rxing/src/luminance_source.rs

/*
 * Copyright 2009 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

//package com.google.zxing;

use crate::Exceptions;

/**
 * The purpose of this class hierarchy is to abstract different bitmap implementations across
 * platforms into a standard interface for requesting greyscale luminance values. The interface
 * only provides immutable methods; therefore crop and rotation create copies. This is to ensure
 * that one Reader does not modify the original luminance source and leave it in an unknown state
 * for other Readers in the chain.
 *
 * @author dswitkin@google.com (Daniel Switkin)
 */
pub trait LuminanceSource {
    //private final int width;
    //private final int height;

    //fn new( width:usize,  height:usize) -> Self;

    /**
     * Fetches one row of luminance data from the underlying platform's bitmap. Values range from
     * 0 (black) to 255 (white). Because Java does not have an unsigned byte type, callers will have
     * to bitwise and with 0xff for each value. It is preferable for implementations of this method
     * to only fetch this row rather than the whole image, since no 2D Readers may be installed and
     * getMatrix() may never be called.
     *
     * @param y The row to fetch, which must be in [0,getHeight())
     * @param row An optional preallocated array. If null or too small, it will be ignored.
     *            Always use the returned object, and ignore the .length of the array.
     * @return An array containing the luminance data.
     */
    fn getRow(&self, y: usize, row: &Vec<u8>) -> Vec<u8>;

    /**
     * Fetches luminance data for the underlying bitmap. Values should be fetched using:
     * {@code int luminance = array[y * width + x] & 0xff}
     *
     * @return A row-major 2D array of luminance values. Do not use result.length as it may be
     *         larger than width * height bytes on some platforms. Do not modify the contents
     *         of the result.
     */
    fn getMatrix(&self) -> Vec<u8>;

    /**
     * @return The width of the bitmap.
     */
    fn getWidth(&self) -> usize;

    /**
     * @return The height of the bitmap.
     */
    fn getHeight(&self) -> usize;

    /**
     * @return Whether this subclass supports cropping.
     */
    fn isCropSupported(&self) -> bool {
        return false;
    }

    /**
     * Returns a new object with cropped image data. Implementations may keep a reference to the
     * original data rather than a copy. Only callable if isCropSupported() is true.
     *
     * @param left The left coordinate, which must be in [0,getWidth())
     * @param top The top coordinate, which must be in [0,getHeight())
     * @param width The width of the rectangle to crop.
     * @param height The height of the rectangle to crop.
     * @return A cropped version of this object.
     */
    fn crop(
        &self,
        left: usize,
        top: usize,
        width: usize,
        height: usize,
    ) -> Result<Box<dyn LuminanceSource>, Exceptions> {
        return Err(Exceptions::UnsupportedOperationException(
            "This luminance source does not support cropping.".to_owned(),
        ));
    }

    /**
     * @return Whether this subclass supports counter-clockwise rotation.
     */
    fn isRotateSupported(&self) -> bool {
        return false;
    }

    /**
     * @return a wrapper of this {@code LuminanceSource} which inverts the luminances it returns -- black becomes
     *  white and vice versa, and each value becomes (255-value).
     */
    fn invert(&mut self); /* {
                            return InvertedLuminanceSource::new_with_delegate(self);
                          }*/

    /**
     * Returns a new object with rotated image data by 90 degrees counterclockwise.
     * Only callable if {@link #isRotateSupported()} is true.
     *
     * @return A rotated version of this object.
     */
    fn rotateCounterClockwise(&self) -> Result<Box<dyn LuminanceSource>, Exceptions> {
        return Err(Exceptions::UnsupportedOperationException(
            "This luminance source does not support rotation by 90 degrees.".to_owned(),
        ));
    }

    /**
     * Returns a new object with rotated image data by 45 degrees counterclockwise.
     * Only callable if {@link #isRotateSupported()} is true.
     *
     * @return A rotated version of this object.
     */
    fn rotateCounterClockwise45(&self) -> Result<Box<dyn LuminanceSource>, Exceptions> {
        return Err(Exceptions::UnsupportedOperationException(
            "This luminance source does not support rotation by 45 degrees.".to_owned(),
        ));
    }

    fn invert_block_of_bytes(&self, vec_to_invert: Vec<u8>) -> Vec<u8> {
        let mut iv = vec_to_invert.clone();
        for itm in iv.iter_mut() {
            let z = *itm;
            *itm = 255 - (z & 0xFF);
        }
        iv
    }

    /*
    @Override
    public final String toString() {
      byte[] row = new byte[width];
      StringBuilder result = new StringBuilder(height * (width + 1));
      for (int y = 0; y < height; y++) {
        row = getRow(y, row);
        for (int x = 0; x < width; x++) {
          int luminance = row[x] & 0xFF;
          char c;
          if (luminance < 0x40) {
            c = '#';
          } else if (luminance < 0x80) {
            c = '+';
          } else if (luminance < 0xC0) {
            c = '.';
          } else {
            c = ' ';
          }
          result.append(c);
        }
        result.append('\n');
      }
      return result.toString();
    }*/
}