bugFree UCS Outline Fonts - Bugs: bug #35715, Sans and Serif are downscaled with...

 
 

bug #35715: Sans and Serif are downscaled with distortions on W32

Submitted by:  -Deleted Account- <lrn>
Submitted on:  Sun 04 Mar 2012 10:16:24 AM UTC  
 
Category: overall font problemSeverity: 3 - Normal
Item Group: screen renderingStatus: Fixed
Privacy: PublicAssigned to: Steve White <Stevan_White>
Open/Closed: ClosedRelease: 2009-01-04

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Mon 12 Mar 2012 06:27:27 AM UTC, comment #8:

I've tried r2147 otf fonts, and the issue is resolved with them.

-Deleted Account- <lrn>
Fri 09 Mar 2012 07:28:48 PM UTC, comment #7:

See the Support item
https://savannah.gnu.org/support/?107814
I'll post some TrueType file snapshots.

Problem is: ClearType only works on quadratic splines (I guess).
But I prefer cubic splines, and that's the default for OpenType anyway.

Solution: Make a special TrueType set based on quadratic splines, and declare that the official set for Windows.

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Sun 04 Mar 2012 01:39:30 PM UTC, comment #6:

I'm saying "W32" as a substitute for "Win32" (which GNU people generally frown upon) or "Windows" (which is a brand of OSes that implement Win32 subsystem, among other things, so Windows and Win32 are not synonyms). "NT", while a good term, is also imprecise, because "NT" is a kernel architecture and a native API interface (largely unknown to the developer community, and often poorly documented).
ReactOS is NT and Win32. Wine is Win32, but not NT.

Back to business: the problem is still present with the snapshot.
Also, i think i should mention that the artifacts are obvious only on some zoom levels:
-1 zoom level (in Nightly) is still ugly
-2 zoom level looks OK
-3 is also mostly OK ("e" looks a bit strange, because it's missing the rightmost pixel in its horizontal line, and looks a bit tilted to the left because of that)
+1 zoom level looks mostly OK (the top curve of "G" looks edgy)
+2 is also mostly OK (horizontal line in "e" is too wide)
At +3 it, apparently, changes something in the rendering, because all artifacts disappear completely, although the text is a bit blurry (which is not an issue at such a large scale).

I can provide screenshots, if you want.

-Deleted Account- <lrn>
Sun 04 Mar 2012 12:46:21 PM UTC, comment #5:

Hi,

Yes, I missed the NT thing...although I wouldn't have understood it to mean Windows 7. Curious: why do you say W32, for the 64-bit version?

The only switch I know of in Windows 7 is the ClearType one.

My understanding is that the native Windows rendering libraries make heavy use of hinting, and that MS fonts are hand-hinted (at great expense), whereas on the other OSs, this approach has been largely replaced by algorithms. This is still my best guess as to the difference, but there are many other possibilities.

LibreOffice has its own cross-platform rendering software, I think.

As I said, I am stumped about this, but it is very possible that I missed something. I'll try to go through the experiments more systematically.

You should get a notification of a snapshot directory.

Cheers!

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Sun 04 Mar 2012 12:25:19 PM UTC, comment #4:

I said "NT 6.1.7601 x86_64", which in software developers' language means "Windows 7 SP1 x64"

If you can point me to the documentation for such switches, i'll gladly try them out (as long as they don't require reboots; i hate rebooting).
I should also mention that enabling or disabling ClearType(TM) makes no difference. Without ClearType the text doesn't have colored edges (i.e. the OS doesn't use display's subpixels to achieve smoothness), but it's still smooth, and still shows the annoying artifacts i've shown you.

https://savannah.gnu.org/support/?107814 looks disturbing. It looks to me as if the guy doesn't have font smoothing enabled. However, i've just tried this in LibreOffice 3.4.5 (#107814 reporter uses OpenOffice, so maybe that contributes, i don't know), and cannot reproduce these results, even with ClearType disabled. Disabling ClearType makes Times look pixelated at small scale (looks like raster font to me), but on large enough scales it is still smooth. With ClearType Times is always smooth (at small scales it, from what i am able to discern, still renders raster glyphs, but with subpixel smoothing they look just as good as the large-scale variants). Free* fonts always look smooth in LibreOffice, with and without ClearType, at any scale (which means that on very small scales they are not very readable and blurry). All of the above applies to LibreOffice.

