/**
* eel_gdk_pixbuf_new_from_existing_buffer:
* @buffer: The existing buffer.
* @buffer_rowstride: The existing buffer's rowstride.
* @buffer_has_alpha: A boolean value indicating whether the buffer has alpha.
* @area: The area within the existing buffer to use for the pixbuf.
* This area needs to be contained within the bounds of the
* buffer, otherwise memory will be trashed.
*
* Return value: A newly allocated pixbuf that uses the existing buffer
* for its pixel data.
*
* Create a pixbuf from an existing buffer.
*
* The resulting pixbuf is only valid for as long as &buffer is valid. It is
* up to the caller to make sure they both exist in the same scope.
* Also, it is up to the caller to make sure that the given area is fully
* contained in the buffer, otherwise memory trashing will happen.
*/
GdkPixbuf *
eel_gdk_pixbuf_new_from_existing_buffer (guchar *buffer,
int buffer_rowstride,
gboolean buffer_has_alpha,
EelIRect area)
{
GdkPixbuf *pixbuf;
guchar *pixels;
g_return_val_if_fail (buffer != NULL, NULL);
g_return_val_if_fail (buffer_rowstride > 0, NULL);
g_return_val_if_fail (!eel_irect_is_empty (&area), NULL);
/* Compute the offset into the buffer */
pixels =
buffer
+ (area.y0 * buffer_rowstride)
+ (area.x0 * (buffer_has_alpha ? 4 : 3));
pixbuf = gdk_pixbuf_new_from_data (pixels,
GDK_COLORSPACE_RGB,
buffer_has_alpha,
8,
eel_irect_get_width (area),
eel_irect_get_height (area),
buffer_rowstride,
NULL,
NULL);
return pixbuf;
}
/**
* eel_gtk_container_child_size_allocate:
*
* @container: A GtkContainer widget.
* @child: A child of @container or NULL;
*
* Invoke the "GtkWidget::size_allocate" method of @child.
* This function is usually called from the "GtkWidget::size_allocate"
* method of @container. The child can be NULL, in which case this
* function is a noop.
*/
void
eel_gtk_container_child_size_allocate (GtkContainer *container,
GtkWidget *child,
EelIRect child_geometry)
{
GtkAllocation child_allocation;
g_return_if_fail (GTK_IS_CONTAINER (container));
if (child == NULL)
{
return;
}
g_return_if_fail (GTK_IS_WIDGET (child));
g_return_if_fail (gtk_widget_get_parent (child) == GTK_WIDGET (container));
if (eel_irect_is_empty (&child_geometry))
{
return;
}
child_allocation.x = child_geometry.x0;
child_allocation.y = child_geometry.y0;
child_allocation.width = eel_irect_get_width (child_geometry);
child_allocation.height = eel_irect_get_height (child_geometry);
gtk_widget_size_allocate (child, &child_allocation);
}
GdkRectangle
eel_irect_to_gdk_rectangle (EelIRect rectangle)
{
GdkRectangle gdk_rect;
gdk_rect.x = rectangle.x0;
gdk_rect.y = rectangle.y0;
gdk_rect.width = eel_irect_get_width (rectangle);
gdk_rect.height = eel_irect_get_height (rectangle);
return gdk_rect;
}
/**
* eel_gdk_pixbuf_new_from_pixbuf_sub_area:
* @pixbuf: The source pixbuf.
* @area: The area within the source pixbuf to use for the sub pixbuf.
* This area needs to be contained within the bounds of the
* source pixbuf, otherwise it will be clipped to that.
*
* Return value: A newly allocated pixbuf that shares the pixel data
* of the source pixbuf in order to represent a sub area.
*
* Create a pixbuf from a sub area of another pixbuf. The resulting pixbuf
* will share the pixel data of the source pixbuf. Memory bookeeping is
* all taken care for the caller. All you need to do is g_object_unref()
* the resulting pixbuf to properly free resources.
*/
GdkPixbuf *
eel_gdk_pixbuf_new_from_pixbuf_sub_area (GdkPixbuf *pixbuf,
EelIRect area)
{
GdkPixbuf *sub_pixbuf;
EelIRect target;
guchar *pixels;
g_return_val_if_fail (eel_gdk_pixbuf_is_valid (pixbuf), NULL);
g_return_val_if_fail (!eel_irect_is_empty (&area), NULL);
/* Clip the pixbuf by the given area; bail if no work */
target = eel_gdk_pixbuf_intersect (pixbuf, 0, 0, area);
if (eel_irect_is_empty (&target))
{
return NULL;
}
/* Since we are going to be sharing the given pixbuf's data, we need
* to ref it. It will be unreffed in the destroy function above */
g_object_ref (pixbuf);
/* Compute the offset into the pixel data */
pixels =
gdk_pixbuf_get_pixels (pixbuf)
+ (target.y0 * gdk_pixbuf_get_rowstride (pixbuf))
+ (target.x0 * (gdk_pixbuf_get_has_alpha (pixbuf) ? 4 : 3));
/* Make a pixbuf pretending its real estate is the sub area */
sub_pixbuf = gdk_pixbuf_new_from_data (pixels,
GDK_COLORSPACE_RGB,
gdk_pixbuf_get_has_alpha (pixbuf),
8,
eel_irect_get_width (target),
eel_irect_get_height (target),
gdk_pixbuf_get_rowstride (pixbuf),
pixbuf_destroy_callback,
pixbuf);
return sub_pixbuf;
}
