Android 图片Bitmap的剪切的示例代码

一、什么是Android中的Bitmap

Bitmap是Android系统中的图像处理的最重要类之一。用它可以获取图像文件信息，进行图像剪切、旋转、缩放等操作，并可以指定格式保存图像文件。

二、Bitmap的剪切基本操作

复制代码 代码如下:

public static Bitmap createBitmap (Bitmap source, int x, int y, int width, int height, Matrix m, boolean filter)

从原始位图剪切图像，这是一种高级的方式。可以用Matrix(矩阵)来实现旋转等高级方式截图

参数说明：

Bitmap source：要从中截图的原始位图

int x:起始x坐标

int y：起始y坐标

int width：要截的图的宽度

int height：要截的图的宽度

Bitmap.Config  config：一个枚举类型的配置，可以定义截到的新位图的质量

返回值：返回一个剪切好的Bitmap

三、Bitmap剪切的封装

实际使用中，因为项目需要时常需要对基本功能进行封装，下面是一段封装的代码，仅供参考。

import java.io.ByteArrayOutputStream; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileNotFoundException; 
import java.io.IOException; 
import java.io.InputStream; 
import java.util.ArrayList; 
import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.Bitmap.Config; 
import android.graphics.BitmapFactory; 
import android.graphics.Canvas; 
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; 
 
public class BitmapCut 
{ 
 
 /** 
 * 通过资源id转化成Bitmap 
 * 
 * @param context 
 * @param resId 
 * @return 
 */ 
 public static Bitmap ReadBitmapById(Context context, int resId) 
 { 
 BitmapFactory.Options opt = new BitmapFactory.Options(); 
 opt.inPreferredConfig = Bitmap.Config.RGB_565; 
 opt.inPurgeable = true; 
 opt.inInputShareable = true; 
 
 InputStream is = context.getResources().openRawResource(resId); 
 return BitmapFactory.decodeStream(is, null, opt); 
 } 
 
 /** 
 * 设置背景为圆角 
 * 
 * @param bitmap 
 * @param pixels 
 * @return 
 */ 
 public static Bitmap removeYuanjiao(Bitmap bitmap, int pixels) 
 { 
 int width = bitmap.getWidth(); 
 int height = bitmap.getHeight(); 
 
 Bitmap creBitmap = Bitmap.createBitmap(width, height, 
  android.graphics.Bitmap.Config.ARGB_8888); 
 Canvas canvas = new Canvas(creBitmap); 
 
 Paint paint = new Paint(); 
 float roundPx = pixels; 
 RectF rectF = new RectF(0, 0, bitmap.getWidth() - pixels, 
  bitmap.getHeight() - pixels); 
 paint.setAntiAlias(true); 
 
 canvas.drawARGB(0, 0, 0, 0); 
 canvas.drawRoundRect(rectF, roundPx, roundPx, paint); 
 paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN)); 
 
 canvas.drawBitmap(bitmap, 0, 0, paint); 
 if (!bitmap.isRecycled()) 
  bitmap.recycle(); 
 
 return creBitmap; 
 } 
 
 /** 
 * 按正方形裁切图片 
 */ 
 public static Bitmap ImageCrop(Bitmap bitmap, boolean isRecycled) 
 { 
 
 if (bitmap == null) 
 { 
  return null; 
 } 
 
 int w = bitmap.getWidth(); // 得到图片的宽，高 
 int h = bitmap.getHeight(); 
 
 int wh = w > h ? h : w;// 裁切后所取的正方形区域边长 
 
 int retX = w > h ? (w - h) / 2 : 0;// 基于原图，取正方形左上角x坐标 
 int retY = w > h ? 0 : (h - w) / 2; 
 
 Bitmap bmp = Bitmap.createBitmap(bitmap, retX, retY, wh, wh, null, 
  false); 
 if (isRecycled && bitmap != null && !bitmap.equals(bmp) 
  && !bitmap.isRecycled()) 
 { 
  bitmap.recycle(); 
  bitmap = null; 
 } 
 
 // 下面这句是关键 
 return bmp;// Bitmap.createBitmap(bitmap, retX, retY, wh, wh, null, 
   // false); 
 } 
 
