Fix video height not scaling down when browser window is narrow

This solution still makes sure the video doesn't jump in height
when it loads, and makes it so the video scales down properly in
aspect ratio as the browser window is made narrower.

2 files changed, 57 insertions, 17 deletions

diff --git a/youtube/templates/watch.html b/youtube/templates/watch.html
index 8c67cfc..89f8daa 100644
--- a/youtube/templates/watch.html
+++ b/youtube/templates/watch.html
@@ -49,14 +49,47 @@
         }
 
     {% if settings.theater_mode %}
-        video{
+        /*  This is the constant aspect ratio trick
+            Percentages in padding-top declarations are based on the width of the
+            parent element. We can use this trick to achieve a constant aspect ratio
+            for video-container-inner by setting height to 0.
+
+            So the video height will decrease if the browser window is narrow,
+            but it will keep same aspect ratio. Must use absolute positioning on
+            video to keep it inside its container since the container's height is 0.
+
+            However, because we widen the video player longer than the video's
+            intrinsic width for long video to make scrubbing easier, we can't use
+            the aspect ratio to set the height. The height needs to be the
+            intrinsic height in these cases. So we use a media query so aspect
+            ratio trick is only used if page width is less than or equal to
+            intrinsic video width.
+        */
+        #video-container{
             grid-column: 1 / span 5;
             justify-self: center;
             max-width: 100%;
             width: {{ theater_video_target_width }}px;
             margin-bottom: 10px;
-            background-color: var(--video-background-color);
         }
+            #video-container-inner{
+                height: {{ video_height}}px;
+                position: relative;
+            }
+            @media(max-width:{{ video_width }}px){
+                #video-container-inner{
+                    padding-top: calc(100%*{{video_height}}/{{video_width}});
+                    height: 0px;
+                }
+            }
+                video{
+                    background-color: var(--video-background-color);
+                    position: absolute;
+                    top: 0px;
+                    left: 0px;
+                    width: 100%;
+                    height: 100%;
+                }
         .side-videos{
             grid-row: 2 /span 3;
             width: 400px;
@@ -65,10 +98,12 @@
             width: 640px;
         }
     {% else %}
-        video{
+        #video-container{
+            grid-column: 2;
+        }
+        #video-container, #video-container-inner, video{
             height: 360px;
             width: 640px;
-            grid-column: 2;
         }
         .side-videos{
             grid-row: 1 /span 4;
@@ -340,20 +375,24 @@ Reload without invidious (for usage of new identity button).</a>
             </ol>
         </div>
     {% else %}
-        <video controls autofocus class="video" height="{{ video_height }}px">
-            {% for video_source in video_sources %}
-                <source src="{{ video_source['src'] }}" type="{{ video_source['type'] }}">
-            {% endfor %}
-
-            {% for source in subtitle_sources %}
-                {% if source['on'] %}
-                    <track label="{{ source['label'] }}" src="{{ source['url'] }}" kind="subtitles" srclang="{{ source['srclang'] }}" default>
-                {% else %}
-                    <track label="{{ source['label'] }}" src="{{ source['url'] }}" kind="subtitles" srclang="{{ source['srclang'] }}">
-                {% endif %}
-            {% endfor %}
+        <div id="video-container">
+            <div id="video-container-inner">
+                <video controls autofocus class="video" height="{{ video_height }}px">
+                    {% for video_source in video_sources %}
+                        <source src="{{ video_source['src'] }}" type="{{ video_source['type'] }}">
+                    {% endfor %}
+
+                    {% for source in subtitle_sources %}
+                        {% if source['on'] %}
+                            <track label="{{ source['label'] }}" src="{{ source['url'] }}" kind="subtitles" srclang="{{ source['srclang'] }}" default>
+                        {% else %}
+                            <track label="{{ source['label'] }}" src="{{ source['url'] }}" kind="subtitles" srclang="{{ source['srclang'] }}">
+                        {% endif %}
+                    {% endfor %}
 
-        </video>
+                </video>
+            </div>
+        </div>
         {% if time_start != 0 %}
             <script>
                 document.querySelector('video').currentTime = {{ time_start|tojson }};
diff --git a/youtube/watch.py b/youtube/watch.py
index 75d9ffd..0746cd6 100644
--- a/youtube/watch.py
+++ b/youtube/watch.py
@@ -473,6 +473,7 @@ def get_watch_page(video_id=None):
         settings                = settings,
 
         video_height            = video_height,
+        video_width             = video_width,
         theater_video_target_width = theater_video_target_width,
 
         title       = info['title'],