. Paint backgrounds first with ShapedLine::paint_background when a row needs to sit behind other content.

Examples

window.update(|_view, window, _cx| {
    let run = TextRun {
        len: "Hi".len(),
        font: font("Lilex"),
        color: hsla(0., 0., 0., 1.),
        ..Default::default()
    };
    let line = window.text_system().shape_line("Hi".into(), px(16.), &[run]);
    assert_eq!(line.text.as_ref(), "Hi");
    assert_eq!(line.len(), 2);
});

Fields

text: SharedString

The text that was shaped for this line.

Implementations

impl ShapedLine

pub fn len(&self) -> usize

Returns the length of the line in UTF-8 bytes.

pub fn width(&self) -> Pixels

Returns the width of the line in logical pixels.

This is the glyph advance width from the text shaping system. Use it to advance a “pen” when you paint several lines or fragments on one row.

pub fn paint( &self, origin: Point<Pixels>, line_height: Pixels, align: TextAlign, align_width: Option<Pixels>, window: &mut Window, cx: &mut App, ) -> Result<()>

Paints the glyphs, underlines, and strikethroughs of the line.

origin is the top-left corner of the line box, which is line_height tall. The baseline is placed inside that box, centered by the font’s ascent and descent. When align_width is Some, the line is aligned within that width using align. Otherwise it is aligned in its own width.

Call this during paint. Background colors are not painted here, so call ShapedLine::paint_background first.

Errors

Returns an error only if the window’s paint layer fails. A glyph that fails to paint is logged and skipped, and the call still succeeds.

pub fn paint_background( &self, origin: Point<Pixels>, line_height: Pixels, align: TextAlign, align_width: Option<Pixels>, window: &mut Window, cx: &mut App, ) -> Result<()>

Paints the background color of each run in the line.

The arguments match ShapedLine::paint. Call this before paint, so that the glyphs are drawn over the backgrounds.

Trait Implementations

impl Clone for ShapedLine

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ShapedLine

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for ShapedLine

type Target = Arc<LineLayout>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl DerefMut for ShapedLine

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.