I am trying to add a label to a GTK3 window and then set the font size of the label. Here is my attempt:
#include <gtk/gtk.h>
static void
add_label (GtkWidget* window, gchar *text)
{
GtkWidget *label = gtk_label_new(text);
PangoAttrList *attrlist = pango_attr_list_new();
PangoAttribute *attr = pango_attr_size_new_absolute(20);
pango_attr_list_insert(attrlist, attr);
gtk_label_set_attributes(GTK_LABEL(label), attrlist);
pango_attr_list_unref(attrlist);
gtk_container_add (GTK_CONTAINER (window), label);
}
static void
activate (GtkApplication* app,
gpointer user_data)
{
GtkWidget *window;
window = gtk_application_window_new (app);
gtk_window_set_title (GTK_WINDOW (window), "Window1");
gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);
add_label( window, "Hello world" );
gtk_widget_show_all (window);
}
int
main (int argc, char **argv)
{
GtkApplication *app;
int status;
app = gtk_application_new ( "org.gtk.example", G_APPLICATION_FLAGS_NONE );
g_signal_connect( app, "activate", G_CALLBACK(activate), NULL);
status = g_application_run(G_APPLICATION(app), argc, argv);
g_object_unref (app);
return status;
}
This does not produce any label at all. If I comment out the line:
gtk_label_set_attributes(GTK_LABEL(label), attrlist);
the label shows up, but the font size is not set.
I think PANGO_SCALE is missing here.
PangoAttribute *attr = pango_attr_size_new_absolute(20 * PANGO_SCALE);
This should give you the desired result:
Related
I have for example this code:
#include <gtk/gtk.h>
static void
print_hello (GtkWidget *widget,
gpointer data)
{
g_print ("Hello World\n");
}
static void
activate (GtkApplication *app,
gpointer user_data)
{
GtkWidget *window;
GtkWidget *button;
GtkWidget *button_box;
window = gtk_application_window_new (app);
gtk_window_set_title (GTK_WINDOW (window), "Window");
gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);
button_box = gtk_button_box_new (GTK_ORIENTATION_HORIZONTAL);
gtk_container_add (GTK_CONTAINER (window), button_box);
button = gtk_button_new_with_label ("Hello World");
g_signal_connect (button, "clicked", G_CALLBACK (print_hello), NULL);
g_signal_connect_swapped (button, "clicked", G_CALLBACK (gtk_widget_destroy), window);
gtk_container_add (GTK_CONTAINER (button_box), button);
gtk_widget_show_all (window);
}
int
main (int argc,
char **argv)
{
GtkApplication *app;
int status;
app = gtk_application_new ("foo.bar", G_APPLICATION_FLAGS_NONE);
g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
status = g_application_run (G_APPLICATION (app), argc, argv);
g_object_unref (app);
return status;
}
It looks like this:
How can I automatically resize the window, so it has the perfect size for the one button.
With Java Swing, you could simply call pack(), but I wasn't able to find a similar method for GTK.
For GtkWindow there would be gtk_window_resize, but it requires giving an height and width, so I would have to calculate it manually.
This would work with just one button, but anything more complex would be error-prone and prone to failure.
Is there any equivalent to pack?
Using GTK3 in C, I have an interface with buttons. I want a user with a mouse to be able to press a button OR use press a single button on the keyboard to do the same thing.
MWE (modified from GTK3 Hello World example):
/*
* Ignore keyboard cursor in GTK3 C
*/
#include <gtk/gtk.h>
void thing() {
printf("did a thing\n");
}
void otherthing() {
printf("did something different\n");
}
static gboolean key_event(GtkWidget *widget, GdkEventKey *event) {
gchar* val = gdk_keyval_name (event->keyval);
if (strcmp(val, "Left") == 0) {
thing();
}
return 0;
}
static void activate (GtkApplication *app, gpointer user_data) {
GtkWidget *window;
GtkWidget *button;
GtkWidget *button2;
GtkWidget *button_box;
window = gtk_application_window_new (app);
gtk_window_set_title (GTK_WINDOW (window), "Window");
gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);
button_box = gtk_button_box_new (GTK_ORIENTATION_HORIZONTAL);
gtk_container_add (GTK_CONTAINER (window), button_box);
button = gtk_button_new_with_label ("Do the thing");
button2 = gtk_button_new_with_label ("xxx");
g_signal_connect(window, "key-release-event", G_CALLBACK(key_event), NULL);
g_signal_connect (button, "clicked", G_CALLBACK (thing), window);
g_signal_connect (button2, "clicked", G_CALLBACK (otherthing), window);
gtk_container_add (GTK_CONTAINER (button_box), button2);
gtk_container_add (GTK_CONTAINER (button_box), button);
gtk_widget_show_all (window);
}
int main (int argc, char **argv) {
GtkApplication *app;
int status;
app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);
g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
status = g_application_run (G_APPLICATION (app), argc, argv);
g_object_unref (app);
return status;
}
In this program, the user can press the left arrow key to execute thing. The user can also click on the gui button to execute thing. However, hitting certain keyboard keys such as space or enter will "click" on the gui button to execute thing.
