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|
/* Un exemple pour tracer un segment elastique <<à la Gimp>>:
*
* Tracer une ligne noire épaisse et une ligne blanche par dessus
* en rafraichissant l'image de fond à chaque déplacement de la souris.
*
* Compiler avec ( -lX11 avec la Xlib only)
* Pour GTK-2
* gcc -g -Wall `pkg-config --cflags gtk+-2.0` segment_elastique.c `pkg-config --libs gtk+-2.0` -lX11
* et GTK-3
* gcc -g -Wall `pkg-config --cflags gtk+-3.0` segment_elastique.c `pkg-config --libs gtk+-3.0` -lX11
*/
#include <math.h>
#include <gtk/gtk.h>
#include <gdk/gdk.h>
#include <cairo.h>
/* Taille de la fenêtre en pixels */
static int ix = 800;
static int iy = 500;
static GdkDisplay *gg_disp;
static GtkWidget *w_main_window ,*w_canvas;
static GdkWindow *gg_win;
static cairo_surface_t *surf_ecran;
static cairo_surface_t *surf_fond;
static int button_pressed = FALSE;
static gdouble x_init ,y_init;
//A26 static gdouble old_x ,old_y;
#define MIN2(a, b) (((a) < (b)) ? a : b)
#define MAX2(a, b) (((a) > (b)) ? a : b)
/*
* On affiche l'image de fond
*/
#if (GTK_MAJOR_VERSION == 2)
gboolean ev_expose (GtkWidget *w ,GdkEventExpose *event ,gpointer data)
{
cairo_t *cr = gdk_cairo_create (gtk_widget_get_window (w_canvas));
cairo_set_source_surface (cr ,surf_fond ,0 ,0);
cairo_paint (cr);
cairo_destroy (cr);
return TRUE;
}
#else
gboolean ev_draw (GtkWidget *w ,cairo_t *cr ,gpointer data)
{
cairo_set_source_surface (cr ,surf_fond ,0 ,0);
cairo_paint (cr);
return TRUE;
}
#endif
/*
* Restore l'image de fond initiale
*/
void restore_fond (cairo_t *cr ,gdouble x ,gdouble y)
{
/* UNE TENTATIVE D'UTILISER UN RECTANGLE DE CLIP */
//A26 gdouble x0 = x_init - 2.0;
//A26 gdouble y0 = y_init - 2.0;
//A26 gdouble dx = (x - x_init) + 4.0;
//A26 gdouble dy = (y - y_init) + 4.0;
//A26
//A26 printf ("restore_fond: x0=%g dx=%g x=%g y0=%g dy =%g y=%g\n" ,x0 ,dx ,x ,y0 ,dy ,y);
//A26
//A26 CE CLIPPING NE MARCHE PAS POUR LA DIRECTION VERTICALE
//A26 cairo_rectangle (cr ,x0 ,y0 ,dx ,dy);
//A26 cairo_clip (cr);
cairo_set_source_surface (cr ,surf_fond ,0 ,0);
cairo_paint (cr);
//A26 cairo_reset_clip (cr);
}
void draw_line (cairo_t *cr ,gdouble x ,gdouble y)
{
cairo_set_line_width (cr ,3.0); /* large black line */
cairo_set_source_rgba (cr ,0.0 ,0.0 ,0.0 ,1.0);
cairo_move_to (cr ,x_init ,y_init);
cairo_line_to (cr ,x ,y);
cairo_stroke (cr);
cairo_set_line_width (cr ,1.0); /* thin white line */
cairo_set_source_rgba (cr ,1.0 ,1.0 ,1.0 ,1.0);
cairo_move_to (cr ,x_init ,y_init);
cairo_line_to (cr ,x ,y);
cairo_stroke (cr);
}
/*
* Reponses aux actions avec la souris
*/
/* Draw the line on w_canvas */
gint ev_button_press (GtkWidget *w ,GdkEvent *event ,gpointer data)
{
gdouble x = event->button.x;
gdouble y = event->button.y;
cairo_t *cr = gdk_cairo_create (gtk_widget_get_window (w_canvas));
x_init = x;
y_init = y;
draw_line (cr ,x ,y);
//A26 old_x = x;
//A26 old_y = y;
cairo_destroy (cr);
button_pressed = TRUE;
return TRUE;
}
/* redraw surf_fond without the line */
