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  • Imagick::setImageCompression()

    (PECL imagick 2.0.0)

    设置图片压缩的类型

    说明

    Imagick::setImageCompression(int $compression): bool

    参数

    $compression

    COMPRESSION常量里的一种

    返回值

    成功时返回TRUE

    错误/异常

    错误时抛出 ImagickException。

    Above it says "One of the COMPRESSION constants" for the parameters. For any of you that found this confusing, you can find a list of the constants here:
    Predefined Constants
    http://www.php.net/manual/en/imagick.constants.php
    As an example for working with a jpeg image:
    <?php
      $image = 'jpeg_image.jpg';
      $comression_type = Imagick::COMPRESSION_JPEG;
      
      $im = new Imagick($image);
      $im->setImageCompression($compression_type);
    ?>
    This class does not actually compress the images but rather sets the compression type that is going to be used. 
    If you would like to see how to compress the image see:
    Imagick::setImageCompressionQuality
    const COMPRESSION_UNDEFINED = 0;
    const COMPRESSION_NO = 1;
    const COMPRESSION_BZIP = 2;
    const COMPRESSION_FAX = 6;
    const COMPRESSION_GROUP4 = 7;
    const COMPRESSION_JPEG = 8;
    const COMPRESSION_JPEG2000 = 9;
    const COMPRESSION_LOSSLESSJPEG = 10;
    const COMPRESSION_LZW = 11;
    const COMPRESSION_RLE = 12;
    const COMPRESSION_ZIP = 13;
    const COMPRESSION_DXT1 = 3;
    const COMPRESSION_DXT3 = 4;
    const COMPRESSION_DXT5 = 5;
    const COMPRESSION_ZIPS = 14;
    const COMPRESSION_PIZ = 15;
    const COMPRESSION_PXR24 = 16;
    const COMPRESSION_B44 = 17;
    const COMPRESSION_B44A = 18;
    const COMPRESSION_LZMA = 19;
    const COMPRESSION_JBIG1 = 20;
    const COMPRESSION_JBIG2 = 21;
    On Ubuntu 18.04, these are the default compression methods used for the following common image formats:
    PNG: Imagick::COMPRESSION_ZIP
    JPEG: Imagick::COMPRESSION_JPEG
    GIF: Imagick::COMPRESSION_LZW