Fix snapshot tool crashes and black images for XY image items

- Fix SystemError when taking snapshots of XYImageItem/MaskedXYImageItem
  by converting src_rect from list to tuple before passing to C extension
- Add export_roi method to XYImageItem to properly handle coordinate
  transformations using _scale_xy instead of _scale_rect
- Fixes snapshot rendering producing black images for non-uniform coordinates

Author: PierreRaybaut

CHANGELOG.md

@@ -8,6 +8,10 @@
   * Added `IExportROIImageItemType` to `XYImageItem.types()` so that `get_items_in_rectangle()` can properly identify XY image items
   * Updated `__implements__` tuples for consistency across `XYImageItem`, `MaskedXYImageItem`, and `MaskedImageItem`
   * The tool now correctly displays statistics for images with non-uniform coordinates
+* Fixed snapshot tool failing with `SystemError` on `XYImageItem` and `MaskedXYImageItem`:
+  * Fixed `assemble_imageitems` passing list instead of tuple to C extension function `_scale_rect`
+  * Added missing `export_roi` method to `XYImageItem` to properly handle non-uniform coordinate transformations
+  * Snapshots of XY images now render correctly instead of producing black images
 
 ## Version 2.8.0 ##
 

plotpy/items/image/misc.py

@@ -474,10 +474,6 @@ def assemble_imageitems(
 
     Returns:
         Pixel data
-
-    .. warning::
-
-        Does not support `XYImageItem` objects
     """
     # align width to 'align' bytes
     if align is not None:
@@ -511,6 +507,8 @@ def assemble_imageitems(
     src_rect[1] += 0.5 * pixel_height
     src_rect[2] -= 0.5 * pixel_width
     src_rect[3] -= 0.5 * pixel_height
+    # Convert to tuple for compatibility with C extension
+    src_rect = tuple(src_rect)
 
     for it in sorted(items, key=lambda obj: obj.z()):
         if it.isVisible() and src_qrect.intersects(it.boundingRect()):
@@ -737,11 +735,6 @@ def get_image_from_plot(
 
     Returns:
         Image pixel data
-
-    .. warning::
-
-        Support only the image items implementing the `IExportROIImageItemType`
-        interface, i.e. this does *not* support `XYImageItem` objects
     """
     if destw is None:
         destw = p1.x() - p0.x() + 1

plotpy/items/image/standard.py

@@ -433,9 +433,10 @@ def export_roi(
         else:
             a, b = 1.0, 0.0
         interp = self.interpolate if apply_interpolation else (INTERP_NEAREST,)
+        rescaled_src = self._rescale_src_rect(src_rect)
         _scale_rect(
             self.data,
-            self._rescale_src_rect(src_rect),
+            rescaled_src,
             dst_image,
             dst_rect,
             (a, b, None),
@@ -689,6 +690,38 @@ def draw_image(
         qrect = QC.QRectF(QC.QPointF(dest[0], dest[1]), QC.QPointF(dest[2], dest[3]))
         painter.drawImage(qrect, self._image, qrect)
 
+    def export_roi(
+        self,
+        src_rect: tuple[float, float, float, float],
+        dst_rect: tuple[float, float, float, float],
+        dst_image: np.ndarray,
+        apply_lut: bool = False,
+        apply_interpolation: bool = False,
+        original_resolution: bool = False,
+        force_interp_mode: str | None = None,
+        force_interp_size: int | None = None,
+    ) -> None:
+        """Export a rectangular area of the image to another image
+
+        Args:
+            src_rect: Source rectangle in plot coordinates
+            dst_rect: Destination rectangle in pixel coordinates
+            dst_image: Destination image array
+            apply_lut: Apply LUT (Default value = False)
+            apply_interpolation: Apply interpolation (Default value = False)
+            original_resolution: Original resolution (Default value = False)
+            force_interp_mode: Force interpolation mode (Default value = None)
+            force_interp_size: Force interpolation size (Default value = None)
+        """
+        if apply_lut:
+            lut = self.lut
+        else:
+            a, b = 1.0, 0.0
+            lut = (a, b, None, np.zeros((1,), np.uint32))
+        interp = self.interpolate if apply_interpolation else (INTERP_NEAREST,)
+        xytr = self.x, self.y, src_rect
+        _scale_xy(self.data, xytr, dst_image, dst_rect, lut, interp)
+
     def get_pixel_coordinates(self, xplot: float, yplot: float) -> tuple[float, float]:
         """Get pixel coordinates from plot coordinates