Merge pull request #111 from Maldela/svg

Svg and icon support

1 files changed, 187 insertions, 0 deletions

diff --git a/native/src/widget/svg.rs b/native/src/widget/svg.rs
new file mode 100644
index 00000000..9580f195
--- /dev/null
+++ b/native/src/widget/svg.rs
@@ -0,0 +1,187 @@
+//! Display vector graphics in your application.
+use crate::{layout, Element, Hasher, Layout, Length, Point, Size, Widget};
+
+use std::{
+    hash::Hash,
+    path::{Path, PathBuf},
+};
+
+/// A vector graphics image.
+///
+/// An [`Svg`] image resizes smoothly without losing any quality.
+///
+/// [`Svg`] images can have a considerable rendering cost when resized,
+/// specially when they are complex.
+///
+/// [`Svg`]: struct.Svg.html
+#[derive(Debug, Clone)]
+pub struct Svg {
+    handle: Handle,
+    width: Length,
+    height: Length,
+}
+
+impl Svg {
+    /// Creates a new [`Svg`] from the given [`Handle`].
+    ///
+    /// [`Svg`]: struct.Svg.html
+    /// [`Handle`]: struct.Handle.html
+    pub fn new(handle: impl Into<Handle>) -> Self {
+        Svg {
+            handle: handle.into(),
+            width: Length::Fill,
+            height: Length::Fill,
+        }
+    }
+
+    /// Sets the width of the [`Svg`].
+    ///
+    /// [`Svg`]: struct.Svg.html
+    pub fn width(mut self, width: Length) -> Self {
+        self.width = width;
+        self
+    }
+
+    /// Sets the height of the [`Svg`].
+    ///
+    /// [`Svg`]: struct.Svg.html
+    pub fn height(mut self, height: Length) -> Self {
+        self.height = height;
+        self
+    }
+}
+
+impl<Message, Renderer> Widget<Message, Renderer> for Svg
+where
+    Renderer: self::Renderer,
+{
+    fn width(&self) -> Length {
+        self.width
+    }
+
+    fn height(&self) -> Length {
+        self.height
+    }
+
+    fn layout(
+        &self,
+        renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        let (width, height) = renderer.dimensions(&self.handle);
+
+        let aspect_ratio = width as f32 / height as f32;
+
+        let mut size = limits
+            .width(self.width)
+            .height(self.height)
+            .resolve(Size::new(width as f32, height as f32));
+
+        let viewport_aspect_ratio = size.width / size.height;
+
+        if viewport_aspect_ratio > aspect_ratio {
+            size.width = width as f32 * size.height / height as f32;
+        } else {
+            size.height = height as f32 * size.width / width as f32;
+        }
+
+        layout::Node::new(size)
+    }
+
+    fn draw(
+        &self,
+        renderer: &mut Renderer,
+        layout: Layout<'_>,
+        _cursor_position: Point,
+    ) -> Renderer::Output {
+        renderer.draw(self.handle.clone(), layout)
+    }
+
+    fn hash_layout(&self, state: &mut Hasher) {
+        self.width.hash(state);
+        self.height.hash(state);
+    }
+}
+
+/// An [`Svg`] handle.
+///
+/// [`Svg`]: struct.Svg.html
+#[derive(Debug, Clone)]
+pub struct Handle {
+    id: u64,
+    path: PathBuf,
+}
+
+impl Handle {
+    /// Creates an SVG [`Handle`] pointing to the vector image of the given
+    /// path.
+    ///
+    /// [`Handle`]: struct.Handle.html
+    pub fn from_path<T: Into<PathBuf>>(path: T) -> Handle {
+        use std::hash::Hasher as _;
+
+        let path = path.into();
+
+        let mut hasher = Hasher::default();
+        path.hash(&mut hasher);
+
+        Handle {
+            id: hasher.finish(),
+            path,
+        }
+    }
+
+    /// Returns the unique identifier of the [`Handle`].
+    ///
+    /// [`Handle`]: struct.Handle.html
+    pub fn id(&self) -> u64 {
+        self.id
+    }
+
+    /// Returns a reference to the path of the [`Handle`].
+    ///
+    /// [`Handle`]: enum.Handle.html
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+}
+
+impl From<String> for Handle {
+    fn from(path: String) -> Handle {
+        Handle::from_path(path)
+    }
+}
+
+impl From<&str> for Handle {
+    fn from(path: &str) -> Handle {
+        Handle::from_path(path)
+    }
+}
+
+/// The renderer of an [`Svg`].
+///
+/// Your [renderer] will need to implement this trait before being able to use
+/// an [`Svg`] in your user interface.
+///
+/// [`Svg`]: struct.Svg.html
+/// [renderer]: ../../renderer/index.html
+pub trait Renderer: crate::Renderer {
+    /// Returns the default dimensions of an [`Svg`] located on the given path.
+    ///
+    /// [`Svg`]: struct.Svg.html
+    fn dimensions(&self, handle: &Handle) -> (u32, u32);
+
+    /// Draws an [`Svg`].
+    ///
+    /// [`Svg`]: struct.Svg.html
+    fn draw(&mut self, handle: Handle, layout: Layout<'_>) -> Self::Output;
+}
+
+impl<'a, Message, Renderer> From<Svg> for Element<'a, Message, Renderer>
+where
+    Renderer: self::Renderer,
+{
+    fn from(icon: Svg) -> Element<'a, Message, Renderer> {
+        Element::new(icon)
+    }
+}