call radial correctly

src/shapes/paint/radial_gradient.cpp

diff --git a/src/shapes/paint/radial_gradient.cpp b/src/shapes/paint/radial_gradient.cpp
index fa32389..e5e45c0 100644
--- a/src/shapes/paint/radial_gradient.cpp
+++ b/src/shapes/paint/radial_gradient.cpp
@@ -6,6 +6,6 @@
 void RadialGradient::makeGradient(Vec2D start, Vec2D end,
                                   const ColorInt colors[], const float stops[], size_t count) {
     auto paint = renderPaint();
-    paint->shader(makeRadialGradient(start[0], start[1], end[0],
+    paint->shader(makeRadialGradient(start[0], start[1], Vec2D::distance(start, end),
                                      colors, stops, count, RenderTileMode::clamp));
 }