[scribus-dev] Where is the text frame word wrap code?

[Drew Vogel]

On Thu, Jun 3, 2010 at 3:38 AM, Andreas Vox <avox at arcor.de> wrote:

> Hi Drew!
>
> >Von: Drew Vogel [mailto:drewpvogel at gmail.com]
> >Gesendet: Mittwoch, 2. Juni 2010 20:08
> >An: scribus-dev at lists.scribus.net
> >Betreff: [scribus-dev] Where is the text frame word wrap code?
> >
> >I am working on an application that will generate a scribus document from
> a
> database of survey >questions. The output of each question will look a bit
> like this image: >http://imgur.com/ha2ag.png
> >
> >The question text is inside the text frame itself. The response options
> are
> in text frames of >their own. In order to determine the appropriate
> vertical
> position for the first response >option, I need to determine where scribus
> will wrap the text inside the text frame (the width >of the text frame is
> pre-determined). I first thought that I could use
> >QFontMetrics::boundingRect() to determine where the text would need to be
> wrapped. However >that seems dependent on the DPI of the QPaintDevice that
> the text is drawn on and, in my >testing, scribus wraps text independent of
> the monitor DPI. Is that true?
>
> Yes, Scribus has ist own text layout code. Unfortunately that's one of the
> most ugly parts of Scribus. :-(
>
> >Thus it seems that I need to emulate the word wrap logic in scribus itself
> but I'm having >trouble locating that part of the scribus code. It seems
> logical to me that the word wrap code >would either be in or called from
> PageItem_TextFrame::DrawObj_
> >Item() but if it's there, it's not obvious to me. Could someone help me
> locate the word wrap >logic?
>
> It's in PageItem_TextFrame::layout(). Unfortunately that particular method
> is 1500 lines long, so I'll outline the basic stuff for you.
>
> Without taking into account Dropcaps, Tabs, Optical Margins, Glyph
> Extension
> or changes to Word Spacing, Scribus relies solely on the width of the
> characters. After calling PageItem::layoutGlyphs() these are stored in
> GlyphLayout.xadvance. The method GlyphLayout::wide() calculates the width
> in
> case the given characters is associated with more than one glyph (that
> happens only to pagenumbers and tabs at the moment). After that Scribus
> just
> fills the line with as many words as fit. In case of hyphenation, the
> possible hyphenation points are marked with "ScText::effects() |
> TextFlag_Hyphenation_Possible" (or something like that).
>
> If you use glyph extension and/or modified word spacing, you can do the
> same, but in addition to the break position you get that way, you also have
> to check the next break opportunity that normally wouldn't fit on this
> line.
> Then multiply all blank widths with the minimal word spacing and all other
> char widths with the minimal glyph extension. If the resulting linewidth is
> closer to the wanted linewidth than the linewidth of the original break
> position, the new one is taken.
>
> I'm currently rewriting all this code; and in 1.5.0 we will export a
> function to scripter that can determine the needed space for a given text.
> For now, the above description is all I can offer.
>
> Cheers,
> Andreas
>
>
Thank you Andreas! I'm sure that this will prove very helpful.
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