Imagick::setImageCompressionQuality

(PECL imagick 2, PECL imagick 3)

Imagick::setImageCompressionQuality — 设置图片压缩的质量

说明

Imagick::setImageCompressionQuality(int $quality): bool

设置图片压缩的质量

参数

quality: 配置压缩质量的整数

返回值

成功时返回 true。

错误／异常

错误时抛出 ImagickException。

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User Contributed Notes 4 notes

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vhpvhp at msn dot com ¶

3 years ago


For a PNG image, `setImageCompressionQuality()` is not work at all, length of the generated files are totally same.

But I found an effective way, that is use `setOption('png:compression-level', 9)`, the value range is 0-9.

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dylan dot arnold at gmail dot com ¶

9 years ago


I had strange results when trying to get good png compression.

I used Imagick::COMPRESSION_ZIP

Here are a few file sizes for a few compression levels.

0: 236,100
1: 274,035
9: 258,379
50: 241,282
100: 240,156

Note the best result at 0. Also I got thrown off for a long time trying to get similar results to gimp. Make sure your image depth is set to 8, it appears to be 16 bits per channel, at least for me.

You can check with identify -verbose filename.png

You can also strip a bit more file size with $image->stripImage();

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snipes2083 [at] yahoo com ¶

12 years ago


This example shows how to set the compression type, set the compression quality, create a thumbnail and remove unnecessary data in order to reduce file size.


This will use the following functions in reference:

Imagick::setImageCompression

Imagick::setImageCompressionQuality

Imagick::stripImage

Imagick::thumbnailImage

Imagick::writeImage


<?php

    $image = 'image.jpg';

    $directory = '/path/to/image';

    $image_location = $directory . "/" . $image;

    $thumb_destination = $directory . "/t" . $image;

    $compression_type = Imagick::COMPRESSION_JPEG;

   

    $im = new Imagick($image_location);

    $thumbnail = $im->clone;


    $thumbnail->setImageCompression($compression_type);

    $thumbnail->setImageCompressionQuality(40);

    $thumbnail->stripImage();

    $thumbnail->thumbnailImage(100,null);

    $thumbnail->writeImage($thumb_destination);

?>



Now, obviously you don't have to do so much with the variables and the file location.  I only used so many to demonstrate where the images are coming from and where they are going.


NOTE:  The $thumbnail->thumbnailImage(100,null); keeps the aspect ration by setting the second parameter to null.  Read about this at Imagick::thumbnailImage


There is another way to create thumbnails that works quite well if you want to crop the image rather than using the entire image.  Check out Imagick::cropThumbnailImage

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-41

Anonymous ¶

10 years ago


The default value fot the JPEG compression quality appears to be 86.

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官方地址：https://www.php.net/manual/en/imagick.setimagecompressionquality.php

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Imagick::setImageCompressionQuality

说明

参数

返回值

错误／异常

User Contributed Notes 4 notes