GridLayout.java

/*
 * -----------------------------------------------------------------------------
 * (c) Copyright IBM Corp. 2003 All rights reserved. The sample program(s)
 * is/are owned by International Business Machines Corporation or one of its
 * subsidiaries ("IBM") and is/are copyrighted and licensed, not sold. You may
 * copy, modify, and distribute this/these sample program(s) in any form without
 * payment to IBM, for any purpose including developing, using, marketing or
 * distributing programs that include or are derivative works of the sample
 * program(s). The sample program(s) is/are provided to you on an "AS IS" basis,
 * without warranty of any kind. IBM HEREBY EXPRESSLY DISCLAIMS ALL WARRANTIES,
 * EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Some
 * jurisdictions do not allow for the exclusion or limitation of implied
 * warranties, so the above limitations or exclusions may not apply to you. IBM
 * shall not be liable for any damages you suffer as a result of using,
 * modifying or distributing the sample program(s) or its/their derivatives.
 * Each copy of any portion of this/these sample program(s) or any derivative
 * work, must include the above copyright notice and disclaimer of warranty.
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package swing2swt.layout;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * Port of AWT GridLayout to SWT.
 * 
 * @author Yannick Saillet
 */
public class GridLayout extends AWTLayout {
    private int rows, columns, hgap, vgap;

    public GridLayout() {
        this(1, 0);
    }

    public GridLayout(int rows, int columns) {
        this(rows, columns, 0, 0);
    }

    public GridLayout(int rows, int columns, int hgap, int vgap) {
        if (rows == 0 && columns == 0)
            throw new IllegalArgumentException("rows and cols cannot both be zero");

        if (rows > 0 && columns > 0)
            columns = 0;

        this.rows = rows;
        this.columns = columns;
        this.hgap = hgap;
        this.vgap = vgap;
    }

    public int getColumns() {
        return columns;
    }

    public int getHgap() {
        return hgap;
    }

    public int getRows() {
        return rows;
    }

    public int getVgap() {
        return vgap;
    }

    public void setColumns(int cols) {
        if (rows == 0 && columns == 0)
            throw new IllegalArgumentException("rows and cols cannot both be zero");

        this.columns = cols;
    }

    public void setHgap(int hgap) {
        this.hgap = hgap;
    }

    public void setRows(int rows) {
        if (rows == 0 && columns == 0)
            throw new IllegalArgumentException("rows and cols cannot both be zero");

        this.rows = rows;
    }

    public void setVgap(int vgap) {
        this.vgap = vgap;
    }

    // ----------

    protected Point computeSize(Composite composite, int wHint, int hHint, boolean flushCache) {
        Control[] children = composite.getChildren();
        int nbOfVisibleChildren = 0;
        for (int i = 0; i < children.length; i++) {
            // if (children[i].isVisible())
            nbOfVisibleChildren++;
        }

        if (nbOfVisibleChildren == 0)
            return new Point(0, 0);
        int r = rows;
        int c = columns;
        if (r == 0)
            r = nbOfVisibleChildren / c + ((nbOfVisibleChildren % c) == 0 ? 0 : 1);
        else if (c == 0)
            c = nbOfVisibleChildren / r + ((nbOfVisibleChildren % r) == 0 ? 0 : 1);
        int width = 0;
        int height = 0;
        for (int i = 0; i < children.length; i++) {
            // if (!children[i].isVisible())
            // continue;
            Point size = getPreferredSize(children[i], SWT.DEFAULT, SWT.DEFAULT, flushCache);
            if (size.x > width)
                width = size.x;
            if (size.y > height)
                height = size.y;
        }
        return new Point(c * width + (c - 1) * hgap, r * height + (r - 1) * vgap);
    }

    protected void layout(Composite composite, boolean flushCache) {
        Rectangle clientArea = composite.getClientArea();
        Control[] children = composite.getChildren();
        int nbOfVisibleChildren = 0;
        for (int i = 0; i < children.length; i++) {
            // if (children[i].isVisible())
            nbOfVisibleChildren++;
        }
        if (nbOfVisibleChildren == 0)
            return;

        int r = rows;
        int c = columns;
        if (r == 0)
            r = nbOfVisibleChildren / c + ((nbOfVisibleChildren % c) == 0 ? 0 : 1);
        else if (c == 0)
            c = nbOfVisibleChildren / r + ((nbOfVisibleChildren % r) == 0 ? 0 : 1);
        int width = (clientArea.width - (c - 1) * hgap) / c;
        int height = (clientArea.height - (r - 1) * vgap) / r;

        int x = clientArea.x;
        int y = clientArea.y;
        for (int i = 0; i < children.length; i++) {
            // if (!children[i].isVisible())
            // continue;
            children[i].setBounds(x, y, width, height);
            if (((i + 1) % c) == 0) // if new line
            {
                x = clientArea.x;
                y += height + vgap;
            } else
                x += width + hgap;
        }
    }
}