1 #ifndef MSP_GLTK_LAYOUT_H_
2 #define MSP_GLTK_LAYOUT_H_
6 #include <sigc++/trackable.h>
16 Positions Widgets inside a Container.
18 A layout operates on constraints, which are used to form a linear program that
19 is then solved to obtain positions and dimensions that fulfill the constraints.
20 There are three kinds of constraints available: ordering, alignment and
23 Ordering constraints specify that the widgets should be placed next to each
24 other along X or Y axis. These operate on one axis at a time, so a widget
25 could be "right of" another even if they are separated by hundreds of pixels
26 vertically. The widgets will be separated by a spacing value, which is
27 settable on a per-layout basis.
29 Alignment constraints make the corresponding edges of two widgets be on the
30 same line. These are incompatible with ordering constraints, so only one or
31 the other should be used between any pair of widgets for the same axis.
33 Dimension matching constraints force the two widgets to have the same dimension
34 along the relevant axis.
36 In addition to constraints, there are some other properties that can be set on
37 widgets to determine how they are laid out. Gravity affects which edge of the
38 container the widget should be placed at. This is a relatively weak hint and
39 will be overridden by many other things. Margins can also be specified to
40 prevent widgets from getting too close to the container's edges.
42 Usually widgets are made as small as their content allows. Setting the expand
43 flag for a widget causes it to use as much space as possible. If multiple co-
44 dependent widgets have the expand flag set, the results are currently
47 Since specifiyng constraints manually can be quite tedious, there are some
48 derived Layout classes that implement common positioning patterns. See Row,
49 Column, MixedRows and Grid.
70 ABOVE = VERTICAL|SELF_POS|TARGET_POS|TARGET_DIM|SPACING,
71 BELOW = VERTICAL|SELF_POS|SELF_DIM|TARGET_POS|SPACING,
72 RIGHT_OF = HORIZONTAL|SELF_POS|TARGET_POS|TARGET_DIM|SPACING,
73 LEFT_OF = HORIZONTAL|SELF_POS|SELF_DIM|TARGET_POS|SPACING,
74 ALIGN_TOP = VERTICAL|SELF_POS|SELF_DIM|TARGET_POS|TARGET_DIM,
75 ALIGN_BOTTOM = VERTICAL|SELF_POS|TARGET_POS,
76 ALIGN_RIGHT = HORIZONTAL|SELF_POS|SELF_DIM|TARGET_POS|TARGET_DIM,
77 ALIGN_LEFT = HORIZONTAL|SELF_POS|TARGET_POS,
78 COPY_WIDTH = HORIZONTAL|SELF_DIM|TARGET_DIM,
79 COPY_HEIGHT = VERTICAL|SELF_DIM|TARGET_DIM
91 Constraint(ConstraintType, Slot &);
102 struct Slot: public sigc::trackable
107 Geometry autosize_geom;
109 std::list<Constraint> constraints;
113 Slot(Layout &, Widget &);
116 void autosize_changed();
117 void visibility_changed(bool);
129 Container *container;
130 std::list<Slot *> slots;
131 unsigned n_active_slots;
133 unsigned row_spacing;
134 unsigned col_spacing;
135 Geometry autosize_geom;
137 static Pointers pointers[2];
143 void set_container(Container &);
144 void set_margin(const Sides &);
146 /** Sets the default spacing between widgets in bothg directions. */
147 void set_spacing(unsigned);
149 /** Sets the default vertical spacing between widgets. Affects the ABOVE
150 and BELOW constraints. */
151 void set_row_spacing(unsigned);
153 /** Sets the default horizontal spacing between widgets. Affects the
154 LEFT_OF and RIGHT_OF constraints. */
155 void set_column_spacing(unsigned);
157 void add_widget(Widget &);
158 void remove_widget(Widget &);
160 virtual Slot *create_slot(Widget &);
161 void update_slot_indices();
162 Slot &get_slot_for_widget(Widget &);
163 static ConstraintType complement(ConstraintType);
164 void create_constraint(Widget &, ConstraintType, Widget &, int);
167 /** Adds a constraint between two widgets. */
168 void add_constraint(Widget &src, ConstraintType type, Widget &tgt);
170 /** Adds a constraint between two widgets, overriding the default spacing.
171 Not all constraint types use a spacing. */
172 void add_constraint(Widget &src, ConstraintType type, Widget &tgt, unsigned);
174 void set_gravity(Widget &, int, int);
175 void set_expand(Widget &, bool, bool);
181 void solve_constraints(int, SolveMode);