pyvxl should not contain implementation code

[drewgilliam]

On a related note, this whole function looks more like an actual implementation than a "wrapping" to me. Can the function be moved to brl somewhere, and then wrapped in the appropriate pyvxl place?

pyvxl/vpgl/pyvpgl.cxx

Lines 323 to 369 in 63b0c1f

	std::tuple<vpgl_local_rational_camera<double>, unsigned, unsigned, unsigned, unsigned>
	crop_image_using_3d_box(unsigned img_ni, unsigned img_nj, vpgl_rational_camera<double> const& cam,
	double lower_left_lon, double lower_left_lat, double lower_left_elev,
	double upper_right_lon, double upper_right_lat, double upper_right_elev,
	double uncertainty, vpgl_lvcs lvcs)
	{
	// generate a lvcs coordinates to transfer camera offset coordinates
	double ori_lon, ori_lat, ori_elev;
	lvcs.get_origin(ori_lat, ori_lon, ori_elev);
	if ( (ori_lat + ori_lon + ori_elev) * (ori_lat + ori_lon + ori_elev) < 1E-7) {
	lvcs = vpgl_lvcs(lower_left_lat, lower_left_lon, lower_left_elev, vpgl_lvcs::wgs84, vpgl_lvcs::DEG, vpgl_lvcs::METERS);
	}
	vgl_box_3d<double> scene_bbox(lower_left_lon, lower_left_lat, lower_left_elev,
	upper_right_lon, upper_right_lat, upper_right_elev);
	vgl_box_2d<double> roi_box_2d;
	bool good = __project_box(cam, lvcs, scene_bbox, uncertainty, roi_box_2d);
	if(!good) {
	throw std::runtime_error("vxl.vpgl.crop_image_using_3d_box: failed to project 2d roi box");
	}
	std::cout << "vxl.vpgl.crop_image_using_3d_box: projected 2d roi box: " << roi_box_2d << " given uncertainty " << uncertainty << " meters." << std::endl;
	// crop the image
	brip_roi broi(img_ni, img_nj);
	vsol_box_2d_sptr bb = new vsol_box_2d();
	bb->add_point(roi_box_2d.min_x(), roi_box_2d.min_y());
	bb->add_point(roi_box_2d.max_x(), roi_box_2d.max_y());
	bb = broi.clip_to_image_bounds(bb);
	// store output
	auto i0 = (unsigned)bb->get_min_x();
	auto j0 = (unsigned)bb->get_min_y();
	auto ni = (unsigned)bb->width();
	auto nj = (unsigned)bb->height();
	if (ni <= 0 || nj <= 0)
	{
	throw std::runtime_error("vxl.vpgl.crop_image_using_3d_box: clipping box is out of image boundary, empty crop image returned");
	}
	// create the local camera
	vpgl_local_rational_camera<double> local_camera = __create_local_rational_camera(cam, lvcs, i0, j0);
	return std::make_tuple(local_camera, i0, j0, ni, nj);
	}

Originally posted by @decrispell in #51 (comment)