From f38b7359557a32be749782cd0df07407f37f03cb Mon Sep 17 00:00:00 2001
From: Nyall Dawson <nyall.dawson@gmail.com>
Date: Wed, 8 Nov 2023 08:59:48 +1000
Subject: [PATCH] Fix exception in interpolation algorithm widgets

Fixes #55138
---
 .../processing/algs/qgis/ui/HeatmapWidgets.py      |  9 ++++++---
 .../algs/qgis/ui/InterpolationWidgets.py           | 14 ++++++--------
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/python/plugins/processing/algs/qgis/ui/HeatmapWidgets.py b/python/plugins/processing/algs/qgis/ui/HeatmapWidgets.py
index 2302c7108ddd8..d13aa556f22f5 100644
--- a/python/plugins/processing/algs/qgis/ui/HeatmapWidgets.py
+++ b/python/plugins/processing/algs/qgis/ui/HeatmapWidgets.py
@@ -99,8 +99,9 @@ def recalculate_bounds(self):
 
     def pixelSizeChanged(self):
         cell_size = self.mCellXSpinBox.value()
-        if cell_size <= 0:
+        if cell_size <= 0 or self.raster_bounds.isNull():
             return
+
         self.mCellYSpinBox.blockSignals(True)
         self.mCellYSpinBox.setValue(cell_size)
         self.mCellYSpinBox.blockSignals(False)
@@ -115,8 +116,9 @@ def pixelSizeChanged(self):
 
     def rowsChanged(self):
         rows = self.mRowsSpinBox.value()
-        if rows <= 0:
+        if rows <= 0 or self.raster_bounds.isNull():
             return
+
         cell_size = self.raster_bounds.height() / rows
         cols = max(round(self.raster_bounds.width() / cell_size) + 1, 1)
         self.mColumnsSpinBox.blockSignals(True)
@@ -129,8 +131,9 @@ def rowsChanged(self):
 
     def columnsChanged(self):
         cols = self.mColumnsSpinBox.value()
-        if cols < 2:
+        if cols < 2 or self.raster_bounds.isNull():
             return
+
         cell_size = self.raster_bounds.width() / (cols - 1)
         rows = max(round(self.raster_bounds.height() / cell_size), 1)
         self.mRowsSpinBox.blockSignals(True)
diff --git a/python/plugins/processing/algs/qgis/ui/InterpolationWidgets.py b/python/plugins/processing/algs/qgis/ui/InterpolationWidgets.py
index eeae50873aecc..2f1bb2e9f2a16 100644
--- a/python/plugins/processing/algs/qgis/ui/InterpolationWidgets.py
+++ b/python/plugins/processing/algs/qgis/ui/InterpolationWidgets.py
@@ -280,11 +280,7 @@ def setLayers(self, layersData: str):
             layer = QgsProcessingUtils.variantToSource(v[0], self.context)
             if layer:
                 self.layers.append(layer)
-                bbox = layer.sourceExtent()
-                if self.extent.isEmpty():
-                    self.extent = bbox
-                else:
-                    self.extent.combineExtentWith(bbox)
+                self.extent.combineExtentWith(layer.sourceExtent())
 
         self.pixelSizeChanged()
 
@@ -307,7 +303,7 @@ def setExtent(self, extent: Optional[str]):
 
     def pixelSizeChanged(self):
         cell_size = self.mCellXSpinBox.value()
-        if cell_size <= 0:
+        if cell_size <= 0 or self.extent.isNull():
             return
 
         self.mCellYSpinBox.blockSignals(True)
@@ -324,8 +320,9 @@ def pixelSizeChanged(self):
 
     def rowsChanged(self):
         rows = self.mRowsSpinBox.value()
-        if rows <= 0:
+        if rows <= 0 or self.extent.isNull():
             return
+
         cell_size = self.extent.height() / rows
         cols = max(round(self.extent.width() / cell_size) + 1, 1)
         self.mColumnsSpinBox.blockSignals(True)
@@ -338,8 +335,9 @@ def rowsChanged(self):
 
     def columnsChanged(self):
         cols = self.mColumnsSpinBox.value()
-        if cols < 2:
+        if cols < 2 or self.extent.isNull():
             return
+
         cell_size = self.extent.width() / (cols - 1)
         rows = max(round(self.extent.height() / cell_size), 1)
         self.mRowsSpinBox.blockSignals(True)