[−][src]Trait piet::TextLayout

pub trait TextLayout {
    fn width(&self) -> f64;
    fn hit_test_point(&self, point: Point) -> HitTestPoint;
    fn hit_test_text_position(
        &self, 
        text_position: usize
    ) -> Option<HitTestTextPosition>;
}

Text Layout

A text position is defined in utf-8 code units, as is standard for Rust strings.

However, text position is also related to valid cursor positions. Therefore:

The end of a line is a valid text position. e.g. text.len() is a valid text position.
If the text position is not at a code point or grapheme boundary, undesirable behavior may occur.

Required methods

`fn width(&self) -> f64`

Measure the advance width of the text.

`fn hit_test_point(&self, point: Point) -> HitTestPoint`

Given a Point, determine the corresponding text position

`fn hit_test_text_position( &self, text_position: usize ) -> Option<HitTestTextPosition>`

Given a text position, determine the corresponding pixel location (currently consider the text layout just one line)

Note: if text position is not at grapheme boundary, rounds the boundary to the text position of the grapheme cluster it is a part of. Returned text position is the original text position.

Note: in directwrite, if text position is not at code point boundary, this method will panic. Cairo and web are more lenient and may not panic.

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Implementors