静态方法,几个参数看一眼就能明白的

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