Resolution indpendence

Felix Miata mrmazda at
Mon Jun 30 17:22:42 PDT 2008

On 2008/07/01 00:25 (GMT+0100) Glynn Clements apparently typed:

> Windows' icon sizes are: 16x16, 24x24, 32x32, 48x48. The first two are
> "small" icons for use in "list" and "detail" views, the last two are
> "large" icons for "icon" view, desktop, start menu etc. In each case,
> the larger version is 50% larger than the smaller version, whereas the
> difference between 1024x768 and 1280x960 is 25%. It's not like fonts,
> where they typically provide bitmaps at 2pt increments.

Sounds to me like you're using the same bogus math as typesetters and web
deeziners use. 8px is not half the size of 16px - it's 25%, length times
width. Size is area, not one single dimension. A 1600x1200 display has 4
times as many logical px (1,920,000) as an 800x600 display (480,000). Thus, a
48x48 icon has 2304px, 2.25 times the 1024px of a 32x32 icon; 4 times as many
as a 24x24 (576).

> The 96 dpi figure was just an arbitrary value, chosen so that various
> common point sizes (6, 8, 12, 16) would work out to an integer number
> of pixels.

It's arbitrary all right, but not necessarily for the reason you claim. e.g.
at 96 DPI:

6pt = 8.000px^~1.5 (not enough px per character box for all complete
character sets to be rendered intelligibly)
8pt = 10.667px^~1.5
10pt = 13.333px^~1.5
12pt = 16.000px^~1.5
16pt = 21.333px^~1.5

The reason anyone else uses it is because M$ uses/used it, and the reason for
that misfortunate legacy is explained on:
"Where were you when I laid the earth's
foundation?"		       Matthew 7:12 NIV

 Team OS/2 ** Reg. Linux User #211409

Felix Miata  ***

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