add rect masking

backend/node_menu.py

@@ -150,6 +150,7 @@ MENU_LAYOUT: dict[str, list[str]] = {
         "MarkDisconnected",
         "MaskShift",
         "MaskNoisify",
+        "RectangularMask",
     ],
     "Grains": [
         "GrainDistanceTransform",

backend/nodes/crop_resize.py

@@ -3,6 +3,7 @@ import numpy as np
 from backend.node_registry import register_node
 from backend.execution_context import emit_overlay
 from backend.data_types import DataField, datafield_to_uint8, encode_preview
+from backend.nodes.helpers import coerce_physical_square
 
 
 @register_node(display_name="Crop / Resize")
@@ -19,6 +20,7 @@ class CropResizeField:
                 "target_width": ("INT", {"default": 0, "min": 0, "max": 8192, "step": 1}),
                 "target_height": ("INT", {"default": 0, "min": 0, "max": 8192, "step": 1}),
                 "interpolation": (["bilinear", "nearest", "bicubic"],),
+                "square": ("BOOLEAN", {"default": False}),
             },
             "optional": {
                 "corner_a": ("COORD",),
@@ -34,7 +36,8 @@ class CropResizeField:
     DESCRIPTION = (
         "Crop a DATA_FIELD with a draggable rectangle defined by two corners, then optionally resize it. "
         "Incoming COORD inputs can lock either corner. Cropping updates physical extents and offsets; "
-        "resizing preserves the cropped physical size."
+        "resizing preserves the cropped physical size. Enable 'square' to constrain the crop region to a "
+        "physical square (longer side shrinks to match shorter)."
     )
 
     KEYWORDS = ("resize", "rescale", "trim", "bilinear", "bicubic", "nearest")
@@ -49,6 +52,7 @@ class CropResizeField:
         target_width: int,
         target_height: int,
         interpolation: str,
+        square: bool = False,
         corner_a=None,
         corner_b=None,
     ) -> tuple:
@@ -62,21 +66,29 @@ class CropResizeField:
         x2 = float(np.clip(x2, 0.0, 1.0))
         y2 = float(np.clip(y2, 0.0, 1.0))
 
-        emit_overlay({
-            "kind": "crop_box",
-            "image": encode_preview(datafield_to_uint8(field, field.colormap)),
-            "x1": x1,
-            "y1": y1,
-            "x2": x2,
-            "y2": y2,
-            "a_locked": corner_a is not None,
-            "b_locked": corner_b is not None,
-        })
-
         left = min(x1, x2)
         right = max(x1, x2)
         top = min(y1, y2)
         bottom = max(y1, y2)
+
+        if square:
+            left, top, right, bottom = coerce_physical_square(
+                left, top, right, bottom, field.xreal, field.yreal,
+            )
+
+        emit_overlay({
+            "kind": "crop_box",
+            "image": encode_preview(datafield_to_uint8(field, field.colormap)),
+            "x1": left,
+            "y1": top,
+            "x2": right,
+            "y2": bottom,
+            "xreal": float(field.xreal),
+            "yreal": float(field.yreal),
+            "a_locked": corner_a is not None,
+            "b_locked": corner_b is not None,
+        })
+
         if right <= left or bottom <= top:
             raise ValueError("Crop region must have non-zero width and height.")
 

backend/nodes/helpers.py

@@ -319,6 +319,20 @@ def bool_to_mask(binary: np.ndarray) -> np.ndarray:
     return np.asarray(binary, dtype=np.uint8) * 255
 
 
+def coerce_physical_square(
+    left: float, top: float, right: float, bottom: float,
+    xreal: float, yreal: float,
+) -> tuple[float, float, float, float]:
+    """Shrink the longer physical side so the rectangle is a physical square,
+    anchored at (left, top)."""
+    side_phys = min((right - left) * xreal, (bottom - top) * yreal)
+    if xreal > 0:
+        right = left + side_phys / xreal
+    if yreal > 0:
+        bottom = top + side_phys / yreal
+    return left, top, right, bottom
+
+
 def normalize_mask(
     mask: np.ndarray | None, shape: tuple[int, int],
 ) -> np.ndarray | None:

