Add option to limit canvas size

JSO struggles with complex subtitles on HiDPI canvasses, so limiting the size can make sense if such subtitles are expected. This was ported from jellyfin's fork and jellyfin-web uses this on at least some devices. In the original implementation prescaleHeightLimit would override maxRenderHeight if it was larger. This undocumentend behaviour was dropped here as it seemed unintuitive and unhelpful. [Vasily <[email protected]>] Original implementation together with prescaling in jellyfin@345d701 jellyfin@4c5f018 [Dmitry Lyzo] Rebased for upstream; seperated from the prescaling; removed default height limit and added docs [Oneric] Renamed hardHeightLimit to maxRenderHeight; split from prescaling. Co-Authored-By: Dmitry Lyzo <[email protected]>
TFSThiagoBR98 · Feb 16, 2022 · 5ebf13d · 5ebf13d
1 parent e9fc7c5
commit 5ebf13d
Show file tree

Hide file tree

Showing 2 changed files with 7 additions and 0 deletions.
diff --git a/README.md b/README.md
@@ -137,6 +137,9 @@ When creating an instance of SubtitleOctopus, you can set the following options:
                     (Default: `1.0` - no scaling; must be a number > 0)
 - `prescaleHeightLimit`: The height beyond which the subtitles canvas won't be prescaled.
                          (Default: `1080`)
+- `maxRenderHeight`: The maximum rendering height of the subtitles canvas.
+                     Beyond this subtitles will be upscaled by the browser.
+                     (Default: `0` - no limit)
 
 ### Rendering Modes
 #### JS Blending

diff --git a/src/subtitles-octopus.js b/src/subtitles-octopus.js
@@ -19,6 +19,7 @@ var SubtitlesOctopus = function (options) {
     self.targetFps = options.targetFps || 24;
     self.prescaleFactor = options.prescaleFactor || 1.0;
     self.prescaleHeightLimit = options.prescaleHeightLimit || 1080;
+    self.maxRenderHeight = options.maxRenderHeight || 0; // 0 - no limit
     self.isOurCanvas = false; // (internal) we created canvas and manage it
     self.video = options.video; // HTML video element (optional if canvas specified)
     self.canvasParent = null; // (internal) HTML canvas parent element
@@ -420,6 +421,9 @@ var SubtitlesOctopus = function (options) {
             else if (sgn * newH < sgn * self.prescaleHeightLimit)
                 newH = self.prescaleHeightLimit;
 
+            if (self.maxRenderHeight > 0 && newH > self.maxRenderHeight)
+                newH = self.maxRenderHeight;
+
             width *= newH / height;
             height = newH;
         }