Implement image support for canvas widget

wgpu/src/image/mod.rs

@@ -149,6 +149,8 @@ impl Pipeline {
                             6 => Float32x2,
                             // Layer
                             7 => Sint32,
+                            // Snap
+                            8 => Uint32,
                         ),
                     }],
                 },
@@ -212,8 +214,6 @@ impl Pipeline {
         transformation: Transformation,
         scale: f32,
     ) {
-        let transformation = transformation * Transformation::scale(scale);
-
         let nearest_instances: &mut Vec<Instance> = &mut Vec::new();
         let linear_instances: &mut Vec<Instance> = &mut Vec::new();
 
@@ -226,6 +226,7 @@ impl Pipeline {
                     bounds,
                     rotation,
                     opacity,
+                    snap,
                 } => {
                     if let Some(atlas_entry) =
                         cache.upload_raster(device, encoder, handle)
@@ -235,6 +236,7 @@ impl Pipeline {
                             [bounds.width, bounds.height],
                             f32::from(*rotation),
                             *opacity,
+                            *snap,
                             atlas_entry,
                             match filter_method {
                                 crate::core::image::FilterMethod::Nearest => {
@@ -268,6 +270,7 @@ impl Pipeline {
                             size,
                             f32::from(*rotation),
                             *opacity,
+                            true,
                             atlas_entry,
                             nearest_instances,
                         );
@@ -300,6 +303,7 @@ impl Pipeline {
             nearest_instances,
             linear_instances,
             transformation,
+            scale,
         );
 
         self.prepare_layer += 1;
@@ -375,9 +379,12 @@ impl Layer {
         nearest_instances: &[Instance],
         linear_instances: &[Instance],
         transformation: Transformation,
+        scale_factor: f32,
     ) {
         let uniforms = Uniforms {
             transform: transformation.into(),
+            scale_factor,
+            _padding: [0.0; 3],
         };
 
         let bytes = bytemuck::bytes_of(&uniforms);
@@ -492,6 +499,7 @@ struct Instance {
     _position_in_atlas: [f32; 2],
     _size_in_atlas: [f32; 2],
     _layer: u32,
+    _snap: u32,
 }
 
 impl Instance {
@@ -502,6 +510,10 @@ impl Instance {
 #[derive(Debug, Clone, Copy, Zeroable, Pod)]
 struct Uniforms {
     transform: [f32; 16],
+    scale_factor: f32,
+    // Uniforms must be aligned to their largest member,
+    // this uses a mat4x4<f32> which aligns to 16, so align to that
+    _padding: [f32; 3],
 }
 
 fn add_instances(
@@ -509,6 +521,7 @@ fn add_instances(
     image_size: [f32; 2],
     rotation: f32,
     opacity: f32,
+    snap: bool,
     entry: &atlas::Entry,
     instances: &mut Vec<Instance>,
 ) {
@@ -525,6 +538,7 @@ fn add_instances(
                 image_size,
                 rotation,
                 opacity,
+                snap,
                 allocation,
                 instances,
             );
@@ -554,8 +568,8 @@ fn add_instances(
                 ];
 
                 add_instance(
-                    position, center, size, rotation, opacity, allocation,
-                    instances,
+                    position, center, size, rotation, opacity, snap,
+                    allocation, instances,
                 );
             }
         }
@@ -569,6 +583,7 @@ fn add_instance(
     size: [f32; 2],
     rotation: f32,
     opacity: f32,
+    snap: bool,
     allocation: &atlas::Allocation,
     instances: &mut Vec<Instance>,
 ) {
@@ -591,6 +606,7 @@ fn add_instance(
             (height as f32 - 1.0) / atlas::SIZE as f32,
         ],
         _layer: layer as u32,
+        _snap: snap as u32,
     };
 
     instances.push(instance);