diff --git a/src/widget/canvas.rs b/src/widget/canvas.rs
index f60c6bf..40f2b35 100644
--- a/src/widget/canvas.rs
+++ b/src/widget/canvas.rs
@@ -104,7 +104,8 @@ impl CanvasWidget {
         CanvasWidget {
             viewport: Viewport {
                 content_size: Size::new(0.0, 0.0),
-                rect: druid::Rect::new(0.0, 0.0, 0.0, 0.0),
+                view_origin: Point::new(0.0, 0.0),
+                view_size: Size::new(0.0, 0.0),
             },
             widget_size: Size::new(0.0, 0.0),
             scroll_component: ScrollComponent::new(),
@@ -112,11 +113,10 @@ impl CanvasWidget {
     }
 
     fn widget_to_viewport(&self) -> Affine {
-        let viewport_rect_size = self.viewport.rect.size();
-        if !viewport_rect_size.is_empty() && !self.widget_size.is_empty() {
-            let scale_x = viewport_rect_size.width / self.widget_size.width;
-            let scale_y = viewport_rect_size.height / self.widget_size.height;
-            Affine::translate(self.viewport.rect.origin().to_vec2())
+        if !self.viewport.view_size.is_empty() && !self.widget_size.is_empty() {
+            let scale_x = self.viewport.view_size.width / self.widget_size.width;
+            let scale_y = self.viewport.view_size.height / self.widget_size.height;
+            Affine::translate(self.viewport.view_origin.to_vec2())
             * Affine::scale_non_uniform(scale_x, scale_y)
         } else {
             Affine::scale(1.0) // identity
@@ -189,7 +189,7 @@ impl Widget<CanvasState> for CanvasWidget {
                 data.handle_event(ctx, event, self.widget_to_viewport(), env);
             }
             if let Some(transform) = viewport_transform {        
-                let mut new_rect = transform.transform_rect_bbox(self.viewport.rect);
+                let mut new_rect = transform.transform_rect_bbox(self.viewport.view_rect());
                 if new_rect.x0 <= 0f64 {
                     new_rect.x1 -= new_rect.x0;
                     new_rect.x0 = 0f64;
@@ -198,7 +198,7 @@ impl Widget<CanvasState> for CanvasWidget {
                     new_rect.y1 -= new_rect.y0;
                     new_rect.y0 = 0f64;
                 }
-                self.viewport.rect = new_rect;
+                self.viewport.view_origin = new_rect.origin();
                 self.scroll_component
                     .reset_scrollbar_fade(|d| ctx.request_timer(d), env);
                 ctx.request_paint();
@@ -267,13 +267,14 @@ impl Widget<CanvasState> for CanvasWidget {
 
         let page_content_size = data.versioned_canvas.get().content_size();
         let transform = self.widget_to_viewport();
-        self.viewport.rect = 
-            transform.transform_rect_bbox(rect)
-                .with_origin(self.viewport.rect.origin());
+        //self.viewport.rect =
+        //    transform.transform_rect_bbox(rect)
+        //        .with_origin(self.viewport.rect.origin());
+        self.viewport.view_size = transform.transform_rect_bbox(rect).size();
 
         self.viewport.content_size = druid::Size::new(
-            self.viewport.rect.x1.max(page_content_size.width),
-            self.viewport.rect.y1.max(page_content_size.height),
+            self.viewport.view_rect().x1.max(page_content_size.width),
+            self.viewport.view_rect().y1.max(page_content_size.height),
         );
         //log::debug!("{:#?}", &self.viewport);