53 lines
1.8 KiB
C
53 lines
1.8 KiB
C
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//
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// NSDataPSDAdditions.h
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// PSDWriter
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//
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// Created by Ben Gotow on 5/24/09.
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// Copyright 2009 __MyCompanyName__. All rights reserved.
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//
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#import <Foundation/Foundation.h>
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@interface NSMutableData (PSDAdditions)
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/** Allows you to append a numeric value to an NSMutableData object and pad it to any length.
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For example, we could say [data appendValue: 2 withLength: 5], and 00002 would be written
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into the data object. Very useful for writing to file formats that have header structures
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that require a certain number of bytes be used for a certain value. i.e. PSD and TIFF
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@param value: The value to append
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@param length: The number of bytes that should be used to store the value. The value will be padded
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to length bytes regardless of the number of bytes required to store it.
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*/
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- (void)appendValue:(long)value withLength:(int)length;
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@end
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@interface NSData (PSDAdditions)
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/** Takes packedBits data and prints out a description of the packed contents by
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running the decode operation and explaining via NSLog how the data is being
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decoded. Useful for checking that packedBits data is correct. */
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- (NSString *)packedBitsDescription;
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/** A special version of packedBits which will take the data and pack every nth
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value.
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This is important for PSDWriter because it's necessary to encode R, then G,
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then B, then A data - so we essentially start at offset 0, skip 4, then do offset 1,
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skip 4, etc... to compress the data with very minimal memory footprint.
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For normal packbits just to skip = 1
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@param range: The range within the data object that should be encoded. Useful
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for specifying a non-zero starting offset to get a certain channel encoded.
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@param skip: The number of bytes to advance as the data is encoded. Skip = 1 will
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encode every byte, skip = 4 will encode every fourth byte, and so on.
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*/
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- (NSData *)packedBitsForRange:(NSRange)range skip:(int)skip;
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@end
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