Android中Bitmap,byte[],Drawable相互转化

转载自：http://blog.csdn.net/xidiancoder/article/details/51649465

在surfaceview中结合Camera获取到摄像头图像，这段代码是我程序中的一部分

@Override public 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(); yuv.compressToJpeg(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); } 123456789101112131415161718192021 123456789101112131415161718192021

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现在对三者具体如何互相转换做一说明：

准备：概念说明

1、Drawable就是一个可画的对象,其可能是一张位图(BitmapDrawable),也可能是一个图形(ShapeDrawable),还有可能是一个图层(LayerDrawable),我们根据画图的需求，创建相应的可画对象 2、Canvas画布，绘图的目的区域，用于绘图 3、Bitmap位图，用于图的处理 4、Matrix矩阵 ,图像矩阵

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1.从resources中获取Bitmap

Resources res = getResources(); Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.icon); 12 12

2.Bitmap → byte[]

public byte[] Bitmap2Bytes(Bitmap bm) { ByteArrayOutputStream baos = new ByteArrayOutputStream(); bm.compress(Bitmap.CompressFormat.PNG, 100, baos); return baos.toByteArray(); } 12345 12345

3.byte[] → Bitmap

public Bitmap Bytes2Bimap(byte[] b) { if (b.length != 0) { return BitmapFactory.decodeByteArray(b, 0, b.length); } else { return null; } } 1234567 1234567

4.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; } 12345678910 12345678910

5.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 bitmap Bitmap 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; } 1234567891011121314151617 1234567891011121314151617

6.获得圆角图片

public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float roundPx) { int w = bitmap.getWidth(); int h = bitmap.getHeight(); Bitmap output = Bitmap.createBitmap(w, h, Config.ARGB_8888); Canvas canvas = new Canvas(output); final int color = 0xff424242; final Paint paint = new Paint(); final Rect rect = new Rect(0, 0, w, h); final RectF rectF = new RectF(rect); 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); return output; } 123456789101112131415161718 123456789101112131415161718

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。 123 123

8.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bitmap Bitmap 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); } 12345678910111213141516 12345678910111213141516 (function () {('pre.prettyprint code').each(function () { var lines = (this).text().split(′\n′).length;var numbering = $(' ').addClass('pre-numbering').hide(); (this).addClass(′has−numbering′).parent().append( numbering); for (i = 1; i