* Copyright 2011, Haiku, Inc. All rights reserved.
* Copyright 2011, Clemens Zeidler <haiku@clemens-zeidler.de>
* Distributed under the terms of the MIT License.
*/
#ifndef ROW_COLUMN_MANAGER_H
#define ROW_COLUMN_MANAGER_H
#include "Area.h"
#include "Column.h"
#include "LinearSpec.h"
#include "Row.h"
#include "Tab.h"
namespace BPrivate {
class SharedSolver;
};
namespace BALM {
into column and rows. For each row and column, a preferred size is
calculated from the areas in the row or column. This preferred size is used
to create a preferred size soft-constraint.
Having only one constraint for each row and column avoids the so called
spring effect. That is each area with a preferred size constraint is pulling
or pressing torwards its preferred size. For example, a row with three areas
pushes stronger than a row with two areas. Assuming that all areas have the
same preferred size, the three-area row gets a different size than the
two-area row. However, one would expect that both rows have the same height.
The row and column approach of the RowColumnManager solves this problem.
*/
class RowColumnManager {
public:
RowColumnManager(LinearSpec* spec);
~RowColumnManager();
void AddArea(Area* area);
void RemoveArea(Area* area);
void UpdateConstraints();
void TabsChanged(Area* area);
private:
friend class BPrivate::SharedSolver;
Row* _FindRowFor(Area* area);
Column* _FindColumnFor(Area* area);
double _PreferredHeight(Row* row,
double& weight);
double _PreferredWidth(Column* column,
double& weight);
void _UpdateConstraints(Row* row);
void _UpdateConstraints(Column* column);
BObjectList<Row> fRows;
BObjectList<Column> fColumns;
LinearSpec* fLinearSpec;
};
}
#endif
