Merge pull request #325 from hecrj/feature/canvas-interaction

Canvas interactivity and Game of Life example

1 files changed, 72 insertions, 0 deletions

diff --git a/wgpu/src/widget/canvas/cursor.rs b/wgpu/src/widget/canvas/cursor.rs
new file mode 100644
index 00000000..456760ea
--- /dev/null
+++ b/wgpu/src/widget/canvas/cursor.rs
@@ -0,0 +1,72 @@
+use iced_native::{Point, Rectangle};
+
+/// The mouse cursor state.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum Cursor {
+    /// The cursor has a defined position.
+    Available(Point),
+
+    /// The cursor is currently unavailable (i.e. out of bounds or busy).
+    Unavailable,
+}
+
+impl Cursor {
+    // TODO: Remove this once this type is used in `iced_native` to encode
+    // proper cursor availability
+    pub(crate) fn from_window_position(position: Point) -> Self {
+        if position.x < 0.0 || position.y < 0.0 {
+            Cursor::Unavailable
+        } else {
+            Cursor::Available(position)
+        }
+    }
+
+    /// Returns the absolute position of the [`Cursor`], if available.
+    ///
+    /// [`Cursor`]: enum.Cursor.html
+    pub fn position(&self) -> Option<Point> {
+        match self {
+            Cursor::Available(position) => Some(*position),
+            Cursor::Unavailable => None,
+        }
+    }
+
+    /// Returns the relative position of the [`Cursor`] inside the given bounds,
+    /// if available.
+    ///
+    /// If the [`Cursor`] is not over the provided bounds, this method will
+    /// return `None`.
+    ///
+    /// [`Cursor`]: enum.Cursor.html
+    pub fn position_in(&self, bounds: &Rectangle) -> Option<Point> {
+        if self.is_over(bounds) {
+            self.position_from(bounds.position())
+        } else {
+            None
+        }
+    }
+
+    /// Returns the relative position of the [`Cursor`] from the given origin,
+    /// if available.
+    ///
+    /// [`Cursor`]: enum.Cursor.html
+    pub fn position_from(&self, origin: Point) -> Option<Point> {
+        match self {
+            Cursor::Available(position) => {
+                Some(Point::new(position.x - origin.x, position.y - origin.y))
+            }
+            Cursor::Unavailable => None,
+        }
+    }
+
+    /// Returns whether the [`Cursor`] is currently over the provided bounds
+    /// or not.
+    ///
+    /// [`Cursor`]: enum.Cursor.html
+    pub fn is_over(&self, bounds: &Rectangle) -> bool {
+        match self {
+            Cursor::Available(position) => bounds.contains(*position),
+            Cursor::Unavailable => false,
+        }
+    }
+}