Ant example source code file (Scale.java)

This example Ant source code file (Scale.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Ant tags/keywords

awt, drawoperation, float, hundred, hundred, image, imageoperation, imageoperation, parameterblock, planarimage, planarimage, proportionsattribute, scale, string, string, transformoperation

The Scale.java source code

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
package org.apache.tools.ant.types.optional.image;

import org.apache.tools.ant.types.EnumeratedAttribute;

import javax.media.jai.JAI;
import javax.media.jai.PlanarImage;
import java.awt.image.BufferedImage;
import java.awt.image.renderable.ParameterBlock;

/**
 *
 * @see org.apache.tools.ant.taskdefs.optional.image.Image
 */
public class Scale extends TransformOperation implements DrawOperation {
    private static final int HUNDRED = 100;

    private String widthStr = "100%";
    private String heightStr = "100%";
    private boolean xPercent = true;
    private boolean yPercent = true;
    private String proportions = "ignore";

    /** Enumerated class for proportions attribute. */
    public static class ProportionsAttribute extends EnumeratedAttribute {
        /** {@inheritDoc}. */
        public String[] getValues() {
            return new String[] {"ignore", "width", "height", "cover", "fit"};
        }
    }

    /**
     *  Sets the behaviour regarding the image proportions.
     * @param pa the enumerated value.
     */
    public void setProportions(ProportionsAttribute pa) {
        proportions = pa.getValue();
    }

    /**
     * Sets the width of the image, either as an integer or a %.
     * Defaults to 100%.
     * @param width the value to use.
     */
    public void setWidth(String width) {
        widthStr = width;
    }

    /**
     *  Sets the height of the image, either as an integer or a %.  Defaults to 100%.
     * @param height the value to use.
     */
    public void setHeight(String height) {
        heightStr = height;
    }

    /**
     * Get the width.
     * @return the value converted from the width string.
     */
    public float getWidth() {
        float width = 0.0F;
        int percIndex = widthStr.indexOf('%');
        if (percIndex > 0) {
            width = Float.parseFloat(widthStr.substring(0, percIndex));
            xPercent = true;
            return width / HUNDRED;
        } else {
            xPercent = false;
            return Float.parseFloat(widthStr);
        }
    }

    /**
     * Get the height.
     * @return the value converted from the height string.
     */
    public float getHeight() {
        int percIndex = heightStr.indexOf('%');
        if (percIndex > 0) {
            float height = Float.parseFloat(heightStr.substring(0, percIndex));
            yPercent = true;
            return height / HUNDRED;
        } else {
            yPercent = false;
            return Float.parseFloat(heightStr);
        }
    }

    /**
     * Scale an image.
     * @param image the image to scale.
     * @return the scaled image.
     */
    public PlanarImage performScale(PlanarImage image) {
        ParameterBlock pb = new ParameterBlock();
        pb.addSource(image);
        float xFl = getWidth();
        float yFl = getHeight();

        if (!xPercent) {
            xFl = (xFl / image.getWidth());
        }
        if (!yPercent) {
            yFl = (yFl / image.getHeight());
        }

        if ("width".equals(proportions)) {
            yFl = xFl;
        } else if ("height".equals(proportions)) {
            xFl = yFl;
        } else if ("fit".equals(proportions)) {
            yFl = Math.min(xFl, yFl);
            xFl = yFl;
        } else if ("cover".equals(proportions)) {
            yFl = Math.max(xFl, yFl);
            xFl = yFl;
        }

        pb.add(new Float(xFl));
        pb.add(new Float(yFl));

        log("\tScaling to " + (xFl * HUNDRED) + "% x "
            + (yFl * HUNDRED) + "%");

        return JAI.create("scale", pb);
    }


    /** {@inheritDoc}. */
    public PlanarImage executeTransformOperation(PlanarImage image) {
        BufferedImage bi = null;
        for (int i = 0; i < instructions.size(); i++) {
            ImageOperation instr = ((ImageOperation) instructions.elementAt(i));
            if (instr instanceof DrawOperation) {
                return performScale(image);
            } else if (instr instanceof TransformOperation) {
                bi = image.getAsBufferedImage();
                image = ((TransformOperation) instr)
                    .executeTransformOperation(PlanarImage.wrapRenderedImage(bi));
                bi = image.getAsBufferedImage();
            }
        }
        return performScale(image);
    }


    /** {@inheritDoc}. */
    public PlanarImage executeDrawOperation() {
        for (int i = 0; i < instructions.size(); i++) {
            ImageOperation instr = ((ImageOperation) instructions.elementAt(i));
            if (instr instanceof DrawOperation) {
                PlanarImage image = null;
                // If this TransformOperation has DrawOperation children
                // then Rotate the first child and return.
                performScale(image);
                return image;
            }
        }
        return null;
    }
}