org.eclipse.swt.snippets.Snippet273.java Source code

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Here is the source code for org.eclipse.swt.snippets.Snippet273.java

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/*******************************************************************************
 * Copyright (c) 2000, 2016 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.snippets;

/*
 * Table snippet: modify the clipping of custom background paints
 *
 * For a detailed explanation of this snippet see
 * http://www.eclipse.org/articles/Article-CustomDrawingTableAndTreeItems/customDraw.htm#_example4
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 *
 * @since 3.2
 */
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;

public class Snippet273 {

    public static void main(String[] args) {
        final String[] MONTHS = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov",
                "Dec" };
        final int[] HIGHS = { -7, -4, 1, 11, 18, 24, 26, 25, 20, 13, 5, -4 };
        final int[] LOWS = { -15, -13, -7, 1, 7, 13, 15, 14, 10, 4, -2, -11 };
        final int SCALE_MIN = -30;
        final int SCALE_MAX = 30;
        final int SCALE_RANGE = Math.abs(SCALE_MIN - SCALE_MAX);

        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setText("Snippet 273");
        shell.setBounds(10, 10, 400, 350);
        shell.setText("Ottawa Average Daily Temperature Ranges");
        final Color blue = display.getSystemColor(SWT.COLOR_BLUE);
        final Color white = display.getSystemColor(SWT.COLOR_WHITE);
        final Color red = display.getSystemColor(SWT.COLOR_RED);
        // final Image parliamentImage = new Image(display, "./parliament.jpg");
        final Table table = new Table(shell, SWT.NONE);
        table.setBounds(10, 10, 350, 300);
        // table.setBackgroundImage(parliamentImage);
        for (int i = 0; i < 12; i++) {
            TableItem item = new TableItem(table, SWT.NONE);
            item.setText(MONTHS[i] + " (" + LOWS[i] + "C..." + HIGHS[i] + "C)");
        }
        final int clientWidth = table.getClientArea().width;

        /*
         * NOTE: MeasureItem and EraseItem are called repeatedly. Therefore it is
         * critical for performance that these methods be as efficient as possible.
         */
        table.addListener(SWT.MeasureItem, event -> {
            int itemIndex = table.indexOf((TableItem) event.item);
            int rightX = (HIGHS[itemIndex] - SCALE_MIN) * clientWidth / SCALE_RANGE;
            event.width = rightX;
        });
        table.addListener(SWT.EraseItem, event -> {
            int itemIndex = table.indexOf((TableItem) event.item);
            int leftX = (LOWS[itemIndex] - SCALE_MIN) * clientWidth / SCALE_RANGE;
            int rightX = (HIGHS[itemIndex] - SCALE_MIN) * clientWidth / SCALE_RANGE;
            GC gc = event.gc;
            Rectangle clipping = gc.getClipping();
            clipping.x = leftX;
            clipping.width = rightX - leftX;
            gc.setClipping(clipping);
            Color oldForeground = gc.getForeground();
            Color oldBackground = gc.getBackground();
            gc.setForeground(blue);
            gc.setBackground(white);
            gc.fillGradientRectangle(event.x, event.y, event.width / 2, event.height, false);
            gc.setForeground(white);
            gc.setBackground(red);
            gc.fillGradientRectangle(event.x + event.width / 2, event.y, event.width / 2, event.height, false);
            gc.setForeground(oldForeground);
            gc.setBackground(oldBackground);
            event.detail &= ~SWT.BACKGROUND;
            event.detail &= ~SWT.HOT;
        });

        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        // parliamentImage.dispose();
        display.dispose();
    }
}