From a6890fc8dd486a2bfbe06a645ea5681e0dbfbf3c Mon Sep 17 00:00:00 2001
From: Alan Evans <alan@signal.org>
Date: Tue, 30 Jul 2019 14:25:35 -0400
Subject: [PATCH] Video playback on TextureView and DepthPageTransformer.

---
 res/layout-v16/video_player.xml               | 17 --------
 res/layout/video_player.xml                   | 23 ++++++-----
 .../securesms/MediaPreviewActivity.java       |  2 +
 .../animation/DepthPageTransformer.java       | 40 +++++++++++++++++++
 4 files changed, 56 insertions(+), 26 deletions(-)
 delete mode 100644 res/layout-v16/video_player.xml
 create mode 100644 src/org/thoughtcrime/securesms/animation/DepthPageTransformer.java

diff --git a/res/layout-v16/video_player.xml b/res/layout-v16/video_player.xml
deleted file mode 100644
index b855fca65a..0000000000
--- a/res/layout-v16/video_player.xml
+++ /dev/null
@@ -1,17 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<FrameLayout
-    xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
-    android:orientation="vertical"
-    android:layout_width="match_parent"
-    android:layout_height="match_parent">
-
-    <com.google.android.exoplayer2.ui.PlayerView
-        android:id="@+id/video_view"
-        android:layout_width="match_parent"
-        android:layout_height="match_parent"
-        android:layout_gravity="center"
-        android:gravity="center"
-        app:player_layout_id="@layout/media_preview_exoplayer_layout"/>
-
-</FrameLayout>
\ No newline at end of file
diff --git a/res/layout/video_player.xml b/res/layout/video_player.xml
index 144e0f51ec..8a958bcb94 100644
--- a/res/layout/video_player.xml
+++ b/res/layout/video_player.xml
@@ -1,13 +1,18 @@
 <?xml version="1.0" encoding="utf-8"?>
-<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
-              android:orientation="vertical"
-              android:layout_width="match_parent"
-              android:layout_height="match_parent">
+<FrameLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:orientation="vertical"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
 
-    <VideoView android:id="@+id/video_view"
-               android:layout_width="match_parent"
-               android:layout_height="match_parent"
-               android:layout_gravity="center"
-               android:gravity="center"/>
+    <com.google.android.exoplayer2.ui.PlayerView
+        android:id="@+id/video_view"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_gravity="center"
+        android:gravity="center"
+        app:surface_type="texture_view"
+        app:player_layout_id="@layout/media_preview_exoplayer_layout"/>
 
 </FrameLayout>
\ No newline at end of file
diff --git a/src/org/thoughtcrime/securesms/MediaPreviewActivity.java b/src/org/thoughtcrime/securesms/MediaPreviewActivity.java
index 809f8f3e3a..a247bfe493 100644
--- a/src/org/thoughtcrime/securesms/MediaPreviewActivity.java
+++ b/src/org/thoughtcrime/securesms/MediaPreviewActivity.java
@@ -47,6 +47,7 @@ import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.viewpager.widget.ViewPager;
 
+import org.thoughtcrime.securesms.animation.DepthPageTransformer;
 import org.thoughtcrime.securesms.attachments.DatabaseAttachment;
 import org.thoughtcrime.securesms.components.viewpager.ExtendedOnPageChangedListener;
 import org.thoughtcrime.securesms.database.Address;
@@ -192,6 +193,7 @@ public final class MediaPreviewActivity extends PassphraseRequiredActionBarActiv
   private void initializeViews() {
     mediaPager = findViewById(R.id.media_pager);
     mediaPager.setOffscreenPageLimit(1);
+    mediaPager.setPageTransformer(true, new DepthPageTransformer());
 
     viewPagerListener = new ViewPagerListener();
     mediaPager.addOnPageChangeListener(viewPagerListener);
diff --git a/src/org/thoughtcrime/securesms/animation/DepthPageTransformer.java b/src/org/thoughtcrime/securesms/animation/DepthPageTransformer.java
new file mode 100644
index 0000000000..da935281b3
--- /dev/null
+++ b/src/org/thoughtcrime/securesms/animation/DepthPageTransformer.java
@@ -0,0 +1,40 @@
+package org.thoughtcrime.securesms.animation;
+
+import android.view.View;
+
+import androidx.annotation.NonNull;
+import androidx.viewpager.widget.ViewPager;
+
+/**
+ * Based on https://developer.android.com/training/animation/screen-slide#depth-page
+ */
+public final class DepthPageTransformer implements ViewPager.PageTransformer {
+  private static final float MIN_SCALE = 0.75f;
+
+  public void transformPage(@NonNull View view, float position) {
+    final int pageWidth = view.getWidth();
+
+    if (position < -1f) {
+      view.setAlpha(0f);
+
+    } else if (position <= 0f) {
+      view.setAlpha(1f);
+      view.setTranslationX(0f);
+      view.setScaleX(1f);
+      view.setScaleY(1f);
+
+    } else if (position <= 1f) {
+      view.setAlpha(1f - position);
+
+      view.setTranslationX(pageWidth * -position);
+
+      final float scaleFactor = MIN_SCALE + (1f - MIN_SCALE) * (1f - Math.abs(position));
+
+      view.setScaleX(scaleFactor);
+      view.setScaleY(scaleFactor);
+
+    } else {
+      view.setAlpha(0f);
+    }
+  }
+}