[C][gegl][webkitgtk][X][tool] get web site thumbnail

getscreenshot_gegl.c

/*
 * get screenshot PNG from web page
 *
 * build:
 *   FLAGS=`pkg-config --cflags --libs gtk+-x11-2.0 webkit-1.0 gegl`
 *   gcc -Wall $FLAGS getscreenshot_gegl.c -o getscreenshot_gegl
 *
 * usage:
 *   xvfb-run -s "-screen 0 1024x768x24" ./getscreenshot_gegl test.html
 *
 */

#include <glib.h>
#include <glib/gprintf.h>
#include <gtk/gtk.h>
#include <webkit/webkit.h>
#include <gegl.h>

typedef struct _ThumbInfo ThumbInfo;
struct _ThumbInfo {
  gint width;
  gint height;
  GString * filename;
};
typedef struct _FontInfo FontInfo;
struct _FontInfo {
  gint point;
  GString * name;
};

/* gegl info see:
 * http://gegl.org/api.html
 * http://gegl.org/operations.html
 */
static void
store_thumbnail(ThumbInfo * thumb, GdkPixbuf * pixbuf)
{
  GeglNode * gegl;
  GeglNode * input;
  GeglNode * output;
  GeglNode * scale;
  GeglRectangle bb;

  gegl = gegl_node_new();
  input = gegl_node_new_child(gegl,
                              "operation", "gegl:pixbuf",
                              "pixbuf", pixbuf,
                              NULL);
  bb = gegl_node_get_bounding_box(input);
  output = gegl_node_new_child(gegl,
                               "operation", "gegl:png-save",
                               "path", thumb->filename->str,
                               "compression", 9,
                               NULL);
  scale = gegl_node_new_child(gegl,
                              "operation", "gegl:scale",
                              "filter", "lanczos",
                              "x", (gdouble) thumb->width / bb.width,
                              "y", (gdouble) thumb->height / bb.height,
                              NULL);
  gegl_node_link_many(input, scale, output, NULL);
  {
    gint dw = 0, dh = 0;
    bb = gegl_node_get_bounding_box(scale);
    while (bb.width > thumb->width) {
      dw++;
      gegl_node_set(scale,
                    "x", (gdouble) (thumb->width - dw) / bb.width,
                    NULL);
      bb = gegl_node_get_bounding_box(scale);
    }
    while (bb.height > thumb->height) {
      dh++;
      gegl_node_set(scale,
                    "y", (gdouble) (thumb->height - dh) / bb.height,
                    NULL);
      bb = gegl_node_get_bounding_box(scale);
    }
  }
  gegl_node_process(output);
  bb = gegl_node_get_bounding_box(scale);

  g_object_unref(gegl);
  g_printf("saved %dx%d PNG into %s\n",
           bb.width, bb.height, thumb->filename->str);
}

/*
 * see: http://webkitgtk.org/reference/webkitgtk-WebKitWebView.html signals
 */
static void
loaded(WebKitWebView * view, WebKitWebFrame * frame, gpointer data)
{
  ThumbInfo * thumb;
  GdkWindow * window;
  GdkColormap * colormap;
  gint width;
  gint height;
  GdkPixbuf * pixbuf;

  thumb = data;

  g_object_get(G_OBJECT(view), "window", &window, NULL);
  gdk_window_get_size(GDK_WINDOW(window), &width, &height);
  colormap = gdk_window_get_colormap(GDK_WINDOW(window));

