Android Open Source - camera-through-wallpaper R G B Luminance Source

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From Project

Back to project page camera-through-wallpaper.

License

The source code is released under:

Apache License

Java Source Code

package com.yaji.viewfinder;
// ww  w .ja  v a2s .c  o  m
import java.io.FileNotFoundException;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

import com.google.zxing.LuminanceSource;

/**
 * This class is used to help decode images from files which arrive as RGB data from Android bitmaps. It does not support cropping or rotation.
 */
public final class RGBLuminanceSource extends LuminanceSource {

    private final byte[] luminances;

    public RGBLuminanceSource(String path) throws FileNotFoundException {
        this(loadBitmap(path));
    }

    public RGBLuminanceSource(Bitmap bitmap) {
        super(bitmap.getWidth(), bitmap.getHeight());

        int width = bitmap.getWidth();
        int height = bitmap.getHeight();
        int[] pixels = new int[width * height];
        bitmap.getPixels(pixels, 0, width, 0, 0, width, height);

        // In order to measure pure decoding speed, we convert the entire image to a greyscale array
        // up front, which is the same as the Y channel of the YUVLuminanceSource in the real app.
        luminances = new byte[width * height];
        for (int y = 0; y < height; y++) {
            int offset = y * width;
            for (int x = 0; x < width; x++) {
                int pixel = pixels[offset + x];
                int r = (pixel >> 16) & 0xff;
                int g = (pixel >> 8) & 0xff;
                int b = pixel & 0xff;
                if (r == g && g == b) {
                    // Image is already greyscale, so pick any channel.
                    luminances[offset + x] = (byte) r;
                } else {
                    // Calculate luminance cheaply, favoring green.
                    luminances[offset + x] = (byte) ((r + g + g + b) >> 2);
                }
            }
        }
    }

    @Override
    public byte[] getRow(int y, byte[] row) {
        if (y < 0 || y >= getHeight()) {
            throw new IllegalArgumentException("Requested row is outside the image: " + y);
        }
        int width = getWidth();
        if (row == null || row.length < width) {
            row = new byte[width];
        }

        System.arraycopy(luminances, y * width, row, 0, width);
        return row;
    }

    // Since this class does not support cropping, the underlying byte array already contains
    // exactly what the caller is asking for, so give it to them without a copy.
    @Override
    public byte[] getMatrix() {
        return luminances;
    }

    private static Bitmap loadBitmap(String path) throws FileNotFoundException {
        Bitmap bitmap = BitmapFactory.decodeFile(path);
        if (bitmap == null) {
            throw new FileNotFoundException("Couldn't open " + path);
        }
        return bitmap;
    }

}

Java Source Code List

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