Declared in NSDataPSDAdditions.h
NSDataPSDAdditions.m

Tasks

  • – packedBitsDescription

    Takes packedBits data and prints out a description of the packed contents by running the decode operation and explaining via NSLog how the data is being decoded. Useful for checking that packedBits data is correct.
  • – packedBitsForRange:skip:

    A special version of packedBits which will take the data and pack every nth value.

Instance Methods

packedBitsDescription

Takes packedBits data and prints out a description of the packed contents by running the decode operation and explaining via NSLog how the data is being decoded. Useful for checking that packedBits data is correct.

- (NSString *)packedBitsDescription

Discussion

Takes packedBits data and prints out a description of the packed contents by running the decode operation and explaining via NSLog how the data is being decoded. Useful for checking that packedBits data is correct.

Declared In

NSDataPSDAdditions.h

packedBitsForRange:skip:

A special version of packedBits which will take the data and pack every nth value.

- (NSData *)packedBitsForRange:(NSRange)range skip:(int)skip

Parameters

skip:

The number of bytes to advance as the data is encoded. Skip = 1 will encode every byte, skip = 4 will encode every fourth byte, and so on.

range:

The range within the data object that should be encoded. Useful for specifying a non-zero starting offset to get a certain channel encoded.

Discussion

A special version of packedBits which will take the data and pack every nth value.

This is important for PSDWriter because it’s necessary to encode R, then G, then B, then A data – so we essentially start at offset 0, skip 4, then do offset 1, skip 4, etc… to compress the data with very minimal memory footprint.

For normal packbits just to skip = 1

Declared In

NSDataPSDAdditions.h