fix(tldraw): only send diffs updates to server

When a shape is changed, the full shape objcect was being transmitted to the server again.
Do a diff to only send what changed (similarly  as it was in tldraw v1) to save upload bw.

TODO:
Draw segments diffs (array) is still not working, so all the segments are still being sent every time.

akka-bbb-apps/src/main/scala/org/bigbluebutton/core/apps/WhiteboardModel.scala

@@ -50,6 +50,7 @@ class WhiteboardModel extends SystemConfiguration {
     val wb = getWhiteboard(wbId)
 
     var annotationsAdded = Array[AnnotationVO]()
+    var annotationsDiffAdded = Array[AnnotationVO]()
     var newAnnotationsMap = wb.annotationsMap
 
     for (annotation <- annotations) {
@@ -57,21 +58,10 @@ class WhiteboardModel extends SystemConfiguration {
       if (oldAnnotation.isDefined) {
         val hasPermission = isPresenter || isModerator || oldAnnotation.get.userId == userId
         if (hasPermission) {
-          // Determine if the annotation is a line shape
+          val mergedAnnotationInfo = deepMerge(oldAnnotation.get.annotationInfo, annotation.annotationInfo)
-          val isLineShape = annotation.annotationInfo.get("type").contains("line")
-
-          // Merge old and new annotation properties with special handling for line shape
-          val mergedAnnotationInfo = if (isLineShape) {
-            val newProps = annotation.annotationInfo.get("props").asInstanceOf[Option[Map[String, Any]]].getOrElse(Map.empty)
-            val oldProps = oldAnnotation.get.annotationInfo.get("props").asInstanceOf[Option[Map[String, Any]]].getOrElse(Map.empty)
-            val updatedProps = overwriteLineShapeHandles(oldProps, newProps)
-            annotation.annotationInfo + ("props" -> updatedProps)
-          } else {
-            deepMerge(oldAnnotation.get.annotationInfo, annotation.annotationInfo)
-          }
 
           // Apply cleaning if it's an arrow annotation
-          val finalAnnotationInfo = if (annotation.annotationInfo.get("type").contains("arrow")) {
+          val finalAnnotationInfo = if (oldAnnotation.get.annotationInfo.get("type").contains("arrow")) {
             cleanArrowAnnotationProps(mergedAnnotationInfo)
           } else {
             mergedAnnotationInfo
@@ -80,6 +70,7 @@ class WhiteboardModel extends SystemConfiguration {
           val newAnnotation = oldAnnotation.get.copy(annotationInfo = finalAnnotationInfo)
           newAnnotationsMap += (annotation.id -> newAnnotation)
           annotationsAdded :+= newAnnotation
+          annotationsDiffAdded :+= annotation
           println(s"Updated annotation on page [${wb.id}]. After numAnnotations=[${newAnnotationsMap.size}].")
         } else {
           println(s"User $userId doesn't have permission to edit annotation ${annotation.id}, ignoring...")
@@ -87,6 +78,7 @@ class WhiteboardModel extends SystemConfiguration {
       } else if (annotation.annotationInfo.contains("type")) {
         newAnnotationsMap += (annotation.id -> annotation)
         annotationsAdded :+= annotation
+        annotationsDiffAdded :+= annotation
         println(s"Adding annotation to page [${wb.id}]. After numAnnotations=[${newAnnotationsMap.size}].")
       } else {
         println(s"New annotation [${annotation.id}] with no type, ignoring...")
@@ -97,7 +89,7 @@ class WhiteboardModel extends SystemConfiguration {
 
     val newWb = wb.copy(annotationsMap = newAnnotationsMap)
     saveWhiteboard(newWb)
-    annotationsAdded
+    annotationsDiffAdded
   }
 
   private def overwriteLineShapeHandles(oldProps: Map[String, Any], newProps: Map[String, Any]): Map[String, Any] = {

bigbluebutton-html5/imports/ui/components/whiteboard/component.jsx

@@ -25,6 +25,7 @@ import {
   mapLanguage,
   isValidShapeType,
   usePrevious,
+  getDifferences,
 } from './utils';
 import { useMouseEvents, useCursor } from './hooks';
 import { notifyShapeNumberExceeded, getCustomEditorAssetUrls, getCustomAssetUrls } from './service';
@@ -507,7 +508,15 @@ const Whiteboard = React.memo((props) => {
             },
           };
 