backend/nodes/mask_rectangular.py

@@ -0,0 +1,113 @@
+from __future__ import annotations
+
+import numpy as np
+
+from backend.data_types import DataField, datafield_to_uint8, encode_preview
+from backend.execution_context import emit_overlay
+from backend.node_registry import register_node
+from backend.nodes.helpers import bool_to_mask, coerce_physical_square
+
+
+@register_node(display_name="Rectangular Mask")
+class RectangularMask:
+    _CUSTOM_PREVIEW = True
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "field": ("DATA_FIELD",),
+                "x1": ("FLOAT", {"default": 0.2, "min": 0.0, "max": 1.0, "step": 0.01, "hidden": True}),
+                "y1": ("FLOAT", {"default": 0.2, "min": 0.0, "max": 1.0, "step": 0.01, "hidden": True}),
+                "x2": ("FLOAT", {"default": 0.8, "min": 0.0, "max": 1.0, "step": 0.01, "hidden": True}),
+                "y2": ("FLOAT", {"default": 0.8, "min": 0.0, "max": 1.0, "step": 0.01, "hidden": True}),
+                "square": ("BOOLEAN", {"default": False}),
+                "invert": ("BOOLEAN", {"default": False}),
+            },
+            "optional": {
+                "corner_a": ("COORD",),
+                "corner_b": ("COORD",),
+            },
+        }
+
+    OUTPUTS = (
+        ('IMAGE', 'mask'),
+    )
+    FUNCTION = "process"
+
+    DESCRIPTION = (
+        "Create a binary mask covering a rectangular region of a DATA_FIELD, "
+        "defined by two draggable corners on the preview. Useful for selecting "
+        "a region of interest without cropping the image. When 'square' is on, "
+        "the mask is coerced to a physical square (the longer side shrinks to "
+        "match the shorter, anchored at the top-left corner). When 'invert' is "
+        "on, the mask covers everything outside the rectangle instead. "
+        "Incoming COORD inputs can lock either corner."
+    )
+
+    KEYWORDS = ("roi", "region", "rectangle", "square", "box", "selection", "crop mask")
+
+    def process(
+        self,
+        field: DataField,
+        x1: float,
+        y1: float,
+        x2: float,
+        y2: float,
+        square: bool,
+        invert: bool,
+        corner_a=None,
+        corner_b=None,
+    ) -> tuple:
+        if corner_a is not None:
+            x1, y1 = float(corner_a[0]), float(corner_a[1])
+        if corner_b is not None:
+            x2, y2 = float(corner_b[0]), float(corner_b[1])
+
+        x1 = float(np.clip(x1, 0.0, 1.0))
+        y1 = float(np.clip(y1, 0.0, 1.0))
+        x2 = float(np.clip(x2, 0.0, 1.0))
+        y2 = float(np.clip(y2, 0.0, 1.0))
+
+        left = min(x1, x2)
+        right = max(x1, x2)
+        top = min(y1, y2)
+        bottom = max(y1, y2)
+
+        if square:
+            left, top, right, bottom = coerce_physical_square(
+                left, top, right, bottom, field.xreal, field.yreal,
+            )
+
+        emit_overlay({
+            "kind": "crop_box",
+            "section_title": "Preview",
+            "image": encode_preview(datafield_to_uint8(field, field.colormap)),
+            "x1": left,
+            "y1": top,
+            "x2": right,
+            "y2": bottom,
+            "xreal": float(field.xreal),
+            "yreal": float(field.yreal),
+            "a_locked": corner_a is not None,
+            "b_locked": corner_b is not None,
+        })
+
+        px0 = int(np.floor(left * field.xres))
+        py0 = int(np.floor(top * field.yres))
+        px1 = int(np.ceil(right * field.xres))
+        py1 = int(np.ceil(bottom * field.yres))
+
+        px0 = min(max(px0, 0), field.xres)
+        py0 = min(max(py0, 0), field.yres)
+        px1 = min(max(px1, px0), field.xres)
+        py1 = min(max(py1, py0), field.yres)
+
+        binary = np.zeros((field.yres, field.xres), dtype=bool)
+        binary[py0:py1, px0:px1] = True
+        if invert:
+            binary = ~binary
+
+        mask = bool_to_mask(binary)
+
+        return (mask,)