Re: [Inkscape-devel] Re: [cairo] Pango + cairo

[Peter Moulder <Peter Moulder infotech monash edu au>]

On Tue, Mar 22, 2005 at 01:13:29PM +0000, Damon Chaplin wrote:

> Why does bidi reordering affect non-rectangular areas?

Good question: this would depend on a couple of decisions as to how text
should behave.

The first is what to do with variable-height text.  Ignore bidi for the
moment in the following discussion, we'll start with plain left-to-right
text.  Say we're fitting into the middle of a circle or wide ellipse,
and a word in the middle of the sentence is much taller (logical rect)
than the rest of the sentence.  I was assuming that we'd let the small
words at the beginning & end of the sentence fill to very near the tips
of the ellipse (i.e. so long as the logical rectangle of each glyph is
within the ellipse), but perhaps we'd instead want the bounding box of
the line to fit entirely within the ellipse.

The other question relates to what to do if there are gaps in the spans.
E.g. suppose the top edge is bumpy/spiky, or suppose we're flowing
around a small picture/hole placed in the middle of the paragraph.
I was assuming that a gappy line would be laid out as if it were a single
line but just avoiding the gap.  This is especially reasonable if the
gap is very small (e.g. just the tip of a spike/bump intruding into the
line).  With this assumption, bidi affects what words go before/after
the gap.

An alternative is to let gaps divide the line into multiple logical
"lines" that happen to be placed next to each other (sharing a
baseline).  This does raise the question of which sub-line should get
the first word of the full line; so bidi may affect us somewhat even
with this alternative.

pjrm.