ImageMagick

ImageMagick是一个免费的创建、编辑、合成图片的软件。它可以读取、转换、写入多种格式的图片。图片切割、颜色替换、各种效果的应用，图片的旋转、组合，文本，直线，多边形，椭圆，曲线，附加到图片伸展旋转。它可以支持以下程序语言： Perl, C, C++, Python, PHP, Ruby, Java

安装

由于依赖lib比较多，mac上最好使用macPort安装，port会自动将所有需要的依赖库安装上，先去 macports官网下一个装上

安装非常简单

sudo port -v selfupdate
sudo port install imagemagick

安装完测试一下

identify -list font
display -display :0

#裁剪图像为64x64
convert sourceimg.jpg -resize 64x64^ distimg.jpg

使用

各种功能参考官网例子 http://www.imagemagick.org/Usage/

Java客户端

官方推荐了一个 JMagick，还有另一个 IM4java

JMagick

JMagick使用JNI调用ImageMagick C-API

优点：With JMagick, you have access to the low-level interface of IM and therefore you have a very detailed control of the processing of images. And you have better performance.

缺点：JNI-hazard

IM4java

优点：the interface of the IM commandline is quite stable, so your java program (and the im4java-library) will work across many versions of IM. im4java also provides a better OO interface (the “language” of the IM-commandline with it’s postfix-operation notation translates very easily into OO-notation). And most important: you can use im4java everywhere JMagick can’t be used because of the JNI hazard (e.g. java application servers). 实际使用中IM4java非常稳定，大概10000/天

缺点：in contrast just generates the commandline for the ImageMagick commands and passes the generated line to the selected IM-command (using the java.lang.ProcessBuilder.start()-method). Your are limited to the capabilities of the IM commands.

图片基本信息

java awt方式

BufferedImage bi = ImageIO.read(is);

使用中发现这种方式不支持JFIF格式图片

Im4java方式

Info imgInfo = new Info(file.getInputStream());
imgInfo.getImageWidth()；

/**
 * 增加一个支持流读入的方法
 *
 * @see org.im4java.core.Info
 *
 * @author chenchun
 * @version 1.0
 * @created 2012-11-14
 */
public Info(InputStream is) throws InfoException, IOException {
    IMOperation op = new IMOperation();
    op.verbose();
    op.addImage("-");
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    Pipe pip = new Pipe(is, bos);
    try {
        IdentifyCmd identify = new IdentifyCmd();
        identify.setSearchPath(ImgUtil.COMMAND_PATH);
        identify.setInputProvider(pip);
        ArrayListOutputConsumer output = new ArrayListOutputConsumer();
        identify.setOutputConsumer(output);
        identify.run(op);
        ArrayList<String> cmdOutput = output.getOutput();

        StringBuilder lineAccu = new StringBuilder(80);
        for (String line : cmdOutput) {
            if (line.length() == 0) {
                // accumulate empty line as part of current attribute
                lineAccu.append("\n\n");
            } else if (line.indexOf(':') == -1) {
                // interpret this as a continuation-line of the current
                // attribute
                lineAccu.append("\n").append(line);
            } else if (lineAccu.length() > 0) {
                // new attribute, process old attribute first
                parseLine(lineAccu.toString());
                lineAccu = new StringBuilder(80);
                lineAccu.append(line);
            } else {
                // new attribute, but nothing old to process
                lineAccu.append(line);
            }
        }
        // process last item
        if (lineAccu.length() > 0) {
            parseLine(lineAccu.toString());
        }

        // finish and add last hashtable to linked-list
        addBaseInfo();
        iAttribList.add(iAttributes);

    } catch (Exception ex) {
        throw new InfoException(ex);
    } finally {
        if (bos != null) {
            bos.close();
        }
        if (is != null) {
            is.close();
        }
    }
}

ImageMagick 比 awt 速度也快一些

缩放图片

java awt方式

public static byte[] resizeByAwt(InputStream is, int width, int height) {
    try {
        BufferedImage bi = ImageIO.read(is);
        BufferedImage reducedImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        reducedImg.getGraphics().drawImage(
                bi.getScaledInstance(width, height, Image.SCALE_SMOOTH), 0, 0, null);
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        ImageIO.write(reducedImg, "jpg", bos);
        // ImageIO.write(reducedImg, "jpg", new
        // File("/Users/cc3514772b/a.jpg"));
        return bos.toByteArray();
    } catch (IOException e) {
        logger.error(e.getMessage(), e);
    }
    return null;
}

Im4java方式

public static byte[] resize(InputStream is, int width, int height) {
    ConvertCmd cmd = new ConvertCmd();
    cmd.setSearchPath("/opt/local/bin");
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    Pipe pip = new Pipe(is, bos);
    cmd.setInputProvider(pip);
    cmd.setOutputConsumer(pip);
    IMOperation op = new IMOperation();
    op.addImage("-");
    op.resize(width, height, '^');
    op.addImage("jpg:-");
    try {
        cmd.run(op);
        return bos.toByteArray();
    } catch (Exception e) {
        logger.error(e.getMessage(), e);
    }
    return null;
}

maven dependency

<dependency>
	<groupId>org.im4java</groupId>
	<artifactId>im4java</artifactId>
	<version>1.2.0</version>
</dependency>