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-rw-r--r--native/src/text.rs114
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+//! 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>);
+}