如何正确的使用Android中的图片工具类

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;

/**
 * 图片工具类
 * @author wwj
 * 2013/7/3
 */
public class ImageUtil {
  /**图片的八个位置**/
  public static final int TOP = 0;      //上  
  public static final int BOTTOM = 1;      //下
  public static final int LEFT = 2;      //左
  public static final int RIGHT = 3;      //右
  public static final int LEFT_TOP = 4;    //左上
  public static final int LEFT_BOTTOM = 5;  //左下
  public static final int RIGHT_TOP = 6;    //右上
  public static final int RIGHT_BOTTOM = 7;  //右下
  
  /**
   * 图像的放大缩小方法
   * @param src    源位图对象
   * @param scaleX  宽度比例系数
   * @param scaleY  高度比例系数
   * @return 返回位图对象
   */
  public static Bitmap zoomBitmap(Bitmap src, float scaleX, float scaleY) {
    Matrix matrix = new Matrix();
    matrix.setScale(scaleX, scaleY);
    Bitmap t_bitmap = Bitmap.createBitmap(src, 0, 0, src.getWidth(), src.getHeight(), matrix, true);
    return t_bitmap;
  }
  
  /**
   * 图像放大缩小--根据宽度和高度
   * @param src
   * @param width
   * @param height
   * @return
   */
  public static Bitmap zoomBimtap(Bitmap src, int width, int height) {
    return Bitmap.createScaledBitmap(src, width, height, true);
  }
  
  /**
   * 将Drawable转为Bitmap对象
   * @param drawable
   * @return
   */
  public static Bitmap drawableToBitmap(Drawable drawable) {
    return ((BitmapDrawable)drawable).getBitmap();
  }
  
  
  /**
   * 将Bitmap转换为Drawable对象
   * @param bitmap
   * @return
   */
  public static Drawable bitmapToDrawable(Bitmap bitmap) {
    Drawable drawable = new BitmapDrawable(bitmap);
    return drawable;
  }
  
  /**
   * Bitmap转byte[]
   * @param bitmap
   * @return
   */
  public static byte[] bitmapToByte(Bitmap bitmap) {
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
    return out.toByteArray();
  }
  
  /**
   * byte[]转Bitmap
   * @param data
   * @return
   */
  public static Bitmap byteToBitmap(byte[] data) {
    if(data.length != 0) {
      return BitmapFactory.decodeByteArray(data, 0, data.length);
    }
    return null;
  }
  
  /**
   * 绘制带圆角的图像
   * @param src
   * @param radius
   * @return
   */
  public static Bitmap createRoundedCornerBitmap(Bitmap src, int radius) {
    final int w = src.getWidth();
    final int h = src.getHeight();
    // 高清量32位图
    Bitmap bitmap = Bitmap.createBitmap(w, h, Config.ARGB_8888);
    Paint paint = new Paint();
    Canvas canvas = new Canvas(bitmap);
    canvas.drawARGB(0, 0, 0, 0);
    paint.setColor(0xff424242);
    // 防止边缘的锯齿
    paint.setFilterBitmap(true);
    Rect rect = new Rect(0, 0, w, h);
    RectF rectf = new RectF(rect);
    // 绘制带圆角的矩形
    canvas.drawRoundRect(rectf, radius, radius, paint);
    
    // 取两层绘制交集，显示上层
    paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
    // 绘制图像
    canvas.drawBitmap(src, rect, rect, paint);
    return bitmap;
  }
  
  /**
   * 创建选中带提示图片
   * @param context
   * @param srcId
   * @param tipId
   * @return
   */
  public static Drawable createSelectedTip(Context context, int srcId, int tipId) {
    Bitmap src = BitmapFactory.decodeResource(context.getResources(), srcId);
    Bitmap tip = BitmapFactory.decodeResource(context.getResources(), tipId);
    final int w = src.getWidth();
    final int h = src.getHeight();
    Bitmap bitmap = Bitmap.createBitmap(w, h, Config.ARGB_8888);
    Paint paint = new Paint();
    Canvas canvas = new Canvas(bitmap);
    //绘制原图
    canvas.drawBitmap(src, 0, 0, paint);
    //绘制提示图片
    canvas.drawBitmap(tip, (w - tip.getWidth()), 0, paint);
    return bitmapToDrawable(bitmap);
  }
  
