fltk/TODO.cairo
Fabien Costantini 82d47bd253 Added cairo todo list for keeping in one place related implementation guidelines.
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@6277 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
2008-09-17 09:29:27 +00:00

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