[Octave-bug-tracker] [bug #39692] text objects ignore backgroundcolor, linestyle, edgecolor

[Pantxo Diribarne]

Follow-up Comment #25, bug #39692 (project octave):

>> For the margin property, Octave is always using pixels while Matlab is
always using points. Maybe file another bug report about this minor
incompatibility? That's a small issue and doesn't need to hold up resolving
this bug report. 

In fact "margin" will be interpreted in pixels onscreen but in points for
printout (see bug #45600).
Currently freetype is setup so that "1 pixel = 1 point" (see bug #45600, we
can't change this easily) and I chose to follow the same convention so that a
2 pixels margin is 20% the actual hight of a 10 "points" text.
We could document this somewhere but we would end up explaining some internal
nasty intricate conventions that we hope (or will have) to change someday (see
also bug #49627). 

>> Does polygon offset need to be set for the lines as well as the background
color patch?

No indeed. Attached is an updated patch.

>> Also, I went back to 2-D plots and the overlap with the axes.  ... Should
this be another test case for Richard?

Since this is another matter, I'll send another request to not hold up
Richard's licence :-). In any event the change is easy. See attached patch.

>> Finally, and there is a separate bug report about this, but could we use
the glRotate code that you have here for the arbitrary rotation of text? 

No. We currently we use glDrawPixels to directly dump pixels produced by
freetype onto the screen. This  function use an independent raster coordinates
system that is not affected by transformations (see e.g.
https://stackoverflow.com/questions/223894/opengl-rotation-using-gldrawpixels#223920)
A solution could be to use textures to display pixels (or "texels") but it is
way more work. Note that we already have a well hidden but functional
implementation of textures on surface objects.

(file #42260, file #42261)
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Additional Item Attachment:

File name: txtback6.patch                 Size:8 KB
File name: axeslinelayer.patch            Size:1 KB


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