Custom UI for bitmap across whole header
I often use header images that cover the whole header area (498x57), which requires the MUI_HEADERIMAGE_BITMAP_NOSTRETCH define (otherwise bitmap is shrunk to 150 pixels). But I neglected the fact that it also prevents the bitmap from being resized on systems with large dpi. Today I tested one of my installers on large dpi for the first time and realized it don't look nice. So I made a custom UI that fixes this problem. It's not exactly big work but I thought I'd share it, in case somebody can use it and don't feel like tampering with UIs.
To use it, add:
!define MUI_UI_HEADERIMAGE "${NSISDIR}\Contrib\UIs\modern_headerbmp_full.exe"
Then you don't need MUI_HEADERIMAGE_BITMAP_NOSTRETCH anymore.
You also don't need MUI_HEADER_TRANSPARENT_TEXT because I removed the header label controls.