(as a side-note, Free fonts are much more blurry in LibreOffice, compared to Times, even on scales large enough, when Times uses vector outlines, not raster; i guess it's somehow related to hinting; and by "blurry" i mean "blurry" as in "over-smoothed, less sharp", not as "pixelated and/or scaled with nearest-neighbor algorithm")

-Deleted Account- <lrn>
Sun 04 Mar 2012 11:55:12 AM UTC, comment #3:

Hi again, LRN,

You said W32, but which version of Windows is this exactly?
Their rendering engine has changed significantly with each major release. Note also there are some switches in Windows regarding which smoothing algorithm is used (depends on the version).

Also, there is an open support issue about "blurry text" in Windows.
https://savannah.gnu.org/support/?107814
Please have a look at it. This remains a mystery: I've spent evenings experimenting without avail. But I'm still seeing pixellation in the screenshots you send, and that doesn't seem like the same thing.

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Sun 04 Mar 2012 11:03:51 AM UTC, comment #2:

I've tried 2010 release, it looks slightly different, but most of the problems are still there. I've attached freesans_20100919_ttf.png

Yes, i am willing to try a snapshot.

(file #25263)

-Deleted Account- <lrn>
Sun 04 Mar 2012 10:53:52 AM UTC, comment #1:

Hi, LRN!

The pictures you posted show pixellation in the 2009 version, which is probably due to poor smoothing. A lot of work was done regarding smoothing in the 2010 release. Could you please try again with that release, and tell us if you still see a problem?

By the way, a new relese is imminent. If you would like to try a snapshot, I'd be glad to provide it!

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Sun 04 Mar 2012 10:16:24 AM UTC, original submission:

When small enough, both fonts are rendered with distorted tops (see the attached images).

Easily seen on gnu.org or any other site that use FreeSans (the image with FreeSerif was obtained by forcing Nightly to use FreeSerif).

Affects IE9 and Mozilla Nightly, but not Notepad or LibreOffice (different font rendering methods?). NT 6.1.7601 x86_64

The problem is not present in freefont-20080323, but in freefont-20090104 and freefont-20100919 it is.

Using OTF variants (tried TTF - same thing).

-Deleted Account- <lrn>

 

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Attach File(s):
   
   
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Attached Files
file #25263:  freesans_20100919_ttf.png added by lrn (9KiB - image/png)
file #25260:  freesans_20080323.png added by lrn (9KiB - image/png)
file #25261:  freesans_20090104.png added by lrn (9KiB - image/png)
file #25262:  freeserif_20090104.png added by lrn (8KiB - image/png)

 

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  • -unavailable- added by Stevan_White (Posted a comment)
  • -unavailable- added by lrn (Submitted the item)
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    Follow 9 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Thu 03 May 2012 03:51:48 PM UTCStevan_WhiteStatusFix posted=>Fixed
      Open/ClosedOpen=>Closed
    Fri 09 Mar 2012 07:28:48 PM UTCStevan_WhiteStatusNeed info=>Fix posted
    Sun 04 Mar 2012 11:03:51 AM UTClrnAttached File-=>Added freesans_20100919_ttf.png, #25263
    Sun 04 Mar 2012 10:53:52 AM UTCStevan_WhiteStatusNone=>Need info
      Assigned toNone=>Stevan_White
    Sun 04 Mar 2012 10:16:24 AM UTClrnAttached File-=>Added freesans_20080323.png, #25260
      Attached File-=>Added freesans_20090104.png, #25261
      Attached File-=>Added freeserif_20090104.png, #25262

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