import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

public class BitmapUtil {
    public static Bitmap readBitmap(Context context, int resId) {
        BitmapFactory.Options opt = new BitmapFactory.Options();
        opt.inPreferredConfig = Bitmap.Config.RGB_565;
        opt.inPurgeable = true;
        opt.inInputShareable = true;
        // 獲取資源圖片
        InputStream is = context.getResources().openRawResource(resId);
        return BitmapFactory.decodeStream(is, null, opt);
    }

    public static byte[] bitmapToBytes(Bitmap bm) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bm.compress(Bitmap.CompressFormat.JPEG, 100, baos);
        return baos.toByteArray();
    }

    /**
     * 通過uri獲取圖片並進行壓縮
     */
    public static Bitmap getBitmapFormUri(Activity ac, Uri uri) throws IOException {
        InputStream input = ac.getContentResolver().openInputStream(uri);
        BitmapFactory.Options onlyBoundsOptions = new BitmapFactory.Options();
        onlyBoundsOptions.inJustDecodeBounds = true;
        onlyBoundsOptions.inDither = true;//optional
        onlyBoundsOptions.inPreferredConfig = Bitmap.Config.ARGB_8888;//optional
        BitmapFactory.decodeStream(input, null, onlyBoundsOptions);
        input.close();
        int originalWidth = onlyBoundsOptions.outWidth;
        int originalHeight = onlyBoundsOptions.outHeight;
        if ((originalWidth == -1) || (originalHeight == -1))
            return null;
        //圖片分辨率以480x800為標準
        float hh = 800f;//設定高度為800f
        float ww = 480f;//設定寬度為480f
        int be = 1;//be=1表示不缩放
        //如果寬度大的畫根據寬度固定大小缩放
        if (originalWidth > originalHeight && originalWidth > ww) {
            be = (int) (originalWidth / ww);
        //如果高度高的話根據寬度固定大小缩放
        } else if (originalWidth < originalHeight && originalHeight > hh) {
            be = (int) (originalHeight / hh);
        }
        if (be <= 0)
            be = 1;
        //比例壓縮
        BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
        bitmapOptions.inSampleSize = be;//設定缩放比例
        bitmapOptions.inDither = true;//optional
        bitmapOptions.inPreferredConfig = Bitmap.Config.ARGB_8888;//optional
        input = ac.getContentResolver().openInputStream(uri);
        Bitmap bitmap = BitmapFactory.decodeStream(input, null, bitmapOptions);
        input.close();

        return compressImage(bitmap);//再進行質量壓縮
    }

    /**
     * 質量壓縮方法
     */
    public static Bitmap compressImage(Bitmap image) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        //質量壓縮方法，100表示不壓縮，把壓縮後的資料存放到baos中
        image.compress(Bitmap.CompressFormat.JPEG, 100, baos);
        int options = 100;
        //循環判斷如果压壓縮後圖片是否大於100kb,大於繼續壓縮,不能小於0
        while (baos.toByteArray().length / 1024 > 100  && options >= 0) {
            baos.reset();
            image.compress(Bitmap.CompressFormat.JPEG, options, baos);
            options -= 10;//每次都减少10
        }
        //把压缩後的資料baos存放到ByteArrayInputStream中
        ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());
        //把ByteArrayInputStream資料生成圖片
        Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, null);
        return bitmap;
    }
}