WebKitViewportAttributes

WebKitViewportAttributes — Represents the viewport properties of a web page

Synopsis

                    WebKitViewportAttributes;
void                webkit_viewport_attributes_recompute
                                                        (WebKitViewportAttributes *viewportAttributes);

Description

WebKitViewportAttributes offers the viewport properties to user agents to control the viewport layout. It contains the viewport size, initial scale with limits, and information about whether a user is able to scale the contents in the viewport. This makes a web page fit the device screen.

The "viewport-attributes-changed" signal will be emitted with WebKitViewportAttributes when the viewport attributes are updated in the case of loading web pages contain the viewport properties and calling webkit_viewport_attributes_recompute.

If the device size, available size, desktop width, or device DPI needs to be changed due to a consequence of an explicit browser request (caused by screen rotation, resizing, or similar reasons), You should call webkit_viewport_attributes_recompute to recompute the viewport properties and override those values in the handler of "viewport-attributes-recompute-requested" signal.

For more information on the viewport properties, refer to the Safari reference library at http://developer.apple.com/safari/library/documentation/appleapplications/reference/safarihtmlref/articles/metatags.html

/* Connect to the viewport-attributes-changes signal */
WebKitViewportAttributes* attributes = webkit_web_view_get_viewport_attributes (web_view);
g_signal_connect (web_view, "viewport-attributes-recompute-requested", G_CALLBACK (viewport_recompute_cb), window);
g_signal_connect (web_view, "viewport-attributes-changed", G_CALLBACK (viewport_changed_cb), window);
g_signal_connect (attributes, "notify::valid", G_CALLBACK (viewport_valid_changed_cb), web_view);

/* Handle the viewport-attributes-recompute-requested signal to override the device width */
static void
viewport_recompute_cb (WebKitWebView* web_view, WebKitViewportAttributes* attributes, GtkWidget* window)
{
    int override_available_width = 480;
    g_object_set (G_OBJECT(attributes), "available-width", override_available_width, NULL);
}

/* Handle the viewport-attributes-changed signal to recompute the initial scale factor */
static void 
viewport_changed_cb (WebKitWebView* web_view, WebKitViewportAttributes* attributes, gpointer data)
{
    gfloat initialScale;
    g_object_get (G_OBJECT (atributes), "initial-scale-factor", &initialScale, NULL);
    webkit_web_view_set_zoom_level (web_view, initialScale);
}

/* Handle the notify::valid signal to initialize the zoom level */
static void
viewport_valid_changed_cb (WebKitViewportAttributes* attributes, GParamSpec* pspec, WebKitWebView* web_view)
{
    gboolean is_valid;
    g_object_get (attributes, "valid", &is_valid, NULL);
    if (!is_valid) 
        webkit_web_view_set_zoom_level (web_view, 1.0);
}

Details