Implement create_texture()

src/canvas.rs

@@ -94,10 +94,15 @@ impl Canvas {
         unimplemented!();
     }
 
-    pub fn create_texture(&mut self, _size: Size, _background: Option<Pixel>)
+    pub fn create_texture(&mut self, size: Size, background: Option<Pixel>)
-        -> Rc<RefCell<Texture>>
+        -> Result<TextureHandle, &'static str>
     {
-        unimplemented!();
+       let buffer = vec!(background.unwrap_or_else(|| Pixel::from(Color::NONE));
+		   (size.w * size.h).try_into().unwrap());
+	   let texture = Texture::create(&self.renderer, &Vec::from(bytemuck::cast_slice(&buffer)),
+		   size);
+
+	   Ok(TextureHandle::from_texture(texture))
     }
 
     pub fn create_texture_from_file(&mut self,

src/renderer/texture.rs

@@ -17,6 +17,7 @@ pub struct Texture {
 
 impl Texture {
 
+	//TODO: take buffer's ownership
     pub fn create(renderer: &WgpuRenderer,
                   buffer: &[u8],
                   size: Size)