/*----------------------------------------------------------------------------*/
#include <gtk/gtk.h>
/**
 * From,
 * https://developer.gnome.org/gtk3/stable/ch01s05.html
 * 
 * - my rewrite to understand these new gtk3 stuffs (cairo surface! :o)
**/
/*----------------------------------------------------------------------------*/
#define MY1APP_FULL "org.my1.gtktest"
#define MY1APP_NAME "GTK Test"
/*----------------------------------------------------------------------------*/
typedef struct _my1gtk_app_t
{
	int stat;
	cairo_surface_t *surf;
	GtkApplication *main;
	GtkWidget *gwin;
	GtkWidget *view;
	GtkWidget *draw;
}
my1gtk_app_t;
/*----------------------------------------------------------------------------*/
void my1gtk_app_destroy(gpointer data)
{
	my1gtk_app_t* gapp = (my1gtk_app_t*)data;
	if (gapp->surf)
		cairo_surface_destroy(gapp->surf);
}
/*----------------------------------------------------------------------------*/
gboolean my1gtk_app_draw_cb(GtkWidget *widget,cairo_t *cr,gpointer data)
{
	my1gtk_app_t* gapp = (my1gtk_app_t*)data;
	cairo_set_source_surface(cr,gapp->surf,0,0);
	cairo_paint(cr);
	return FALSE;
}
/*----------------------------------------------------------------------------*/
void clear_surface(my1gtk_app_t* gapp)
{
	cairo_t *cr  = cairo_create(gapp->surf);
	cairo_set_source_rgb (cr, 1, 1, 1);
	cairo_paint(cr);
	cairo_destroy(cr);
}
/*----------------------------------------------------------------------------*/
gboolean my1gtk_app_conf_cb(GtkWidget *widget, 
	GdkEventConfigure *event, gpointer data)
{
	my1gtk_app_t* gapp = (my1gtk_app_t*)data;
	if (gapp->surf)
		cairo_surface_destroy(gapp->surf);
	gapp->surf = gdk_window_create_similar_surface(
		gtk_widget_get_window(widget), CAIRO_CONTENT_COLOR,
		gtk_widget_get_allocated_width(widget),
		gtk_widget_get_allocated_height (widget));
		clear_surface(gapp);
	return TRUE;
}
/*----------------------------------------------------------------------------*/
void draw_brush(GtkWidget *widget, gdouble x, gdouble y, gpointer data)
{
	my1gtk_app_t* gapp = (my1gtk_app_t*)data;
	cairo_t *cr = cairo_create (gapp->surf);
	cairo_rectangle (cr,x-3,y-3,6,6);
	cairo_fill (cr);
	cairo_destroy (cr);
	gtk_widget_queue_draw_area(widget,x-3,y-3,6,6);
}
/*----------------------------------------------------------------------------*/
gboolean my1gtk_app_motion_cb(GtkWidget *widget,
	GdkEventMotion *event, gpointer data)
{
	my1gtk_app_t* gapp = (my1gtk_app_t*)data;
	if (!gapp->surf)
		return FALSE;
	if (event->state&GDK_BUTTON1_MASK)
		draw_brush(widget,event->x,event->y,data);
	return TRUE;
}
/*----------------------------------------------------------------------------*/
gboolean my1gtk_app_bpress_cb(GtkWidget *widget, 
	GdkEventButton *event, gpointer data)
{
	my1gtk_app_t* gapp = (my1gtk_app_t*)data;
	if (!gapp->surf)
		return FALSE;
	if (event->button == GDK_BUTTON_PRIMARY)
		draw_brush (widget,event->x,event->y,data);
	else if (event->button == GDK_BUTTON_SECONDARY)
    {
		clear_surface(gapp);
		gtk_widget_queue_draw(widget);
	}
	return TRUE;
}
/*----------------------------------------------------------------------------*/
void my1gtk_app_activate(GtkApplication *app, gpointer data)
{
	my1gtk_app_t* gapp = (my1gtk_app_t*)data;
	/** app === gapp->main! assert?*/
	gapp->gwin = gtk_application_window_new(app);
	gtk_window_set_title(GTK_WINDOW(gapp->gwin),MY1APP_NAME);
	g_signal_connect_swapped(gapp->gwin,"destroy",
		G_CALLBACK(my1gtk_app_destroy),data);
	gtk_container_set_border_width(GTK_CONTAINER(gapp->gwin),4);
	gapp->view = gtk_frame_new(0x0);
	gtk_frame_set_shadow_type(GTK_FRAME(gapp->view),GTK_SHADOW_IN);
	gtk_container_add(GTK_CONTAINER(gapp->gwin),gapp->view);
	gapp->draw = gtk_drawing_area_new();
	/* set a minimum size */
	gtk_widget_set_size_request(gapp->draw,100,100);
	gtk_container_add(GTK_CONTAINER(gapp->view),gapp->draw);
	g_signal_connect(gapp->draw,"draw",
		G_CALLBACK(my1gtk_app_draw_cb),data);
	g_signal_connect(gapp->draw,"configure-event",
		G_CALLBACK(my1gtk_app_conf_cb),data);
	g_signal_connect(gapp->draw,"motion-notify-event",
		G_CALLBACK(my1gtk_app_motion_cb),data);
	g_signal_connect(gapp->draw,"button-press-event",
		G_CALLBACK(my1gtk_app_bpress_cb),data);
	gtk_widget_set_events(gapp->draw,gtk_widget_get_events(gapp->draw)
		| GDK_BUTTON_PRESS_MASK | GDK_POINTER_MOTION_MASK);
	gtk_widget_show_all(gapp->gwin);
}
/*----------------------------------------------------------------------------*/
void my1gtk_app_init(my1gtk_app_t* gapp)
{
	gapp->stat = 0;
	gapp->surf = 0x0;
	gapp->main = gtk_application_new(MY1APP_FULL,G_APPLICATION_FLAGS_NONE);
	g_signal_connect(gapp->main,"activate",
		G_CALLBACK(my1gtk_app_activate),(gpointer)gapp);
}
/*----------------------------------------------------------------------------*/
void my1gtk_app_exec(my1gtk_app_t* gapp, int argc, char* argv[])
{
	gapp->stat = g_application_run(G_APPLICATION(gapp->main),argc,argv);
	g_object_unref(gapp->main);
}
/*----------------------------------------------------------------------------*/
int main (int argc, char **argv)
{
	my1gtk_app_t gapp;
	my1gtk_app_init(&gapp);
	my1gtk_app_exec(&gapp,argc,argv);
	return gapp.stat;
}
/*----------------------------------------------------------------------------*/