--- a/layout/generic/nsTextFrame.cpp
+++ b/layout/generic/nsTextFrame.cpp
@@ -6631,17 +6631,17 @@ nsTextFrame::PaintText(const PaintTextPa
                             : textPaintStyle.GetWebkitTextStrokeColor();
   if (aOpacity != 1.0f) {
     gfx::Color gfxColor = gfx::Color::FromABGR(textStrokeColor);
     gfxColor.a *= aOpacity;
     textStrokeColor = gfxColor.ToABGR();
   }
 
   range = Range(startOffset, startOffset + maxLength);
-  if (!aParams.callbacks) {
+  if (!aParams.callbacks && !aParams.generateTextMask) {
     const nsStyleText* textStyle = StyleText();
     PaintShadowParams shadowParams(aParams);
     shadowParams.range = range;
     shadowParams.textBaselinePt = textBaselinePt;
     shadowParams.leftSideOffset = snappedStartEdge;
     shadowParams.provider = &provider;
     shadowParams.foregroundColor = foregroundColor;
     shadowParams.clipEdges = &clipEdges;