fltk/FL/Fl_Cairo.H
Albrecht Schlosser 0f41797b7a Cairo: introduce Fl::cairo_flush() in FLTK API
Flushing the Cairo context is necessary on Windows to make Cairo
drawings appear on the device (screen). This new method makes it easy
for user code to do this correctly after using Cairo drawings.

- add Fl::cairo_flush(cairo_t *)
- document Fl::cairo_flush(cairo_t *)
- reformat Cairo doxygen docs and code (partially)
- use the new method in Fl_Cairo_Window
- use the new method in test/cairo_test.cxx
- other minor (text) changes in test/cairo_test.cxx
- add test/cairo_test to the demo menu (test/demo.menu)
2023-03-14 19:51:34 +01:00

102 lines
3.4 KiB
C++

//
// Main Cairo support header file for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2023 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file. If this
// file is missing or damaged, see the license at:
//
// https://www.fltk.org/COPYING.php
//
// Please see the following page on how to report bugs and issues:
//
// https://www.fltk.org/bugs.php
//
/** \file Fl_Cairo.H
Cairo is currently supported for the following platforms:
Windows, macOS, Unix/Linux (X11 + Wayland).
\note In FLTK 1.3.x this header file (Fl_Cairo.H) included the platform
specific Cairo headers. This is no longer true since 1.4.0.
This header file is platform agnostic. If you need platform specific Cairo
headers you need to \#include them in your source file.
To use FLTK's builtin Cairo support you need to <tt>\#include \<FL/Fl.H></tt>
\b before you include any other FLTK header which is officially required anyway.
Since FLTK 1.4.0 the preprocessor constants \p FLTK_HAVE_CAIRO and/or
\p FLTK_HAVE_CAIROEXT are defined in \<FL/Fl.H> by including \<FL/fl_config.h>.
*/
#ifndef FL_CAIRO_H
#define FL_CAIRO_H
#include <FL/Fl.H>
# ifdef FLTK_HAVE_CAIRO
# include <cairo.h>
/**
\addtogroup group_cairo
@{
*/
/**
Contains all the necessary info on the current cairo context.
A private internal & unique corresponding object is created to
permit cairo context state handling while keeping it opaque.
For internal use only.
\note Only available when configure has the --enable-cairo or
--enable-cairoext option or one or both of the CMake options
OPTION_CAIRO or OPTION_CAIROEXT is set (ON)
*/
class FL_EXPORT Fl_Cairo_State {
public:
Fl_Cairo_State()
: cc_(0)
, own_cc_(false)
, autolink_(false)
, window_(0)
, gc_(0) {}
// access attributes
cairo_t *cc() const { return cc_; } ///< Gets the current cairo context
bool autolink() const { return autolink_; } ///< Gets the autolink option. See Fl::cairo_autolink_context(bool)
/** Sets the current cairo context.
\p own == \e true (the default) indicates that the cairo context \p c
will be deleted by FLTK internally when another cc is set later.
\p own == \e false indicates cc deletion is handled externally
by the user program.
*/
void cc(cairo_t *c, bool own = true) {
if (cc_ && own_cc_)
cairo_destroy(cc_);
cc_ = c;
if (!cc_)
window_ = 0;
own_cc_ = own;
}
void autolink(bool b); ///< Sets the autolink option, only available with --enable-cairoext
void window(void *w) { window_ = w; } ///< Sets the window \p w to keep track on
void *window() const { return window_; } ///< Gets the last window attached to a cc
void gc(void *c) { gc_ = c; } ///< Sets the gc \p c to keep track on
void *gc() const { return gc_; } ///< Gets the last gc attached to a cc
private:
cairo_t *cc_; // contains the unique autoupdated cairo context
bool own_cc_; // indicates whether we must delete the cc, useful for internal cleanup
bool autolink_; // false by default, prevents the automatic cairo mapping on fltk windows
// for custom cairo implementations.
void *window_, *gc_; // for keeping track internally of last win+gc treated
};
/** @} */
#endif // FLTK_HAVE_CAIRO
#endif // FL_CAIRO_H