PlayerAndroid/app/src/main/java/code/name/monkey/retromusic/util/ImageUtil.java

package code.name.monkey.retromusic.util;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffColorFilter;
import android.media.ExifInterface;
import android.support.annotation.NonNull;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

/**
 * Created on : June 18, 2016 Author     : zetbaitsu Name       : Zetra GitHub     :
 * https://github.com/zetbaitsu
 */
public class ImageUtil {

    private static final int TOLERANCE = 20;
    // Alpha amount for which values below are considered transparent.
    private static final int ALPHA_TOLERANCE = 50;
    private static int[] mTempBuffer;

    private ImageUtil() {

    }

    public static boolean isGrayscale(Bitmap bitmap) {
        final int height = bitmap.getHeight();
        final int width = bitmap.getWidth();
        int size = height * width;
        ensureBufferSize(size);
        bitmap.getPixels(mTempBuffer, 0, width, 0, 0, width, height);
        for (int i = 0; i < size; i++) {
            if (!isGrayscale(mTempBuffer[i])) {
                return false;
            }
        }
        return true;
    }

    /**
     * Makes sure that {@code mTempBuffer} has at least length {@code size}.
     */
    private static void ensureBufferSize(int size) {
        if (mTempBuffer == null || mTempBuffer.length < size) {
            mTempBuffer = new int[size];
        }
    }

    public static Bitmap setBitmapColor(Bitmap bitmap, int color) {
        Bitmap result = Bitmap
                .createBitmap(bitmap, 0, 0, bitmap.getWidth() - 1, bitmap.getHeight() - 1);
        Paint paint = new Paint();
        paint.setColorFilter(new PorterDuffColorFilter(color, PorterDuff.Mode.SRC_ATOP));

        Canvas canvas = new Canvas(result);
        canvas.drawBitmap(result, 0, 0, paint);

        return result;
    }

    public static boolean isGrayscale(int color) {
        int alpha = 0xFF & (color >> 24);
        if (alpha < ALPHA_TOLERANCE) {
            return true;
        }
        int r = 0xFF & (color >> 16);
        int g = 0xFF & (color >> 8);
        int b = 0xFF & color;
        return Math.abs(r - g) < TOLERANCE
                && Math.abs(r - b) < TOLERANCE
                && Math.abs(g - b) < TOLERANCE;
    } // Amount (max is 255) that two channels can differ before the color is no longer "gray".

    public static Bitmap resizeBitmap(@NonNull Bitmap src, int maxForSmallerSize) {
        int width = src.getWidth();
        int height = src.getHeight();

        final int dstWidth;
        final int dstHeight;

        if (width < height) {
            if (maxForSmallerSize >= width) {
                return src;
            }
            float ratio = (float) height / width;
            dstWidth = maxForSmallerSize;
            dstHeight = Math.round(maxForSmallerSize * ratio);
        } else {
            if (maxForSmallerSize >= height) {
                return src;
            }
            float ratio = (float) width / height;
            dstWidth = Math.round(maxForSmallerSize * ratio);
            dstHeight = maxForSmallerSize;
        }

        return Bitmap.createScaledBitmap(src, dstWidth, dstHeight, false);
    }

    public static int calculateInSampleSize(int width, int height, int reqWidth) {
        // setting reqWidth matching to desired 1:1 ratio and screen-size
        if (width < height) {
            reqWidth = (height / width) * reqWidth;
        } else {
            reqWidth = (width / height) * reqWidth;
        }

        int inSampleSize = 1;

        if (height > reqWidth || width > reqWidth) {
            final int halfHeight = height / 2;
            final int halfWidth = width / 2;

            // Calculate the largest inSampleSize value that is a power of 2 and keeps both
            // height and width larger than the requested height and width.
            while ((halfHeight / inSampleSize) > reqWidth
                    && (halfWidth / inSampleSize) > reqWidth) {
                inSampleSize *= 2;
            }
        }

        return inSampleSize;
    }

    static File compressImage(File imageFile, int reqWidth, int reqHeight,
                              Bitmap.CompressFormat compressFormat, int quality, String destinationPath)
            throws IOException {
        FileOutputStream fileOutputStream = null;
        File file = new File(destinationPath).getParentFile();
        if (!file.exists()) {
            file.mkdirs();
        }
        try {
            fileOutputStream = new FileOutputStream(destinationPath);
            // write the compressed bitmap at the destination specified by destinationPath.
            decodeSampledBitmapFromFile(imageFile, reqWidth, reqHeight)
                    .compress(compressFormat, quality, fileOutputStream);
        } finally {
            if (fileOutputStream != null) {
                fileOutputStream.flush();
                fileOutputStream.close();
            }
        }

        return new File(destinationPath);
    }

    static Bitmap decodeSampledBitmapFromFile(File imageFile, int reqWidth, int reqHeight)
            throws IOException {
        // First decode with inJustDecodeBounds=true to check dimensions
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(imageFile.getAbsolutePath(), options);

        // Calculate inSampleSize
        options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

        // Decode bitmap with inSampleSize set
        options.inJustDecodeBounds = false;

        Bitmap scaledBitmap = BitmapFactory.decodeFile(imageFile.getAbsolutePath(), options);

        //check the rotation of the image and display it properly
        ExifInterface exif;
        exif = new ExifInterface(imageFile.getAbsolutePath());
        int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 0);
        Matrix matrix = new Matrix();
        if (orientation == 6) {
            matrix.postRotate(90);
        } else if (orientation == 3) {
            matrix.postRotate(180);
        } else if (orientation == 8) {
            matrix.postRotate(270);
        }
        scaledBitmap = Bitmap
                .createBitmap(scaledBitmap, 0, 0, scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix,
                        true);
        return scaledBitmap;
    }

    private static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth,
                                             int reqHeight) {
        // Raw height and width of image
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {

            final int halfHeight = height / 2;
            final int halfWidth = width / 2;

            // Calculate the largest inSampleSize value that is a power of 2 and keeps both
            // height and width larger than the requested height and width.
            while ((halfHeight / inSampleSize) >= reqHeight && (halfWidth / inSampleSize) >= reqWidth) {
                inSampleSize *= 2;
            }
        }

        return inSampleSize;
    }

    public static Bitmap getResizedBitmap(Bitmap image, int maxSize) {
        int width = image.getWidth();
        int height = image.getHeight();

        float bitmapRatio = (float) width / (float) height;
        if (bitmapRatio > 1) {
            width = maxSize;
            height = (int) (width / bitmapRatio);
        } else {
            height = maxSize;
            width = (int) (height * bitmapRatio);
        }
        return Bitmap.createScaledBitmap(image, width, height, true);
    }
}