/* Pixbufs

 *

 * A GdkPixbuf represents an image, normally in RGB or RGBA format.

 * Pixbufs are normally used to load files from disk and perform

 * image scaling.

 *

 * This demo is not all that educational, but looks cool. It was written

 * by Extreme Pixbuf Hacker Federico Mena Quintero. It also shows

 * off how to use GtkDrawingArea to do a simple animation.

 *

 * Look at the Image demo for additional pixbuf usage examples.

 *

 */

#include <stdlib.h>

#include <gtk/gtk.h>

#include <math.h>

#include "demo-common.h"

#define FRAME_DELAY 50

#define BACKGROUND_NAME "background.jpg"

static const char *image_names[] = {

  "apple-red.png",

  "gnome-applets.png",

  "gnome-calendar.png",

  "gnome-foot.png",

  "gnome-gmush.png",

  "gnome-gimp.png",

  "gnome-gsame.png",

  "gnu-keys.png"

};

#define N_IMAGES G_N_ELEMENTS (image_names)

/* demo window */

static GtkWidget *window = NULL;

/* Current frame */

static GdkPixbuf *frame;

/* Background image */

static GdkPixbuf *background;

static gint back_width, back_height;

/* Images */

static GdkPixbuf *images[N_IMAGES];

/* Widgets */

static GtkWidget *da;

/* Loads the images for the demo and returns whether the operation succeeded */

static gboolean

load_pixbufs (GError **error)

{

  gint i;

  char *filename;

  if (background)

    return TRUE; /* already loaded earlier */

  /* demo_find_file() looks in the current directory first,

   * so you can run gtk-demo without installing GTK, then looks

   * in the location where the file is installed.

   */

  filename = demo_find_file (BACKGROUND_NAME, error);

  if (!filename)

    return FALSE; /* note that "error" was filled in and returned */

  background = gdk_pixbuf_new_from_file (filename, error);

  g_free (filename);

  if (!background)

    return FALSE; /* Note that "error" was filled with a GError */

  back_width = gdk_pixbuf_get_width (background);

  back_height = gdk_pixbuf_get_height (background);

  for (i = 0; i < N_IMAGES; i++)

    {

      filename = demo_find_file (image_names[i], error);

      if (!filename)

        return FALSE; /* Note that "error" was filled with a GError */

      images[i] = gdk_pixbuf_new_from_file (filename, error);

      g_free (filename);

      if (!images[i])

        return FALSE; /* Note that "error" was filled with a GError */

    }

  return TRUE;

}

/* Expose callback for the drawing area */

static gint

expose_cb (GtkWidget      *widget,

           GdkEventExpose *event,

           gpointer        data)

{

  cairo_t *cr;

  cr = gdk_cairo_create (event->window);

  gdk_cairo_set_source_pixbuf (cr, frame, 0, 0);

  gdk_cairo_rectangle (cr, &event->area);

  cairo_fill (cr);

  cairo_destroy (cr);

  return TRUE;

}

#define CYCLE_LEN 60

static int frame_num;

/* Timeout handler to regenerate the frame */

static gint

timeout (gpointer data)

{

  double f;

  int i;

  double xmid, ymid;

  double radius;

  gdk_pixbuf_copy_area (background, 0, 0, back_width, back_height,

                        frame, 0, 0);

  f = (double) (frame_num % CYCLE_LEN) / CYCLE_LEN;

  xmid = back_width / 2.0;

  ymid = back_height / 2.0;

  radius = MIN (xmid, ymid) / 2.0;

  for (i = 0; i < N_IMAGES; i++)

    {

      double ang;

      int xpos, ypos;

      int iw, ih;

      double r;

      GdkRectangle r1, r2, dest;

      double k;

      ang = 2.0 * G_PI * (double) i / N_IMAGES - f * 2.0 * G_PI;

      iw = gdk_pixbuf_get_width (images[i]);

      ih = gdk_pixbuf_get_height (images[i]);

      r = radius + (radius / 3.0) * sin (f * 2.0 * G_PI);

      xpos = floor (xmid + r * cos (ang) - iw / 2.0 + 0.5);

      ypos = floor (ymid + r * sin (ang) - ih / 2.0 + 0.5);

      k = (i & 1) ? sin (f * 2.0 * G_PI) : cos (f * 2.0 * G_PI);

      k = 2.0 * k * k;

      k = MAX (0.25, k);

      r1.x = xpos;

      r1.y = ypos;

      r1.width = iw * k;

      r1.height = ih * k;

      r2.x = 0;

      r2.y = 0;

      r2.width = back_width;

      r2.height = back_height;

      if (gdk_rectangle_intersect (&r1, &r2, &dest))

        gdk_pixbuf_composite (images[i],

                              frame,

                              dest.x, dest.y,

                              dest.width, dest.height,

                              xpos, ypos,

                              k, k,

                              GDK_INTERP_NEAREST,

                              ((i & 1)

                               ? MAX (127, fabs (255 * sin (f * 2.0 * G_PI)))

                               : MAX (127, fabs (255 * cos (f * 2.0 * G_PI)))));

    }

  GDK_THREADS_ENTER ();

  gtk_widget_queue_draw (da);

  GDK_THREADS_LEAVE ();

  frame_num++;

  return TRUE;

}

static guint timeout_id;

static void

cleanup_callback (GtkObject *object,

                  gpointer   data)

{

  g_source_remove (timeout_id);

  timeout_id = 0;

}

GtkWidget *

do_pixbufs (GtkWidget *do_widget)

{

  if (!window)

    {

      GError *error;

      window = gtk_window_new (GTK_WINDOW_TOPLEVEL);

      gtk_window_set_screen (GTK_WINDOW (window),

                             gtk_widget_get_screen (do_widget));

      gtk_window_set_title (GTK_WINDOW (window), "Pixbufs");

      gtk_window_set_resizable (GTK_WINDOW (window), FALSE);

      g_signal_connect (window, "destroy",

                        G_CALLBACK (gtk_widget_destroyed), &window);

      g_signal_connect (window, "destroy",

                        G_CALLBACK (cleanup_callback), NULL);

      error = NULL;

      if (!load_pixbufs (&error))

        {

          GtkWidget *dialog;

          dialog = gtk_message_dialog_new (GTK_WINDOW (window),

                                           GTK_DIALOG_DESTROY_WITH_PARENT,

                                           GTK_MESSAGE_ERROR,

                                           GTK_BUTTONS_CLOSE,

                                           "Failed to load an image: %s",

                                           error->message);

          g_error_free (error);

          g_signal_connect (dialog, "response",

                            G_CALLBACK (gtk_widget_destroy), NULL);

          gtk_widget_show (dialog);

        }

      else

        {

          gtk_widget_set_size_request (window, back_width, back_height);

          frame = gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE, 8, back_width, back_height);

          da = gtk_drawing_area_new ();

          g_signal_connect (da, "expose-event",

                            G_CALLBACK (expose_cb), NULL);

          gtk_container_add (GTK_CONTAINER (window), da);

          timeout_id = g_timeout_add (FRAME_DELAY, timeout, NULL);

        }

    }

  if (!gtk_widget_get_visible (window))

    {

      gtk_widget_show_all (window);

    }

  else

    {

      gtk_widget_destroy (window);

      window = NULL;

      g_object_unref (frame);

    }

  return window;

}