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Diffstat (limited to 'native/src/text.rs')
-rw-r--r-- | native/src/text.rs | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/native/src/text.rs b/native/src/text.rs new file mode 100644 index 00000000..8b9205e3 --- /dev/null +++ b/native/src/text.rs @@ -0,0 +1,114 @@ +//! Draw and interact with text. +use crate::alignment; +use crate::{Color, Point, Rectangle, Size, Vector}; + +/// A paragraph. +#[derive(Debug, Clone, Copy)] +pub struct Text<'a, Font> { + /// The content of the paragraph. + pub content: &'a str, + + /// The bounds of the paragraph. + pub bounds: Rectangle, + + /// The size of the [`Text`]. + pub size: f32, + + /// The color of the [`Text`]. + pub color: Color, + + /// The font of the [`Text`]. + pub font: Font, + + /// The horizontal alignment of the [`Text`]. + pub horizontal_alignment: alignment::Horizontal, + + /// The vertical alignment of the [`Text`]. + pub vertical_alignment: alignment::Vertical, +} + +/// The result of hit testing on text. +#[derive(Debug, Clone, Copy, PartialEq)] +pub enum Hit { + /// The point was within the bounds of the returned character index. + CharOffset(usize), + /// The provided point was not within the bounds of a glyph. The index + /// of the character with the closest centeroid position is returned, + /// as well as its delta. + NearestCharOffset(usize, Vector), +} + +impl Hit { + /// Computes the cursor position corresponding to this [`HitTestResult`] . + pub fn cursor(self) -> usize { + match self { + Self::CharOffset(i) => i, + Self::NearestCharOffset(i, delta) => { + if delta.x > f32::EPSILON { + i + 1 + } else { + i + } + } + } + } +} + +/// A renderer capable of measuring and drawing [`Text`]. +pub trait Renderer: crate::Renderer { + /// The font type used. + type Font: Default + Copy; + + /// The icon font of the backend. + const ICON_FONT: Self::Font; + + /// The `char` representing a ✔ icon in the [`ICON_FONT`]. + /// + /// [`ICON_FONT`]: Self::ICON_FONT + const CHECKMARK_ICON: char; + + /// The `char` representing a ▼ icon in the built-in [`ICON_FONT`]. + /// + /// [`ICON_FONT`]: Self::ICON_FONT + const ARROW_DOWN_ICON: char; + + /// Returns the default size of [`Text`]. + fn default_size(&self) -> u16; + + /// Measures the text in the given bounds and returns the minimum boundaries + /// that can fit the contents. + fn measure( + &self, + content: &str, + size: u16, + font: Self::Font, + bounds: Size, + ) -> (f32, f32); + + /// Measures the width of the text as if it were laid out in a single line. + fn measure_width(&self, content: &str, size: u16, font: Self::Font) -> f32 { + let (width, _) = self.measure(content, size, font, Size::INFINITY); + + width + } + + /// Tests whether the provided point is within the boundaries of text + /// laid out with the given parameters, returning information about + /// the nearest character. + /// + /// If `nearest_only` is true, the hit test does not consider whether the + /// the point is interior to any glyph bounds, returning only the character + /// with the nearest centeroid. + fn hit_test( + &self, + contents: &str, + size: f32, + font: Self::Font, + bounds: Size, + point: Point, + nearest_only: bool, + ) -> Option<Hit>; + + /// Draws the given [`Text`]. + fn fill_text(&mut self, text: Text<'_, Self::Font>); +} |