gint ev_button_release (GtkWidget *w ,GdkEvent *event ,gpointer data)
{
cairo_t *cr = gdk_cairo_create (gtk_widget_get_window (w_canvas));
restore_fond (cr ,((GdkEventMotion *)event)->x ,((GdkEventMotion *)event)->y);
cairo_destroy (cr);
button_pressed = FALSE;
return TRUE;
}
int ev_pointer_motion (GtkWidget *w ,GdkEventMotion *event ,gpointer data)
{
if (button_pressed ) {
cairo_t *cr = gdk_cairo_create (gtk_widget_get_window (w_canvas));
restore_fond (cr ,((GdkEventMotion *)event)->x ,((GdkEventMotion *)event)->y);
draw_line (cr ,event->x ,event->y);
cairo_destroy (cr);
}
return TRUE;
}
/*
* Programme principal
*/
int main( int argc ,char *argv[] )
{
gdouble w ,h ,dx ,dy;
cairo_t *cr;
gtk_init (&argc ,&argv);
printf ("GTK_MAJOR_VERSION = %d\n" ,GTK_MAJOR_VERSION);
printf ("GTK_MINOR_VERSION = %d\n" ,GTK_MINOR_VERSION);
w_main_window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gg_disp = gdk_display_get_default ();
w_canvas = gtk_drawing_area_new ();
gtk_widget_set_size_request (w_main_window ,ix ,iy);
gtk_container_add (GTK_CONTAINER (w_main_window) ,w_canvas );
gtk_widget_add_events (w_canvas
, GDK_BUTTON_PRESS_MASK
| GDK_BUTTON_RELEASE_MASK
| GDK_POINTER_MOTION_MASK
);
gtk_widget_show_all (w_main_window);
gg_win = gtk_widget_get_window (w_canvas);
#if (GTK_MAJOR_VERSION == 2)
g_signal_connect (w_canvas ,"expose_event" ,G_CALLBACK (ev_expose) ,NULL);
#else
g_signal_connect (w_canvas ,"draw" ,G_CALLBACK (ev_draw) ,NULL);
#endif
g_signal_connect (w_canvas ,"button-press-event" ,G_CALLBACK (ev_button_press) ,NULL);
g_signal_connect (w_canvas ,"button-release-event" ,G_CALLBACK (ev_button_release) ,NULL);
g_signal_connect (w_canvas ,"motion-notify-event" ,G_CALLBACK (ev_pointer_motion) ,NULL);
g_signal_connect (w_main_window ,"delete_event" ,G_CALLBACK (gtk_main_quit) ,NULL);
gtk_widget_show_all (w_main_window);
/* Creation de surf_fond, le buffer pour l'image de fond */
cr = gdk_cairo_create (gtk_widget_get_window (w_canvas));
surf_ecran = cairo_get_target (cr);
surf_fond = cairo_surface_create_similar (surf_ecran ,CAIRO_CONTENT_COLOR_ALPHA ,ix ,iy);
cairo_destroy (cr);
/* on dessine le fond dans surf_fond */
w = (gdouble)ix;
h = (gdouble)iy;
cr = cairo_create (surf_fond);
/* set the background color */
cairo_set_source_rgb (cr ,1.0 ,1.0 ,1.0);
cairo_rectangle (cr ,0 ,0 ,w ,h);
cairo_fill (cr);
dx = w / 6.0;
dy = h / 6.0;
/* rectangle noir */
cairo_set_source_rgb (cr ,0.0 ,0.0, 0.0);
cairo_rectangle (cr ,dx ,dy ,dx ,dy);
cairo_fill (cr);
/* cercle rouge */
cairo_set_source_rgb (cr ,1.0 ,0.0, 0.0);
cairo_arc (cr ,3*dx ,1.5*dy ,dx/2.0 ,0.0 ,6.2831853);
cairo_fill (cr);
/* cercle vert */
cairo_set_source_rgb (cr ,0.0 ,1.0, 0.0);
cairo_arc (cr ,1.5*dx ,3*dy ,dx/2.0 ,0.0 ,6.2831853);
cairo_fill (cr);
/* rectangle bleu */
cairo_set_source_rgb (cr ,0.0 ,0.0, 1.0);
cairo_rectangle (cr ,2.5*dx ,2.5*dy ,dx ,dy);
cairo_fill (cr);
/* on copie l'image dans surf_fond */
cairo_set_source_surface (cr ,surf_fond ,0 ,0);
cairo_paint (cr);
cairo_destroy (cr);
gtk_main ();
return 0;
} |
