I'm guessing you moved on, but you can do this using Vector Drawables.
The following is not accurate (the line is not completely straight), but should give you a good start:
New XML file:
<?xml version="1.0" encoding="utf-8"?>
<vector xmlns:android="http://schemas.android.com/apk/res/android"
android:height="100dp"
android:width="100dp"
android:viewportHeight="100"
android:viewportWidth="100">
<path
android:name="dark_triangle"
android:fillColor="@color/blue"
android:pathData="M 0,100 L 0,80 60,70 100,80 100,100 z" />
<path
android:name="light_triangle"
android:fillColor="@color/color_light_blue"
android:pathData="M 60,70 L 100,65 100,80 z" />
</vector>
In your layout:
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="fitCenter"
app:srcCompat="@drawable/test"
/>
You might need to add this to your layout as well:
xmlns:app="http://schemas.android.com/apk/res-auto"
Notes: