Java Edition Resource Pack Shaders - Scaled Post Render Targets

In a Shaders/Post .json file (e.g. transparency.json), a width and height for custom render targets can be specified e.g {name:"mytarget" width:512 height:512} but this is not useful when targets need to be scaled off of the game resolution for purposes such as Downsampling or Blur Pyramid techniques.

This is why I suggest a non-hardcoded method of specifying the width and height of render targets, such as:
{name: "mytarget" width:(minecraft:main:width) / 2 height: (minecraft:main:height) / 2}

This method of scaling render targets (or some variation of it) will be very useful for developers of resource pack shaders.