diff --git a/shaders/gles2/xcaa-multi-edge-mask-line.fs.glsl b/shaders/gles2/xcaa-multi-edge-mask-line.fs.glsl
index 6558dd3c..cf8cfc25 100644
--- a/shaders/gles2/xcaa-multi-edge-mask-line.fs.glsl
+++ b/shaders/gles2/xcaa-multi-edge-mask-line.fs.glsl
@@ -23,7 +23,7 @@ void main() {
     vec4 p0DPX = clipLineToPixelColumn(p0, dP, pixelCenter.x);
 
     // Discard if not edge.
-    if (!isPartiallyCovered(p0DPX.xy, p0DPX.zw - p0DPX.xy, pixelCenter.y))
+    if (!isPartiallyCovered(p0DPX.xy, p0DPX.zw, pixelCenter.y))
         discard;
     gl_FragColor = vec4(1.0);
 }