Trait embedded_graphics::text::renderer::TextRenderer

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pub trait TextRenderer {
    type Color: PixelColor;

    // Required methods
    fn draw_string<D>(
        &self,
        text: &str,
        position: Point,
        baseline: Baseline,
        target: &mut D
    ) -> Result<Point, D::Error>
       where D: DrawTarget<Color = Self::Color>;
    fn draw_whitespace<D>(
        &self,
        width: u32,
        position: Point,
        baseline: Baseline,
        target: &mut D
    ) -> Result<Point, D::Error>
       where D: DrawTarget<Color = Self::Color>;
    fn measure_string(
        &self,
        text: &str,
        position: Point,
        baseline: Baseline
    ) -> TextMetrics;
    fn line_height(&self) -> u32;
}
Expand description

Text renderer.

The TextRenderer trait is used to integrate text renderers into embedded-graphics. Users should not call it directly and instead use the functions provided by the Text type.

Required Associated Types§

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type Color: PixelColor

Color type.

Required Methods§

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fn draw_string<D>( &self, text: &str, position: Point, baseline: Baseline, target: &mut D ) -> Result<Point, D::Error>where D: DrawTarget<Color = Self::Color>,

Draws a string.

The method returns the start position of the next character to allow chaining of multiple draw calls.

Implementation notes

This method must not interpret any control characters and only render a single line of text. Any control character in the text should be handled the same way as any other character that isn’t included in the font.

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fn draw_whitespace<D>( &self, width: u32, position: Point, baseline: Baseline, target: &mut D ) -> Result<Point, D::Error>where D: DrawTarget<Color = Self::Color>,

Draws whitespace of the given width.

The method returns the start position of the next character to allow chaining of multiple draw calls.

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fn measure_string( &self, text: &str, position: Point, baseline: Baseline ) -> TextMetrics

Returns the text metrics for a string.

Implementation notes

The returned bounding box must be independent of the text color. This is different to the Dimensions trait, which should return a zero sized bounding box for completely transparent drawables. But this behavior would make it impossible to correctly layout text which contains a mixture of transparent and non transparent words.

This method must not interpret any control characters and only render a single line of text. Any control character in the text should be handled the same way as any other character that isn’t included in the font.

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fn line_height(&self) -> u32

Returns the default line height.

The line height is defined as the vertical distance between the baseline of two adjacent lines in pixels.

Implementors§