mirror of https://github.com/fltk/fltk
220 lines
7.3 KiB
C++
220 lines
7.3 KiB
C++
//
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// Cairo drawing test program for the Fast Light Tool Kit (FLTK).
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//
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// Copyright 1998-2023 by Bill Spitzak and others.
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//
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// This library is free software. Distribution and use rights are outlined in
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// the file "COPYING" which should have been included with this file. If this
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// file is missing or damaged, see the license at:
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//
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// https://www.fltk.org/COPYING.php
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//
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// Please see the following page on how to report bugs and issues:
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//
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// https://www.fltk.org/bugs.php
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//
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#include <FL/Fl.H> // includes <FL/fl_config.h>
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#ifdef FLTK_HAVE_CAIRO // defined in <FL/fl_config.h> since FLTK 1.4.0
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#include <FL/Fl_Cairo_Window.H>
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#include <FL/Fl_Box.H>
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#include <FL/platform.H>
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#include <FL/fl_draw.H>
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#include <FL/math.h>
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#define DEF_WIDTH 0.03
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// This demo program can be used in 3 modes. All 3 modes require configure
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// option --enable-cairo or CMake OPTION_CAIRO.
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//
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// 1) using class Fl_Cairo_Window useful when all the content of a window
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// is drawn with Cairo.
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// This is achieved setting #define USE_FL_CAIRO_WINDOW 1 below
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// or
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// 2) showing how to draw in an Fl_Double_Window using both Cairo and
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// the FLTK drawing API.
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// This is achieved setting #define USE_FL_CAIRO_WINDOW 0 below
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// or
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// 3) showing how to use "cairo extended use".
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// This is achieved when FLTK was built with one more option
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// (configure --enable-cairoext or CMake OPTION_CAIROEXT)
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// which defines the preprocessor variable FLTK_HAVE_CAIROEXT.
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// If Fl::cairo_autolink_context(true); is called at the beginning
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// of main(), any overridden draw() function gets access to an adequate
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// Cairo context with Fl::cairo_cc() without having to call
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// Fl::cairo_make_current(Fl_Window*).
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#define USE_FL_CAIRO_WINDOW 1
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// draw centered text
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static void centered_text(cairo_t *cr, double x0, double y0, double w0, double h0, const char *my_text) {
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cairo_select_font_face(cr, "Sans", CAIRO_FONT_SLANT_OBLIQUE, CAIRO_FONT_WEIGHT_BOLD);
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cairo_set_source_rgba(cr, 0.9, 0.9, 0.4, 0.6);
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cairo_text_extents_t extents;
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cairo_text_extents(cr, my_text, &extents);
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double x = (extents.width / 2 + extents.x_bearing);
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double y = (extents.height / 2 + extents.y_bearing);
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cairo_move_to(cr, x0 + w0 / 2 - x, y0 + h0 / 2 - y);
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cairo_text_path(cr, my_text);
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cairo_fill_preserve(cr);
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cairo_set_source_rgba(cr, 0, 0, 0, 1);
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cairo_set_line_width(cr, 0.004);
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cairo_stroke(cr);
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cairo_set_line_width(cr, DEF_WIDTH);
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}
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// draw a button object with rounded corners and a label
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static void round_button(cairo_t *cr, double x0, double y0,
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double rect_width, double rect_height, double radius,
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double r, double g, double b) {
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double x1, y1;
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x1 = x0 + rect_width;
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y1 = y0 + rect_height;
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if (!rect_width || !rect_height)
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return;
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if (rect_width / 2 < radius) {
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if (rect_height / 2 < radius) {
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cairo_move_to(cr, x0, (y0 + y1) / 2);
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cairo_curve_to(cr, x0, y0, x0, y0, (x0 + x1) / 2, y0);
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cairo_curve_to(cr, x1, y0, x1, y0, x1, (y0 + y1) / 2);
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cairo_curve_to(cr, x1, y1, x1, y1, (x1 + x0) / 2, y1);
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cairo_curve_to(cr, x0, y1, x0, y1, x0, (y0 + y1) / 2);
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} else {
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cairo_move_to(cr, x0, y0 + radius);
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cairo_curve_to(cr, x0, y0, x0, y0, (x0 + x1) / 2, y0);
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cairo_curve_to(cr, x1, y0, x1, y0, x1, y0 + radius);
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cairo_line_to(cr, x1, y1 - radius);
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cairo_curve_to(cr, x1, y1, x1, y1, (x1 + x0) / 2, y1);
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cairo_curve_to(cr, x0, y1, x0, y1, x0, y1 - radius);
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}
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} else {
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if (rect_height / 2 < radius) {
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cairo_move_to(cr, x0, (y0 + y1) / 2);
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cairo_curve_to(cr, x0, y0, x0, y0, x0 + radius, y0);
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cairo_line_to(cr, x1 - radius, y0);
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cairo_curve_to(cr, x1, y0, x1, y0, x1, (y0 + y1) / 2);
