The #GtkCellRenderer is a base class of a set of objects used for
rendering a cell to a #cairo_t. These objects are used primarily by
the #GtkTreeView widget, though they aren’t tied to them in any
specific way. It is worth noting that #GtkCellRenderer is not a
#GtkWidget and cannot be treated as such.
The primary use of a #GtkCellRenderer is for drawing a certain graphical
elements on a #cairo_t. Typically, one cell renderer is used to
draw many cells on the screen. To this extent, it isn’t expected that a
CellRenderer keep any permanent state around. Instead, any state is set
just prior to use using #GObjects property system. Then, the
cell is measured using gtk.cell_renderer.CellRenderer.getSize. Finally, the cell
is rendered in the correct location using gtk.cell_renderer.CellRenderer.render.
There are a number of rules that must be followed when writing a new
#GtkCellRenderer. First and foremost, it’s important that a certain set
of properties will always yield a cell renderer of the same size,
barring a #GtkStyle change. The #GtkCellRenderer also has a number of
generic properties that are expected to be honored by all children.
Beyond merely rendering a cell, cell renderers can optionally
provide active user interface elements. A cell renderer can be
“activatable” like #GtkCellRendererToggle,
which toggles when it gets activated by a mouse click, or it can be
“editable” like #GtkCellRendererText, which
allows the user to edit the text using a widget implementing the
#GtkCellEditable interface, e.g. #GtkEntry.
To make a cell renderer activatable or editable, you have to
implement the #GtkCellRendererClass.activate or
#GtkCellRendererClass.start_editing virtual functions, respectively.
Many properties of #GtkCellRenderer and its subclasses have a
corresponding “set” property, e.g. “cell-background-set” corresponds
to “cell-background”. These “set” properties reflect whether a property
has been set or not. You should not set them independently.
The #GtkCellRenderer is a base class of a set of objects used for rendering a cell to a #cairo_t. These objects are used primarily by the #GtkTreeView widget, though they aren’t tied to them in any specific way. It is worth noting that #GtkCellRenderer is not a #GtkWidget and cannot be treated as such.
The primary use of a #GtkCellRenderer is for drawing a certain graphical elements on a #cairo_t. Typically, one cell renderer is used to draw many cells on the screen. To this extent, it isn’t expected that a CellRenderer keep any permanent state around. Instead, any state is set just prior to use using #GObjects property system. Then, the cell is measured using gtk.cell_renderer.CellRenderer.getSize. Finally, the cell is rendered in the correct location using gtk.cell_renderer.CellRenderer.render.
There are a number of rules that must be followed when writing a new #GtkCellRenderer. First and foremost, it’s important that a certain set of properties will always yield a cell renderer of the same size, barring a #GtkStyle change. The #GtkCellRenderer also has a number of generic properties that are expected to be honored by all children.
Beyond merely rendering a cell, cell renderers can optionally provide active user interface elements. A cell renderer can be “activatable” like #GtkCellRendererToggle, which toggles when it gets activated by a mouse click, or it can be “editable” like #GtkCellRendererText, which allows the user to edit the text using a widget implementing the #GtkCellEditable interface, e.g. #GtkEntry. To make a cell renderer activatable or editable, you have to implement the #GtkCellRendererClass.activate or #GtkCellRendererClass.start_editing virtual functions, respectively.
Many properties of #GtkCellRenderer and its subclasses have a corresponding “set” property, e.g. “cell-background-set” corresponds to “cell-background”. These “set” properties reflect whether a property has been set or not. You should not set them independently.