[ft-devel] R: freetype rendering problems

[Mauro Conzato]

Hello Toshiya,

we have finally been able to solve the issue. our platform team was providing a freetype library build with

#define TT_CONFIG_OPTION_UNPATENTED_HINTING

uncommented. this is generating the issue. as the documentation says, this may happen if you build the library and use it with western charsets. so this is not a new bug.

i would like to express my appreciation for your support on this issue.

 

thanks a lot,

Mauro

 

 

 

---

Da: suzuki toshiya [mailto:address@hidden
Inviato: ven 10/08/2012 4.46
A: Mauro Conzato
Cc: address@hidden
Oggetto: Re: [ft-devel] freetype rendering problems

Dear Mauro,

Could you tell me how to reproduce the reported issue?
I built test.cpp, and trying to print the rasterized
bitmap & dump other parameters, but I could not find
which character and which size should be specified.

In my case, "r" at size 11-13 is similar, but different.

$ ./mauro-test.exe r 13 /usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf

O.OO
OO..
O...
O...
O...
O...
O...

bitmapGlyph->metrics:
bitmapGlyph->metrics.height 7
bitmapGlyph->metrics.horiAdvance 5
bitmapGlyph->metrics.horiBearingX 1
bitmapGlyph->metrics.horiBearingY 7
bitmapGlyph->metrics.vertAdvance 13
bitmapGlyph->metrics.vertBearingX -2
bitmapGlyph->metrics.vertBearingY 3
bitmapGlyph->metrics.width 4

Regards,
mpsuzuki

Mauro Conzato wrote:
> Hello,
>
> 
>
> We have a strange rendering issue with freetype library that is driving
> us to ask an opinion from you.
>
> Our application is using two free true type fonts: DejaVuSans.ttf and
> DejaVuSans-Bold.ttf, in monochrome bitmap way, with horizontal
> alignment; the issue basically consists in the following: the 'r'
> character is being displayed in a higher position, on the baseline. 
>
> 
>
> 
>
> 
>
> Two different versions of freetype library are producing a different
> result:
>
> -  a relative recent version of ft (2.4.6) is showing the problem
>
> -  an older version of ft (2.3.9) is properly displaying the character
>
> 
>
> 
>
> I have made some debug and discovered the following:
>
> - If I reduce the horizontal bearing Y parameter, the char is properly
> aligned on the baseline
>
> - the metrics are showing me that there is not difference on the values
> that are managing the bitmap glyph, so it seems that the horizontal
> bearing Y recovered from the font file, through the library are the
> same. So,  since the code base that is managing the application is the
> same, I am wondering where the issue is.
>
> 
>
> I have created a prototype application that loads the font, render them
> in a txt file with a specific char in the pixels that are full of color
> ('o') and also prints out the metrics values. The code is in attachment.
> The final result is that old version of freetype load the glyph in this
> way
>
> 
>
> ....
>
> OOO.
>
> O...
>
> O...
>
> O...
>
> O...
>
> O...
>
> 
>
> bitmapGlyph->metrics:
>
> bitmapGlyph->metrics.height 7
>
> bitmapGlyph->metrics.horiAdvance 4
>
> bitmapGlyph->metrics.horiBearingX 1
>
> bitmapGlyph->metrics.horiBearingY 7
>
> bitmapGlyph->metrics.vertAdvance 11
>
> bitmapGlyph->metrics.vertBearingX -2
>
> bitmapGlyph->metrics.vertBearingY 3
>
> bitmapGlyph->metrics.width 4
>
> 
>
> 
>
> while the new one:
>
> 
>
> OOO
>
> O..
>
> O..
>
> O..
>
> O..
>
> O..
>
> 
>
> bitmapGlyph->metrics:
>
> bitmapGlyph->metrics.height 7
>
> bitmapGlyph->metrics.horiAdvance 4
>
> bitmapGlyph->metrics.horiBearingX 1
>
> bitmapGlyph->metrics.horiBearingY 7
>
> bitmapGlyph->metrics.vertAdvance 11
>
> bitmapGlyph->metrics.vertBearingX -2
>
> bitmapGlyph->metrics.vertBearingY 3
>
> bitmapGlyph->metrics.width 4
>
> 
>
> 
>
> So I can see a difference on the bitmap, but since the font file is the
> same, the code is the same, just the freetype libraries are different.
>
> I am wondering if there is another parameter or test that I can do in
> order to understand what is going on; have you got any suggestions?
>
> 
>
> Thanks in advance for your consideration.
>
> Mauro
>
>
>
>
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