diff --git a/graphics.cpp b/graphics.cpp
index f0b73a8..7eb52e7 100644
--- a/graphics.cpp
+++ b/graphics.cpp
@@ -18,6 +18,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include "graphics.h"
+#include "mpreal.h"
 #include <SDL2/SDL.h>
 #include <SDL2/SDL_pixels.h>
 #include <SDL2/SDL_render.h>
@@ -428,6 +429,16 @@ void Graphics::mainLoop()
                     this->m_end.x = event.motion.x;
                     this->m_end.y = event.motion.y;
                     break;
+                case SDL_KEYUP:
+                    if (event.key.keysym.scancode == SDL_SCANCODE_R) {
+                        mpreal::set_default_prec(mpfr::digits2bits(20));
+                        m.f.x = mpreal(-2.0);
+                        m.f.y = mpreal(-1.0);
+                        m.t.x = mpreal(1.0);
+                        m.t.y = mpreal(1.0);
+                        m.diff = mpreal(0.0001);
+                    }
+                    break;
             }
         }