Add an interactive constraint solver test
This is an example described in the original Cassowary paper, reimplemented from scratch. It exposes some instability and crashiness in our solver.
This commit is contained in:
Matthias Clasen
381
tests/constrainttree.c
Normal file
381
tests/constrainttree.c
Normal file
@@ -0,0 +1,381 @@
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#include <gtk/gtk.h>
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#include "../../gtk/gtkconstrainttypesprivate.h"
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#include "../../gtk/gtkconstraintsolverprivate.h"
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#include "../../gtk/gtkconstraintexpressionprivate.h"
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typedef struct _Node Node;
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static GtkConstraintSolver *solver;
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static Node *tree;
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static Node *drag_node;
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static double drag_start_x;
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static double drag_start_y;
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static GtkConstraintVariable *width_var;
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static GtkConstraintVariable *height_var;
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struct _Node {
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double x;
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double y;
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Node *parent;
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Node *left;
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Node *right;
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GtkConstraintVariable *x_var;
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GtkConstraintVariable *y_var;
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};
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static Node *
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make_tree (Node *parent,
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int depth,
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int x,
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int y,
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int dx,
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int dy)
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{
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Node *node;
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node = g_new0 (Node, 1);
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node->parent = parent;
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if (depth > 0)
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{
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node->left = make_tree (node, depth - 1, x - dx, y + dy, dx / 2, dy);
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node->right = make_tree (node, depth - 1, x + dx, y + dy, dx / 2, dy);
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}
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node->x = x;
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node->y = y;
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node->x_var = gtk_constraint_solver_create_variable (solver, NULL, "x", x);
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node->y_var = gtk_constraint_solver_create_variable (solver, NULL, "y", y);
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/* weak stay for the current position */
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gtk_constraint_solver_add_stay_variable (solver, node->x_var, GTK_CONSTRAINT_WEIGHT_WEAK);
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gtk_constraint_solver_add_stay_variable (solver, node->y_var, GTK_CONSTRAINT_WEIGHT_WEAK);
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/* require to stay in area */
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gtk_constraint_solver_add_constraint (solver,
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node->x_var,
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GTK_CONSTRAINT_RELATION_GE,
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gtk_constraint_expression_new (0.0),
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GTK_CONSTRAINT_WEIGHT_REQUIRED);
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gtk_constraint_solver_add_constraint (solver,
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node->x_var,
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GTK_CONSTRAINT_RELATION_LE,
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gtk_constraint_expression_new (1600.0),
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//gtk_constraint_expression_new_from_variable (width_var),
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GTK_CONSTRAINT_WEIGHT_REQUIRED);
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gtk_constraint_solver_add_constraint (solver,
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node->y_var,
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GTK_CONSTRAINT_RELATION_GE,
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gtk_constraint_expression_new (0.0),
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GTK_CONSTRAINT_WEIGHT_REQUIRED);
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gtk_constraint_solver_add_constraint (solver,
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node->y_var,
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GTK_CONSTRAINT_RELATION_LE,
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gtk_constraint_expression_new (600.0),
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//gtk_constraint_expression_new_from_variable (height_var),
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GTK_CONSTRAINT_WEIGHT_REQUIRED);
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if (node->left)
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{
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GtkConstraintExpressionBuilder builder;
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/* left.y = right.y */
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gtk_constraint_solver_add_constraint (solver,
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node->left->y_var,
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GTK_CONSTRAINT_RELATION_EQ,
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gtk_constraint_expression_new_from_variable (node->right->y_var),
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GTK_CONSTRAINT_WEIGHT_REQUIRED);
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/* left.y >= parent.y + 10 */
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gtk_constraint_expression_builder_init (&builder, solver);
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gtk_constraint_expression_builder_term (&builder, node->y_var);
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gtk_constraint_expression_builder_plus (&builder);
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gtk_constraint_expression_builder_constant (&builder, 10.0);
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gtk_constraint_solver_add_constraint (solver,
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node->left->y_var,
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GTK_CONSTRAINT_RELATION_GE,
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gtk_constraint_expression_builder_finish (&builder),
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GTK_CONSTRAINT_WEIGHT_REQUIRED);
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/* right.y >= parent.y + 10 */
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gtk_constraint_expression_builder_init (&builder, solver);
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gtk_constraint_expression_builder_term (&builder, node->y_var);
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gtk_constraint_expression_builder_plus (&builder);
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gtk_constraint_expression_builder_constant (&builder, 10.0);
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gtk_constraint_solver_add_constraint (solver,
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node->right->y_var,
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GTK_CONSTRAINT_RELATION_GE,
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gtk_constraint_expression_builder_finish (&builder),
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GTK_CONSTRAINT_WEIGHT_REQUIRED);
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/* parent.x = (left.x + right.x) / 2 */
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gtk_constraint_expression_builder_init (&builder, solver);
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gtk_constraint_expression_builder_term (&builder, node->left->x_var);
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gtk_constraint_expression_builder_plus (&builder);
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gtk_constraint_expression_builder_term (&builder, node->right->x_var);
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gtk_constraint_expression_builder_divide_by (&builder);
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gtk_constraint_expression_builder_constant (&builder, 2.0);
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gtk_constraint_solver_add_constraint (solver,
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node->x_var,
