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/* Paintable/Simple Paintable
*
* GdkPaintable is an interface used by GTK for drawings of any sort
* that do not require layouting or positioning.
*
* This demo code gives a simple example on how a paintable can
* be created.
*
* Paintables can be used in many places inside GTK widgets, but the
* most common usage is inside GtkImage and that's what we're going
* to do here.
*/
#include <gtk/gtk.h>
#include "paintable.h"
static GtkWidget *window = NULL;
/* First, add the boilerplate for the object itself.
* This part would normally go in the header.
*/
#define GTK_TYPE_NUCLEAR_ICON (gtk_nuclear_icon_get_type ())
G_DECLARE_FINAL_TYPE (GtkNuclearIcon, gtk_nuclear_icon, GTK, NUCLEAR_ICON, GObject)
/* Declare the struct. */
struct _GtkNuclearIcon
{
GObject parent_instance;
/* We store this rotation value here.
* We are not doing with it here, but it will come in
* very useful in the followup demos.
*/
double rotation;
};
struct _GtkNuclearIconClass
{
GObjectClass parent_class;
};
/* This is the function that draws the actual icon.
* We make it a custom function and define it in the paintable.h header
* so that it can be called from all the other demos, too.
*/
void
gtk_nuclear_snapshot (GtkSnapshot *snapshot,
double width,
double height,
double rotation,
gboolean draw_background)
{
#define RADIUS 0.3
cairo_t *cr;
double size;
if (draw_background)
gtk_snapshot_append_color (snapshot,
&(GdkRGBA) { 0.9, 0.75, 0.15, 1.0 },
&GRAPHENE_RECT_INIT (0, 0, width, height));
size = MIN (width, height);
cr = gtk_snapshot_append_cairo (snapshot,
&GRAPHENE_RECT_INIT ((width - size) / 2.0,
(height - size) / 2.0,
size, size));
cairo_translate (cr, width / 2.0, height / 2.0);
cairo_scale (cr, size, size);
cairo_rotate (cr, rotation);
cairo_arc (cr, 0, 0, 0.1, - G_PI, G_PI);
cairo_fill (cr);
cairo_set_line_width (cr, RADIUS);
cairo_set_dash (cr, (double[1]) { RADIUS * G_PI / 3 }, 1, 0.0);
cairo_arc (cr, 0, 0, RADIUS, - G_PI, G_PI);
cairo_stroke (cr);
cairo_destroy (cr);
}
/* Here, we implement the functionality required by the GdkPaintable interface */
static void
gtk_nuclear_icon_snapshot (GdkPaintable *paintable,
GdkSnapshot *snapshot,
double width,
double height)
{
GtkNuclearIcon *nuclear = GTK_NUCLEAR_ICON (paintable);
/* The snapshot function is the only function we need to implement.
* It does the actual drawing of the paintable.
*/
gtk_nuclear_snapshot (snapshot,
width, height,
nuclear->rotation,
TRUE);
}
static GdkPaintableFlags
gtk_nuclear_icon_get_flags (GdkPaintable *paintable)
{
/* The flags are very useful to let GTK know that this image
* is never going to change.
* This allows many optimizations and should therefore always
* be set.
*/
return GDK_PAINTABLE_STATIC_CONTENTS | GDK_PAINTABLE_STATIC_SIZE;
}
static void
gtk_nuclear_icon_paintable_init (GdkPaintableInterface *iface)
{
iface->snapshot = gtk_nuclear_icon_snapshot;
iface->get_flags = gtk_nuclear_icon_get_flags;
}
/* When defining the GType, we need to implement the GdkPaintable interface */
G_DEFINE_TYPE_WITH_CODE (GtkNuclearIcon, gtk_nuclear_icon, G_TYPE_OBJECT,
G_IMPLEMENT_INTERFACE (GDK_TYPE_PAINTABLE,
gtk_nuclear_icon_paintable_init))
/* Here's the boilerplate for the GObject declaration.
* We don't need to do anything special here, because we keep no
* data of our own.
*/
static void
gtk_nuclear_icon_class_init (GtkNuclearIconClass *klass)
{
}
static void
gtk_nuclear_icon_init (GtkNuclearIcon *nuclear)
{
}
/* And finally, we add a simple constructor.
* It is declared in the header so that the other examples
* can use it.
*/
GdkPaintable *
gtk_nuclear_icon_new (double rotation)
{
GtkNuclearIcon *nuclear;
nuclear = g_object_new (GTK_TYPE_NUCLEAR_ICON, NULL);
nuclear->rotation = rotation;
return GDK_PAINTABLE (nuclear);
}
GtkWidget *
do_paintable (GtkWidget *do_widget)
{
GdkPaintable *nuclear;
GtkWidget *image;
if (!window)
{
window = gtk_window_new ();
gtk_window_set_display (GTK_WINDOW (window),
gtk_widget_get_display (do_widget));
gtk_window_set_title (GTK_WINDOW (window), "Nuclear Icon");
gtk_window_set_default_size (GTK_WINDOW (window), 300, 200);
g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
nuclear = gtk_nuclear_icon_new (0.0);
image = gtk_image_new_from_paintable (nuclear);
gtk_window_set_child (GTK_WINDOW (window), image);
g_object_unref (nuclear);
}
if (!gtk_widget_get_visible (window))
gtk_widget_show (window);
else
gtk_window_destroy (GTK_WINDOW (window));
return window;
}
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