Trait TextRenderer

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;
}

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

type Color: PixelColor

Color type.

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>,

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.

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.

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.

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.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<C> TextRenderer for MonoTextStyle<'_, C>

where C: PixelColor,

type Color = C