GTK+ Code Demos - compile Color Selector - gcc

Question

I found out that Color Selector from the GTK+ Code Demos is a quite nice color chooser. Thus, I would like to use it as a standalone application without having to run gtk-demos every time.
I tried to compile the example code which is:
#include <gtk/gtk.h>
static GtkWidget *window = NULL;
static GtkWidget *da;
static GdkColor color;
static GtkWidget *frame;
/* Expose callback for the drawing area
*/
static gboolean
expose_event_callback (GtkWidget *widget,
GdkEventExpose *event,
gpointer data)
{
GdkWindow *window = gtk_widget_get_window (widget);
if (window)
{
GtkStyle *style;
cairo_t *cr;
style = gtk_widget_get_style (widget);
cr = gdk_cairo_create (window);
gdk_cairo_set_source_color (cr, &style->bg[GTK_STATE_NORMAL]);
gdk_cairo_rectangle (cr, &event->area);
cairo_fill (cr);
cairo_destroy (cr);
}
return TRUE;
}
static void
change_color_callback (GtkWidget *button,
gpointer data)
{
GtkWidget *dialog;
GtkColorSelection *colorsel;
gint response;
dialog = gtk_color_selection_dialog_new ("Changing color");
gtk_window_set_transient_for (GTK_WINDOW (dialog), GTK_WINDOW (window));
colorsel =
GTK_COLOR_SELECTION (gtk_color_selection_dialog_get_color_selection (GTK_COLOR_SELECTION_DIALOG (dialog)));
gtk_color_selection_set_previous_color (colorsel, &color);
gtk_color_selection_set_current_color (colorsel, &color);
gtk_color_selection_set_has_palette (colorsel, TRUE);
response = gtk_dialog_run (GTK_DIALOG (dialog));
if (response == GTK_RESPONSE_OK)
{
gtk_color_selection_get_current_color (colorsel,
&color);
gtk_widget_modify_bg (da, GTK_STATE_NORMAL, &color);
}
gtk_widget_destroy (dialog);
}
GtkWidget *
do_colorsel (GtkWidget *do_widget)
{
GtkWidget *vbox;
GtkWidget *button;
GtkWidget *alignment;
if (!window)
{
color.red = 0;
color.blue = 65535;
color.green = 0;
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_screen (GTK_WINDOW (window),
gtk_widget_get_screen (do_widget));
gtk_window_set_title (GTK_WINDOW (window), "Color Selection");
g_signal_connect (window, "destroy",
G_CALLBACK (gtk_widget_destroyed), &window);
gtk_container_set_border_width (GTK_CONTAINER (window), 8);
vbox = gtk_vbox_new (FALSE, 8);
gtk_container_set_border_width (GTK_CONTAINER (vbox), 8);
gtk_container_add (GTK_CONTAINER (window), vbox);
/*
* Create the color swatch area
*/
frame = gtk_frame_new (NULL);
gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
gtk_box_pack_start (GTK_BOX (vbox), frame, TRUE, TRUE, 0);
da = gtk_drawing_area_new ();
g_signal_connect (da, "expose_event",
G_CALLBACK (expose_event_callback), NULL);
/* set a minimum size */
gtk_widget_set_size_request (da, 200, 200);
/* set the color */
gtk_widget_modify_bg (da, GTK_STATE_NORMAL, &color);
gtk_container_add (GTK_CONTAINER (frame), da);
alignment = gtk_alignment_new (1.0, 0.5, 0.0, 0.0);
button = gtk_button_new_with_mnemonic ("_Change the above color");
gtk_container_add (GTK_CONTAINER (alignment), button);
gtk_box_pack_start (GTK_BOX (vbox), alignment, FALSE, FALSE, 0);
g_signal_connect (button, "clicked",
G_CALLBACK (change_color_callback), NULL);
}
if (!gtk_widget_get_visible (window))
{
gtk_widget_show_all (window);
}
else
{
gtk_widget_destroy (window);
window = NULL;
}
return window;
}
The error is:
[orschiro#thinkpad ~]$ gcc `pkg-config --cflags --libs gtk+-3.0` -o colorSelector colorSelector.ccolorSelector.c: In function ‘expose_event_callback’:
colorSelector.c:26:7: warning: ‘gdk_cairo_set_source_color’ is deprecated (declared at /usr/include/gtk-3.0/gdk/gdkcairo.h:58): Use 'gdk_cairo_set_source_rgba' instead [-Wdeprecated-declarations]
colorSelector.c: In function ‘change_color_callback’:
colorSelector.c:44:3: warning: ‘gtk_color_selection_dialog_new’ is deprecated (declared at /usr/include/gtk-3.0/gtk/deprecated/gtkcolorseldialog.h:73): Use 'gtk_color_chooser_dialog_new' instead [-Wdeprecated-declarations]
colorSelector.c:49:5: warning: ‘gtk_color_selection_dialog_get_color_selection’ is deprecated (declared at /usr/include/gtk-3.0/gtk/deprecated/gtkcolorseldialog.h:75): Use 'GtkColorChooser' instead [-Wdeprecated-declarations]
colorSelector.c:51:3: warning: ‘gtk_color_selection_set_previous_color’ is deprecated (declared at /usr/include/gtk-3.0/gtk/deprecated/gtkcolorsel.h:148) [-Wdeprecated-declarations]
colorSelector.c:52:3: warning: ‘gtk_color_selection_set_current_color’ is deprecated (declared at /usr/include/gtk-3.0/gtk/deprecated/gtkcolorsel.h:142): Use 'gtk_color_chooser_set_rgba' instead [-Wdeprecated-declarations]
colorSelector.c:53:3: warning: ‘gtk_color_selection_set_has_palette’ is deprecated (declared at /usr/include/gtk-3.0/gtk/deprecated/gtkcolorsel.h:100) [-Wdeprecated-declarations]
colorSelector.c:59:7: warning: ‘gtk_color_selection_get_current_color’ is deprecated (declared at /usr/include/gtk-3.0/gtk/deprecated/gtkcolorsel.h:145): Use 'gtk_color_chooser_get_rgba' instead [-Wdeprecated-declarations]
colorSelector.c: In function ‘do_colorsel’:
colorSelector.c:91:7: warning: ‘gtk_vbox_new’ is deprecated (declared at /usr/include/gtk-3.0/gtk/deprecated/gtkvbox.h:60): Use 'gtk_box_new' instead [-Wdeprecated-declarations]
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/../../../../lib/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: error: ld returned 1 exit status
Installed packages:
gtk2 2.24.14-1
gtk3 3.6.2-1
gcc-libs-multilib 4.7.2-2
gcc-multilib 4.7.2-2
Could someone please explain me the error?

Answer 1

Your source code is incomplete, the main function is missing. gtk-demo is organised so it has a single main that calls some submodules and processes them the same way, and you're missing that main.
The other warning come from the fact that this example code you're trying to compile was done for GTK 2, and you're trying to build it against GTK 3.
You'll find all the missing parts in the gtk-demo directory of the GTK+ repository.