BitmapUtil.java

package com.forfan.bigbang.cropper;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.net.Uri;

import java.io.FileNotFoundException;

public class BitmapUtil {

    public static Bitmap decodeUriAsBitmap(Context context, Uri uri) {
        if (context == null || uri == null) return null;

        Bitmap bitmap;
        try {
            bitmap = BitmapFactory.decodeStream(context.getContentResolver().openInputStream(uri));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return null;
        }
        return bitmap;
    }
    /**
     * 根据原图和变长绘制圆形图片
     *
     * @param source
     * @param min
     * @return
     */
    public static Bitmap createCircleImage(Bitmap source, int min)
    {
        final Paint paint = new Paint();
        paint.setAntiAlias(true);
        Bitmap target = Bitmap.createBitmap(min, min, Bitmap.Config.ARGB_8888);
        /**
         * 产生一个同样大小的画布
         */
        Canvas canvas = new Canvas(target);
        /**
         * 首先绘制圆形
         */
        canvas.drawCircle(min / 2, min / 2, min / 2, paint);
        /**
         * 使用SRC_IN
         */
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        /**
         * 绘制图片
         */
        canvas.drawBitmap(source, 0, 0, paint);
        return target;
    }
}