Move resize from APP to DRAW

Because resizing blanks the canvas, it's better to do it immediately before we
instruct Pixi render to it.

The old code did resize in APP, which meant that after resizing,
the canvas would flash "black" until the next animation frame.

modules/pixi/PixiRenderer.js

@@ -493,24 +493,6 @@ export class PixiRenderer extends EventEmitter {
     const mapTransform = mapViewport.transform;
     const pixiTransform = pixiViewport.transform;
 
-    // Resize Pixi canvas if needed
-    const pixiDims = pixiViewport.dimensions;
-    const canvasDims = [this.pixi.screen.width, this.pixi.screen.height];
-    if (!vecEqual(pixiDims, canvasDims)) {
-      const [w, h] = pixiDims;
-
-      // Resize supersurface and overlay to cover the screen dimensions.
-      const ssnode = this.supersurface.node();
-      ssnode.style.width = `${w}px`;
-      ssnode.style.height = `${h}px`;
-      const onode = this.overlay.node();
-      onode.style.width = `${w}px`;
-      onode.style.height = `${h}px`;
-
-      // Resize pixi canvas
-      this.pixi.renderer.resize(w, h);
-    }
-
     // Determine "offset"
     // We try to avoid reprojecting the pixi geometries unless zoom has changed, or map has translated very far.
     // If the user is just panning, we can leave the geometries alone and add an offset translation to the origin.
@@ -556,10 +538,27 @@ export class PixiRenderer extends EventEmitter {
 
   /**
    * _draw
-   * The "Pixi" part of the drawing
+   * The "Pixi" part of the drawing.
    * Where it converts Pixi geometries into WebGL instructions.
    */
   _draw() {
+    // Resize Pixi canvas if needed..
+    // It will clear the canvas, so do this immediately before we render.
+    const pixiDims = this.pixiViewport.dimensions;
+    const canvasDims = [this.pixi.screen.width, this.pixi.screen.height];
+    if (!vecEqual(pixiDims, canvasDims)) {
+      const [w, h] = pixiDims;
+      // Resize supersurface and overlay to cover the screen dimensions.
+      const ssnode = this.supersurface.node();
+      ssnode.style.width = `${w}px`;
+      ssnode.style.height = `${h}px`;
+      const onode = this.overlay.node();
+      onode.style.width = `${w}px`;
+      onode.style.height = `${h}px`;
+      // Resize pixi canvas
+      this.pixi.renderer.resize(w, h);
+    }
+
     // Let's go!
     this.pixi.render();
 
@@ -580,7 +579,10 @@ export class PixiRenderer extends EventEmitter {
   }
 
 
-  /* renders some debug shapes */
+  /**
+   * _renderDebug
+   * Render some debug shapes (usually commented out)
+   */
   _renderDebug() {
     const context = this.context;
     const mapViewport = context.viewport;