diff --git a/java/res/values/attrs.xml b/java/res/values/attrs.xml
index e601397..7e8c77e 100644
--- a/java/res/values/attrs.xml
+++ b/java/res/values/attrs.xml
@@ -90,7 +90,8 @@
         <!-- Interval of updating gesture preview trail in millisecond. -->
         <attr name="gesturePreviewTrailUpdateInterval" format="integer" />
         <attr name="gesturePreviewTrailColor" format="color" />
-        <attr name="gesturePreviewTrailWidth" format="dimension" />
+        <attr name="gesturePreviewTrailStartWidth" format="dimension" />
+        <attr name="gesturePreviewTrailEndWidth" format="dimension" />
     </declare-styleable>
 
     <declare-styleable name="MainKeyboardView">
diff --git a/java/res/values/dimens.xml b/java/res/values/dimens.xml
index 9ccaaaf..d92a715 100644
--- a/java/res/values/dimens.xml
+++ b/java/res/values/dimens.xml
@@ -100,7 +100,8 @@
     <fraction name="center_suggestion_percentile">36%</fraction>
 
     <!-- Gesture preview trail parameters -->
-    <dimen name="gesture_preview_trail_width">2.5dp</dimen>
+    <dimen name="gesture_preview_trail_start_width">18.0dp</dimen>
+    <dimen name="gesture_preview_trail_end_width">2.5dp</dimen>
     <!-- Gesture floating preview text parameters -->
     <dimen name="gesture_floating_preview_text_size">24dp</dimen>
     <dimen name="gesture_floating_preview_text_offset">73dp</dimen>
diff --git a/java/res/values/styles.xml b/java/res/values/styles.xml
index 94fdbeb..ed92440 100644
--- a/java/res/values/styles.xml
+++ b/java/res/values/styles.xml
@@ -77,7 +77,8 @@
         <item name="gesturePreviewTrailFadeoutDuration">@integer/config_gesture_preview_trail_fadeout_duration</item>
         <item name="gesturePreviewTrailUpdateInterval">@integer/config_gesture_preview_trail_update_interval</item>
         <item name="gesturePreviewTrailColor">@android:color/holo_blue_light</item>
-        <item name="gesturePreviewTrailWidth">@dimen/gesture_preview_trail_width</item>
+        <item name="gesturePreviewTrailStartWidth">@dimen/gesture_preview_trail_start_width</item>
+        <item name="gesturePreviewTrailEndWidth">@dimen/gesture_preview_trail_end_width</item>
         <!-- Common attributes of MainKeyboardView -->
         <item name="keyHysteresisDistance">@dimen/config_key_hysteresis_distance</item>
         <item name="touchNoiseThresholdTime">@integer/config_touch_noise_threshold_time</item>