[cairo] Bug#474136: Error when creating pdf charts for new FreeSerifItalic.ttf

[Carl Worth]

On Thu, 03 Apr 2008 17:18:57 -0700, Carl Worth wrote:
> Adrian, ready to work your magic again? I'll look and see if I can't
> figure out something myself in the meantime.

In the failing PostScript output the part that attempts to position
and display the glyphs:

BT
/f-0-0 1 Tf
20 0 0 20 10 290 Tm
<01> Tj 0 -1.5 Td <02> Tj 0 -1.5 Td <03> Tj 0 -1.5 Td <04> Tj 0 -1.5 Td <05>
 Tj 0 -1.5 Td <06> Tj 0 -1.5 Td <07> Tj 0 -1.5 Td <08> Tj 0 -1.5 Td <09>
 Tj 0 -1.5 Td <0a> Tj 1.5 13.5 Td <0b> Tj 0 -1.5 Td <0c> Tj 0 -1.5 Td <0d>
 Tj 0 -1.5 Td <0e> Tj 0 -1.5 Td <0f> Tj 0 -1.5 Td <10> Tj 0 -1.5 Td <11>
 Tj 0 -1.5 Td <12> Tj 0 -1.5 Td <13> Tj 0 -1.5 Td <14> Tj 1.5 13.5 Td <15>
 Tj 0 -1.5 Td <16> Tj 0 -1.5 Td <17> Tj 0 -1.5 Td <18> Tj 0 -1.5 Td <19>
 Tj 0 -1.5 Td <1a> Tj 0 -1.5 Td <1b> Tj 0 -1.5 Td <1c> Tj 0 -1.5 Td <1d>
 Tj 0 -1.5 Td <1e> Tj 1.5 13.5 Td <1f> Tj 0 -1.5 Td <20> Tj 0 -1.5 Td <21>
 Tj 0 -1.5 Td <22> Tj 0 -1.5 Td <23> Tj 0 -1.5 Td <24> Tj 0 -1.5 Td <25>
 Tj 0 -1.5 Td <26> Tj 0 -1.5 Td <27> Tj 0 -1.5 Td <28> Tj ET

Looks exactly like the functional PDF version (as expected). (Of
course that takes "pdftk ft-show-glyphs-table-pdf-argb32-out.pdf
uncompress legible.pdf" before it can be easily read.)

So then the question is whether there's a bug in the PostScript
emulations of Td and Tj. They certainly look simple enough:

	/Td { moveto } bind def
	/Tj { show } bind def

I compared with the working ft-show-glyphs-positioning case, and there
the text is all placed with TM and TJ. So those are presumably
working, (which is fine by me since their PostScript emulations are
much trickier).

I'll probably have to do some more specification reading before I can
be of any more help here, (unless Adrian has the bug fixed before I
get around to that). The fact that the values passed to Td each time
are the same in every case suggests that there's some relative
positioning desired here. And the small values suggest that we want
these to be multiplied by the font matrix. Meanwhile the
implementation with just "moveto" suggests absolute placement, and the
resulting output suggests that we're not getting transformed values.

-Carl
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