Fix key previews positioned offscreen (outside keyboard)

Author: yawnoc

app/src/main/java/io/github/yawnoc/strokeinput/InputContainer.java

@@ -40,6 +40,8 @@
 
 import androidx.core.graphics.ColorUtils;
 
+import io.github.yawnoc.utilities.Valuey;
+
 /*
   A container that holds:
     - Candidates bar
@@ -682,7 +684,15 @@ private void updateKeyPreview() {
     final int previewHeight = keyPreview.height;
 
     final int previewMargin = activeKey.previewMargin;
-    final int previewX = activeKey.x - (previewWidth - activeKey.width) / 2;
+    
+    final int keyboardLeftX = 0;
+    final int keyboardRightX = keyboard.getWidth() - previewWidth;
+    final int previewX =
+      (int) Valuey.clipValueToRange(
+        activeKey.x - (previewWidth - activeKey.width) / 2f,
+        keyboardLeftX,
+        keyboardRightX
+      );
     final int previewY = activeKey.y - previewHeight - previewMargin;
 
     if (keyPreviewPopup.isShowing()) {

app/src/main/java/io/github/yawnoc/utilities/Valuey.java

@@ -29,6 +29,15 @@ private Valuey() {
     // Do not instantiate
   }
 
+  public static float clipValueToRange(
+    final float value,
+    final float rangeMin,
+    final float rangeMax
+  )
+  {
+    return Math.max(rangeMin, Math.min(rangeMax, value));
+  }
+  
   public static int getDimensionOrFraction(
     final TypedArray array,
     final int attributeIndex,