How do I prevent the keyboard from "clicking" on a button which the keyboard cursor is on in this case?
Fake Button Hack
I have hacked a workaround into my code for now using a useless button. I will not be marking this answer as solved since it is very sloppy, but it does the job until something better becomes available.
Description
This hack adds another button with no functions assigned. Using gtk_widget_grab_focus, we force this useless "fakebutton" to hold keyboard focus. We reissue this command every time a button is pressed.
Problems
Grabbing focus back to the fakebutton is slow. The user can issue a quick succession of commands (in the case of the MWE by pressing Left and Space to erroneously issue the otherthing function).
MWE
/*
* Ignore keyboard cursor in GTK3 C
*/
#include <gtk/gtk.h>
GtkWidget *fakebutton;
void thing() {
printf("did a thing\n");
}
void otherthing() {
printf("did something different\n");
}
static gboolean key_event(GtkWidget *widget, GdkEventKey *event) {
gchar* val = gdk_keyval_name (event->keyval);
if (strcmp(val, "Left") == 0) {
thing();
gtk_widget_grab_focus(fakebutton);
} else {
gtk_widget_grab_focus(fakebutton);
}
return 0;
}
static void activate (GtkApplication *app, gpointer user_data) {
GtkWidget *window;
GtkWidget *button;
GtkWidget *button2;
GtkWidget *button_box;
window = gtk_application_window_new (app);
gtk_window_set_title (GTK_WINDOW (window), "Window");
gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);
button_box = gtk_button_box_new (GTK_ORIENTATION_HORIZONTAL);
gtk_container_add (GTK_CONTAINER (window), button_box);
button = gtk_button_new_with_label ("Do the thing");
button2 = gtk_button_new_with_label ("xxx");
fakebutton = gtk_button_new();
g_signal_connect(window, "key-release-event", G_CALLBACK(key_event), NULL);
g_signal_connect (button, "clicked", G_CALLBACK (thing), window);
g_signal_connect (button2, "clicked", G_CALLBACK (otherthing), window);
gtk_container_add (GTK_CONTAINER (button_box), button2);
gtk_container_add (GTK_CONTAINER (button_box), fakebutton);
gtk_container_add (GTK_CONTAINER (button_box), button);
gtk_widget_show_all (window);
}
int main (int argc, char **argv) {
GtkApplication *app;
int status;
app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);
g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
status = g_application_run (G_APPLICATION (app), argc, argv);
g_object_unref (app);
return status;
}
I am trying to set the background color of all labels in GtkGrid. Here is a simplified example:
#include <gtk/gtk.h>
static void activate (GtkApplication* app, gpointer user_data)
{
GtkWidget *window = gtk_application_window_new (app);
gtk_window_set_title (GTK_WINDOW (window), "Window1");
gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);
GtkWidget *grid = gtk_grid_new ();
gtk_container_add (GTK_CONTAINER (window), grid);
GtkWidget *label1 = gtk_label_new("Hello world!");
gtk_widget_set_hexpand( label1, TRUE);
gtk_grid_attach(GTK_GRID (grid), label1, 0,0,1,1);
GtkWidget *label2 = gtk_label_new("Simple Gtk example");
gtk_widget_set_hexpand( label2, TRUE);
gtk_grid_attach(GTK_GRID (grid), label2, 0,1,1,1);
GtkCssProvider *provider = gtk_css_provider_new ();
gtk_css_provider_load_from_data (
provider, "label {background-color: #AAAAAA;}", -1, NULL);
GtkStyleContext *context = gtk_widget_get_style_context (grid);
gtk_style_context_add_provider(
context, GTK_STYLE_PROVIDER(provider), GTK_STYLE_PROVIDER_PRIORITY_USER);
gtk_widget_show_all (window);
}
int main (int argc, char **argv) {
GtkApplication *app = gtk_application_new(
"org.gtk.example", G_APPLICATION_FLAGS_NONE );
g_signal_connect( app, "activate", G_CALLBACK(activate), NULL);
int status = g_application_run(G_APPLICATION(app), argc, argv);
g_object_unref (app);
return status;
}
However, adding the style context provider to the grid's context (as shown above) does not work.
