On 2007-09-19 00:04-0400 Hazen Babcock wrote: > Er, not a bug, a feature... I did this deliberately because I did not think > it made sense to be able to shear the text so that it was drawn "below" the > baseline. Also, in the documentation we say that the text will be drawn > parallel to the shear line, but don't mention anything about directionality. > It isn't hard to change though if you think this approach is incorrect.
Yes, please. >> [...]I can make the >> Hershey >> result agree with the modern font result if I specify just = -0.5 (!) for >> the plptex3 call so I assume this bug is due to some quadrant sign error >> in >> how just is interpreted for this particular inclination in the Hershey >> code >> path (but the first screenshot shows this bug does not occur in the modern >> font code path). > > I'll have a look, but plptex3 does not change the just parameter, it simply > passes it through to the core PLplot text drawing routine plP_text. Thanks. I assume the Hershey code path is making some incorrect assumption about the X, Y, Z inclination of the text that is being justified while the modern font code path handles the issue correctly. > >> One final issue is the "revolution" pattern shown by both screen shots is >> in the form of a 3D ellipse (which projects to a 2D circle). It appears >> from this evidence that the overall 2D font size (both height and width of >> characters) appears not to be adjusted to account for the various >> inclinations as transformed to 2D via the 3D perspective plot >> transformation. As a result, the "revolution" pattern looks like a circle >> in 2D, but in 3D perspective you would interpret that 2D circle as an >> ellipse in 3D space (i.e., the effective 3D character size depends on >> inclination and viewing angle). Since plptex3 is supposed to be in (3D) >> world coordinates, I suspect it will be used by users to identify specific >> areas of 3D surfaces, and it will be an annoyance to have the effective 3D >> character size on that surface change with inclination and viewing angle. >> Hazen, it would be great if you could deal with this issue before the >> stable >> release, but if you prefer to put it off until post 5.8.0, that is fine as >> far as I am concerned. > > I'm not sure I understand. If the text is drawn in a plane then wouldn't you > expect it's size to depend on the angle at which you viewed the plane? My point is the inferred 3D size of characters should stay the same regardless of viewing angle. According to that criterion, the end of the "revolution" pattern should form a circle in the Z=0 plane, but inspection of the screenshots shows it doesn't. For example, in the second screen shot (Hershey fonts) compare the omega = -PI/4 result with the omega = PI/4 result. The first one reaches half way to the corner while the second one reaches all the way to the corner. Instead, they should both reach a consistent fraction of the way to the corner. The first screen shot has exactly the same issue, but the fonts are systematically smaller so the -PI/4 result reaches 1/3 of the way to the corner while the PI/4 result reaches 2/3 of the way to the corner. Alan __________________________ Alan W. Irwin Astronomical research affiliation with Department of Physics and Astronomy, University of Victoria (astrowww.phys.uvic.ca). Programming affiliations with the FreeEOS equation-of-state implementation for stellar interiors (freeeos.sf.net); PLplot scientific plotting software package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project (lbproject.sf.net). __________________________ Linux-powered Science __________________________ ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
