1 The way that the GtkTreeView calculates sizing is pretty confusing.
2 This is written down to help keep track of it in my head, and thus help
3 anyone who hopes to work with the code in the future.
5 HOW THE GTKTREEVIEW CALCULATES SIZE:
6 ====================================
7 When the view is given a new model, the first thing it does is walk
8 through the model at the top level, creating an GtkRBNode for each
9 element of the model. Each node has a height of 0. The RBTree is kept
10 updated as the models structure changes. Additionally, the user can
11 expand, collapse, and select rows at this stage. The RBTree is accurate
12 -- it just doesn't have a height for any row.
14 When the TreeView is realized, it calculates the actual height of each
15 row by walking the tree and measuring them. While doing so, it gets the
20 Columns are initially marked as 'dirty'. When sized,
21 gtk_tree_view_check_dirty_and_clean () is called on each column. This
22 function walks through all visible columns, and sees if they're dirty or
23 not. If any are dirty, it then walks the tree, calling
24 gtk_tree_view_calc_size on each row. gtk_tree_view_calc_size requests
25 the size of every dirty column in the tree. Finally, it updates the
26 size of the widget (including adjustments).
29 HOW THE GTKTREEVIEWCOLUMN STORES SIZE:
30 ======================================
32 There are a number of size related fields in the GtkTreeViewColumn
33 structure. These are all valid after realization:
35 sizing The sizing method to use when calculating the size
36 of the column. Can be grow_only, resizable, auto, and fixed.
38 requested_width The width of the column as requested by the column
40 width The actual width. This is requested width for all
41 columns but possibly the last one.
43 fixed_width The requested fixed width for the column iff it's
44 sizing type is set to GTK_TREE_VIEW_COLUMN_FIXED.
46 min_width The minimum width the column can be
48 max_width The maximum width the column can be. This can be
49 overridden for the last column, if the tree_view is
50 actually wider than the sum of all of the columns
53 The following invariants are true:
55 min_width is less than or equal to width
57 max_width is greater than or equal to width
59 (sizing == GTK_TREE_VIEW_COLUMN_FIXED) => (requested_width == fixed_width)
61 (column != last visible column) => width == requested_width
64 /* Functions needed by gtktreeview for gtktreeviewcolumn */
66 set_width (for resizing resizable columns)