gtk2/demos/gtk-demo/css_blendmodes.c
2020-05-11 22:21:39 -04:00

146 lines
3.8 KiB
C

/* Theming/CSS Blend Modes
*
* You can blend multiple backgrounds using the CSS blend modes available.
*/
#include <gtk/gtk.h>
#define WID(x) ((GtkWidget*) gtk_builder_get_object (builder, x))
/*
* These are the available blend modes.
*/
struct {
const char *name;
const char *id;
} blend_modes[] =
{
{ "Color", "color" },
{ "Color (burn)", "color-burn" },
{ "Color (dodge)", "color-dodge" },
{ "Darken", "darken" },
{ "Difference", "difference" },
{ "Exclusion", "exclusion" },
{ "Hard Light", "hard-light" },
{ "Hue", "hue" },
{ "Lighten", "lighten" },
{ "Luminosity", "luminosity" },
{ "Multiply", "multiply" },
{ "Normal", "normal" },
{ "Overlay", "overlay" },
{ "Saturate", "saturation" },
{ "Screen", "screen" },
{ "Soft Light", "soft-light" },
{ NULL }
};
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
static void
update_css_for_blend_mode (GtkCssProvider *provider,
const gchar *blend_mode)
{
GBytes *bytes;
gchar *css;
bytes = g_resources_lookup_data ("/css_blendmodes/css_blendmodes.css", 0, NULL);
css = g_strdup_printf ((gchar*) g_bytes_get_data (bytes, NULL),
blend_mode,
blend_mode,
blend_mode);
gtk_css_provider_load_from_data (provider, css, -1);
g_bytes_unref (bytes);
g_free (css);
}
#pragma GCC diagnostic pop
static void
row_activated (GtkListBox *listbox,
GtkListBoxRow *row,
GtkCssProvider *provider)
{
const gchar *blend_mode;
blend_mode = blend_modes[gtk_list_box_row_get_index (row)].id;
update_css_for_blend_mode (provider, blend_mode);
}
static void
setup_listbox (GtkBuilder *builder,
GtkStyleProvider *provider)
{
GtkWidget *normal_row;
GtkWidget *listbox;
gint i;
normal_row = NULL;
listbox = gtk_list_box_new ();
gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (WID ("scrolledwindow")), listbox);
g_signal_connect (listbox, "row-activated", G_CALLBACK (row_activated), provider);
/* Add a row for each blend mode available */
for (i = 0; blend_modes[i].name != NULL; i++)
{
GtkWidget *label;
GtkWidget *row;
row = gtk_list_box_row_new ();
label = g_object_new (GTK_TYPE_LABEL,
"label", blend_modes[i].name,
"xalign", 0.0,
NULL);
gtk_list_box_row_set_child (GTK_LIST_BOX_ROW (row), label);
gtk_list_box_insert (GTK_LIST_BOX (listbox), row, -1);
/* The first selected row is "normal" */
if (g_strcmp0 (blend_modes[i].id, "normal") == 0)
normal_row = row;
}
/* Select the "normal" row */
gtk_list_box_select_row (GTK_LIST_BOX (listbox), GTK_LIST_BOX_ROW (normal_row));
g_signal_emit_by_name (G_OBJECT (normal_row), "activate");
gtk_widget_grab_focus (normal_row);
}
GtkWidget *
do_css_blendmodes (GtkWidget *do_widget)
{
static GtkWidget *window = NULL;
if (!window)
{
GtkStyleProvider *provider;
GtkBuilder *builder;
builder = gtk_builder_new_from_resource ("/css_blendmodes/blendmodes.ui");
window = WID ("window");
gtk_window_set_transient_for (GTK_WINDOW (window), GTK_WINDOW (do_widget));
g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
/* Setup the CSS provider for window */
provider = GTK_STYLE_PROVIDER (gtk_css_provider_new ());
gtk_style_context_add_provider_for_display (gdk_display_get_default (),
provider,
GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
setup_listbox (builder, provider);
}
if (!gtk_widget_get_visible (window))
gtk_widget_show (window);
else
gtk_window_destroy (GTK_WINDOW (window));
return window;
}