gtk2/demos/gtk-demo/css_multiplebgs.c

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/* Theming/Multiple Backgrounds
*
* GTK themes are written using CSS. Every widget is build of multiple items
* that you can style very similarly to a regular website.
*/
#include <gtk/gtk.h>
G_GNUC_BEGIN_IGNORE_DEPRECATIONS
static void
show_parsing_error (GtkCssProvider *provider,
GtkCssSection *section,
const GError *error,
GtkTextBuffer *buffer)
{
const GtkCssLocation *start_location, *end_location;
GtkTextIter start, end;
const char *tag_name;
start_location = gtk_css_section_get_start_location (section);
gtk_text_buffer_get_iter_at_line_index (buffer,
&start,
start_location->lines,
start_location->line_bytes);
end_location = gtk_css_section_get_end_location (section);
gtk_text_buffer_get_iter_at_line_index (buffer,
&end,
end_location->lines,
end_location->line_bytes);
if (error->domain == GTK_CSS_PARSER_WARNING)
tag_name = "warning";
else
tag_name = "error";
gtk_text_buffer_apply_tag_by_name (buffer, tag_name, &start, &end);
}
static void
css_text_changed (GtkTextBuffer *buffer,
GtkCssProvider *provider)
{
GtkTextIter start, end;
char *text;
gtk_text_buffer_get_start_iter (buffer, &start);
gtk_text_buffer_get_end_iter (buffer, &end);
gtk_text_buffer_remove_all_tags (buffer, &start, &end);
text = gtk_text_buffer_get_text (buffer, &start, &end, FALSE);
gtk_css_provider_load_from_data (provider, text, -1);
g_free (text);
}
static void
drawing_area_draw (GtkDrawingArea *da,
cairo_t *cr,
int width,
int height,
gpointer data)
{
GtkStyleContext *context = gtk_widget_get_style_context (GTK_WIDGET (da));
gtk_render_background (context, cr, 0, 0, width, height);
gtk_render_frame (context, cr, 0, 0, width, height);
}
static void
apply_css (GtkWidget *widget, GtkStyleProvider *provider)
{
GtkWidget *child;
gtk_style_context_add_provider (gtk_widget_get_style_context (widget), provider, G_MAXUINT);
for (child = gtk_widget_get_first_child (widget);
child != NULL;
child = gtk_widget_get_next_sibling (child))
apply_css (child, provider);
}
GtkWidget *
do_css_multiplebgs (GtkWidget *do_widget)
{
static GtkWidget *window = NULL;
if (!window)
{
GtkWidget *paned, *overlay, *child, *sw;
GtkStyleProvider *provider;
GtkTextBuffer *text;
GBytes *bytes;
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window = gtk_window_new ();
gtk_window_set_title (GTK_WINDOW (window), "Multiple Backgrounds");
gtk_window_set_transient_for (GTK_WINDOW (window), GTK_WINDOW (do_widget));
gtk_window_set_default_size (GTK_WINDOW (window), 400, 300);
g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
overlay = gtk_overlay_new ();
gtk_window_set_child (GTK_WINDOW (window), overlay);
child = gtk_drawing_area_new ();
gtk_widget_set_name (child, "canvas");
gtk_drawing_area_set_draw_func (GTK_DRAWING_AREA (child),
drawing_area_draw,
NULL, NULL);
gtk_overlay_set_child (GTK_OVERLAY (overlay), child);
child = gtk_button_new ();
gtk_overlay_add_overlay (GTK_OVERLAY (overlay), child);
gtk_widget_set_name (child, "bricks-button");
gtk_widget_set_halign (child, GTK_ALIGN_CENTER);
gtk_widget_set_valign (child, GTK_ALIGN_CENTER);
gtk_widget_set_size_request (child, 250, 84);
paned = gtk_paned_new (GTK_ORIENTATION_VERTICAL);
gtk_overlay_add_overlay (GTK_OVERLAY (overlay), paned);
/* Need a filler so we get a handle */
child = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
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gtk_paned_set_start_child (GTK_PANED (paned), child);
text = gtk_text_buffer_new (NULL);
gtk_text_buffer_create_tag (text,
"warning",
"underline", PANGO_UNDERLINE_SINGLE,
NULL);
gtk_text_buffer_create_tag (text,
"error",
"underline", PANGO_UNDERLINE_ERROR,
NULL);
provider = GTK_STYLE_PROVIDER (gtk_css_provider_new ());
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sw = gtk_scrolled_window_new ();
gtk_paned_set_end_child (GTK_PANED (paned), sw);
child = gtk_text_view_new_with_buffer (text);
gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (sw), child);
g_signal_connect (text,
"changed",
G_CALLBACK (css_text_changed),
provider);
bytes = g_resources_lookup_data ("/css_multiplebgs/css_multiplebgs.css", 0, NULL);
gtk_text_buffer_set_text (text, g_bytes_get_data (bytes, NULL), g_bytes_get_size (bytes));
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g_bytes_unref (bytes);
g_signal_connect (provider,
"parsing-error",
G_CALLBACK (show_parsing_error),
gtk_text_view_get_buffer (GTK_TEXT_VIEW (child)));
apply_css (window, provider);
}
if (!gtk_widget_get_visible (window))
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gtk_widget_show (window);
else
gtk_window_destroy (GTK_WINDOW (window));
return window;
}