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GTK_CONSTRAINT_RELATION_EQ,
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gtk_constraint_expression_builder_finish (&builder),
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GTK_CONSTRAINT_WEIGHT_REQUIRED);
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}
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return node;
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}
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static void
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draw_node (Node *node, cairo_t *cr)
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{
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if (node->left)
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draw_node (node->left, cr);
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if (node->right)
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draw_node (node->right, cr);
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if (node->parent)
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{
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cairo_set_source_rgb (cr, 0, 0, 0);
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cairo_move_to (cr, node->parent->x, node->parent->y);
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cairo_line_to (cr, node->x, node->y);
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cairo_stroke (cr);
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}
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if (node == drag_node)
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cairo_set_source_rgb (cr, 1, 0, 0);
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else
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cairo_set_source_rgb (cr, 0, 0, 0);
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cairo_move_to (cr, node->x, node->y);
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cairo_arc (cr, node->x, node->y, 5, 0, 2*M_PI);
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cairo_close_path (cr);
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cairo_fill (cr);
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}
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static void
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draw_func (GtkDrawingArea *da,
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cairo_t *cr,
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int width,
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int height,
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gpointer data)
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{
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cairo_set_line_width (cr, 1);
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cairo_set_source_rgb (cr, 1, 1, 1);
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cairo_paint (cr);
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draw_node (tree, cr);
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}
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static Node *
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find_node (Node *node,
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double x,
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double y)
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{
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Node *ret;
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double dx = x - node->x;
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double dy = y - node->y;
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if (dx*dx + dy*dy < 10*10)
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return node;
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if (node->left)
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{
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ret = find_node (node->left, x, y);
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if (ret)
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return ret;
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}
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if (node->right)
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{
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ret = find_node (node->right, x, y);
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if (ret)
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return ret;
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}
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return NULL;
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}
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static void
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drag_begin (GtkGestureDrag *drag,
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double start_x,
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double start_y,
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gpointer data)
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{
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drag_node = find_node (tree, start_x, start_y);
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if (!drag_node)
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return;
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drag_start_x = start_x;
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drag_start_y = start_y;
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gtk_widget_queue_draw (gtk_event_controller_get_widget (GTK_EVENT_CONTROLLER (drag)));
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}
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static void
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update_tree (Node *node)
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{
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if (!node)
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return;
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node->x = gtk_constraint_variable_get_value (node->x_var);
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node->y = gtk_constraint_variable_get_value (node->y_var);
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update_tree (node->left);
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update_tree (node->right);
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}
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static void
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drag_update (GtkGestureDrag *drag,
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double offset_x,
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double offset_y,
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gpointer data)
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{
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if (!drag_node)
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return;
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gtk_constraint_solver_add_edit_variable (solver,
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drag_node->x_var,
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GTK_CONSTRAINT_WEIGHT_REQUIRED);
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gtk_constraint_solver_add_edit_variable (solver,
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drag_node->y_var,
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GTK_CONSTRAINT_WEIGHT_REQUIRED);
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gtk_constraint_solver_begin_edit (solver);
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gtk_constraint_solver_suggest_value (solver,
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drag_node->x_var,
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drag_start_x + offset_x);
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gtk_constraint_solver_suggest_value (solver,
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drag_node->y_var,
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drag_start_y + offset_y);
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gtk_constraint_solver_resolve (solver);
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update_tree (tree);
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gtk_constraint_solver_remove_edit_variable (solver, drag_node->x_var);
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gtk_constraint_solver_remove_edit_variable (solver, drag_node->y_var);
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gtk_constraint_solver_end_edit (solver);
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gtk_widget_queue_draw (gtk_event_controller_get_widget (GTK_EVENT_CONTROLLER (drag)));
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}
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static void
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drag_end (GtkGestureDrag *drag,
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double offset_x,
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double offset_y,
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gpointer data)
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{
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if (!drag_node)
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return;
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drag_node = NULL;
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gtk_widget_queue_draw (gtk_event_controller_get_widget (GTK_EVENT_CONTROLLER (drag)));
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}
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static void
