spieleprogrammierer.de - Forum und Wiki zur Spieleprogrammierung und Spieleentwicklung

C-/C++-Quelltext

            void Slider::set_value(std::size_t value)
            {
                if (value < m_range.first) value = m_range.first;
                else if (value > m_range.second) value = m_range.second;
                else if (m_value == value) return;
            
                ::RECT rect;
                ::GetClientRect(m_hWnd, &rect);
                
                // value multiplier

                const double multiplier(static_cast<double>(rect.right - rect.left - 10) / (m_range.second - m_range.first));

                // old cursor pos

                const long old_x(rect.left + static_cast<long>(multiplier * (m_value - m_range.first)));
                
                // old cursor rect

                const ::RECT old_rect = { old_x - 5, rect.top, old_x + 5, rect.bottom };
        
                const std::size_t old_value(m_value);
                m_value = value;
                
                // new cursor pos

                const long new_x(rect.left + 5 + static_cast<long>(multiplier * (m_value - m_range.first)));
                rect.left   = new_x - 5;
                rect.right  = new_x + 5;

                // redraw old and new rect

                ::InvalidateRect(m_hWnd, &old_rect, TRUE);
                ::InvalidateRect(m_hWnd, &rect, TRUE);

                ::SendMessageW(m_pParentWnd->get_safe_hwnd(), SMN_POSCHANGE, MAKEWPARAM(old_value, m_value), reinterpret_cast<LPARAM>(m_hWnd));
            }