[DirectWrite] Disable subpixel font positioning for old fonts

[DirectWrite] Disable subpixel font positioning for certain fonts/sizes

Conditionally disable subpixel text for certain older fonts at sizes
below 16px in order to improve legibility and rendering quality. This is
limited to a specific set of fonts and does not apply to webfonts.
This list of fonts in question includes all fonts in the "Microsoft Core
fonts for the Web" collection.

Specifically the following fonts: arial, courier new, times new roman,
andale mono, comic sans, impact, georgia, trebuchet, verdana, webdings,
tahoma, and lucida console.

R=cpu@chromium.org, scottmg@chromium.org
BUG=405445, 395425
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=181492

[eae, 2014-09-05 14:50:57]

eae@chromium.org changed reviewers:
+ cpu@chromium.org, scottmg@chromium.org

[eae, 2014-09-05 15:44:33]

On 2014/09/05 14:52:16, eae wrote:

Will obviously need a bunch of rebaselines, will grab list of tests from trybot
once it cycles and add to TestExpectations.

[scottmg, 2014-09-05 16:55:42]

LGTM

(patching in now to try it out)

https://codereview.chromium.org/544843004/diff/20001/Source/platform/fonts/wi...
File Source/platform/fonts/win/FontCacheSkiaWin.cpp (right):

https://codereview.chromium.org/544843004/diff/20001/Source/platform/fonts/wi...
Source/platform/fonts/win/FontCacheSkiaWin.cpp:254: const static wchar_t*
noSubpixelForSmallSizeFont[] = {
nit; sort this list

https://codereview.chromium.org/544843004/diff/20001/Source/platform/fonts/wi...
Source/platform/fonts/win/FontCacheSkiaWin.cpp:262: L"trebuchet",
does this need to be "trebuchet ms"?

[eae, 2014-09-05 18:15:54]

On 2014/09/05 16:55:42, scottmg wrote:
> LGTM
> 
> (patching in now to try it out)
> 
>
https://codereview.chromium.org/544843004/diff/20001/Source/platform/fonts/wi...
> File Source/platform/fonts/win/FontCacheSkiaWin.cpp (right):
> 
>
https://codereview.chromium.org/544843004/diff/20001/Source/platform/fonts/wi...
> Source/platform/fonts/win/FontCacheSkiaWin.cpp:254: const static wchar_t*
> noSubpixelForSmallSizeFont[] = {
> nit; sort this list

Will do.

> 
>
https://codereview.chromium.org/544843004/diff/20001/Source/platform/fonts/wi...
> Source/platform/fonts/win/FontCacheSkiaWin.cpp:262: L"trebuchet",
> does this need to be "trebuchet ms"?

It does, thanks!

[eae, 2014-09-05 18:25:02]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2014-09-05 18:25:41]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/eae@chromium.org/544843004/40001

[scottmg, 2014-09-05 18:33:58]

Looks good on a local build, I think a lot of older sites will be improved which
will make people happy.

I guess we'll see who feels the opposite way soon enough!

I should have asked this earlier, but this shouldn't really affect hidpi, except
at extremely small sizes right? e.g. at 150%, the font size would need to be <
16/1.5?

[eae, 2014-09-05 18:36:48]

On 2014/09/05 18:33:58, scottmg wrote:
> Looks good on a local build, I think a lot of older sites will be improved
which
> will make people happy.
> 
> I guess we'll see who feels the opposite way soon enough!
> 
> I should have asked this earlier, but this shouldn't really affect hidpi,
except
> at extremely small sizes right? e.g. at 150%, the font size would need to be <
> 16/1.5?

If this sticks I plan to limit it to DPIs < 150. Will require quite a bit of
plumbing though as the DPI isn't exposed to the blink font code.

[cpu_(ooo_6.6-7.5), 2014-09-05 20:04:31]

lgtm

[commit-bot: I haz the power, 2014-09-06 00:26:06]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-09-06 00:26:07]

Exceeded time limit waiting for builds to trigger.

[eae, 2014-09-06 00:28:14]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2014-09-06 00:28:55]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/eae@chromium.org/544843004/40001

[commit-bot: I haz the power, 2014-09-06 06:29:42]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-09-06 06:29:43]

Exceeded time limit waiting for builds to trigger.

[eae, 2014-09-06 15:01:10]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2014-09-06 15:02:29]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/eae@chromium.org/544843004/40001

[commit-bot: I haz the power, 2014-09-06 15:03:19]

Committed patchset #3 (id:40001) as 181492