feat: Throttle InteractiveViewer update events (flet-dev#4704)

* initial commit * update pubspec.lock * rename to interaction_update_interval * reformat --------- Co-authored-by: Feodor Fitsner <feodor@appveyor.com>

Author: ndonkoHenri

packages/flet/lib/src/controls/interactive_viewer.dart

@@ -41,6 +41,7 @@ class _InteractiveViewerControlState extends State<InteractiveViewerControl>
  late AnimationController _animationController;
  Animation<Matrix4>? _animation;
  Matrix4? _savedMatrix;
+ int _interactionUpdateTimestamp = DateTime.now().millisecondsSinceEpoch;
 
  @override
  void initState() {
@@ -158,22 +159,30 @@ class _InteractiveViewerControlState extends State<InteractiveViewerControl>
  : null,
  onInteractionUpdate: !disabled
  ? (ScaleUpdateDetails details) {
- debugPrint(
- "InteractiveViewer ${widget.control.id} onInteractionUpdate");
- widget.backend.triggerControlEvent(
- widget.control.id,
- "interaction_update",
- jsonEncode({
- "pc": details.pointerCount,
- "fp_x": details.focalPoint.dx,
- "fp_y": details.focalPoint.dy,
- "lfp_x": details.localFocalPoint.dx,
- "lfp_y": details.localFocalPoint.dy,
- "s": details.scale,
- "hs": details.horizontalScale,
- "vs": details.verticalScale,
- "rot": details.rotation,
- }));
+ var interactionUpdateInterval =
+ widget.control.attrInt("interactionUpdateInterval", 0)!;
+ var now = DateTime.now().millisecondsSinceEpoch;
+ if (now - _interactionUpdateTimestamp >
+ interactionUpdateInterval) {
+ debugPrint(
+ "InteractiveViewer ${widget.control.id} onInteractionUpdate");
+ _interactionUpdateTimestamp = now;
+ widget.backend.triggerControlEvent(
+ widget.control.id,
+ "interaction_update",
+ jsonEncode({
+ "pc": details.pointerCount,
+ "fp_x": details.focalPoint.dx,
+ "fp_y": details.focalPoint.dy,
+ "lfp_x": details.localFocalPoint.dx,
+ "lfp_y": details.localFocalPoint.dy,
+ "s": details.scale,
+ "hs": details.horizontalScale,
+ "vs": details.verticalScale,
+ "rot": details.rotation,
+ }));
+ ;
+ }
  }
  : null,
  child: contentCtrls.isNotEmpty

sdk/python/packages/flet/src/flet/core/interactive_viewer.py

@@ -79,6 +79,7 @@ def __init__(
  clip_behavior: Optional[ClipBehavior] = None,
  alignment: Optional[Alignment] = None,
  boundary_margin: Optional[MarginValue] = None,
+ interaction_update_interval: Optional[int] = None,
  on_interaction_start: Optional[
  Callable[[InteractiveViewerInteractionStartEvent], None]
  ] = None,
@@ -189,6 +190,7 @@ def __init__(
  self.on_interaction_start = on_interaction_start
  self.on_interaction_end = on_interaction_end
  self.on_interaction_update = on_interaction_update
+ self.interaction_update_interval = interaction_update_interval
 
  def _get_control_name(self):
  return "interactiveviewer"
@@ -228,6 +230,15 @@ def min_scale(self) -> float:
  def min_scale(self, value: OptionalNumber):
  self._set_attr("minScale", value)
 
+ # interaction_update_interval
+ @property
+ def interaction_update_interval(self) -> int:
+ return self._get_attr("interactionUpdateInterval", data_type="int", def_value=0)
+
+ @interaction_update_interval.setter
+ def interaction_update_interval(self, value: Optional[int]):
+ self._set_attr("interactionUpdateInterval", value)
+
  # max_scale
  @property
  def max_scale(self) -> float: