Re: fo:character and zero width space

This is the result of my tests so far:

treat-as-word-space doesn't have any effect. Looking at the compliance 
page, it's listed as not supported!

By wrapping the thai text in a fo:inline, using a regular space as word 
separator and setting word-spacing property, I get some results but I 
haven't been able to get zero width on the spaces for non-justified 
text. According to the spec, word-spacing is used to adjust the word 
spacing "in addition to normal spacing", so I tried something like the 
following:

<fo:inline word-spacing.minimum="-2em" 
word-spacing.maximum="0.05em">Thai text with normal spaces as word 
separators</fo:inline>

When justifying I do get some lines where the word spacing is zero, but 
when justifying left, there's always some interword spacing. I tried 
several values, but can't get it to zero.
One complication I have is how to know the "normal" word space so I can 
adjust it to zero.

Anyway to get word-spacing optimum and minimum to zero?

Carlos

On 2/12/16 15:11, Glenn Adams wrote:
>
>
> On Thu, Feb 11, 2016 at 9:23 PM, Carlos Villegas <[email protected]> wrote:
>
>     I'm trying to use FOP 2.0 to render Thai language. FOP doesn't
>     really support Thai script
>
>
> FOP does support Thai, at least glyph composition, though there 
> appears to be a few open issues (FOP-2092 
> <https://issues.apache.org/jira/browse/FOP-2092>, FOP-2355 
> <https://issues.apache.org/jira/browse/FOP-2355>). It is also true 
> that FOP is not presently performing line breaking in phrase internal 
> positions (FOP-2066 <https://issues.apache.org/jira/browse/FOP-2266>), 
> which proposes a solution to employ ICU and use dictionary based LB.
>
>     , so I'm using an external program (libthai) to do glyph
>     composition and word breaking.
>     Thai doesn't use spaces to separate words, so I was just inserting
>     zero width spaces to separate words. This works fine.
>     However, for justified text, these zero width spaces don't
>     stretch, so nothing happens, I get no justified text.
>     So, I tried to use fo:character with character set to zero width
>     space, and setting the letter-spacing.maximum to allow some
>     stretching.
>
>
> Zero width space (U+200B) is not treated as a word separator space by 
> default. Have you tried something like:
>
> <fo:character treat-as-word-space='true'>&#x200B</fo:character>
>
> If that doesn't work, then keep in mind that letter spacing has no 
> meaning when applied to a single character, but applies to a sequence 
> of characters. Accordingly, I would try something like:
>
> <fo:inline letter-spacing.minimum="0em" 
> letter-spacing.maximum="0.1em">&#x200B;&#x200B;</fo:inline>
>
> or
>
> <fo:inline letter-spacing.minimum="0em" 
> letter-spacing.maximum="0.1em">&#x200B;<fo:character 
> treat-as-word-space='true'>&#x200B;</fo:character></fo:inline>
>
> If neither approach works, it may require some time with a visual 
> debugger, e.g., Eclipse, to step through the code and find out where 
> things go wrong.
>
>     But now FOP doesn't seem to treat the zero width space as such
>     this way, it doesn't break anymore at all!
>
>     Note that Thai does make use of regular spaces to separate
>     sentences and for other purposes but there's no guarantee that you
>     have spaces in a given paragraph or in case of long sentences.
>
>     Is there a way to insert a breakable space with minimum and
>     optimum to zero width and some small value for maximum?
>
>     Carlos
>
>
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