Hi Nate,
based on my experience, you have 3 ways:
1) First, see if there are standard CSS classes provided by the theme for
your use case. For example, GtkButton
<https://developer.gnome.org/gtk3/stable/GtkButton.html> has the
*.suggegsted-action* and *.destructive-action* CSS classes, which all
themes shall provide. GtkEntry has *.warning* and *.error* CSS classes.
This blends nicely with every theme you may use.
You use gtk_widget_get_style_context() and gtk_style_context_add_class().
In one line it is:
gtk_style_context_add_class(gtk_widget_get_style_context(button),
"suggested-action");
See:
https://stackoverflow.com/a/37628324
https://wiki.gnome.org/HowDoI/Buttons.
2) Create one CSS where you define *your own* CSS classes. It can be either
a string in your source file, an external .css file that you load at
runtime, or a .css file embedded as a GResource
<https://developer.gnome.org/gio/stable/GResource.html>). Load your custom
CSS at startup:
void setup_application_css() {
const gchar *css_string = ".red_text { color: red; }";
GtkCssProvider *css = gtk_css_provider_new();
gtk_css_provider_load_from_data(css, css_string, -1, NULL);
gtk_style_context_add_provider_for_screen(gdk_screen_get_default(),
GTK_STYLE_PROVIDER(css),
GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
g_object_unref(css);
}
int main(int argc, char **argv) {
gtk_init(&argc, &argv);
setup_application_css();
init();
gtk_main();
return 0;
}
then apply the class to any widget you want:
GtkEntry *entry = gtk_entry_new();
gtk_style_context_add_class(gtk_widget_get_style_context(entry),
"red_text");
NOTE: if you want to work with CSS id, just change the css string to:
const gchar *css_string = "#myentry1 { color: red; }";
then set the CSS id to the entry:
GtkEntry *entry = gtk_entry_new();
gtk_widget_set_name(entry, "myentry1");
3) If you have to style just a few widgets, it's best to style them
directly at creation site, without loading a CSS globally:
GtkEntry* create_entry() {
GtkEntry *entry = gtk_entry_new();
const gchar *css_string = "entry { color: red; }";
GtkCssProvider *css = gtk_css_provider_new();
gtk_css_provider_load_from_data(css, css_string, -1, NULL);
gtk_style_context_add_provider(gtk_widget_get_style_context(entry),
GTK_STYLE_PROVIDER(css),
GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
g_object_unref(css);
return entry;
}
I suggest you use the Gtk Inspector
<https://blogs.gnome.org/mclasen/2014/05/15/introducing-gtkinspector/> to
experiment with all that at runtime. You can write live CSS and you can
also set properties of your widgets like name, classes. See also
https://blog.gtk.org/2017/04/05/the-gtk-inspector/
I have attached examples for all three points.
Luca
Il giorno lun 17 dic 2018 alle ore 15:46 Nate Bargmann <n...@n0nb.us> ha
scritto:
> Greetings to the list.
>
> Several years ago I took over maintainership of a useful amateur radio
> application written for GTK+ 2. As a winter project I've decided to
> port it to GTK+ 3 and have used the transition guide to accomplish
> much. I set the build system to generate warnings for deprecated
> constructs and one of the things that has me stumped is how to replace a
> call to GTK+ 2's gtk_widget_modify_text() with CSS in GTK+ 3. Now, I'm
> not a complete newcomer to CSS having used it with HTML years back so
> that is not the issue.
>
> In the program source there are lines like this which merely set the
> foreground color of some text based on a default or some later user
> preference:
>
> gtk_widget_modify_text(highentry1, GTK_STATE_NORMAL,
> &preferences.highcolor1);
>
> Building now generates this warning (I have a lot of these):
>
> CC main.o
> ../../xdx/src/main.c: In function ‘main’:
> ../../xdx/src/main.c:332:5: warning: ‘gtk_widget_modify_text’ is
> deprecated: Use 'CSS style classes' instead [-Wdeprecated-declarations]
> gtk_widget_modify_text(highentry1, GTK_STATE_NORMAL,
> &preferences.highcolor1);
> ^~~~~~~~~~~~~~~~~~~~~~
>
> I have been looking through the reference documentation and various
> examples to find something relatively simple to change the foreground
> color of the text. Right now what I am looking for is a clue of how to
> get from "here" to "there". What I am finding seems to be rather
> complicated and involved. Hopefully my impression is incorrect.
>
> Is there a function that I've missed that can apply CSS inline similar
> to this deprecated function?
>
> TIA
>
> - Nate
>
> --
>
> "The optimist proclaims that we live in the best of all
> possible worlds. The pessimist fears this is true."
>
> Web: http://www.n0nb.us GPG key: D55A8819 GitHub: N0NB
> _______________________________________________
> gtk-app-devel-list mailing list
> gtk-app-devel-list@gnome.org
> https://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
#include <gtk/gtk.h>
void load_application_css() {
const gchar *css_string = ".red_text { color: red; }";
GtkCssProvider *css = gtk_css_provider_new();
gtk_css_provider_load_from_data(css, css_string, -1, NULL);
gtk_style_context_add_provider_for_screen(gdk_screen_get_default(),
GTK_STYLE_PROVIDER(css),
GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
g_object_unref(css);
}
GtkWidget* create_entry() {
GtkWidget *entry = gtk_entry_new();
/* style this entry. */
/* Apply one of our own CSS classes. */
gtk_style_context_add_class(gtk_widget_get_style_context(entry), "red_text");
return entry;
}
void init() {
GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
GtkWidget *entry = create_entry();
gtk_container_add(GTK_CONTAINER(window), entry);
gtk_widget_show_all(window);
g_signal_connect(window, "destroy", gtk_main_quit, NULL);
}
int main(int argc, char **argv) {
gtk_init(&argc, &argv);
load_application_css();
init();
gtk_main();
return 0;
}
#include <gtk/gtk.h>
GtkWidget* create_entry() {
GtkWidget *entry = gtk_entry_new();
/* style this entry. */
/* GTK predefined CSS class for entry widget. All themes provide this class */
gtk_style_context_add_class(gtk_widget_get_style_context(entry), "error");
return entry;
}
void init() {
GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
GtkWidget *entry = create_entry();
gtk_container_add(GTK_CONTAINER(window), entry);
gtk_widget_show_all(window);
g_signal_connect(window, "destroy", gtk_main_quit, NULL);
}
int main(int argc, char **argv) {
gtk_init(&argc, &argv);
init();
gtk_main();
return 0;
}
#include <gtk/gtk.h>
GtkWidget* create_entry() {
GtkWidget *entry = gtk_entry_new();
/* style this entry, directly. */
const gchar *css_string = "entry { color: red; }";
GtkCssProvider *css = gtk_css_provider_new();
gtk_css_provider_load_from_data(css, css_string, -1, NULL);
gtk_style_context_add_provider(gtk_widget_get_style_context(entry),
GTK_STYLE_PROVIDER(css),
GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
g_object_unref(css);
return entry;
}
void init() {
GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
GtkWidget *entry = create_entry();
gtk_container_add(GTK_CONTAINER(window), entry);
gtk_widget_show_all(window);
g_signal_connect(window, "destroy", gtk_main_quit, NULL);
}
int main(int argc, char **argv) {
gtk_init(&argc, &argv);
init();
gtk_main();
return 0;
}
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