Update the background of the Daltonizer preview.

Add the corner radii in to be consistent with the Settings style.

Bug: 213440059
Test: manual test
Change-Id: I68edf243ae33e9bb1e39020ad7553451fad66477
diff --git a/res/layout/daltonizer_preview.xml b/res/layout/daltonizer_preview.xml
index de462f1..c500554 100644
--- a/res/layout/daltonizer_preview.xml
+++ b/res/layout/daltonizer_preview.xml
@@ -18,7 +18,9 @@
 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/preview_viewport"
     android:layout_width="match_parent"
-    android:layout_height="wrap_content">
+    android:layout_height="wrap_content"
+    android:paddingStart="?android:attr/listPreferredItemPaddingStart"
+    android:paddingEnd="?android:attr/listPreferredItemPaddingEnd">
 
     <LinearLayout
         android:id="@+id/palette_view"
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index 2468db6..70ac746 100755
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -289,6 +289,7 @@
     <dimen name="accessibility_layout_margin_start_end">16dp</dimen>
     <dimen name="accessibility_button_preference_padding_top_bottom">18dp</dimen>
     <dimen name="accessibility_imageview_size">176dp</dimen>
+    <dimen name="accessibility_illustration_view_radius">28dp</dimen>
     <!-- The margin between two Textviews-->
     <dimen name="accessibility_textview_layout_margin_bottom">24dp</dimen>
 
diff --git a/src/com/android/settings/accessibility/PaletteListPreference.java b/src/com/android/settings/accessibility/PaletteListPreference.java
index ac552eb..4e10b93 100644
--- a/src/com/android/settings/accessibility/PaletteListPreference.java
+++ b/src/com/android/settings/accessibility/PaletteListPreference.java
@@ -148,6 +148,8 @@
 
             rootView.addView(textView);
         }
+
+        updateFirstAndLastItemsBackground(context, rootView, paletteData.size());
     }
 
     private GradientDrawable createGradientDrawable(ViewGroup rootView, @ColorInt int color) {
@@ -164,6 +166,19 @@
         return gradientDrawable;
     }
 
+    private void updateFirstAndLastItemsBackground(Context context, ViewGroup rootView, int size) {
+        final int radius =
+                context.getResources().getDimensionPixelSize(
+                        R.dimen.accessibility_illustration_view_radius);
+        final int lastIndex = size - 1;
+        final GradientDrawable firstItem =
+                (GradientDrawable) rootView.getChildAt(0).getBackground();
+        final GradientDrawable lastItem =
+                (GradientDrawable) rootView.getChildAt(lastIndex).getBackground();
+        firstItem.setCornerRadii(new float[]{radius, radius, radius, radius, 0, 0, 0, 0});
+        lastItem.setCornerRadii(new float[]{0, 0, 0, 0, radius, radius, radius, radius});
+    }
+
     private List<Integer> getPaletteColors(Context context) {
         final int[] paletteResources =
                 context.getResources().getIntArray(R.array.setting_palette_colors);