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cairo_curve_to(cr, x1, y1, x1, y1, x1 - radius, y1);
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cairo_line_to(cr, x0 + radius, y1);
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cairo_curve_to(cr, x0, y1, x0, y1, x0, (y0 + y1) / 2);
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} else {
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cairo_move_to(cr, x0, y0 + radius);
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cairo_curve_to(cr, x0, y0, x0, y0, x0 + radius, y0);
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cairo_line_to(cr, x1 - radius, y0);
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cairo_curve_to(cr, x1, y0, x1, y0, x1, y0 + radius);
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cairo_line_to(cr, x1, y1 - radius);
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cairo_curve_to(cr, x1, y1, x1, y1, x1 - radius, y1);
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cairo_line_to(cr, x0 + radius, y1);
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cairo_curve_to(cr, x0, y1, x0, y1, x0, y1 - radius);
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}
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}
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cairo_close_path(cr);
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cairo_pattern_t *pat =
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// cairo_pattern_create_linear (0.0, 0.0, 0.0, 1.0);
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cairo_pattern_create_radial(0.25, 0.24, 0.11, 0.24, 0.14, 0.35);
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cairo_pattern_set_extend(pat, CAIRO_EXTEND_REFLECT);
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cairo_pattern_add_color_stop_rgba(pat, 1.0, r, g, b, 1);
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cairo_pattern_add_color_stop_rgba(pat, 0.0, 1, 1, 1, 1);
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cairo_set_source(cr, pat);
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cairo_fill_preserve(cr);
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cairo_pattern_destroy(pat);
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// cairo_set_source_rgb (cr, 0.5, 0.5, 1); cairo_fill_preserve (cr);
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cairo_set_source_rgba(cr, 0, 0, 0.5, 0.3);
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cairo_stroke(cr);
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cairo_set_font_size(cr, 0.075);
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centered_text(cr, x0, y0, rect_width, rect_height, "FLTK loves Cairo!");
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}
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// draw the entire image (3 buttons), scaled to the given width and height
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void draw_image(cairo_t *cr, int w, int h) {
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cairo_set_line_width(cr, DEF_WIDTH);
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cairo_scale(cr, w, h);
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round_button(cr, 0.1, 0.1, 0.8, 0.2, 0.4, 1, 0, 0);
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round_button(cr, 0.1, 0.4, 0.8, 0.2, 0.4, 0, 1, 0);
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round_button(cr, 0.1, 0.7, 0.8, 0.2, 0.4, 0, 0, 1);
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} // draw_image()
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#if USE_FL_CAIRO_WINDOW && !defined(FLTK_HAVE_CAIROEXT)
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typedef Fl_Cairo_Window cairo_using_window;
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#else // !USE_FL_CAIRO_WINDOW || defined(FLTK_HAVE_CAIROEXT)
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class cairo_using_window : public Fl_Double_Window {
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void (*draw_with_cairo_)(cairo_using_window*, cairo_t*);
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public:
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cairo_using_window(int w, int h, const char *title) : Fl_Double_Window(w, h, title) {
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Fl_Box *box = new Fl_Box(FL_NO_BOX, 0, 0, w, 25,
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"Cairo and FLTK API in Fl_Double_Window");
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box->labelfont(FL_TIMES_BOLD);
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box->labelsize(12);
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box->labelcolor(FL_BLUE);
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}
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void draw() FL_OVERRIDE {
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Fl_Window::draw(); // perform drawings with the FLTK API
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#ifndef FLTK_HAVE_CAIROEXT
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Fl::cairo_make_current(this); // announce Cairo will be used in this window
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#endif
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cairo_t *cc = Fl::cairo_cc(); // get the adequate Cairo context
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draw_with_cairo_(this, cc); // draw in this window using Cairo
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// flush Cairo drawings: necessary at least for Windows
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Fl::cairo_flush(cc);
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}
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void set_draw_cb( void (*cb)(cairo_using_window*, cairo_t*)) {
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draw_with_cairo_ = cb;
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}
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};
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#endif // USE_FL_CAIRO_WINDOW
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// Cairo rendering cb called during Fl_Cairo_Window::draw()
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// or cairo_using_window::draw().
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static void my_cairo_draw_cb(cairo_using_window *window, cairo_t *cr) {
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draw_image(cr, window->w(), window->h());
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}
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int main(int argc, char **argv) {
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#ifdef FLTK_HAVE_CAIROEXT
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Fl::cairo_autolink_context(true);
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#endif
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cairo_using_window window(350, 350, "FLTK loves Cairo");
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window.resizable(&window);
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window.color(FL_WHITE);
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window.set_draw_cb(my_cairo_draw_cb);
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window.show(argc, argv);
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return Fl::run();
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}
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#else // (!FLTK_HAVE_CAIRO)
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#include <FL/fl_ask.H>
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int main(int argc, char **argv) {
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fl_message_title("This program needs a Cairo enabled FLTK library");
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fl_message(
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"Please configure FLTK with Cairo enabled (--enable-cairo or --enable-cairoext)\n"
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"or one of the CMake options OPTION_CAIRO or OPTION_CAIROEXT, respectively.");
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return 0;
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}
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#endif // (FLTK_HAVE_CAIRO)
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