I've modified your code, this will change the background of the labels:
#include <gtk/gtk.h>
static void activate (GtkApplication* app, gpointer user_data)
{
GtkWidget *window = gtk_application_window_new (app);
gtk_window_set_title (GTK_WINDOW (window), "Window1");
gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);
GtkWidget *grid = gtk_grid_new ();
gtk_container_add (GTK_CONTAINER (window), grid);
GtkWidget *label1 = gtk_label_new("Hello world!");
gtk_widget_set_hexpand( label1, TRUE);
gtk_grid_attach(GTK_GRID (grid), label1, 0,0,1,1);
GtkWidget *label2 = gtk_label_new("Simple Gtk example");
gtk_widget_set_hexpand( label2, TRUE);
gtk_grid_attach(GTK_GRID (grid), label2, 0,1,1,1);
GtkCssProvider *provider = gtk_css_provider_new ();
GdkDisplay *display = gdk_display_get_default();
GdkScreen *screen = gdk_display_get_default_screen (display);
gtk_style_context_add_provider_for_screen (screen, GTK_STYLE_PROVIDER(provider), GTK_STYLE_PROVIDER_PRIORITY_USER);
gtk_css_provider_load_from_data (
provider, "GtkLabel { background-color: #AAAAAA;}", -1, NULL);
gtk_widget_show_all (window);
}
int main (int argc, char **argv) {
GtkApplication *app = gtk_application_new(
"org.gtk.example", G_APPLICATION_FLAGS_NONE );
g_signal_connect( app, "activate", G_CALLBACK(activate), NULL);
int status = g_application_run(G_APPLICATION(app), argc, argv);
g_object_unref (app);
return status;
}
Result:
I have a GTK+2 program which combining GtkScrolledWindow and GtkLayout. It works fine. But, I found if I put a GtkEvent object to GtkLayout, it will not display properly. Anybody knows why ? Thanks.
#include <gtk/gtk.h>
int main( int argc, char *argv[] )
{
GtkWidget *window, *button, *layout, *eventbox, *scrollwindow;
gtk_init (&argc, &argv);
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_widget_set_size_request (window, 150, 150);
button = gtk_button_new_with_label ("button");
layout = gtk_layout_new(NULL, NULL);
gtk_layout_set_size( GTK_LAYOUT(layout), 300, 300);
scrollwindow = gtk_scrolled_window_new(GTK_LAYOUT(layout)->hadjustment, GTK_LAYOUT(layout)->vadjustment);
gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrollwindow), GTK_POLICY_AUTOMATIC, GTK_POLICY_AUTOMATIC);
gtk_layout_put( GTK_LAYOUT(layout), button, 50, 250 );
/* uncomment to use eventbox
eventbox = gtk_event_box_new();
gtk_container_add( GTK_CONTAINER(eventbox), layout);
gtk_scrolled_window_add_with_viewport( GTK_SCROLLED_WINDOW(scrollwindow), eventbox);
*/
// comment this line when use eventbox
gtk_container_add( GTK_CONTAINER(scrollwindow), layout);
gtk_container_add((GtkContainer*)window, scrollwindow);
gtk_widget_show_all(window);
gtk_main ();
return 0;
}
The picture if the eventbox is used.
I found it does not have to use GtkEventBox here. The GtkLayout can capture events directly.
The following widgets do not have an associated window. So, It should be used with the GtkEventBox if you want to capture events.
