Cancel obsolete requests

volumina/pixelpipeline/datasources/minmaxsource.py

@@ -22,6 +22,9 @@ def wait(self):
 
         return self._result
 
+    def cancel(self):
+        self._rawRequest.cancel()
+
 
 class MinMaxSource(QObject, DataSourceABC):
     """

volumina/pixelpipeline/imagesources.py

@@ -173,6 +173,9 @@ def __init__(self, arrayrequest, normalize=None, direct=False):
     def wait(self):
         return self.toImage()
 
+    def cancel(self):
+        self._arrayreq.cancel()
+
     def toImage(self):
         t = time.time()
 
@@ -273,6 +276,9 @@ def __init__(self, arrayrequest, tintColor, normalize=(0, 255)):
     def wait(self):
         return self.toImage()
 
+    def cancel(self):
+        self._arrayreq.cancel()
+
     def toImage(self):
         t = time.time()
 
@@ -384,6 +390,9 @@ def __init__(self, arrayrequest, colorTable, normalize, direct=False):
     def wait(self):
         return self.toImage()
 
+    def cancel(self):
+        self._arrayreq.cancel()
+
     def toImage(self):
         t = time.time()
 
@@ -541,6 +550,10 @@ def wait(self):
             req.wait()
         return self.toImage()
 
+    def cancel(self):
+        for req in self._requests:
+            req.cancel()
+
     def toImage(self):
         for i, req in enumerate(self._requests):
             a = req.wait()
@@ -720,6 +733,9 @@ def __init__(self, arrayreq, layer, rect, is_clickable):
         self._layer = layer
         self._is_clickable = is_clickable
 
+    def cancel(self):
+        self._arrayreq.cancel()
+
     def wait(self):
         array_data = self._arrayreq.wait()
 

volumina/pixelpipeline/interface.py

@@ -37,6 +37,10 @@ class RequestABC(ABC):
     def wait(self):
         """waits until completion and returns result"""
 
+    @abstractmethod
+    def cancel(self):
+        ...
+
 
 class ImageSourceABC(QABC):
     """
@@ -55,6 +59,7 @@ def setDirty(self, slicing):
         pass
 
 
+
 class PlanarSliceSourceABC(QABC):
     """
     Provides a way to retrieve 2D slices of ND array

volumina/tiling.py

@@ -497,6 +497,7 @@ def __init__(
         """
 
         QObject.__init__(self, parent=parent)
+        self._current_requests = {}
 
         self.tiling = tiling
         self.axesSwapped = False
@@ -554,6 +555,7 @@ def waitForTiles(self, rectF=QRectF()):
             for tile in tiles:
                 finished &= tile.progress >= 1.0
 
+
     def requestRefresh(self, rectF, stack_id=None, prefetch=False, layer_indexes=None):
         """Requests tiles to be refreshed.
 
@@ -563,6 +565,12 @@ def requestRefresh(self, rectF, stack_id=None, prefetch=False, layer_indexes=Non
         """
         stack_id = stack_id or self._current_stack_id
         tile_nos = self.tiling.intersected(rectF)
+        to_cancel = self._current_requests
+        self._current_requests = {}
+
+        for id_, rq in to_cancel.items():
+            rq.cancel()
+
         for tile_no in tile_nos:
             self._refreshTile(stack_id, tile_no, prefetch, layer_indexes)
 
@@ -653,6 +661,7 @@ def _refreshTile(self, stack_id, tile_no, prefetch=False, layer_indexes=None):
                 try:
                     # Create the request object right now, from the main thread.
                     ims_req = ims.request(dataRect, stack_id[1])
+                    self._current_requests[(stack_id[1], tile_no)] = ims_req
                 except IndeterminateRequestError:
                     # In ilastik, the viewer is still churning even as the user might be changing settings in the UI.
                     # Settings changes can cause 'slot not ready' errors during graph setup.