-          shapeBatchRef.current[updatedRecord.id] = updatedRecord;
+          const diff = getDifferences(prevShapesRef.current[record?.id], updatedRecord);
+
+          if (diff) {
+            diff.id = record.id;
+
+            shapeBatchRef.current[updatedRecord.id] = diff;
+          } else {
+            shapeBatchRef.current[updatedRecord.id] = updatedRecord;
+          }
         });
 
         // Handle removed shapes immediately (not batched)

bigbluebutton-html5/imports/ui/components/whiteboard/utils.js

@@ -30,11 +30,40 @@ const mapLanguage = (language) => {
   }
 };
 
+const getDifferences = (prev, next) => {
+  // Check if the two values are the same
+  if (prev === next) return undefined;
+
+  // If both are arrays, find the differences
+  if (Array.isArray(prev) && Array.isArray(next)) {
+    const differences = next.filter((item, index) => prev[index] !== item);
+    return differences.length > 0 ? differences : [];
+  }
+
+  // If both are objects, recursively check their properties
+  if (typeof prev === 'object' && typeof next === 'object' && prev !== null && next !== null) {
+    const differences = {};
+
+    Object.keys(next).forEach((key) => {
+      if (Object.prototype.hasOwnProperty.call(next, key)) {
+        const diff = getDifferences(prev[key], next[key]);
+        if (diff !== undefined) {
+          differences[key] = diff;
+        }
+      }
+    });
+    return Object.keys(differences).length > 0 ? differences : undefined;
+  }
+
+  // For other types, return the next value if different
+  return next;
+};
+
 const Utils = {
-  usePrevious, mapLanguage, isValidShapeType,
+  usePrevious, mapLanguage, isValidShapeType, getDifferences,
 };
 
 export default Utils;
 export {
-  usePrevious, mapLanguage, isValidShapeType,
+  usePrevious, mapLanguage, isValidShapeType, getDifferences,
 };

record-and-playback/presentation/scripts/publish/presentation.rb

@@ -575,6 +575,17 @@ def determine_slide_number(slide, current_slide)
   slide
 end
 
+def clean_arrow_end_or_start_props(props)
+  if props['type'] == 'binding'
+    # Remove 'x' and 'y' for 'binding' type
+    props = props.except('x', 'y')
+  elsif props['type'] == 'point'
+    # Remove unwanted properties for 'point' type
+    props = props.except('boundShapeId', 'normalizedAnchor', 'isExact', 'isPrecise')
+  end
+  props
+end
+
 def events_parse_tldraw_shape(shapes, event, current_presentation, current_slide, timestamp)
   presentation = event.at_xpath('presentation')
   slide = event.at_xpath('pageNumber')
@@ -615,6 +626,11 @@ def events_parse_tldraw_shape(shapes, event, current_presentation, current_slide
     prev_shape[:out] = timestamp
     shape[:shape_unique_id] = prev_shape[:shape_unique_id]
     shape[:shape_data] = prev_shape[:shape_data].deep_merge(shape[:shape_data])
+    # special handling to remove unwanted merged arrow props in tldraw v2
+    if shape[:shape_data]['type'] == 'arrow' && shape[:shape_data].key?('props')
+      shape[:shape_data]['props']['start'] = clean_arrow_end_or_start_props(shape[:shape_data]['props']['start'])
+      shape[:shape_data]['props']['end'] = clean_arrow_end_or_start_props(shape[:shape_data]['props']['end'])
+    end
   else
     shape[:shape_unique_id] = @svg_shape_unique_id
     @svg_shape_unique_id += 1