GtkAlignment
GtkArrow
GtkBin
GtkBox
GtkImage
GtkItem
GtkLabel
GtkPaned
GtkPixmap
GtkScrolledWindow
GtkSeparator
GtkTable
GtkViewport
GtkAspectFrame
GtkFrame
GtkVPaned
GtkHPaned
GtkVBox
GtkHBox
GtkVSeparator
GtkHSeparator
The fixed program :
#include <gtk/gtk.h>
static gboolean button_press_event( GtkWidget *widget, GdkEventButton *event ) {
if (event->button == 1 ) printf("but down %i , %i\n", (int)event->x, (int)event->y);
return TRUE;
}
int main( int argc, char *argv[] )
{
GtkWidget *window, *button, *layout, *eventbox, *scrollwindow;
gtk_init (&argc, &argv);
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_widget_set_size_request (window, 150, 150);
button = gtk_button_new_with_label ("button");
layout = gtk_layout_new(NULL, NULL);
gtk_layout_set_size( GTK_LAYOUT(layout), 300, 300);
scrollwindow = gtk_scrolled_window_new(gtk_layout_get_hadjustment(layout), gtk_layout_get_vadjustment(layout));
gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrollwindow), GTK_POLICY_AUTOMATIC, GTK_POLICY_AUTOMATIC);
gtk_layout_put( GTK_LAYOUT(layout), button, 50, 250 );
gtk_container_add( GTK_CONTAINER(scrollwindow), layout);
gtk_container_add(GTK_CONTAINER(window), scrollwindow);
g_signal_connect (layout, "button_press_event", G_CALLBACK (button_press_event), NULL);
gtk_widget_set_events(layout, GDK_EXPOSURE_MASK
| GDK_LEAVE_NOTIFY_MASK | GDK_BUTTON_PRESS_MASK
| GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK);
gtk_widget_show_all(window);
gtk_main ();
return 0;
}
The result of clicking on GtkLayout :
I have worked recently with gtk+ in c language.
I have tried to communicate between two callbacks in a dialog and not in the main window (like here). But, unlike the solutions in the link, the program crushes (in the second callback when I try to use the widget I get from the parameters).
This is my code for This:
#include <gtk/gtk.h>
#include <stdlib.h>
#include <stdio.h>
static void print_text (GtkWidget *widget, gpointer data)
{
GtkEntry* entry = data;
printf("%s", gtk_entry_get_text(entry));
}
static void open_dialog (GtkWidget *widget, gpointer data)
{
GtkWidget *window = data;
GtkWidget *dialog;
GtkWidget *content_area;
GtkWidget *grid;
GtkWidget *label;
GtkWidget *button;
static GtkEntry *textbox;
dialog = gtk_dialog_new_with_buttons ("Get Text",
window,
GTK_DIALOG_MODAL,
GTK_STOCK_OK,
GTK_RESPONSE_OK,
NULL);
content_area = gtk_dialog_get_content_area (GTK_DIALOG (dialog));
grid = gtk_grid_new();
gtk_container_add (GTK_CONTAINER (content_area), grid);
label = gtk_label_new("Value: ");
gtk_grid_attach(GTK_GRID(grid), label, 0, 0, 1, 1);
textbox = gtk_entry_new();
gtk_entry_set_text(textbox, "<Value>");
gtk_grid_attach(GTK_GRID(grid), textbox, 1, 0, 1, 1);
gtk_widget_show_all (dialog);
g_signal_connect (GTK_DIALOG (dialog), "response", G_CALLBACK (print_text), textbox);
}
static void activate (GtkApplication *app, gpointer user_data)
{
GtkWidget *window;
GtkWidget *button;
GtkWidget *entry;
GtkWidget *grid;
window = gtk_application_window_new (app);
gtk_window_set_title (GTK_WINDOW (window), "Window");
gtk_container_set_border_width (GTK_CONTAINER (window), 10);
grid = gtk_grid_new ();
gtk_container_add (GTK_CONTAINER (window), grid);
button = gtk_button_new_with_label ("Print Text");
g_signal_connect (button, "clicked", G_CALLBACK (open_dialog), window);
gtk_grid_attach (GTK_GRID (grid), button, 0, 1, 1, 1);
gtk_widget_show_all (window);
}
int main (int argc, char **argv)
{
GtkApplication *app;
int status;
app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);
g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
status = g_application_run (G_APPLICATION (app), argc, argv);
g_object_unref (app);
return status;
}
The program should have printed the value of the entry box which in the dialog after closing the dialog. Note: in the main window there is a button that opens the dialog.
Thanks for helping!
Problem is on the print_text function. The prototype for GtkDialog response signal is:
void user_function (GtkDialog *dialog,
gint response_id,
gpointer user_data)
So you must change your function to:
static void print_text (GtkWidget *widget, gint response_id, gpointer data)
{
GtkEntry* entry = data;
printf("%s", gtk_entry_get_text(entry));
gtk_widget_destroy (widget); // This will close the dialog
}