1 #ifndef MSP_GLTK_LAYOUT_H_
2 #define MSP_GLTK_LAYOUT_H_
6 #include <sigc++/trackable.h>
7 #include <msp/strings/lexicalcast.h>
18 Positions Widgets inside a Container.
20 A layout operates on constraints, which are used to form a linear program that
21 is then solved to obtain positions and dimensions that fulfill the constraints.
22 There are three kinds of constraints available: ordering, alignment and
25 Ordering constraints specify that the widgets should be placed next to each
26 other along X or Y axis. These operate on one axis at a time, so a widget
27 could be "right of" another even if they are separated by hundreds of pixels
28 vertically. The widgets will be separated by a spacing value, which is
29 settable on a per-layout basis.
31 Alignment constraints make the corresponding edges of two widgets be on the
32 same line. These are incompatible with ordering constraints, so only one or
33 the other should be used between any pair of widgets for the same axis.
35 Dimension matching constraints force the two widgets to have the same dimension
36 along the relevant axis.
38 In addition to constraints, there are some other properties that can be set on
39 widgets to determine how they are laid out. Gravity affects which edge of the
40 container the widget should be placed at. This is a relatively weak hint and
41 will be overridden by many other things. Margins can also be specified to
42 prevent widgets from getting too close to the container's edges.
44 Usually widgets are made as small as their content allows. Setting the expand
45 flag for a widget causes it to use as much space as possible. If multiple co-
46 dependent widgets have the expand flag set, the results are currently
49 Since specifiyng constraints manually can be quite tedious, an Arrangement
50 interface is provided to automatically arrange widgets. See classes Row,
51 Column and Grid for some commonly used arrangements.
73 ABOVE = VERTICAL|SELF_POS|TARGET_POS|TARGET_DIM|SPACING,
74 BELOW = VERTICAL|SELF_POS|SELF_DIM|TARGET_POS|SPACING,
75 RIGHT_OF = HORIZONTAL|SELF_POS|TARGET_POS|TARGET_DIM|SPACING,
76 LEFT_OF = HORIZONTAL|SELF_POS|SELF_DIM|TARGET_POS|SPACING,
77 FAR_ABOVE = VERTICAL|SELF_POS|TARGET_POS|TARGET_DIM|SPACING|SLACK,
78 FAR_BELOW = VERTICAL|SELF_POS|SELF_DIM|TARGET_POS|SPACING|SLACK,
79 FAR_RIGHT_OF = HORIZONTAL|SELF_POS|TARGET_POS|TARGET_DIM|SPACING|SLACK,
80 FAR_LEFT_OF = HORIZONTAL|SELF_POS|SELF_DIM|TARGET_POS|SPACING|SLACK,
81 ALIGN_TOP = VERTICAL|SELF_POS|SELF_DIM|TARGET_POS|TARGET_DIM,
82 ALIGN_BOTTOM = VERTICAL|SELF_POS|TARGET_POS,
83 ALIGN_RIGHT = HORIZONTAL|SELF_POS|SELF_DIM|TARGET_POS|TARGET_DIM,
84 ALIGN_LEFT = HORIZONTAL|SELF_POS|TARGET_POS,
85 COPY_WIDTH = HORIZONTAL|SELF_DIM|TARGET_DIM,
86 COPY_HEIGHT = VERTICAL|SELF_DIM|TARGET_DIM
98 Constraint(ConstraintType, Slot &);
109 struct Slot: public sigc::trackable
114 Geometry autosize_geom;
116 std::list<Constraint> constraints;
120 Slot(Layout &, Widget &);
122 void autosize_changed();
123 void visibility_changed(bool);
135 Container *container;
136 std::list<Slot *> slots;
137 unsigned n_active_slots;
138 unsigned n_slack_constraints[2];
140 unsigned row_spacing;
141 unsigned col_spacing;
142 Geometry autosize_geom;
143 std::list<Arrangement *> arrangement_stack;
145 static Pointers pointers[2];
151 void set_container(Container &);
152 void set_margin(const Sides &);
154 /** Sets the default spacing between widgets in bothg directions. */
155 void set_spacing(unsigned);
157 /** Sets the default vertical spacing between widgets. Affects the ABOVE
158 and BELOW constraints. */
159 void set_row_spacing(unsigned);
161 /** Sets the default horizontal spacing between widgets. Affects the
162 LEFT_OF and RIGHT_OF constraints. */
163 void set_column_spacing(unsigned);
165 void push_arrangement(Arrangement &);
166 Arrangement *get_arrangement() const;
167 void pop_arrangement(Arrangement &);
169 void add_widget(Widget &);
170 void remove_widget(Widget &);
172 void update_slot_indices();
173 Slot &get_slot_for_widget(Widget &);
174 static ConstraintType complement(ConstraintType);
175 void create_constraint(Widget &, ConstraintType, Widget &, int);
178 /** Adds a constraint between two widgets. */
179 void add_constraint(Widget &src, ConstraintType type, Widget &tgt);
181 /** Adds a constraint between two widgets, overriding the default spacing.
182 Not all constraint types use a spacing. */
183 void add_constraint(Widget &src, ConstraintType type, Widget &tgt, unsigned);
185 void set_gravity(Widget &, int, int);
186 void set_expand(Widget &, bool, bool);
192 void solve_constraints(int, SolveMode);
195 void operator>>(const LexicalConverter &, Layout::ConstraintType &);