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size_change (GtkWidget *da,
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int width,
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int height,
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int baseline,
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gpointer data)
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{
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gtk_constraint_variable_set_value (width_var, width);
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gtk_constraint_variable_set_value (height_var, height);
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gtk_constraint_solver_resolve (solver);
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}
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static void
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reset_tree (Node *node,
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int x,
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int y,
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int dx,
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int dy)
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{
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node->x = x;
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node->y = y;
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gtk_constraint_solver_remove_stay_variable (solver, node->x_var);
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gtk_constraint_solver_remove_stay_variable (solver, node->y_var);
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gtk_constraint_variable_set_value (node->x_var, x);
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gtk_constraint_variable_set_value (node->y_var, y);
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gtk_constraint_solver_add_stay_variable (solver, node->x_var, GTK_CONSTRAINT_WEIGHT_WEAK);
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gtk_constraint_solver_add_stay_variable (solver, node->y_var, GTK_CONSTRAINT_WEIGHT_WEAK);
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if (node->left)
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reset_tree (node->left, x - dx, y + dy, dx / 2, dy);
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if (node->right)
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reset_tree (node->right, x + dx, y + dy, dx / 2, dy);
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}
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static void
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reset (GtkButton *button,
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GtkWidget *da)
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{
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int width, height;
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width = gtk_widget_get_allocated_width (da);
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height = gtk_widget_get_allocated_height (da);
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gtk_constraint_solver_freeze (solver);
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reset_tree (tree, width / 2, 20, width / 4 - 40, (height - 40) / 7);
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gtk_constraint_solver_thaw (solver);
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gtk_widget_queue_draw (da);
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}
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int
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main (int argc, char *argv[])
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{
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GtkWidget *window;
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GtkWidget *header;
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GtkWidget *button;
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GtkWidget *da;
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GtkGesture *drag;
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int width = 1600;
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int height = 600;
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gtk_init ();
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da = gtk_drawing_area_new ();
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window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
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header = gtk_header_bar_new ();
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gtk_header_bar_set_show_title_buttons (GTK_HEADER_BAR (header), TRUE);
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button = gtk_button_new_with_label ("Reset");
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g_signal_connect (button, "clicked", G_CALLBACK (reset), da);
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gtk_header_bar_pack_start (GTK_HEADER_BAR (header), button);
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gtk_window_set_titlebar (GTK_WINDOW (window), header);
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gtk_drawing_area_set_content_width (GTK_DRAWING_AREA (da), width);
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gtk_drawing_area_set_content_height (GTK_DRAWING_AREA (da), height);
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gtk_drawing_area_set_draw_func (GTK_DRAWING_AREA (da), draw_func, NULL, NULL);
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gtk_container_add (GTK_CONTAINER (window), da);
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drag = gtk_gesture_drag_new ();
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g_signal_connect (drag, "drag-begin", G_CALLBACK (drag_begin), NULL);
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g_signal_connect (drag, "drag-update", G_CALLBACK (drag_update), NULL);
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g_signal_connect (drag, "drag-end", G_CALLBACK (drag_end), NULL);
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gtk_widget_add_controller (da, GTK_EVENT_CONTROLLER (drag));
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solver = g_object_new (g_type_from_name ("GtkConstraintSolver"), NULL);
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gtk_constraint_solver_freeze (solver);
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width_var = gtk_constraint_solver_create_variable (solver, NULL, "width", width);
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height_var = gtk_constraint_solver_create_variable (solver, NULL, "height", height);
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gtk_constraint_solver_add_stay_variable (solver, width_var, GTK_CONSTRAINT_WEIGHT_REQUIRED);
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gtk_constraint_solver_add_stay_variable (solver, height_var, GTK_CONSTRAINT_WEIGHT_REQUIRED);
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g_signal_connect (da, "size-allocate", G_CALLBACK (size_change), NULL);
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tree = make_tree (NULL, 7, width / 2, 20, width / 4 - 40, (height - 40) / 7);
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gtk_constraint_solver_thaw (solver);
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gtk_widget_show (window);
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gtk_main ();
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return 0;
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}
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@@ -1,5 +1,10 @@
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gtk_tests = [
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# testname, optional extra sources
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['constrainttree', [
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'../gtk/gtkconstraintsolver.c',
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'../gtk/gtkconstraintexpression.c',
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], ['-DGTK_COMPILATION', '-UG_ENABLE_DEBUG', '-DGTK_TEST_EXTERNAL']
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],
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['rendernode'],
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['rendernode-create-tests'],
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['overlayscroll'],
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@@ -142,9 +147,12 @@ test_args = ['-DGTK_SRCDIR="@0@"'.format(meson.current_source_dir())]
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foreach t: gtk_tests
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test_name = t.get(0)
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test_srcs = ['@0@.c'.format(test_name), t.get(1, [])]
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test_extra_cargs = t.get(2, [])
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test_extra_ldflags = t.get(3, [])
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executable(test_name, test_srcs,
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include_directories: [confinc, gdkinc],
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c_args: test_args,
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c_args: test_args + test_extra_cargs,
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link_args : test_extra_ldflags,
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dependencies: [libgtk_dep, libm])
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endforeach
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