Draft Editor API and TextEditor widget

core/src/text/editor.rs

@@ -0,0 +1,68 @@
+use crate::text::LineHeight;
+use crate::{Pixels, Point, Rectangle, Size};
+
+pub trait Editor: Sized + Default {
+    type Font: Copy + PartialEq + Default;
+
+    /// Creates a new [`Editor`] laid out with the given text.
+    fn with_text(text: &str) -> Self;
+
+    fn cursor(&self) -> Cursor;
+
+    fn perform(&mut self, action: Action);
+
+    /// Returns the current boundaries of the [`Editor`].
+    fn bounds(&self) -> Size;
+
+    /// Returns the minimum boundaries that can fit the contents of the
+    /// [`Editor`].
+    fn min_bounds(&self) -> Size;
+
+    /// Updates the [`Editor`] with some new attributes.
+    fn update(
+        &mut self,
+        new_bounds: Size,
+        new_font: Self::Font,
+        new_size: Pixels,
+        new_line_height: LineHeight,
+    );
+
+    /// Returns the minimum width that can fit the contents of the [`Editor`].
+    fn min_width(&self) -> f32 {
+        self.min_bounds().width
+    }
+
+    /// Returns the minimum height that can fit the contents of the [`Editor`].
+    fn min_height(&self) -> f32 {
+        self.min_bounds().height
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum Action {
+    MoveLeft,
+    MoveRight,
+    MoveUp,
+    MoveDown,
+    MoveLeftWord,
+    MoveRightWord,
+    MoveHome,
+    MoveEnd,
+    SelectWord,
+    SelectLine,
+    Insert(char),
+    Backspace,
+    Delete,
+    Click(Point),
+    Drag(Point),
+}
+
+/// The cursor of an [`Editor`].
+#[derive(Debug, Clone)]
+pub enum Cursor {
+    /// Cursor without a selection
+    Caret(Point),
+
+    /// Cursor selecting a range of text
+    Selection(Vec<Rectangle>),
+}