Data visualization similar to hex workshop.

[Uzver123]

There is a data visualizer in hex workshop that shows map for each line of hex code in the nearby window located next to editor. However i think its best to have this feature apply directly to the hex code the editor.

Is there way to define color ranges according to decimal value of each byte?

The segmented palette displays bands of colors based on the byte value of the data.
[ 0 - 31]  Grey scale; ASCII Control characters
[ 32 - 127 ] Green; ASCII characters
[ 127 - 254 ]  Blue; Extended ASCII characters
[ 255 ]  Black

[WerWolv]

ImHex has a minimap since a few commits ago if that's what you mean. Not yet in a release but it's available in the nightly builds.

It works line-by-line and not byte-by-byte though.

If you want to do highlighting of the hex cells directly, look into Highlighting Rules. Edit -> Modify highlighting rules...