How do I override the default icon selection algorithm?

re: How do I override the default icon selection algorithm?

Clipboarder Gadget — Mon, 08 Oct 2012 16:59:52 GMT

No the programs are DPI-aware.

Even if you take a simple program from Petzolds samples with an icon and make it DPI-aware, Windows will take the 16-sized icon and scale it up even though there is a 32-sized icon.

You can prevent this by calling LoadIconWithScaleDown or ExtractIconEx instead of LoadIcon but most programs don't seem to do that.

re: How do I override the default icon selection algorithm?

JamesJohnston — Mon, 08 Oct 2012 14:10:18 GMT

@Clipboarder Gadget: Maybe the offending apps/icons are not DPI-aware? If the app hasn't declared itself DPI-aware in the manifest, Windows Vista/7 will emulate 96 DPI which might explain your behavior.

re: How do I override the default icon selection algorithm?

Lockwood — Mon, 08 Oct 2012 13:30:08 GMT

blogs.msdn.com/.../10007461.aspx

Loadicon also sounds like a Transformer.

re: How do I override the default icon selection algorithm?

Giulia Q — Mon, 08 Oct 2012 08:28:21 GMT

Shouldn't pointers to resource data be decorated with const and __unaligned?

[Resource data is 4-byte aligned, so you don't need to say __unaligned unless you have data that requires stricter alignment. You can say const if you want. That wasn't really the point of the article. -Raymond]

re: How do I override the default icon selection algorithm?

640k — Mon, 08 Oct 2012 00:33:18 GMT

[It's a surprise if you aren't the one who compiled the binary. LoadImage("Notepad.exe", 16, 16)...]

LoadIcon isn't LoadImage. If you don't specify a size (i.e. LoadIcon), then it's a surprise that the whole icon, including all it's resolutions, isn't loaded.

[LoadIcon loads the icon at standard size (typically 32x32). I can't wait for Alex to say "designed without adult supervision." -Raymond]

re: How do I override the default icon selection algorithm?

Clipboarder Gadget — Sat, 06 Oct 2012 11:03:49 GMT

Sadly it seems that the LoadIcon algorithm is broken since Vista. On a 150% scale DPI setting it loads always the lower resolution and never the higher. Because of that almost all application icons look blurry on the taskbar if you disable "Always combine" for the taskbar. Only some MS applications dont seem to do that, but only because they provide icons in all kinds of sizes.

re: How do I override the default icon selection algorithm?

Klimax — Sat, 06 Oct 2012 10:24:04 GMT

Just a reminder that LoadIcon and co are from time, where RAM saving had high prioirty.

re: How do I override the default icon selection algorithm?

AndyCadley — Sat, 06 Oct 2012 09:15:11 GMT

@640K: If you always load *all* versions of an icon, there's of course no surprise that it uses lots more ram than if you only load what was actually needed.

re: How do I override the default icon selection algorithm?

640k — Sat, 06 Oct 2012 08:16:13 GMT

If a 0.25mb ico file is compiled into the binary, there's of course no surprise that it will use 0.25 of ram when loading it.

[It's a surprise if you aren't the one who compiled the binary. LoadImage("Notepad.exe", 16, 16) suddenly requires 25x more memory than it used to. A folder in small icon mode would not be able to show more than 4000 files in a directory before running out of memory *just for the icons*. -Raymond]

re: How do I override the default icon selection algorithm?

640k — Sat, 06 Oct 2012 02:13:42 GMT

LoadIcon should have loaded all icons, and DrawIcon/DrawIconEx should have decided which resolution to use. The current architectural choices makes me cringe!

["Why does my 16x16 icon take up a quarter megabyte of memory?" -Raymond]