 /** 
 * 按长方形裁切图片 
 * 
 * @param bitmap 
 * @return 
 */ 
 public static Bitmap ImageCropWithRect(Bitmap bitmap) 
 { 
 if (bitmap == null) 
 { 
  return null; 
 } 
 
 int w = bitmap.getWidth(); // 得到图片的宽，高 
 int h = bitmap.getHeight(); 
 
 int nw, nh, retX, retY; 
 if (w > h) 
 { 
  nw = h / 2; 
  nh = h; 
  retX = (w - nw) / 2; 
  retY = 0; 
 } else 
 { 
  nw = w / 2; 
  nh = w; 
  retX = w / 4; 
  retY = (h - w) / 2; 
 } 
 
 // 下面这句是关键 
 Bitmap bmp = Bitmap.createBitmap(bitmap, retX, retY, nw, nh, null, 
  false); 
 if (bitmap != null && !bitmap.equals(bmp) && !bitmap.isRecycled()) 
 { 
  bitmap.recycle(); 
  bitmap = null; 
 } 
 return bmp;// Bitmap.createBitmap(bitmap, retX, retY, nw, nh, null, 
   // false); 
 } 
 
 /** 
 * Bitmap --> byte[] 
 * 
 * @param bmp 
 * @return 
 */ 
 public static byte[] readBitmap(Bitmap bmp) 
 { 
 ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
 bmp.compress(Bitmap.CompressFormat.JPEG, 60, baos); 
 try 
 { 
  baos.flush(); 
  baos.close(); 
 } catch (IOException e) 
 { 
  e.printStackTrace(); 
 } 
 return baos.toByteArray(); 
 } 
 
 
 /** 
 * 将图像裁剪成圆形 
 * 
 * @param bitmap 
 * @return 
 */ 
 public static Bitmap toRoundBitmap(Bitmap bitmap) 
 { 
 if (bitmap == null) 
 { 
  return null; 
 } 
 
 int width = bitmap.getWidth(); 
 int height = bitmap.getHeight(); 
 float roundPx; 
 float left, top, right, bottom, dst_left, dst_top, dst_right, dst_bottom; 
 if (width <= height) 
 { 
  roundPx = width / 2; 
  top = 0; 
  bottom = width; 
  left = 0; 
  right = width; 
  height = width; 
  dst_left = 0; 
  dst_top = 0; 
  dst_right = width; 
  dst_bottom = width; 
 } else 
 { 
  roundPx = height / 2; 
  float clip = (width - height) / 2; 
  left = clip; 
  right = width - clip; 
  top = 0; 
  bottom = height; 
  width = height; 
  dst_left = 0; 
  dst_top = 0; 
  dst_right = height; 
  dst_bottom = height; 
 } 
 
 Bitmap output = Bitmap.createBitmap(width, height, Config.ARGB_8888); 
 Canvas canvas = new Canvas(output); 
 
 final int color = 0xff424242; 
 final Paint paint = new Paint(); 
 final Rect src = new Rect((int) left, (int) top, (int) right, 
  (int) bottom); 
 final Rect dst = new Rect((int) dst_left, (int) dst_top, 
  (int) dst_right, (int) dst_bottom); 
 final RectF rectF = new RectF(dst); 
 
 paint.setAntiAlias(true); 
 
 canvas.drawARGB(0, 0, 0, 0); 
 paint.setColor(color); 
 canvas.drawRoundRect(rectF, roundPx, roundPx, paint); 
 
 paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); 
 canvas.drawBitmap(bitmap, src, dst, paint); 
 if (bitmap != null && !bitmap.isRecycled()) 
 { 
  bitmap.recycle(); 
  bitmap = null; 
 } 
 return output; 
 } 
 
