Re: fo:character and zero width space

On Fri, Feb 12, 2016 at 3:17 AM, Carlos Villegas <[email protected]> wrote:

> 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!
>

Perhaps adding support for treat-as-word-space would be a sufficient fix
for this problem. Feel free to post a patch.


>
> 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]>
> [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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>
>