Fix recording and playback issues

- Fix download filename handling in converter and export functions
- Make updateRecordCanvas return Promise to handle async loadFromJSON correctly
- Add setCoords() call in setObjectValue to fix object selection after updates
- Update recorder initialization and animation frame handling

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/js/converter.js

@@ -94,7 +94,7 @@ function PostBlob(blob) {
   const a = document.createElement('a');
   a.style.display = 'none';
   a.href = url;
-  a.download = name;
+  a.download = blob.name || 'video';
   document.body.appendChild(a);
   a.click();
   recording = false;

src/js/functions.js

@@ -506,6 +506,9 @@ function updateRecordCanvas() {
     'inGroup',
   ]);
   canvas.clipPath = artboard;
+  // loadFromJSON is asynchronous (it clears the canvas first, then revives the
+  // objects), so callers that record straight afterwards must await this.
+  return new Promise(function (resolve) {
     canvasrecord.loadFromJSON(canvassave, function () {
       if (canvasrecord.getItemById('center_h')) {
         canvasrecord.remove(canvasrecord.getItemById('center_h'));
@@ -528,6 +531,8 @@ function updateRecordCanvas() {
         );
         replaceSource(canvas.getItemById(object.id), canvas);
       });
+      resolve();
+    });
   });
 }
 
@@ -543,7 +548,7 @@ function downloadRecording(chunks) {
     const a = document.createElement('a');
     a.style.display = 'none';
     a.href = url;
-    a.download = name;
+    a.download = 'video.webm';
     document.body.appendChild(a);
     a.click();
     recording = false;
@@ -1223,6 +1228,7 @@ function setObjectValue(prop, object, value, inst) {
   } else if (prop != 'width') {
     object.set(prop, value);
   }
+  object.setCoords();
   inst.renderAll();
 }
 
@@ -1508,18 +1514,20 @@ async function recordAnimate(time) {
       if (!canvas.getItemById(keyframe.id)) {
         reGroup(keyframe.id);
       }
-      const object = canvas.getItemById(keyframe.id);
+      const object = inst.getItemById(keyframe.id);
+      if (!object) {
+        return;
+      }
       if (
-        currenttime <
+        time <
         p_keyframes.find((x) => x.id == keyframe.id).trimstart +
           p_keyframes.find((x) => x.id == keyframe.id).start
       ) {
         object.set('visible', false);
         inst.renderAll();
       } else if (
-        currenttime >
-          p_keyframes.find((x) => x.id == keyframe.id).end ||
-        currenttime > duration
+        time > p_keyframes.find((x) => x.id == keyframe.id).end ||
+        time > duration
       ) {
         object.set('visible', false);
         inst.renderAll();
@@ -1528,7 +1536,7 @@ async function recordAnimate(time) {
         inst.renderAll();
       }
       if (
-        currenttime >=
+        time >=
         p_keyframes.find((x) => x.id == keyframe.id).trimstart +
           p_keyframes.find((x) => x.id == keyframe.id).start
       ) {
@@ -1573,6 +1581,7 @@ async function recordAnimate(time) {
       } else if (prop != 'width') {
         object.set(prop, value);
       }
+      object.setCoords();
       inst.renderAll();
     }
 
@@ -1601,9 +1610,12 @@ async function recordAnimate(time) {
     }
 
     var object = canvasrecord.getItemById(keyframe.id);
+    if (!object) {
+      return;
+    }
     if (
       keyframe.t >= time &&
-      currenttime >=
+      time >=
         p_keyframes.find((x) => x.id == keyframe.id).trimstart +
           p_keyframes.find((x) => x.id == keyframe.id).start
     ) {
@@ -1621,7 +1633,11 @@ async function recordAnimate(time) {
         lasttime = lastkey.t;
         lastprop = lastkey.value;
       }
-      if (lastkey && lastkey.t >= time && !play) {
+      // Every recorded frame is rendered like a seek, so a keyframe whose
+      // preceding keyframe is still in the future has not started yet.
+      // (This used to read an undeclared `play`, throwing a ReferenceError
+      // and aborting the rest of the frame.)
+      if (lastkey && lastkey.t >= time) {
         return;
       }
 
@@ -1686,24 +1702,28 @@ async function recordAnimate(time) {
 
   objects.forEach(function (object) {
     if (object.id.indexOf('Group') == -1) {
-      const object2 = canvas.getItemById(object.id);
+      // Visibility has to be applied to the object on the recording canvas,
+      // at the time of the frame being rendered (not the editor playhead).
+      const object2 = inst.getItemById(object.id);
+      if (!object2) {
+        return;
+      }
       if (
-        currenttime <
+        time <
         p_keyframes.find((x) => x.id == object.id).trimstart +
           p_keyframes.find((x) => x.id == object.id).start
       ) {
         object2.set('visible', false);
       } else if (
-        currenttime >
-          p_keyframes.find((x) => x.id == object.id).end ||
-        currenttime > duration
+        time > p_keyframes.find((x) => x.id == object.id).end ||
+        time > duration
       ) {
         object2.set('visible', false);
       } else {
         object2.set('visible', true);
       }
       if (
-        currenttime >=
+        time >=
         p_keyframes.find((x) => x.id == object.id).trimstart +
           p_keyframes.find((x) => x.id == object.id).start
       ) {

src/js/init.js

@@ -988,6 +988,11 @@ var canvasrecord = new fabric.Canvas('canvasrecord', {
   backgroundColor: '#FFF',
   width: artboard.width,
   height: artboard.height,
+  // Objects are repositioned to artboard-relative coordinates while
+  // recording. Their cached aCoords are not always refreshed in step, and
+  // fabric's offscreen culling would then skip drawing them entirely,
+  // producing blank frames.
+  skipOffscreen: false,
 });
 
 var timelineslider = document.getElementById('timeline-zoom');

src/js/recorder.js

@@ -67,11 +67,13 @@ async function exportRecording() {
 
 // Record canvas
 async function record() {
-  updateRecordCanvas();
+  // loadFromJSON clears the record canvas and revives the objects
+  // asynchronously, so nothing may be drawn or captured until it resolves.
+  await updateRecordCanvas();
   if ($('input[name=radio]:checked').val() == 'image') {
     recording = true;
     paused = true;
-    animate(false, currenttime);
+    await recordAnimate(currenttime);
     const dataURL = canvasrecord.toDataURL({
       format: 'png',
     });
@@ -82,12 +84,12 @@ async function record() {
     link.click();
     document.body.removeChild(link);
     recording = false;
+    updateRecordCanvas();
   } else {
     if (!recording) {
       recording = true;
       paused = true;
-      recordAnimate(false, (frame / FPS) * 1000);
-      recording = true;
+      await recordAnimate(0);
       $('#download-real').html('Rendering...');
       $('#download-real').addClass('downloading');
       var fps = 60;