I often need to export my assets in multiple sizes. The '1x' and '2x' option in Sketch simply isn't enough, as I sometimes need the same icon in let's say 200x200, 300x300 and 400x400 while the original artboard might be 800x800.
Is there a way to export the contents of an artboard at a certain size? Scaling isn't always easy in Sketch as things like text etc don't scale.
You can use fractions in export dialog.
And since you can export slices (which are like bounding boxes of sorts, for export purposes), which size you can define as you want, it's easy to define a slice - based on your example - on 1000x1000 dimensions, and export it as 0.2x, 0.3x, 0.4x and 0.8x.
You can also use notation with h or w. So if you want it 400 by 400, and it's square. You can put 400w in the size field of export.
