src/test/java/org/apache/commons/imaging/formats/png/PngWriteReadTest.java

/*
 * 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.commons.imaging.formats.png;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

import org.apache.commons.imaging.ImageFormat;
import org.apache.commons.imaging.ImageReadException;
import org.apache.commons.imaging.ImageWriteException;
import org.apache.commons.imaging.Sanselan;
import org.apache.commons.imaging.SanselanTest;
import org.apache.commons.imaging.util.IoUtils;

public class PngWriteReadTest extends SanselanTest
{
    //    public PngWriteReadTest(String name)
    //    {
    //        super(name);
    //    }

    private int[][] getSimpleRawData(int width, int height, int value)
    {
        int[][] result = new int[height][width];
        for (int y = 0; y < height; y++)
            for (int x = 0; x < width; x++)
                result[y][x] = value;
        return result;
    }

    private int[][] getAscendingRawData(int width, int height)
    {
        int[][] result = new int[height][width];
        for (int y = 0; y < height; y++)
            for (int x = 0; x < width; x++)
            {
                int alpha = (x + y) % 256;
                int value = (x + y) % 256;
                int argb = (0xff & alpha) << 24 | (0xff & value) << 16
                        | (0xff & value) << 8 | (0xff & value) << 0;

                result[y][x] = argb;
            }
        return result;
    }

    private int[][] randomRawData(int width, int height)
    {
        Random random = new Random();
        int[][] result = new int[height][width];
        for (int y = 0; y < height; y++)
            for (int x = 0; x < width; x++)
            {
                int argb = random.nextInt();
                result[y][x] = argb;
            }
        return result;
    }

    public void test() throws Exception
    {
        int[][] smallBlackPixels = getSimpleRawData(256, 256, 0);
        int[][] singleBlackPixel = getSimpleRawData(1, 1, 0);
        int[][] smallRedPixels = getSimpleRawData(256, 256, 0xffff0000);
        int[][] singleRedPixel = getSimpleRawData(1, 1, 0xffff0000);
        int[][] smallAscendingPixels = getAscendingRawData(256, 256);
        int[][] smallRandomPixels = randomRawData(256, 256);

        int[][][] testData = {
                smallBlackPixels, singleBlackPixel, smallRedPixels,
                singleRedPixel, smallAscendingPixels, smallRandomPixels,
        };

        for (int i = 0; i < testData.length; i++)
        {
            int rawData[][] = testData[i];
            writeAndReadImageData(rawData);
        }
    }

    public void testTransparency() throws Exception
    {
        // Test for https://issues.apache.org/jira/browse/SANSELAN-52
        int[][] smallAscendingPixels = getAscendingRawData(256, 256);
        byte[] pngBytes = Sanselan.writeImageToBytes(
                imageDataToBufferedImage(smallAscendingPixels),
                ImageFormat.IMAGE_FORMAT_PNG, null);
        assertTrue(Sanselan.getImageInfo(pngBytes).isTransparent());
    }

    private BufferedImage imageDataToBufferedImage(int[][] rawData)
    {
        int width = rawData[0].length;
        int height = rawData.length;
        BufferedImage image = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_ARGB);
        for (int y = 0; y < height; y++)
            for (int x = 0; x < width; x++)
            {
                image.setRGB(x, y, rawData[y][x]);
            }
        return image;
    }

    private int[][] bufferedImageToImageData(BufferedImage image)
    {
        int width = image.getWidth();
        int height = image.getHeight();
        int[][] result = new int[height][width];

        for (int y = 0; y < height; y++)
            for (int x = 0; x < width; x++)
            {
                result[y][x] = image.getRGB(x, y);
            }
        return result;
    }

    private void writeAndReadImageData(int[][] rawData) throws IOException,
            ImageReadException, ImageWriteException
    {
        BufferedImage srcImage = imageDataToBufferedImage(rawData);

        Map writeParams = new HashMap();
        //        writeParams.put(SanselanConstants.PARAM_KEY_FORMAT, ImageFormat.IMAGE_FORMAT_PNG);
        //        writeParams.put(PngConstants.PARAM_KEY_PNG_FORCE_TRUE_COLOR,
        //                Boolean.TRUE);

        byte bytes[] = Sanselan.writeImageToBytes(srcImage,
                ImageFormat.IMAGE_FORMAT_PNG, writeParams);

        //        Debug.debug("bytes", bytes);

        File tempFile = createTempFile("temp", ".png");
        IoUtils.writeToFile(bytes, tempFile);

        BufferedImage dstImage = Sanselan.getBufferedImage(bytes);

        assertNotNull(dstImage);
        assertTrue(srcImage.getWidth() == dstImage.getWidth());
        assertTrue(srcImage.getHeight() == dstImage.getHeight());

        int dstData[][] = bufferedImageToImageData(dstImage);
        compare(rawData, dstData);
    }

    private void compare(int[][] a, int[][] b)
    {
        assertNotNull(a);
        assertNotNull(b);
        assertTrue(a.length == b.length);

        for (int y = 0; y < a.length; y++)
        {
            assertTrue(a[y].length == b[y].length);
            // make sure row lengths consistent.
            assertTrue(a[0].length == b[y].length);
            for (int x = 0; x < a[y].length; x++)
            {
                assertTrue(a[y][x] == b[y][x]);
            }
        }
    }

}