1 | /* Constraints/VFL |
2 | * |
3 | * GtkConstraintLayout allows defining constraints using a |
4 | * compact syntax called Visual Format Language, or VFL. |
5 | * |
6 | * A typical example of a VFL specification looks like this: |
7 | * |
8 | * H:|-[button1(==button2)]-12-[button2]-| |
9 | */ |
10 | |
11 | #include <glib/gi18n.h> |
12 | #include <gtk/gtk.h> |
13 | |
14 | G_DECLARE_FINAL_TYPE (VflGrid, vfl_grid, VFL, GRID, GtkWidget) |
15 | |
16 | struct _VflGrid |
17 | { |
18 | GtkWidget parent_instance; |
19 | |
20 | GtkWidget *button1, *button2; |
21 | GtkWidget *button3; |
22 | }; |
23 | |
24 | G_DEFINE_TYPE (VflGrid, vfl_grid, GTK_TYPE_WIDGET) |
25 | |
26 | static void |
27 | vfl_grid_dispose (GObject *object) |
28 | { |
29 | VflGrid *self = VFL_GRID (ptr: object); |
30 | |
31 | g_clear_pointer (&self->button1, gtk_widget_unparent); |
32 | g_clear_pointer (&self->button2, gtk_widget_unparent); |
33 | g_clear_pointer (&self->button3, gtk_widget_unparent); |
34 | |
35 | G_OBJECT_CLASS (vfl_grid_parent_class)->dispose (object); |
36 | } |
37 | |
38 | static void |
39 | vfl_grid_class_init (VflGridClass *klass) |
40 | { |
41 | GObjectClass *object_class = G_OBJECT_CLASS (klass); |
42 | GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass); |
43 | |
44 | object_class->dispose = vfl_grid_dispose; |
45 | |
46 | gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_CONSTRAINT_LAYOUT); |
47 | } |
48 | |
49 | /* Layout: |
50 | * |
51 | * +-----------------------------+ |
52 | * | +-----------+ +-----------+ | |
53 | * | | Child 1 | | Child 2 | | |
54 | * | +-----------+ +-----------+ | |
55 | * | +-------------------------+ | |
56 | * | | Child 3 | | |
57 | * | +-------------------------+ | |
58 | * +-----------------------------+ |
59 | * |
60 | * Constraints: |
61 | * |
62 | * super.start = child1.start - 8 |
63 | * child1.width = child2.width |
64 | * child1.end = child2.start - 12 |
65 | * child2.end = super.end - 8 |
66 | * super.start = child3.start - 8 |
67 | * child3.end = super.end - 8 |
68 | * super.top = child1.top - 8 |
69 | * super.top = child2.top - 8 |
70 | * child1.bottom = child3.top - 12 |
71 | * child2.bottom = child3.top - 12 |
72 | * child3.height = child1.height |
73 | * child3.height = child2.height |
74 | * child3.bottom = super.bottom - 8 |
75 | * |
76 | * Visual format: |
77 | * |
78 | * H:|-8-[view1(==view2)-12-[view2]-8-| |
79 | * H:|-8-[view3]-8-| |
80 | * V:|-8-[view1]-12-[view3(==view1)]-8-| |
81 | * V:|-8-[view2]-12-[view3(==view2)]-8-| |
82 | */ |
83 | static void |
84 | build_constraints (VflGrid *self, |
85 | GtkConstraintLayout *manager) |
86 | { |
87 | const char * const vfl[] = { |
88 | "H:|-[button1(==button2)]-12-[button2]-|" , |
89 | "H:|-[button3]-|" , |
90 | "V:|-[button1]-12-[button3(==button1)]-|" , |
91 | "V:|-[button2]-12-[button3(==button2)]-|" , |
92 | }; |
93 | GError *error = NULL; |
94 | |
95 | gtk_constraint_layout_add_constraints_from_description (layout: manager, lines: vfl, G_N_ELEMENTS (vfl), |
96 | hspacing: 8, vspacing: 8, |
97 | error: &error, |
98 | first_view: "button1" , self->button1, |
99 | "button2" , self->button2, |
100 | "button3" , self->button3, |
101 | NULL); |
102 | if (error != NULL) |
103 | { |
104 | g_printerr (format: "VFL parsing error:\n%s" , error->message); |
105 | g_error_free (error); |
106 | } |
107 | } |
108 | |
109 | static void |
110 | vfl_grid_init (VflGrid *self) |
111 | { |
112 | GtkWidget *widget = GTK_WIDGET (self); |
113 | |
114 | self->button1 = gtk_button_new_with_label (label: "Child 1" ); |
115 | gtk_widget_set_parent (widget: self->button1, parent: widget); |
116 | gtk_widget_set_name (widget: self->button1, name: "button1" ); |
117 | |
118 | self->button2 = gtk_button_new_with_label (label: "Child 2" ); |
119 | gtk_widget_set_parent (widget: self->button2, parent: widget); |
120 | gtk_widget_set_name (widget: self->button2, name: "button2" ); |
121 | |
122 | self->button3 = gtk_button_new_with_label (label: "Child 3" ); |
123 | gtk_widget_set_parent (widget: self->button3, parent: widget); |
124 | gtk_widget_set_name (widget: self->button3, name: "button3" ); |
125 | |
126 | GtkLayoutManager *manager = gtk_widget_get_layout_manager (GTK_WIDGET (self)); |
127 | build_constraints (self, manager: GTK_CONSTRAINT_LAYOUT (ptr: manager)); |
128 | } |
129 | |
130 | GtkWidget * |
131 | do_constraints_vfl (GtkWidget *do_widget) |
132 | { |
133 | static GtkWidget *window; |
134 | |
135 | if (!window) |
136 | { |
137 | GtkWidget *box, *grid; |
138 | |
139 | window = gtk_window_new (); |
140 | gtk_window_set_display (GTK_WINDOW (window), display: gtk_widget_get_display (widget: do_widget)); |
141 | gtk_window_set_title (GTK_WINDOW (window), title: "Constraints — VFL" ); |
142 | gtk_window_set_default_size (GTK_WINDOW (window), width: 260, height: -1); |
143 | g_object_add_weak_pointer (G_OBJECT (window), weak_pointer_location: (gpointer *)&window); |
144 | |
145 | box = gtk_box_new (orientation: GTK_ORIENTATION_VERTICAL, spacing: 12); |
146 | gtk_window_set_child (GTK_WINDOW (window), child: box); |
147 | |
148 | grid = g_object_new (object_type: vfl_grid_get_type (), NULL); |
149 | gtk_widget_set_hexpand (widget: grid, TRUE); |
150 | gtk_widget_set_vexpand (widget: grid, TRUE); |
151 | gtk_box_append (GTK_BOX (box), child: grid); |
152 | } |
153 | |
154 | if (!gtk_widget_get_visible (widget: window)) |
155 | gtk_widget_show (widget: window); |
156 | else |
157 | gtk_window_destroy (GTK_WINDOW (window)); |
158 | |
159 | return window; |
160 | } |
161 | |