Implement clipping for quads

wgpu/src/quad.rs

@@ -1,4 +1,5 @@
 use crate::Transformation;
+use iced_native::Rectangle;
 
 use std::mem;
 
@@ -165,6 +166,7 @@ impl Pipeline {
         encoder: &mut wgpu::CommandEncoder,
         instances: &[Quad],
         transformation: Transformation,
+        bounds: Rectangle<u32>,
         target: &wgpu::TextureView,
     ) {
         let matrix: [f32; 16] = transformation.into();
@@ -227,6 +229,12 @@ impl Pipeline {
                     0,
                     &[(&self.vertices, 0), (&self.instances, 0)],
                 );
+                render_pass.set_scissor_rect(
+                    bounds.x,
+                    bounds.y,
+                    bounds.width,
+                    bounds.height,
+                );
 
                 render_pass.draw_indexed(
                     0..QUAD_INDICES.len() as u32,

wgpu/src/renderer.rs

@@ -251,7 +251,7 @@ impl Renderer {
                 border_radius,
             } => {
                 layer.quads.push(Quad {
-                    position: [bounds.x, bounds.y],
+                    position: [bounds.x, bounds.y - layer.y_offset as f32],
                     scale: [bounds.width, bounds.height],
                     color: match background {
                         Background::Color(color) => color.into_linear(),
@@ -304,6 +304,7 @@ impl Renderer {
             encoder,
             &layer.quads,
             transformation,
+            layer.bounds,
             target,
         );