Hi, Thanks for your reply, I knew that. Oh, let me clarify what problem I actually have: Consider the class Image: class Image { public: Image() { } Image(std::string& file) { // using io extension to read image. // ... } Image(const Image& other) { img = other.img; // view = boost::gil::view(img); view = other.view; } Image& Image::Crop(int x, int y, int width, int height) { view = boost::gil::subimage_view(view, x, y, width, height); return *this; } void Image::Crop(int x, int y, int width, int height, Image& out) const { out = *this; out.Crop(x, y, width, height); } Image& Image::Fill(int x1, int y1, int x2, int y2, int r, int g, int b) { boost::gil::rgb8_pixel_t pixel(r, g, b); boost::gil::fill_pixels( boost::gil::subimage_view(view, x1, y1, x2 - x1, y2 - y1), pixel); return *this; } private: boost::gil::rgb8_image_t img; boost::gil::rgb8_image_t::view_t view; }; Image a("a.png"); // 100x100 size. a.Crop(100, 100, 50, 50); // Now, the a should be 50x50 size. Image b; a.Crop(0, 0, 10, 10, b); // b should be 10x10. a.Fill(0, 0, 10, 10, 0xff, 0xff, 0xff); // This will cause b also filled with white color. How to change my Image class to make a.Fill not to affect b? Thank you very much. -- View this message in context: http://www.nabble.com/-GIL--How-can-I-copy-a-subimage_view-to-a-view--tp2323... Sent from the Boost - Users mailing list archive at Nabble.com.