Android Bitmap,byte[],Drawable,InputStream相互转化

  • 1

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);
    }

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


1.从resources中获取Bitmap

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

2.Bitmap → byte[]

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

3.byte[] → Bitmap

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

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;
    }

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;
    }

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;
    }

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.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);
    }
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