mirror of https://github.com/fltk/fltk
36 lines
1.6 KiB
Plaintext
36 lines
1.6 KiB
Plaintext
Reminder for present and potential future considerations
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From Bill:
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First there is the HAVE_CAIRO configuration option. This indicates that
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any cairo calls are available. In this case you get something like this:
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// static variable holding the last cairo context fltk set:
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cairo_t* Fl::cr;
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// Make cr draw in this window. This hides the ugly platform-dependent
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// part of getting cairo going:
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void Fl::cairo_make_current(Fl_Window*)
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*** POST 1.3 potential cairo use:
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// Set cr to something you made yourself. This lets you reuse functions
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// that use cr, and also tells fltk that cr is not one of it's own and
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// thus cannot be destroyed or reused for a different window:
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void Fl::cairo_make_current(cairo_t*)
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Second there is the USE_CAIRO configuration option. This means that all
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drawing is done using Cairo. In this case when a widget draw() method is
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called, it is exactly as though cairo_make_current(window) has been done.
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***
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Note that it should be possible to compile so HAVE_CAIRO works even if
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USE_CAIRO does not, and so that turning on USE_CAIRO does not break any
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programs written for HAVE_CAIRO.
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From Fabien
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We will provide some service for users to use cairo with fltk 1.3 :
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A HAVE_CAIRO configuration option will be created.
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A simple Fl_Cairo_Window will be implemented and will provide basic
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cairo surface transparent handling (hiding non portable cairo context creation and so on).
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A demo program called cairo_test will be added in demo, providing a new test case.
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This program will raise an alert dialog box in case HAVE_CAIRO is not set, indicating that cairo lib is not available.
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