GTK How to set font for a text_view - gtk3

Question

How can I set the font name and size for a text_view? Or do I have to set the font information at the buffer or at the window? Do I have to create some sort of style-sheet?
#include <gtk/gtk.h>
int main(int argc, char *argv[]) {
GtkWidget *window;
GtkWidget *view;
GtkTextBuffer *buffer;
gtk_init(&argc, &argv);
view = gtk_text_view_new();
buffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW(view));
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
g_signal_connect_swapped(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), NULL);
gtk_window_set_default_size(GTK_WINDOW(window), 350, 300);
gtk_container_add(GTK_CONTAINER(window), view);
gtk_widget_show_all(window);
gtk_main();
return 0;
}

Answer 1

The following code works.
my.c
#include <gtk/gtk.h>
int main(int argc, char *argv[]) {
GtkWidget *view;
GtkTextBuffer *buffer;
GtkWidget *window;
GdkDisplay *display;
GdkScreen *screen;
GtkCssProvider *provider;
GError *error;
gtk_init(&argc, &argv);
view = gtk_text_view_new();
buffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW(view));
display = gdk_display_get_default ();
screen = gdk_display_get_default_screen (display);
provider = gtk_css_provider_new();
gtk_style_context_add_provider_for_screen (screen, GTK_STYLE_PROVIDER (provider), GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
error = NULL;
gtk_css_provider_load_from_file (provider, g_file_new_for_path("my.css"), &error);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), NULL);
gtk_window_set_default_size(GTK_WINDOW(window), 350, 300);
gtk_container_add(GTK_CONTAINER(window), view);
gtk_widget_show_all(window);
gtk_main();
return 0;
}
my.css
GtkTextView
{
font:Monospace 10;
}.

Answer 2

I know it is 2 years old question but in case someone encounter any issues.
Note, that Pango syntax for the font is deprecated in Gtk+3.
If you want to use GtkSourceView:
#include <gtksourceview/gtksource.h>
must be installed separately and compiled with
`pkg-config --cflags --libs gtksourceview-3.0`
or use regular GtkTextView
GtkCssProvider *cssProvider;
GtkSourceView *view;
GError *error = NULL;
GtkStyleContext *context;
/* new css provider */
cssProvider = gtk_css_provider_new();
view = GTK_SOURCE_VIEW(gtk_source_view_new ());
/* widget name for css syntax */
gtk_widget_set_name (GTK_WIDGET(view), "cssView");
/* load css file */
gtk_css_provider_load_from_path (cssProvider, "main.css", &error);
/* get GtkStyleContext from widget */
context = gtk_widget_get_style_context(GTK_WIDGET(view));
/* finally load style provider */
gtk_style_context_add_provider(context,
GTK_STYLE_PROVIDER(cssProvider),
GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
and "main.css" file in the same directory
#cssView {
font: 15px "Monospace";
color: #ff0000; /*in case you need red color*/
}
Actually in Gtk+3 you can add and remove CSS classes in very easy way:
in one callback you need to call:
gtk_style_context_add_class(context, "redFonts");
then in another one:
gtk_style_context_remove_class(context, "redFonts");
your "main.css" should be like:
#tab1Content {
font: 15px "Monospace";
}
.redFonts{
color: #ff0000;
}