diff --git a/src/shaders/piechart.frag b/src/shaders/piechart.frag
index 889ec39..2bc2b32 100644
--- a/src/shaders/piechart.frag
+++ b/src/shaders/piechart.frag
@@ -1,68 +1,75 @@
 /*
  * This file is part of KQuickCharts
  * SPDX-FileCopyrightText: 2019 Arjen Hiemstra <ahiemstra@heimr.nl>
  *
  * SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
  */
 
 // This requires "sdf.frag" which is included through SDFShader.
 
 // The maximum number of segments we can support for a single pie.
 // This is based on OpenGL's MAX_FRAGMENT_UNIFORM_COMPONENTS.
 // MAX_FRAGMENT_UNIFORM_COMPONENTS is required to be at least 1024.
 // Assuming a segment of size 1, each segment needs
 // 2 (size of a vec2) * 2 (number of points) + 4 (size of vec4) + 1 (segment size)
 // components. We also need to leave some room for the other uniforms.
 #define MAX_SEGMENTS 100
 
 uniform lowp float opacity;
 uniform lowp float innerRadius;
 uniform lowp float outerRadius;
 uniform lowp vec4 backgroundColor;
 uniform bool smoothEnds;
 uniform lowp float fromAngle;
 uniform lowp float toAngle;
 
 uniform lowp vec2 segments[MAX_SEGMENTS];
 uniform lowp vec4 colors[MAX_SEGMENTS];
 uniform int segmentCount;
 
 #ifdef LEGACY_STAGE_INOUT
 varying lowp vec2 uv;
 #else
 in lowp vec2 uv;
 out lowp vec4 out_color;
 #endif
 
 const lowp vec2 origin = vec2(0.0, 0.0);
 const lowp float lineSmooth = 0.001;
 
 lowp float rounded_segment(lowp float from, lowp float to, lowp float inner, lowp float outer, lowp float rounding)
 {
     return sdf_torus_segment(uv, from + rounding, to - rounding, inner + rounding, outer - rounding) - rounding;
 }
 
 void main()
 {
     lowp vec4 color = vec4(0.0);
 
     lowp float thickness = (outerRadius - innerRadius) / 2.0;
     lowp float rounding = smoothEnds ? thickness : 0.0;
 
     // Background first, slightly smaller than the actual pie to avoid antialiasing artifacts.
-    lowp float torus = sdf_annular(sdf_torus_segment(uv,   innerRadius + thickness), thickness - 0.001);
-    color = sdf_render(torus, color, backgroundColor);
+    lowp float background = sdf_null;
+    if ((toAngle - fromAngle) >= 2.0 * pi) {
+        // In this case, we want the entire background to be filled, regardless of smoothing.
+        // So use a full circle instead of just a segment, since the segment will be rounded.
+        background = sdf_annular(sdf_circle(uv, innerRadius + thickness), thickness - 0.001);
+    } else {
+        background = rounded_segment(fromAngle, toAngle, innerRadius, outerRadius, rounding + 0.001);
+    }
+    color = sdf_render(background, color, backgroundColor);
 
     for (int i = 0; i < segmentCount && i < MAX_SEGMENTS; ++i) {
         lowp vec2 segment = segments[i];
 
         lowp float segment_sdf = rounded_segment(segment.x, segment.y, innerRadius, outerRadius, rounding);
         color = sdf_render(segment_sdf, color, colors[i]);
     }
 
 #ifdef LEGACY_STAGE_INOUT
     gl_FragColor = color * opacity;
 #else
     out_color = color * opacity;
 #endif
 }