1、byte[](YuvImage )->Bitmap

在相机开发中，Camera获取到摄像头每一帧的图像数据byte[]，有时候需要把它转为Bitmap

@Overridepublic void onPreviewFrame(final byte[] data, Camera camera) {camera.setPreviewCallback(null);if (mCamera == null)return;Camera.Parameters parameters = camera.getParameters();int width = parameters.getPreviewSize().width;int height = parameters.getPreviewSize().height;YuvImage yuv = new YuvImage(data, parameters.getPreviewFormat(), width, height, null);ByteArrayOutputStream out = new ByteArrayOutputStream();pressToJpeg(new Rect(0, 0, width, height), 50, out);byte[] bytes = out.toByteArray();final Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);this.mCamera.setPreviewCallback(this);}

2、byte[](YuvImage )顺时针旋转90度

Camera获取到摄像头图像帧数据，直接把byte[]数据进行图像旋转。

private byte[] rotateYUV420Degree90(byte[] data, int imageWidth, int imageHeight) {byte [] yuv = new byte[imageWidth*imageHeight*3/2];// Rotate the Y lumaint i = 0;for(int x = 0;x < imageWidth;x++){for(int y = imageHeight-1;y >= 0;y--) {yuv[i] = data[y*imageWidth+x];i++;}}// Rotate the U and V color components i = imageWidth*imageHeight*3/2-1;for(int x = imageWidth-1;x > 0;x=x-2){for(int y = 0;y < imageHeight/2;y++) {yuv[i] = data[(imageWidth*imageHeight)+(y*imageWidth)+x];i--;yuv[i] = data[(imageWidth*imageHeight)+(y*imageWidth)+(x-1)];i--;}}return yuv;}

Android很多使用zxing扫码工具，关于获取预览帧进行旋转的代码，大多数都是错误的，包括徐医生的在内的。我从Zxing官方项目，下载源码进行了优化和精简，使用了很多不错的特性。源码地址/JantHsueh/ZxingAndroid

3 、从resources中获取Bitmap

Resources res = getResources();Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.icon);

4、Bitmap → byte[]

public byte[] Bitmap2Bytes(Bitmap bm) {ByteArrayOutputStream baos = new ByteArrayOutputStream();press(pressFormat.PNG, 100, baos);return baos.toByteArray();}

5、byte[] → Bitmap

public Bitmap Bytes2Bimap(byte[] b) {if (b.length != 0) {return BitmapFactory.decodeByteArray(b, 0, b.length);} else {return null;}}

6、将Drawable转化为Bitmap

public static Bitmap drawableToBitmap(Drawable drawable) {// 取 drawable 的长宽int w = drawable.getIntrinsicWidth();int h = drawable.getIntrinsicHeight();// 取 drawable 的颜色格式Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888: Bitmap.Config.RGB_565;// 建立对应 bitmapBitmap bitmap = Bitmap.createBitmap(w, h, config);// 建立对应 bitmap 的画布Canvas canvas = new Canvas(bitmap);drawable.setBounds(0, 0, w, h);// 把 drawable 内容画到画布中drawable.draw(canvas);return bitmap;}

7、Bitmap转换成Drawable

Bitmap bm=xxx; //xxx根据你的情况获取BitmapDrawable bd= new BitmapDrawable(getResource(), bm); //因为BtimapDrawable是Drawable的子类，最终直接使用bd对象即可。

8、Bitmap缩放

public static Bitmap zoomBitmap(Bitmap bitmap, int width, int height) {int w = bitmap.getWidth();int h = bitmap.getHeight();Matrix matrix = new Matrix();float scaleWidth = ((float) width / w);float scaleHeight = ((float) height / h);matrix.postScale(scaleWidth, scaleHeight);Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true);return newbmp;}

9、Drawable缩放

public static Drawable zoomDrawable(Drawable drawable, int w, int h) {int width = drawable.getIntrinsicWidth();int height = drawable.getIntrinsicHeight();// drawable转换成bitmapBitmap oldbmp = drawableToBitmap(drawable);// 创建操作图片用的Matrix对象Matrix matrix = new Matrix();// 计算缩放比例float sx = ((float) w / width);float sy = ((float) h / height);// 设置缩放比例matrix.postScale(sx, sy);// 建立新的bitmap，其内容是对原bitmap的缩放后的图Bitmap newbmp = Bitmap.createBitmap(oldbmp, 0, 0, width, height,matrix, true);return new BitmapDrawable(newbmp);}

参考：

Android开发——Bitmap,byte[],Drawable相互转化

关于android的YuvImage旋转

Rotate an YUV byte array on Android

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