  /**
   * 带倒影的图像
   * @param src
   * @return
   */
  public static Bitmap createReflectionBitmap(Bitmap src) {
    // 两个图像间的空隙
    final int spacing = 4;
    final int w = src.getWidth();
    final int h = src.getHeight();
    // 绘制高质量32位图
    Bitmap bitmap = Bitmap.createBitmap(w, h + h / 2 + spacing, Config.ARGB_8888);
    // 创建燕X轴的倒影图像
    Matrix m = new Matrix();
    m.setScale(1, -1);
    Bitmap t_bitmap = Bitmap.createBitmap(src, 0, h / 2, w, h / 2, m, true);
    
    Canvas canvas = new Canvas(bitmap);
    Paint paint = new Paint();
    //  绘制原图像
    canvas.drawBitmap(src, 0, 0, paint);
    // 绘制倒影图像
    canvas.drawBitmap(t_bitmap, 0, h + spacing, paint);
    // 线性渲染-沿Y轴高到低渲染
    Shader shader = new LinearGradient(0, h + spacing, 0, h + spacing + h / 2, 0x70ffffff, 0x00ffffff, Shader.TileMode.MIRROR);
    paint.setShader(shader);
    // 取两层绘制交集，显示下层。
    paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
    // 绘制渲染倒影的矩形
    canvas.drawRect(0, h + spacing, w, h + h / 2 + spacing, paint);
    return bitmap;
  }
  
  
  /**
   * 独立的倒影图像
   * @param src
   * @return
   */
  public static Bitmap createReflectionBitmapForSingle(Bitmap src) {
    final int w = src.getWidth();
    final int h = src.getHeight();
    // 绘制高质量32位图
    Bitmap bitmap = Bitmap.createBitmap(w, h / 2, Config.ARGB_8888);
    // 创建沿X轴的倒影图像
    Matrix m = new Matrix();
    m.setScale(1, -1);
    Bitmap t_bitmap = Bitmap.createBitmap(src, 0, h / 2, w, h / 2, m, true);

    Canvas canvas = new Canvas(bitmap);
    Paint paint = new Paint();
    // 绘制倒影图像
    canvas.drawBitmap(t_bitmap, 0, 0, paint);
    // 线性渲染-沿Y轴高到低渲染  
    Shader shader = new LinearGradient(0, 0, 0, h / 2, 0x70ffffff,
        0x00ffffff, Shader.TileMode.MIRROR);
    paint.setShader(shader);
    // 取两层绘制交集。显示下层。
    paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
    // 绘制渲染倒影的矩形
    canvas.drawRect(0, 0, w, h / 2, paint);
    return bitmap;
  }
  
  
  public static Bitmap createGreyBitmap(Bitmap src) {
    final int w = src.getWidth();
    final int h = src.getHeight();
    Bitmap bitmap = Bitmap.createBitmap(w, h, Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    Paint paint = new Paint();
    // 颜色变换的矩阵
    ColorMatrix matrix = new ColorMatrix();
    // saturation 饱和度值，最小可设为0，此时对应的是灰度图；为1表示饱和度不变，设置大于1，就显示过饱和
    matrix.setSaturation(0);
    ColorMatrixColorFilter filter = new ColorMatrixColorFilter(matrix);
    paint.setColorFilter(filter);
    canvas.drawBitmap(src, 0, 0, paint);
    return bitmap;
  }
  