 // 将图片变成带圆边的圆形图片 
 public static Bitmap getRoundBitmap(Bitmap bitmap, int width, int height) 
 { 
 if (bitmap == null) 
 { 
  return null; 
 } 
 // 将图片变成圆角 
 Bitmap roundBitmap = Bitmap.createBitmap(width, height, 
  Config.ARGB_8888); 
 Canvas canvas = new Canvas(roundBitmap); 
 Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); 
 int len = (width > height) ? height : width; 
 canvas.drawCircle(width / 2, height / 2, len / 2 - 8, paint); 
 paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); 
 Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmap, len, len, true); 
 canvas.drawBitmap(scaledBitmap, 0, 0, paint); 
 // 将图片加圆边 
 Bitmap outBitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888); 
 canvas = new Canvas(outBitmap); 
 paint = new Paint(Paint.ANTI_ALIAS_FLAG); 
 paint.setColor(0xffffffff); 
 canvas.drawCircle(width / 2, height / 2, len / 2 - 4, paint); 
 paint.setXfermode(new PorterDuffXfermode(Mode.SRC_OVER)); 
 canvas.drawBitmap(roundBitmap, 0, 0, paint); 
 bitmap.recycle(); 
 bitmap = null; 
 roundBitmap.recycle(); 
 roundBitmap = null; 
 scaledBitmap.recycle(); 
 scaledBitmap = null; 
 return outBitmap; 
 } 
 
 // 将图片变成带圆边的圆形图片 
 public static Bitmap getRoundBitmap(Bitmap bitmap, int width, int height, 
  int color) 
 { 
 if (bitmap == null) 
 { 
  return null; 
 } 
 // 将图片变成圆角 
 Bitmap roundBitmap = Bitmap.createBitmap(width, height, 
  Config.ARGB_8888); 
 Canvas canvas = new Canvas(roundBitmap); 
 Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); 
 int len = (width > height) ? height : width; 
 canvas.drawCircle(width / 2, height / 2, len / 2 - 8, paint); 
 paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); 
 Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmap, len, len, true); 
 canvas.drawBitmap(scaledBitmap, 0, 0, paint); 
 // 将图片加圆边 
 Bitmap outBitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888); 
 canvas = new Canvas(outBitmap); 
 paint = new Paint(Paint.ANTI_ALIAS_FLAG); 
 paint.setColor(color); 
 canvas.drawCircle(width / 2, height / 2, len / 2 - 4, paint); 
 paint.setXfermode(new PorterDuffXfermode(Mode.SRC_OVER)); 
 canvas.drawBitmap(roundBitmap, 0, 0, paint); 
 bitmap.recycle(); 
 bitmap = null; 
 roundBitmap.recycle(); 
 roundBitmap = null; 
 scaledBitmap.recycle(); 
 scaledBitmap = null; 
 return outBitmap; 
 } 
 
 /** 
 * function:图片转圆角 
 * 
 * @param bitmap 
 *  需要转的bitmap 
 * @param pixels 
 *  转圆角的弧度 
 * @return 转圆角的bitmap 
 */ 
 public static Bitmap toRoundCorner(Bitmap bitmap, int pixels) 
 { 
 Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), 
  bitmap.getHeight(), Config.ARGB_8888); 
 Canvas canvas = new Canvas(output); 
 final int color = 0xff424242; 
 final Paint paint = new Paint(); 
 final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); 
 final RectF rectF = new RectF(rect); 
 final float roundPx = pixels; 
 paint.setAntiAlias(true); 
 canvas.drawARGB(0, 0, 0, 0); 
 paint.setColor(color); 
 canvas.drawRoundRect(rectF, roundPx, roundPx, paint); 
 paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); 
 canvas.drawBitmap(bitmap, rect, rect, paint); 
 if (bitmap != null && !bitmap.isRecycled()) 
 { 
  bitmap.recycle(); 
 } 
 return output; 
 } 
 
 /** 
 * 获取指定的圆角图片 
 * 
 * @param bitmap 
 * @return 
 */ 
 public static Bitmap getRadiusBitmap(Bitmap bitmap) 
 { 
 Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); 
 paint.setColor(0xffffffff); 
 Bitmap radiusBitmap = Bitmap.createBitmap(bitmap.getWidth(), 
  bitmap.getHeight(), Config.ARGB_8888); 
 Canvas canvas = new Canvas(radiusBitmap); 
 RectF rectF = new RectF(0, 0, bitmap.getWidth(), bitmap.getHeight()); 
 canvas.drawRoundRect(rectF, 7, 7, paint); 
 paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); 
 canvas.drawBitmap(bitmap, 0, 0, paint); 
 if (bitmap != null && !bitmap.isRecycled()) 
 { 
  bitmap.recycle(); 
 } 
 return radiusBitmap; 
 } 
 
