render: implement surface mapping api

src/render.rs

@@ -21,10 +21,12 @@ pub trait Surface: Default + Clone + Debug {
     fn with_shader<F: FnMut(&dyn Shader)>(&self, f: F);
     fn set_shader(&mut self, shader: Box<dyn Shader>);
     fn clear_shader(&mut self);
+
+    fn rect(&self) -> Rectangle<u8, Virtual>;
 }
 
 pub trait Surfaces<T: Surface>: Debug {
-    fn new_surface(&mut self) -> Result<T, io::Error>;
+    fn new_surface(&mut self, area: &Rectangle<u8, Virtual>) -> Result<T, io::Error>;
 }
 
 pub trait Display<T: Surface>: Surfaces<T> {
@@ -69,6 +71,7 @@ impl<T: Display<S>, S: Surface> Task for Renderer<T, S> {
 #[derive(Debug)]
 pub struct ShaderBinding {
     shader: Option<Box<dyn Shader>>,
+    rect: Rectangle<u8, Virtual>
 }
 
 #[derive(Clone)]
@@ -91,12 +94,17 @@ impl Default for BoundSurface<Rc<RefCell<ShaderBinding>>>{
         Self {
             binding: Rc::new(RefCell::new(ShaderBinding {
                 shader: None,
+                rect: Rectangle::everything()
             })),
         }
     }
 }
 
 impl Surface for BoundSurface<Rc<RefCell<ShaderBinding>>> {
+    fn rect(&self) -> Rectangle<u8, Virtual> {
+        self.binding.borrow().rect.clone()
+    }
+
     fn with_shader<F: FnMut(&dyn Shader)>(&self, mut f: F) {
         if let Some(ref shader) = self.binding.borrow().shader {
             f(shader.as_ref());
@@ -175,8 +183,8 @@ impl<S: Surface + Default> SurfacePool<S> {
     }
 }
 
-impl<S: Surface + Default + Clone> Surfaces<S> for SurfacePool<S> {
-    fn new_surface(&mut self) -> Result<S, io::Error> {
+impl<S: Surface + Default> Surfaces<S> for SurfacePool<S> {
+    fn new_surface(&mut self, _area: &Rectangle<u8, Virtual>) -> Result<S, io::Error> {
         let surface = S::default();
         self.surfaces.push(surface.clone());
         return Ok(surface);