Desktop Notifications Specification
5 Icons and Images #
A notification can optionally have an associated icon and/or image.
The icon is defined by the "app_icon" parameter. The image can be defined by the "image-path", the "image-data" hint or the deprecated "icon_data" hint.
5.1 Priorities #
An implementation which only displays one image or icon must choose which one to display using the following order:
"image-data"
"image-path"
app_icon parameter
for compatibility reason, "icon_data"
An implementation which can display both the image and icon must show the icon from the "app_icon" parameter and choose which image to display using the following order:
"image-data"
"image-path"
for compatibility reason, "icon_data"
5.2 Formats #
The "image-data" and "icon_data" hints should be a DBus structure of signature (iiibiiay). The components of this structure are as follows:
width (i): Width of image in pixels
height (i): Height of image in pixels
rowstride (i): Distance in bytes between row starts
has_alpha (b): Whether the image has an alpha channel
bits_per_sample (i): Must always be 8
channels (i): If has_alpha is TRUE, must be 4, otherwise 3
data (ay): The image data, in RGB byte order
This image format is derived from gdk-pixbuf (http://developer.gnome.org/gdk-pixbuf/stable/).
The "app_icon" parameter and "image-path" hint should be either an URI (file:// is the only URI schema supported right now) or a name in a freedesktop.org-compliant icon theme (not a GTK+ stock ID).