PNG Quant

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The PngquantPostProcessor is a built-in post-processor that performs a number of safe, lossy optimizations on PNG encoded images.

To add this post-processor to the filter set created in the thumbnail usage example use:

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# app/config/config.yml

liip_imagine:
    filter_sets:
        my_thumb:
            filters:
                thumbnail: { size: [120, 90], mode: outbound }
                background: { size: [124, 94], position: center, color: '#000' }
            post_processors:
                pngquant: { quality: "75-85" }

This configuration sets a quality factor range of 75 to 85 for the resulting image binary.

Note

The default executable path is /usr/bin/pngquant. If installed elsewhere on your system, you must set the liip_imagine.pngquant.binary parameter accordingly.

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# app/config/config.yml

parameters:
    liip_imagine.pngquant.binary: /your/custom/path/to/pngquant

Options

quality: int|int[]
When set to an int this sets the maximum image quality level. When set to an int[] (such as [60,80]) the first array int is used to define the lowest acceptable quality level and the second to define the maximum quality level (in this mode, the executable will use the least amount of colors required to meet or exceed the maximum quality, but if the conversion results in a quality below the minimum quality the converted file will be discarded and the original one used instead).
speed: int
The speed/quality trade-off value to use. Valid values: 1 (slowest/best) through 11 (fastest/worst).
dithering: bool|float
When set to false the Floyd-Steinberg dithering algorithm is completely disabled. Otherwise, when a float, the dithering level is set.

Parameters

liip_imagine.pngquant.binary: string
Sets the location of the pngquant executable. Default is /usr/bin/pngquant.
This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.
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