  /**
   * 保存图片
   * @param src
   * @param filepath
   * @param format:[Bitmap.CompressFormat.PNG,Bitmap.CompressFormat.JPEG]
   * @return
   */
  public static boolean saveImage(Bitmap src, String filepath, CompressFormat format) {
    boolean rs = false;
    File file = new File(filepath);
    try {
      FileOutputStream out = new FileOutputStream(file);
      if(src.compress(format, 100, out)) {
        out.flush();  //写入流
      }
      out.close();
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
    return rs;
  }
  
  /**
   * 添加水印效果
   * @param src    源位图
   * @param watermark  水印
   * @param direction  方向
   * @param spacing 间距
   * @return
   */
  public static Bitmap createWatermark(Bitmap src, Bitmap watermark, int direction, int spacing) {
    final int w = src.getWidth();
    final int h = src.getHeight();
    Bitmap bitmap = Bitmap.createBitmap(w, h, Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    canvas.drawBitmap(src, 0, 0, null);
    if(direction == LEFT_TOP) {
      canvas.drawBitmap(watermark, spacing, spacing, null);
    } else if(direction == LEFT_BOTTOM){
      canvas.drawBitmap(watermark, spacing, h - watermark.getHeight() - spacing, null);
    } else if(direction == RIGHT_TOP) {
      canvas.drawBitmap(watermark, w - watermark.getWidth() - spacing, spacing, null);
    } else if(direction == RIGHT_BOTTOM) {
      canvas.drawBitmap(watermark, w - watermark.getWidth() - spacing, h - watermark.getHeight() - spacing, null);
    }
    return bitmap;
  }
  
  
  /**
   * 合成图像
   * @param direction
   * @param bitmaps
   * @return
   */
  public static Bitmap composeBitmap(int direction, Bitmap... bitmaps) {
    if(bitmaps.length < 2) {
      return null;
    }
    Bitmap firstBitmap = bitmaps[0];
    for (int i = 0; i < bitmaps.length; i++) {
      firstBitmap = composeBitmap(firstBitmap, bitmaps[i], direction);
    }
    return firstBitmap;
  }

  /**
   * 合成两张图像
   * @param firstBitmap
   * @param secondBitmap
   * @param direction
   * @return
   */
  private static Bitmap composeBitmap(Bitmap firstBitmap, Bitmap secondBitmap,
      int direction) {
    if(firstBitmap == null) {
      return null;
    }
    if(secondBitmap == null) {
      return firstBitmap;
    }
    final int fw = firstBitmap.getWidth();
    final int fh = firstBitmap.getHeight();
    final int sw = secondBitmap.getWidth();
    final int sh = secondBitmap.getHeight();
    Bitmap bitmap = null;
    Canvas canvas = null;
    if(direction == TOP) {
      bitmap = Bitmap.createBitmap(sw > fw ? sw : fw, fh + sh, Config.ARGB_8888);
      canvas = new Canvas(bitmap);
      canvas.drawBitmap(secondBitmap, 0, 0, null);
      canvas.drawBitmap(firstBitmap, 0, sh, null);
    } else if(direction == BOTTOM) {
      bitmap = Bitmap.createBitmap(fw > sw ? fw : sw, fh + sh, Config.ARGB_8888);
      canvas = new Canvas(bitmap);
      canvas.drawBitmap(firstBitmap, 0, 0, null);
      canvas.drawBitmap(secondBitmap, 0, fh, null);
    } else if(direction == LEFT) {
      bitmap = Bitmap.createBitmap(fw + sw, sh > fh ? sh : fh, Config.ARGB_8888);
      canvas = new Canvas(bitmap);
      canvas.drawBitmap(secondBitmap, 0, 0, null);
      canvas.drawBitmap(firstBitmap, sw, 0, null);
    } else if(direction == RIGHT) {
      bitmap = Bitmap.createBitmap(fw + sw, fh > sh ? fh : sh,
          Config.ARGB_8888);
      canvas = new Canvas(bitmap);
      canvas.drawBitmap(firstBitmap, 0, 0, null);
      canvas.drawBitmap(secondBitmap, fw, 0, null);
    }
    return bitmap;
  }
  
  
}