Main.java Source code

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Here is the source code for Main.java

Source

//package com.java2s;
//License from project: Open Source License 

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Build;
import android.util.TypedValue;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;

public class Main {
    private static final int DECODE_BUFFER_SIZE = 16 * 1024;
    private static final int DENSITY_240 = 240;
    private static final int DENSITY_400 = 400;
    private static final float SCALE_FACTOR = 0.8f;
    private static final float SCALE_FACTOR_2 = 0.7f;
    private static final Bitmap.Config DEFAULT_BITMAP_CONFIG = Bitmap.Config.RGB_565;

    public static Bitmap compressBitmap(Context context, int resId, int maxWidth, int maxHeight) {
        checkParam(context);
        final TypedValue value = new TypedValue();
        InputStream is = null;
        try {
            is = context.getResources().openRawResource(resId, value);
            return compressBitmap(context, is, maxWidth, maxHeight);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }

    public static Bitmap compressBitmap(Context context, String pathName, int maxWidth, int maxHeight) {
        checkParam(context);
        InputStream is = null;
        try {
            is = new FileInputStream(pathName);
            return compressBitmap(context, is, maxWidth, maxHeight);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }

    public static Bitmap compressBitmap(Context context, InputStream is, int maxWidth, int maxHeight) {
        checkParam(context);
        checkParam(is);
        BitmapFactory.Options opt = new BitmapFactory.Options();
        opt.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(is, null, opt);
        int height = opt.outHeight;
        int width = opt.outWidth;
        int sampleSize = computeSampleSize(width, height, maxWidth, maxHeight);
        BitmapFactory.Options options = getBitmapOptions(context);
        options.inSampleSize = sampleSize;
        return BitmapFactory.decodeStream(is, null, options);
    }

    private static <T> void checkParam(T param) {
        if (param == null)
            throw new NullPointerException();
    }

    private static int computeSampleSize(int width, int height, int maxWidth, int maxHeight) {
        int inSampleSize = 1;
        if (height > maxHeight || width > maxWidth) {
            final int heightRate = Math.round((float) height / (float) maxHeight);
            final int widthRate = Math.round((float) width / (float) maxWidth);
            inSampleSize = heightRate < widthRate ? heightRate : widthRate;
        }
        if (inSampleSize % 2 != 0) {
            inSampleSize -= 1;
        }
        return inSampleSize <= 1 ? 1 : inSampleSize;
    }

    private static BitmapFactory.Options getBitmapOptions(Context context) {
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inScaled = true;
        options.inPreferredConfig = DEFAULT_BITMAP_CONFIG;
        options.inPurgeable = true;
        options.inInputShareable = true;
        options.inJustDecodeBounds = false;
        options.inTempStorage = new byte[DECODE_BUFFER_SIZE];
        if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.GINGERBREAD_MR1) {
            Field field = null;
            try {
                field = BitmapFactory.Options.class.getDeclaredField("inNativeAlloc");
                field.setAccessible(true);
                field.setBoolean(options, true);
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        }
        int displayDensityDpi = context.getResources().getDisplayMetrics().densityDpi;
        float displayDensity = context.getResources().getDisplayMetrics().density;
        int density = 0;
        if (displayDensityDpi > DENSITY_240 && displayDensityDpi <= DENSITY_400 && displayDensity > 1.5f) {
            density = (int) (displayDensityDpi * SCALE_FACTOR);
        } else if (displayDensityDpi > DENSITY_400 && displayDensity > 2.5f) {
            density = (int) (displayDensityDpi * SCALE_FACTOR_2);
        }
        if (density == 0)
            return options;
        options.inDensity = density;
        options.inTargetDensity = density;
        return options;
    }
}