(0)REF:
https://cairographics.org/tutorial/
http://zetcode.com/gfx/cairo/basicdrawing/
(1) 在GTK視窗的Drawing Area顯示影像並偵測滑鼠按鍵位置(gtk9.c)
treehrt@hrt:~/mysqlc$ cat gtk9.c
//http://zetcode.com/gfx/cairo/basicdrawing/
//resize :https://ubuntuforums.org/showthread.php?t=761973
#include <gtk/gtk.h>
#include <cairo.h>
#include <math.h>
int cx,cy;
GdkPixbuf *pix;
static gboolean on_window_draw (GtkWidget *da, GdkEvent *event, gpointer data)
{
(void)event; (void)data;
cairo_t *cr;
cr = gdk_cairo_create (gtk_widget_get_window(da));
gdk_cairo_set_source_pixbuf(cr, pix, 0, 0);
cairo_paint(cr);
cairo_destroy (cr);
return TRUE;
}
static gboolean clicked(GtkWidget *widget, GdkEventButton *event, gpointer user_data)
{
if (event->button == 1) {
g_print ("1:%f,%f\n", event->x, event->y);
cx=event->x;
cy=event->y;
cairo_t *cr;
cr = gdk_cairo_create (gtk_widget_get_window(widget));
cairo_set_line_width(cr, 5);
cairo_set_source_rgb(cr, 0, 1, 0);
cairo_arc (cr, cx, cy, 10, 0, 2 * M_PI);
cairo_stroke(cr);
cairo_destroy (cr);
}
if (event->button == 3) {
g_print ("3:%f,%f\n", event->x, event->y);
gtk_widget_queue_draw(widget);
}
return TRUE;
}
int main (int argc, char *argv[])
{
GtkWidget *window;
GtkWidget *canvas;
gtk_init (&argc, &argv);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
GError *err = NULL;
pix = gdk_pixbuf_new_from_file("map.png", &err);
if(err)
{
printf("Error : %s\n", err->message);
g_error_free(err);
return FALSE;
}
int w=gdk_pixbuf_get_width(pix);
int h=gdk_pixbuf_get_height(pix);
canvas = gtk_drawing_area_new ();
gtk_window_set_default_size(GTK_WINDOW(window), 100, 100);
gtk_widget_set_size_request (canvas, w,h);
gtk_widget_set_size_request (window, w,h);
gtk_container_add (GTK_CONTAINER (window), canvas);
gtk_widget_add_events(window, GDK_BUTTON_PRESS_MASK);
g_signal_connect (window, "destroy", G_CALLBACK (gtk_main_quit) , NULL);
g_signal_connect(window, "button-press-event", G_CALLBACK(clicked), NULL);
g_signal_connect (canvas, "draw", (GCallback) on_window_draw, NULL);
gtk_widget_set_app_paintable(canvas, TRUE);
gtk_widget_show_all (window);
gtk_main();
return 0;
}
(2) 編譯執行
treehrt@treehrt-BM6AE-BM1AE-BP1AE:~/mysqlc$ gcc gtk9.c -Wall `pkg-config --cflags --libs gtk+-3.0` -export-dynamic
treehrt@treehrt-BM6AE-BM1AE-BP1AE:~/mysqlc$ ./a.out &
[15] 5774
treehrt@treehrt-BM6AE-BM1AE-BP1AE:~/mysqlc$ 3:347.677872,151.101303
3:347.677872,151.101303
3:347.677872,151.101303
3:347.677872,151.101303
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