Fix playback of empty slice.

app/svganim/strokes.py

@@ -232,7 +232,7 @@ class AnimationSlice:
         strokes = self.getStrokeSlices(frame_in, frame_out, t_in)
         # TODO shift t of points with t_in
         viewboxes = self.getViewboxesSlice(t_in, t_out)
-        print(viewboxes[0])
+        
         audio = self.audio.getSlice(t_in, t_out) if self.audio else None
         return AnimationSlice([self.id[0], t_in, t_out], strokes, viewboxes, t_in, t_out, audio)
 
@@ -287,8 +287,17 @@ class AnimationSlice:
     ) -> list[Stroke]:
         """Get list of Stroke/StrokeSlice based in in and out indexes
         Based on annotation.js getStrokesSliceForPathRange(in_point, out_point)
+        If either in point or out point is [None, None], return an empty set.
         """
         slices = []
+        if index_in[0] is None and index_in[1] is None:
+            # If no inpoint is set, in_point is after the last stroke
+            return slices
+        
+        if index_out[0] is None and index_out[1] is None:
+            # If no out point is set, out_point is before the last stroke
+            return slices
+
         for i in range(index_in[0], index_out[0] + 1):
             try:
                 stroke = self.strokes[i]
@@ -308,8 +317,8 @@ class AnimationSlice:
         The In point version (so the first index after ms)
         Equal to annotations.js findPositionForTime(ms)
         """
-        path_i = 0
-        point_i = 0
+        path_i = None
+        point_i = None
         for i, stroke in enumerate(self.strokes):
             start_at = stroke.points[0].t
             end_at = stroke.points[-1].t
@@ -329,6 +338,9 @@ class AnimationSlice:
                     if point.t > ms:
                         break  # stop when finding the next point after in point
                 break  # done :-)
+        if path_i is None or point_i is None:
+            logger.warn("in point after last stroke. Not sure if this works")
+            pass
         return (path_i, point_i)
 
     def getIndexForOutPoint(self, ms: Milliseconds) -> FrameIndex:
@@ -342,8 +354,8 @@ class AnimationSlice:
         """Get the frame index (path, point) based on the given time
         Equal to annotations.js findPositionForTime(ms)
         """
-        path_i = 0
-        point_i = 0
+        path_i = None
+        point_i = None
         for i, stroke in enumerate(self.strokes):
             start_at = stroke.points[0].t
             end_at = stroke.points[-1].t
@@ -363,6 +375,10 @@ class AnimationSlice:
                 # best option thus far
                 path_i = i
                 point_i = len(stroke.points) - 1
+        
+        if path_i is None or point_i is None:
+            logger.warn("OUT point after last stroke. Not sure if this works")
+            pass
         return (path_i, point_i)
 
 audiocache = {}

app/www/annotate.js

@@ -716,8 +716,8 @@ class Annotator extends EventTarget {
         // bgEl.setAttribute("height", this.dimensions[1]);
         // bgEl.classList.add('background');
         // this.svgEl.prepend(bgEl);
-
-        this.firstFrameTime = this.strokes[0].points[0][3];
+        
+        this.firstFrameTime = this.strokes.length == 0 ? 0 : this.strokes[0].points[0][3];
         this.lastFrameTime = this.getFinalFrameTime();
         this.playheadEl.max = this.lastFrameTime;
         this.nextFrameTimeout = null;
@@ -817,7 +817,7 @@ class Annotator extends EventTarget {
                 this.audioEl.setAttribute('controls', true);
 
             this.audioEl.addEventListener('canplaythrough', (ev) => {
-                console.log('loaded audio', ev);
+                console.debug('loaded audio');
                 // this.audioEl.play();
             });
 
@@ -959,6 +959,7 @@ class Annotator extends EventTarget {
     }
 
     getFinalFrameTime() {
+        if(this.strokes.length == 0) return null; // when no strokes are loaded (eg. for annotation)
         const points = this.strokes[this.strokes.length - 1].points;
         return points[points.length - 1][3];
     }
@@ -1093,9 +1094,15 @@ class Annotator extends EventTarget {
     }
 
     playStrokePosition(path_i, point_i, allow_interrupt) {
+        if (this.strokes.length === 0) {
+            console.debug('No video to play back');
+            this.videoIsPlaying = false;
+            return;
+        }
+
         if (allow_interrupt) {
             if (!this.videoIsPlaying) {
-                console.log('not playing because of interrupt');
+                console.debug('not playing because of interrupt');
                 return;
             }
         } else {
@@ -1121,7 +1128,7 @@ class Annotator extends EventTarget {
     playViewboxPosition(box_i, allow_interrupt) {
         if (allow_interrupt) {
             if (!this.videoIsPlaying) {
-                console.log('not playing because of interrupt');
+                console.debug('not playing because of interrupt');
                 return;
             }
         }
@@ -1196,7 +1203,7 @@ class Annotator extends EventTarget {
             this._setPausedFlag(false);
 
             const startPlayback = () => {
-                console.log('start playback');
+                console.debug('start playback');
                 this.wrapperEl.classList.remove('loading'); // no loading anymore
 
                 this.startTimeMs = window.performance.now() - this._currentTimeMs;
@@ -1221,7 +1228,7 @@ class Annotator extends EventTarget {
             }
 
             if (this.audioEl.src.length && this.audioEl.readyState !== 4) { // not ready to play after seeking audio.
-                console.log('wait for audio before playback');
+                console.debug('wait for audio before playback');
                 this.wrapperEl.classList.add('loading');
                 this.audioEl.addEventListener('canplaythrough', () => {
                     startPlayback()