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Accelerate Framework Reference vImage Decompression Filtering Reference

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vImage Decompression Filtering Reference

The vImage framework provides one function for filtering data prior to decompression.

Functions

Constants

  • Filtering algorithms to apply to image data before compressing the data.

    Declaration

    Swift

    var kvImage_PNG_FILTER_VALUE_NONE: Int { get } var kvImage_PNG_FILTER_VALUE_SUB: Int { get } var kvImage_PNG_FILTER_VALUE_UP: Int { get } var kvImage_PNG_FILTER_VALUE_AVG: Int { get } var kvImage_PNG_FILTER_VALUE_PAETH: Int { get }

    Objective-C

    enum { kvImage_PNG_FILTER_VALUE_NONE = 0, kvImage_PNG_FILTER_VALUE_SUB = 1, kvImage_PNG_FILTER_VALUE_UP = 2, kvImage_PNG_FILTER_VALUE_AVG = 3, kvImage_PNG_FILTER_VALUE_PAETH = 4 };

    Constants

    • kvImage_PNG_FILTER_VALUE_NONE

      kvImage_PNG_FILTER_VALUE_NONE

      No filtering.

      Available in OS X v10.4 and later.

    • kvImage_PNG_FILTER_VALUE_SUB

      kvImage_PNG_FILTER_VALUE_SUB

      A filter that computes the difference between each byte of a pixel and the value of the corresponding byte of the pixel located to the left.

      Available in OS X v10.4 and later.

    • kvImage_PNG_FILTER_VALUE_UP

      kvImage_PNG_FILTER_VALUE_UP

      A filter that computes the difference between each byte of a pixel and the value of the corresponding byte of the pixel located above.

      Available in OS X v10.4 and later.

    • kvImage_PNG_FILTER_VALUE_AVG

      kvImage_PNG_FILTER_VALUE_AVG

      A filter that predicts a pixel value from the average of the pixels to the left and above the predicted pixel location.

      Available in OS X v10.4 and later.

    • kvImage_PNG_FILTER_VALUE_PAETH

      kvImage_PNG_FILTER_VALUE_PAETH

      A filter that predicts a pixel value by applying a linear function to the pixels located to the left, above, and to the upper left of the predicted pixel location.

      Available in OS X v10.4 and later.