Android 图片Bitmap的剪切

本是古典何须时尚 2022-08-26 12:22 1842阅读 0赞

### 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 ###

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<Bitmap> 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<Bitmap> list = new ArrayList<Bitmap>();
    		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：http://download.csdn.net/detail/stop\_pig/7162695