Alignment

Questions
,
1

How can this code be modified to position the darker rectangle in the upper right corner of the lighter rectangle? Thanks.

Overlay[{
  Graphics[{Opacity[.4], Rectangle[]}, ImageSize -> .2 {300, 787}, 
   ImagePadding -> 0, PlotRangePadding -> 0], 
  Graphics[{Opacity[.2], Rectangle[]}, ImagePadding -> 0, 
   PlotRangePadding -> 0]},
 Alignment -> {1, 1}]

189×189 150 Bytes

2

Inset will probably be easier to work with:

Graphics[{Opacity[.4], Rectangle[], 
  Inset[Graphics[{Opacity[.2], Rectangle[]}], {1, 1}, {1, 1}, 0.2]}, 
 ImageSize -> 300, ImagePadding -> 0, PlotRangePadding -> 0]

181×179 140 Bytes

3

The small square has padding from the explicit image width and height:

Overlay[{
  Graphics[{Opacity[.4], Rectangle[]}, ImageSize -> .2 {300, 787}, 
   ImagePadding -> 0, PlotRangePadding -> 0, Background -> Red], 
  Graphics[{Opacity[.2], Rectangle[]}, ImagePadding -> 0, 
   PlotRangePadding -> 0]},
 Alignment -> {1, 1}]

221×221 171 Bytes

Using an Automatic setting, or at least sizes that match the aspect ratio of the graphic, will work:

Overlay[{
  Graphics[{Opacity[.4], Rectangle[]}, 
   ImageSize -> {0.2*300, Automatic}, ImagePadding -> 0, 
   PlotRangePadding -> 0, Background -> Red], 
  Graphics[{Opacity[.2], Rectangle[]}, ImagePadding -> 0, 
   PlotRangePadding -> 0]}, Alignment -> {1, 1}]

221×219 158 Bytes