====== GUI programming using GTK ======

//dumping things from my1gtktest_single...//

A useful makefile. To compile more.c that uses GTK2 (default is GTK3), run ''make APP_NAME=more GTK_VERS=2.0''.
<file make makefile>
# makefile for simple gtk application written in single c source file

ALLAPP = $(subst .c,,$(subst src/,,$(wildcard src/*.c)))
ALLAPP += $(subst .c,,$(wildcard *.c))

GTKVER ?= 3.0

CFLAGS += $(shell pkg-config --cflags gtk+-$(GTKVER))
LFLAGS += $(shell pkg-config --libs gtk+-$(GTKVER))

.PHONY: dummy $(TARGET)

dummy:
	@echo
	@echo "Run 'make <app>' or 'make <app> GTKVER=2.0'"
	@echo "  <app> = { $(ALLAPP) }"
	@echo

%: %.c
	gcc -Wall $(CFLAGS) -o $@ $+ $(LFLAGS)

clean:
	rm -rf $(ALLAPP)
</file>

===== Sample Codes =====

<file c tray.c>
/*----------------------------------------------------------------------------*/
#include <gtk/gtk.h>
/*----------------------------------------------------------------------------*/
void tray_icon_on_click(GtkStatusIcon *status_icon, gpointer user_data)
{
	printf("Clicked on tray icon\n");
}
/*----------------------------------------------------------------------------*/
void tray_icon_on_menu(GtkStatusIcon *status_icon, guint button,
	guint activate_time, gpointer user_data)
{
	printf("Popup menu\n");
	gtk_main_quit();
}
/*----------------------------------------------------------------------------*/
static GtkStatusIcon *create_tray_icon()
{
	GtkStatusIcon *tray_icon;
	tray_icon = gtk_status_icon_new();
	g_signal_connect(G_OBJECT(tray_icon), "activate",
		G_CALLBACK(tray_icon_on_click), NULL);
	g_signal_connect(G_OBJECT(tray_icon), "popup-menu",
		G_CALLBACK(tray_icon_on_menu), NULL);
	gtk_status_icon_set_from_icon_name(tray_icon, GTK_STOCK_MEDIA_STOP);
	gtk_status_icon_set_tooltip(tray_icon, "Example Tray Icon");
	gtk_status_icon_set_visible(tray_icon, TRUE);
	return tray_icon;
}
/*----------------------------------------------------------------------------*/
int main(int argc, char **argv)
{
	GtkStatusIcon *tray_icon;
	gtk_init(&argc, &argv);
	tray_icon = create_tray_icon();
	printf("embedded: ");
	if (!gtk_status_icon_is_embedded(tray_icon))
	{
		printf("yes\n");
		gtk_main();
		printf("done\n");
	}
	else
	{
		printf("no\nCannot embed tray icon - aborting!\n");
	}
	return 0;
}
/*----------------------------------------------------------------------------*/
</file>

<file c draw.c>
/*----------------------------------------------------------------------------*/
#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;
}
/*----------------------------------------------------------------------------*/
</file>

<file c testcss.c>
/*----------------------------------------------------------------------------*/
#include <gtk/gtk.h>
/*----------------------------------------------------------------------------*/
#define MY1APP_FULL "org.my1.gtktest"
#define MY1APP_NAME "GTK Test"
/*----------------------------------------------------------------------------*/
GtkCssProvider *ccss;
/*----------------------------------------------------------------------------*/
gboolean on_show_resize(GtkWidget *widget, GtkAllocation *allocation,
	gpointer user_data)
{
	char test[] = "GtkLabel { background-color: #AAAAAA; font-size: %.0fpx; }";
	char buff[128];
	snprintf(buff,128,test,((float)allocation->height*12.0/40.0));
	printf("Resize: %d x %d => %s\n",allocation->width,allocation->height,buff);
	gtk_css_provider_load_from_data(ccss,buff, -1, NULL);
/**
	my1image_view_t* view = (my1image_view_t*) user_data;
	printf("Resize: %d x %d\n",allocation->width,allocation->height);
*/
	return TRUE;
}
/*----------------------------------------------------------------------------*/
static void activate(GtkApplication* app, gpointer data)
{
	GtkWidget *gwin, *grid, *show;
	GtkCssProvider *gcss;
	GdkDisplay *disp;
    GdkScreen *gscr;
	gwin = gtk_application_window_new(app);
	gtk_window_set_title(GTK_WINDOW(gwin),MY1APP_FULL);
	grid = gtk_grid_new();
	gtk_container_add(GTK_CONTAINER(gwin),grid);
	show = gtk_label_new("HAHA");
	gtk_widget_set_hexpand(show,TRUE);
	gtk_widget_set_halign(show,GTK_ALIGN_FILL);
	gtk_widget_set_vexpand(show,TRUE);
	gtk_widget_set_valign(show,GTK_ALIGN_FILL);
	gtk_grid_attach(GTK_GRID(grid),show,0,0,1,1);
	gcss = gtk_css_provider_new();
	disp = gdk_display_get_default();
	gscr = gdk_display_get_default_screen(disp);
	gtk_style_context_add_provider_for_screen(gscr,
		GTK_STYLE_PROVIDER(gcss),GTK_STYLE_PROVIDER_PRIORITY_USER);
	gtk_css_provider_load_from_data(gcss,
		"GtkLabel { background-color: #AAAAAA;}\n"
		"GtkGrid  { background-color: #4444AA;}", -1, NULL);
	ccss = gtk_css_provider_new();
	gtk_style_context_add_provider_for_screen(gscr,
		GTK_STYLE_PROVIDER(ccss),GTK_STYLE_PROVIDER_PRIORITY_USER);
	g_signal_connect(G_OBJECT(show),"size-allocate",
		G_CALLBACK(on_show_resize),0x0);
	/**gtk_window_fullscreen(GTK_WINDOW(gwin));*/
	gtk_widget_show_all(gwin);
}
/*----------------------------------------------------------------------------*/
int main(int argc, char **argv)
{
	int stat;
	GtkApplication *gapp;
	gapp = gtk_application_new(MY1APP_FULL,G_APPLICATION_FLAGS_NONE);
	g_signal_connect(gapp,"activate",G_CALLBACK(activate),NULL);
	stat = g_application_run(G_APPLICATION(gapp),argc,argv);
	g_object_unref(gapp);
	return stat;
}
/*----------------------------------------------------------------------------*/
</file>