Create an alpha letter scroller

- The function used is a raised cosine function to determine the sections to animate.

Tested flag: adb shell device_config put launcher com.android.launcher3.letter_fast_scroller true
Based on recent figmaspec, size of selected letter is 28dp and regular is 20dp. That means scaling should be 28/20.
Colors are:
onSurface for letter
surfaceContainer for background.
Figma shows selected colors are materialColorOnSecondary

bug:358673724
Test manually: https://drive.google.com/file/d/1gvJd5KoK8X_Sv8jXg1cZ65R4AuqHuvcd/view?usp=sharing
Flag: com.android.launcher3.letter_fast_scroller

Change-Id: Ia86eb0e8c41bc043fda3c44aeaf59e204429f337

1 files changed, 23 insertions, 0 deletions

diff --git a/res/drawable/bg_letter_list_text.xml b/res/drawable/bg_letter_list_text.xml
new file mode 100644
index 0000000000..427702b045
--- /dev/null
+++ b/res/drawable/bg_letter_list_text.xml
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  ~ Copyright (C) 2024 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="oval">
+    <solid android:color="?attr/materialColorSurfaceContainer" />
+    <corners android:radius="100dp"/>
+    <size
+        android:width="@dimen/bg_letter_list_text_size"
+        android:height="@dimen/bg_letter_list_text_size"/>
+</shape>
\ No newline at end of file