From 9ef418bf5597d4be77adc3c0c88c1c1619c9aa2f Mon Sep 17 00:00:00 2001
From: wyzula-jan <jan.wyzula@psi.ch>
Date: Tue, 10 Jun 2025 10:48:40 +0200
Subject: [PATCH] fix(image_roi): coordinates are emitted correctly when
 handles are inverted; closes #672

---
 bec_widgets/widgets/plots/roi/image_roi.py | 49 ++++++++++++++--------
 1 file changed, 31 insertions(+), 18 deletions(-)

diff --git a/bec_widgets/widgets/plots/roi/image_roi.py b/bec_widgets/widgets/plots/roi/image_roi.py
index 93ba66a0..9bd0d499 100644
--- a/bec_widgets/widgets/plots/roi/image_roi.py
+++ b/bec_widgets/widgets/plots/roi/image_roi.py
@@ -437,6 +437,23 @@ class RectangularROI(BaseROI, pg.RectROI):
         self.hoverPen = fn.mkPen(color=(255, 0, 0), width=3, style=QtCore.Qt.DashLine)
         self.handleHoverPen = fn.mkPen("lime", width=4)
 
+    def _normalized_edges(self) -> tuple[float, float, float, float]:
+        """
+        Return rectangle edges as (left, bottom, right, top) with consistent
+        ordering even when the ROI has been inverted by its scale handles.
+
+        Returns:
+            tuple: A tuple containing the left, bottom, right, and top edges
+                of the ROI rectangle in normalized coordinates.
+        """
+        x0, y0 = self.pos().x(), self.pos().y()
+        w, h = self.state["size"]
+        x_left = min(x0, x0 + w)
+        x_right = max(x0, x0 + w)
+        y_bottom = min(y0, y0 + h)
+        y_top = max(y0, y0 + h)
+        return x_left, y_bottom, x_right, y_top
+
     def add_scale_handle(self):
         """
         Add scale handles at every corner and edge of the ROI.
@@ -465,17 +482,15 @@ class RectangularROI(BaseROI, pg.RectROI):
 
     def _on_region_changed(self):
         """
-        Handles ROI region change events.
+        Handles changes to the ROI's region.
 
         This method is called whenever the ROI's position or size changes.
         It calculates the new corner coordinates and emits the edgesChanged signal
         with the updated coordinates.
         """
-        x0, y0 = self.pos().x(), self.pos().y()
-        w, h = self.state["size"]
-        self.edgesChanged.emit(x0, y0, x0 + w, y0 + h)
-        viewBox = self.parent_plot_item.vb
-        viewBox.update()
+        x_left, y_bottom, x_right, y_top = self._normalized_edges()
+        self.edgesChanged.emit(x_left, y_bottom, x_right, y_top)
+        self.parent_plot_item.vb.update()
 
     def mouseDragEvent(self, ev):
         """
@@ -489,9 +504,8 @@ class RectangularROI(BaseROI, pg.RectROI):
         """
         super().mouseDragEvent(ev)
         if ev.isFinish():
-            x0, y0 = self.pos().x(), self.pos().y()
-            w, h = self.state["size"]
-            self.edgesReleased.emit(x0, y0, x0 + w, y0 + h)
+            x_left, y_bottom, x_right, y_top = self._normalized_edges()
+            self.edgesReleased.emit(x_left, y_bottom, x_right, y_top)
 
     def get_coordinates(self, typed: bool | None = None) -> dict | tuple:
         """
@@ -510,17 +524,16 @@ class RectangularROI(BaseROI, pg.RectROI):
         if typed is None:
             typed = self.description
 
-        x0, y0 = self.pos().x(), self.pos().y()
-        w, h = self.state["size"]
-        x1, y1 = x0 + w, y0 + h
+        x_left, y_bottom, x_right, y_top = self._normalized_edges()
+
         if typed:
             return {
-                "bottom_left": (x0, y0),
-                "bottom_right": (x1, y0),
-                "top_left": (x0, y1),
-                "top_right": (x1, y1),
+                "bottom_left": (x_left, y_bottom),
+                "bottom_right": (x_right, y_bottom),
+                "top_left": (x_left, y_top),
+                "top_right": (x_right, y_top),
             }
-        return ((x0, y0), (x1, y0), (x0, y1), (x1, y1))
+        return (x_left, y_bottom), (x_right, y_bottom), (x_left, y_top), (x_right, y_top)
 
     def _lookup_scene_image(self):
         """
@@ -654,7 +667,7 @@ class CircularROI(BaseROI, pg.CircleROI):
         if typed is None:
             typed = self.description
 
-        d = self.state["size"][0]
+        d = abs(self.state["size"][0])
         cx = self.pos().x() + d / 2
         cy = self.pos().y() + d / 2