 // 获得指定大小的圆边的bitmap数组 
 public static ArrayList getRadiusBitmapList(String[] pathArray, 
  int size, int len, float radius, int color) 
 { 
 Bitmap canvasBitmap = null; 
 Canvas canvas = null; 
 Paint paint = null; 
 RectF rectF = new RectF(0, 0, len - radius, len - radius); 
 File file = null; 
 FileInputStream fis = null; 
 Bitmap bitmap = null; 
 Bitmap scaledBitmap = null; 
 
 ArrayList list = new ArrayList(); 
 for (int i = 0; i < pathArray.length; i++) 
 { 
  file = new File(pathArray[i]); 
  if (!file.exists()) 
  continue; 
  try 
  { 
  fis = new FileInputStream(file); 
  bitmap = BitmapFactory.decodeStream(fis); 
  if (bitmap != null) 
  { 
   canvasBitmap = Bitmap.createBitmap(len, len, 
    Config.ARGB_8888); 
   canvas = new Canvas(canvasBitmap); 
   paint = new Paint(Paint.ANTI_ALIAS_FLAG); 
   paint.setColor(color); 
   canvas.drawRoundRect(rectF, radius, radius, paint); 
   paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); 
 
   scaledBitmap = Bitmap.createScaledBitmap(bitmap, len, len, 
    true); 
   canvas.drawBitmap(scaledBitmap, 0, 0, paint); 
   list.add(canvasBitmap); 
  } 
  } catch (FileNotFoundException e) 
  { 
  } finally 
  { 
  if (fis != null) 
  { 
   try 
   { 
   fis.close(); 
   } catch (IOException e1) 
   { 
   } 
  } 
  } 
  if (list.size() == size) 
  break; 
 } 
 if (scaledBitmap != null && !scaledBitmap.isRecycled()) 
 { 
  scaledBitmap.recycle(); 
  scaledBitmap = null; 
 } 
 if (bitmap != null && !bitmap.isRecycled()) 
 { 
  bitmap.recycle(); 
  bitmap = null; 
 } 
 return list; 
 } 
 
 /** 
 * 按照一定的宽高比例裁剪图片 
 * 
 * @param bitmap 
 * @param num1 
 *  长边的比例 
 * @param num2 
 *  短边的比例 
 * @return 
 */ 
 public static Bitmap ImageCrop(Bitmap bitmap, int num1, int num2, 
  boolean isRecycled) 
 { 
 if (bitmap == null) 
 { 
  return null; 
 } 
 int w = bitmap.getWidth(); // 得到图片的宽，高 
 int h = bitmap.getHeight(); 
 int retX, retY; 
 int nw, nh; 
 if (w > h) 
 { 
  if (h > w * num2 / num1) 
  { 
  nw = w; 
  nh = w * num2 / num1; 
  retX = 0; 
  retY = (h - nh) / 2; 
  } else 
  { 
  nw = h * num1 / num2; 
  nh = h; 
  retX = (w - nw) / 2; 
  retY = 0; 
  } 
 } else 
 { 
  if (w > h * num2 / num1) 
  { 
  nh = h; 
  nw = h * num2 / num1; 
  retY = 0; 
  retX = (w - nw) / 2; 
  } else 
  { 
  nh = w * num1 / num2; 
  nw = w; 
  retY = (h - nh) / 2; 
  retX = 0; 
  } 
 } 
 Bitmap bmp = Bitmap.createBitmap(bitmap, retX, retY, nw, nh, null, 
  false); 
 if (isRecycled && bitmap != null && !bitmap.equals(bmp) 
  && !bitmap.isRecycled()) 
 { 
  bitmap.recycle(); 
  bitmap = null; 
 } 
 return bmp;// Bitmap.createBitmap(bitmap, retX, retY, nw, nh, null, 
   // false); 
 } 
} 

示例代码：Bitmaptest_jb51.rar

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