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Re: [fltk.coredev] Linux drawing in widget error: error in cairo_matrix_invert

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Re: Linux drawing in widget error: error in cairo_matrix_invert Gonzalo Garramuño 08:01 May 21  
 

El 21/5/23 a las 10:18, Gonzalo Garramuño escribió:
Find attached a program that shows the issue.  The first time draw_pixel() is called, the matrix error does not appear.  On the second and other calls it does.

Ok.  The issue is with fl_scale.  It seems our Cairo implementation scales points with fl_scale() instead of always drawing them at one pixel size like GDI+ on Windows or Quartz on macOS. (or.. it tries to invert the matrix and it can't as the scale is sometimes 0).  This is a different behavior than the other platforms and it should be changed or at least documented.

I google for drawing points in cairo, and it turns out there's no function to do it, but you need to draw a filled rectangle.  Are we doing that?

--
Gonzalo Garramuño
ggarra13@gmail.com

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