  /* gdk-pixbuf api: http://library.gnome.org/devel/gdk-pixbuf/stable/  */
  pixbuf = gdk_pixbuf_new(GDK_COLORSPACE_RGB, FALSE, 8, width, height);
  gdk_pixbuf_get_from_drawable(pixbuf, GDK_DRAWABLE(window), colormap,
                               0, 0, 0, 0, width, height);
  store_thumbnail(thumb, pixbuf);

  g_object_unref(G_OBJECT(pixbuf));

  gtk_main_quit();
}

static GtkWidget *
init_window(GString * url, ThumbInfo * thumb, FontInfo * font)
{
  GtkWidget * window;
  GtkWidget * webview;
  GdkScreen * screen;
  WebKitWebSettings * settings;

  screen = gdk_screen_get_default();
  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  gtk_window_move(GTK_WINDOW(window), 0, 0);
  gtk_window_resize(GTK_WINDOW(window),
                    gdk_screen_get_width(screen),
                    gdk_screen_get_height(screen));

  webview = webkit_web_view_new();
  /* webkit settings props:
   * http://webkitgtk.org/reference/webkitgtk-WebKitWebSettings.html
   */
  settings = webkit_web_settings_new();
  g_object_set(G_OBJECT(settings),
               "serif-font-family", font->name->str,
               "sans-serif-font-family", font->name->str,
               "monospace-font-family", font->name->str,
               "default-font-family", font->name->str,
               "default-font-size", font->point,
               NULL);
  webkit_web_view_set_settings(WEBKIT_WEB_VIEW(webview), settings);

  gtk_container_add(GTK_CONTAINER(window), webview);

  gtk_signal_connect(GTK_OBJECT(webview), "load-finished",
                     GTK_SIGNAL_FUNC(loaded), thumb);

  webkit_web_view_open(WEBKIT_WEB_VIEW(webview), url->str);

  gtk_widget_show_all(window);
  return window;
}

static void
parse_option(gint * pargc, gchar ** pargv[],
             ThumbInfo * thumb, FontInfo * font)
{
    /* glib commandline option parser:
     * http://library.gnome.org/devel/glib/stable/
     */
    GOptionContext *context;
    gchar * filename = NULL;
    gchar * fontname = NULL;
    GOptionEntry entries[] = {
      {"width", 'w', 0, G_OPTION_ARG_INT,
       &thumb->width,
       "thumbnail width pixel", "WIDTH"},
      {"height", 'h', 0, G_OPTION_ARG_INT,
       &thumb->height,
       "thumbnail height pixel", "HEIGHT"},
      {"output", 'o', G_OPTION_FLAG_FILENAME, G_OPTION_ARG_FILENAME,
       &filename,
       "thumbnail PNG file name", "PNG_FILENAME"},
      {"font", 'f', 0, G_OPTION_ARG_STRING,
       &fontname,
       "font name", "FONT_NAME"},
      {"point", 'p', 0, G_OPTION_ARG_INT,
       &font->point,
       "default font point", "POINT"},
      {NULL}
    };
    context = g_option_context_new("get web page thumbnail");
    g_option_context_add_main_entries(context, entries, NULL);
    /* gtk_get_option_group see:
     * http://library.gnome.org/devel/gtk/stable/gtk-General.html */
    g_option_context_add_group(context, gtk_get_option_group(TRUE));
    g_option_context_add_group(context, gegl_get_option_group());
    if (!g_option_context_parse(context, pargc, pargv, NULL)) {
      gtk_exit(0);
    }
    if (filename) {
      g_string_overwrite(thumb->filename, 0, filename);
    }
    if (fontname) {
      g_string_overwrite(font->name, 0, fontname);
    }
    g_option_context_free(context);

}

int
main(int argc, char * argv[])
{
  GString * url;
  ThumbInfo thumb;
  FontInfo font;
  GtkWidget * window;

  font.point = 14;
  font.name = g_string_new("VLGothic");

  thumb.width = 200;
  thumb.height = 150;
  thumb.filename = g_string_new("screenshot.png");

  g_thread_init(NULL);
  gdk_threads_init();
  gdk_threads_enter();

  parse_option(&argc, &argv, &thumb, &font);
  url = g_string_new(argv[1]);
  if (!g_str_has_prefix(url->str, "http")) {
    url = g_string_prepend(url, "file://");
  }

  window = init_window(url, &thumb, &font);

  gtk_main();
  gegl_exit();
  gdk_threads_leave();

  g_string_free(url, TRUE);
  g_string_free(font.name, TRUE);
  g_string_free(thumb.filename, TRUE);

  return 0;
}