Interline bug and paragraph borders

I submitted a patch in bugzilla for bug 13101 (Line spacing has no
effect). The patch is rather long, most of it is necessary to set the
correct line heights in paragraphs with borders (note: there is still
one case that is not implemented; a paragraph with borders which
starts on one page and continues on the next).

The current implementation of paragraph borders does not seems ideal.
Because the line height depends on the position of a line inside a
block and on neighboring blocks properties, it is creating a mess in
the fp_Line and fl_BlockLayout classes. Also, the current scheme makes
the implementation difficult for multiple paragraph boxes. As
currently coded, paragraphs cannot be separated using "margin after"
and the left and right margins cannot be set independently of the box
width (so the second paragraph cannot have margins different from the
first paragraph and be in the same box). Another difficulty is that in
paragraphs with frame images, the image is not necessarily on top of
the shading.

A different implementation of the paragraph borders could be to create
a frame object that interacts with the fp_Column and fp_BlockLayout
classes. It would act on the fp_Line class only indirectly; it would
leave the line height completely untouched and would modify the line
width only through the left and right block margins properties. That
implementation would likely have a much smaller footprint in the code.

Simon
Received on Thu Nov 24 04:05:26 2011