/**
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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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* @author dswitkin@google.com (Daniel Switkin)
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*/
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declare abstract class LuminanceSource {
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private width;
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private height;
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protected constructor(width: number, height: number);
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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, which must be in [0,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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abstract getRow(y: number, row?: Uint8ClampedArray): Uint8ClampedArray;
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/**
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* Fetches luminance data for the underlying bitmap. Values should be fetched using:
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* {@code 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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abstract getMatrix(): Uint8ClampedArray;
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/**
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* @return The width of the bitmap.
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*/
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getWidth(): number;
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/**
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* @return The height of the bitmap.
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*/
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getHeight(): number;
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/**
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* @return Whether this subclass supports cropping.
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*/
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isCropSupported(): boolean;
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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, which must be in [0,getWidth())
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* @param top The top coordinate, which must be in [0,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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crop(left: number, top: number, width: number, height: number): LuminanceSource;
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/**
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* @return Whether this subclass supports counter-clockwise rotation.
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*/
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isRotateSupported(): boolean;
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/**
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* @return a wrapper of this {@code LuminanceSource} 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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abstract invert(): LuminanceSource;
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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 {@link #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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rotateCounterClockwise(): LuminanceSource;
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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 {@link #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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rotateCounterClockwise45(): LuminanceSource;
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toString(): string;
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}
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export default LuminanceSource;
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