On very high resolution screens, it is necessary to enlarge fonts and images so they will still be a readable size. I personally have a 170 pixels per inch display, and although I have set my DPI and enlarged my default font size, webpages that specify font sizes in pixels have unreadably small fonts. Also, fixed-width tables and images are still too small. IE6 has implemented a solution for this which works very well. If a registry key is set, IE6 scales all px units so that objects on screen will appear the same size as on a 96 dpi display. Thus on a 170 dpi display, a 250x250 image is scaled to (170/96)*250 = 443x443 pixels. Font sizes are increased similarly, even (especially) when the size is specified in pixels. So are fixed-width tables, and everything else specified in pixels too. This has the effect of making objects a usable size while preserving correct layout. I'd like to see this feature implemented in Mozilla as an optional switch.
similar: bug 102755
Duplicate of "Page Zoom" *** This bug has been marked as a duplicate of 112018 ***