Move OverlayPlugin and PlotPlugin to their own modules.

skimage/viewer/plugins/overlayplugin.py

@@ -0,0 +1,37 @@
+from ..utils import clear_red
+
+from .base import Plugin
+
+
+class OverlayPlugin(Plugin):
+    """Plugin for ImageViewer that displays an overlay on top of main image.
+
+    Attributes
+    ----------
+    overlay : array
+        Overlay displayed on top of image. This overlay defaults to a color map
+        with alpha values varying linearly from 0 to 1.
+    """
+
+    def __init__(self, image_viewer, **kwargs):
+        Plugin.__init__(self, image_viewer, **kwargs)
+        self.overlay_cmap = clear_red
+        self._overlay_plot = None
+        self._overlay = None
+
+    @property
+    def overlay(self):
+        return self._overlay
+
+    @overlay.setter
+    def overlay(self, image):
+        self._overlay = image
+        ax = self.image_viewer.ax
+        if image is None:
+            ax.images.remove(self._overlay_plot)
+            self._overlay_plot = None
+        elif self._overlay_plot is None:
+            self._overlay_plot = ax.imshow(image, cmap=self.overlay_cmap)
+        else:
+            self._overlay_plot.set_array(image)
+        self.image_viewer.redraw()