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#include <gtk/gtk.h>
#include <math.h>
GtkAdjustment *adjustment;
int cursor_x, cursor_y;
static gboolean
event_cb (GtkWidget *window,
GdkEvent *event)
{
if (gdk_event_get_event_type (event) == GDK_MOTION_NOTIFY &&
gdk_event_get_surface (event) == gtk_widget_get_surface (window))
{
gdouble x, y;
float processing_ms = gtk_adjustment_get_value (adjustment);
g_usleep (processing_ms * 1000);
gdk_event_get_coords ((GdkEvent *)event, &x, &y);
cursor_x = x;
cursor_y = y;
gtk_widget_queue_draw (window);
}
return GDK_EVENT_PROPAGATE;
}
static void
on_draw (GtkDrawingArea *da,
cairo_t *cr,
int width,
int height,
gpointer data)
{
cairo_set_source_rgb (cr, 1, 1, 1);
cairo_paint (cr);
cairo_set_source_rgb (cr, 0, 0.5, 0.5);
cairo_arc (cr, cursor_x, cursor_y, 10, 0, 2 * M_PI);
cairo_stroke (cr);
}
int
main (int argc, char **argv)
{
GtkWidget *window;
GtkWidget *vbox;
GtkWidget *label;
GtkWidget *scale;
GtkWidget *da;
gtk_init ();
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_default_size (GTK_WINDOW (window), 300, 300);
vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
gtk_container_add (GTK_CONTAINER (window), vbox);
adjustment = gtk_adjustment_new (20, 0, 200, 1, 10, 0);
scale = gtk_scale_new (GTK_ORIENTATION_HORIZONTAL, adjustment);
gtk_box_pack_end (GTK_BOX (vbox), scale);
label = gtk_label_new ("Event processing time (ms):");
gtk_widget_set_halign (label, GTK_ALIGN_CENTER);
gtk_box_pack_end (GTK_BOX (vbox), label);
da = gtk_drawing_area_new ();
gtk_drawing_area_set_draw_func (GTK_DRAWING_AREA (da), on_draw, NULL, NULL);
gtk_widget_set_vexpand (da, TRUE);
gtk_box_pack_end (GTK_BOX (vbox), da);
g_signal_connect (window, "event",
G_CALLBACK (event_cb), NULL);
g_signal_connect (window, "destroy",
G_CALLBACK (gtk_main_quit), NULL);
gtk_widget_show (window);
gtk_main ();
return 0;
}
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