[Layers API] Layer viewport on setLayerImage call not set, if no options are passed

[gohabereg]

On setLayerImage call there is an if statement to check if layer.viewport exists:

  if (!layer.viewport) {
    const defaultViewport = getDefaultViewport(enabledElement.canvas, image);

    // Override the defaults if any optional viewport settings
    // have been specified
    if (layer.options && layer.options.viewport) {
      layer.viewport = Object.assign(defaultViewport, layer.options.viewport);
    }

    if (baseLayer.layerId !== layerId) {
      rescaleImage(baseLayer, layer);
    }
  }

So in code above, layer.viewport is set only if layer has layer.options.viewport otherwise, it leaves it undefined. This cause an error on next drawCompositeImage execution, as it gets layers to render and requires viewport for calculations

[dannyrb]

@gohabereg, are you able to author a PR that addresses this issue?

[gohabereg]

Hi @dannyrb Sure, will do. It's enough to pass default viewport if it's not specified, isn't it?