109 lines
3.9 KiB
Objective-C
109 lines
3.9 KiB
Objective-C
/*
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* Copyright 2012 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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@class ZXByteArray;
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/**
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* The purpose of this class hierarchy is to abstract different bitmap implementations across
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* platforms into a standard interface for requesting greyscale luminance values. The interface
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* only provides immutable methods; therefore crop and rotation create copies. This is to ensure
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* that one Reader does not modify the original luminance source and leave it in an unknown state
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* for other Readers in the chain.
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*/
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@interface ZXLuminanceSource : NSObject
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/**
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* @return The width of the bitmap.
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*/
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@property (nonatomic, assign, readonly) int width;
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/**
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* @return The height of the bitmap.
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*/
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@property (nonatomic, assign, readonly) int height;
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/**
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* @return Whether this subclass supports cropping.
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*/
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@property (nonatomic, assign, readonly) BOOL cropSupported;
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/**
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* @return Whether this subclass supports counter-clockwise rotation.
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*/
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@property (nonatomic, assign, readonly) BOOL rotateSupported;
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- (id)initWithWidth:(int)width height:(int)height;
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/**
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* Fetches one row of luminance data from the underlying platform's bitmap. Values range from
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* 0 (black) to 255 (white). Because Java does not have an unsigned byte type, callers will have
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* to bitwise and with 0xff for each value. It is preferable for implementations of this method
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* to only fetch this row rather than the whole image, since no 2D Readers may be installed and
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* getMatrix() may never be called.
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*
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* @param y The row to fetch, 0 <= y < getHeight().
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* @param row An optional preallocated array. If null or too small, it will be ignored.
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* Always use the returned object, and ignore the .length of the array.
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* @return An array containing the luminance data.
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*/
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- (ZXByteArray *)rowAtY:(int)y row:(ZXByteArray *)row;
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/**
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* Fetches luminance data for the underlying bitmap. Values should be fetched using:
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* int luminance = array[y * width + x] & 0xff;
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*
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* @return A row-major 2D array of luminance values. Do not use result.length as it may be
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* larger than width * height bytes on some platforms. Do not modify the contents
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* of the result.
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*/
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- (ZXByteArray *)matrix;
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/**
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* Returns a new object with cropped image data. Implementations may keep a reference to the
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* original data rather than a copy. Only callable if isCropSupported() is true.
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*
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* @param left The left coordinate, 0 <= left < getWidth().
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* @param top The top coordinate, 0 <= top <= getHeight().
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* @param width The width of the rectangle to crop.
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* @param height The height of the rectangle to crop.
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* @return A cropped version of this object.
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*/
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- (ZXLuminanceSource *)crop:(int)left top:(int)top width:(int)width height:(int)height;
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/**
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* @return a wrapper of this ZXLuminanceSource which inverts the luminances it returns -- black becomes
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* white and vice versa, and each value becomes (255-value).
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*/
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- (ZXLuminanceSource *)invert;
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/**
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* Returns a new object with rotated image data by 90 degrees counterclockwise.
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* Only callable if isRotateSupported is true.
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*
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* @return A rotated version of this object.
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*/
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- (ZXLuminanceSource *)rotateCounterClockwise;
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/**
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* Returns a new object with rotated image data by 45 degrees counterclockwise.
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* Only callable if isRotateSupported is true.
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*
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* @return A rotated version of this object.
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*/
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- (ZXLuminanceSource *)rotateCounterClockwise45;
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@end
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