docs: protected void viewportChanged (int pixelWidth, int pixelHeight) {
      viewPixelWidth = pixelWidth;
      viewPixelHeight = pixelHeight;
      viewSizeM.width = scale.invScaled(pixelWidth);
      viewSizeM.height = scale.invScaled(pixelHeight);
      plat.log().info("viewPortChanged " + pixelWidth + "x" + pixelHeight + " / " + scale.factor +
                      " -> " + viewSize);
    }