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On 12/31/21 8:54 PM Greg Ercolano
wrote:
Trying to just draw a simple "X" to all four corners of the
Fl_Cairo_Window.
Having trouble getting this working.
My understanding is the default coordinate space of cairo is:
(0.0, 0.0) = top/left
(1.0, 1.0) = bottom/right
..and to use FLTK's coordinate space, you'd use cairo_scale(cr,
w(), h())
to convert to the window's integer coordinate space.
Here's what I have (it doesn't work - weird behavior).
Am I missing something?
I don't know how the coordinate systems are (or should be)
translated, but if I change only your two drawing code lines to
cairo_move_to(cr, 0.0, 0.0); cairo_line_to(cr, 1.0, 1.0); // draw diagonal "\" cairo_move_to(cr, 0.0, 1.0); cairo_line_to(cr, 1.0, 0.0); // draw diagonal "/"
the "green X" works for me.
If you look at test/cairo_test.cxx you can see that all the
"buttons" are drawn inside the (0.0 ... 1.0) coordinate space, using
the same cairo_scale instruction as you do.
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