Draft: Add 'dynamic colormap' mode

examples/dynamic_colormap.py

@@ -0,0 +1,60 @@
+# /*##########################################################################
+#
+# Copyright (c) 2018-2021 European Synchrotron Radiation Facility
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+# ###########################################################################*/
+"""This script shows how to dyamically adjust the colormap to a small region 
+around the cursor position. The DynamicColormapMode can be activated either by
+the icon in the widget toolbar or by simply pressing the w-key.
+The image has 4 regions with different contrasts (but same levels =0). When activated, the 
+DynamicColormap mode will adjust the colormap to enhance the contrast in the 
+region close to the cursor.
+More precissely: it computes the min and max in the region surrounded by the blue 
+rectangle and applies these values to the current colormap.
+
+The pan and zoom modes (the two other interaction modes) can be activated either 
+by their respective icon or by pressing the P- and Z-key respectively.
+"""
+
+import numpy
+from silx.gui import qt
+from silx.gui.plot import Plot2D
+
+
+def main():
+    app = qt.QApplication([])
+
+    # Create the ad hoc plot widget and change its default colormap
+    x = numpy.zeros((100, 100),dtype=numpy.float32)
+    x[:50,:50] = numpy.random.randn(50,50)
+    x[:50,50:] = 10 * numpy.random.randn(50,50)
+    x[50:,:50] = 100 * numpy.random.randn(50,50)
+    x[50:,50:] = 5 * numpy.random.randn(50,50)
+
+    example = Plot2D()
+    example.addImage(x)
+    example.show()
+
+    app.exec()
+
+
+if __name__ == "__main__":
+    main()

src/silx/gui/plot/PlotInteraction.py

@@ -37,6 +37,8 @@
 from typing import NamedTuple
 
 from silx.gui import qt
+from silx.math.combo import min_max
+
 from .. import colors
 from . import items
 from .Interaction import (
@@ -1643,6 +1645,73 @@ def endDrag(self, startPos, endPos, btn):
             return super().endDrag(startPos, endPos, btn)
 
 
+class DynamicColormapMode(ItemsInteraction):
+    """This mode automatically adjusts the colormap range of the image
+    based on a NxM ROI centered on the current cursor position. N and M are defined in the ROI_SIZE class variable.
+
+    :param plot: The Plot to which this interaction is attached
+    """
+
+    ROI_SIZE = (10, 10)  # (y,x). The ROI <<radius>>
+    COLOR = "blue"
+    LINESTYLE = "--"
+
+    @staticmethod
+    def _compute_vmin_vmax(data: numpy.ndarray, dataPos: tuple[float, float]):
+        """Compute the min and max values of the data in a ROI centered on (x,y)"""
+        roi_size = DynamicColormapMode.ROI_SIZE
+        idx_x, idx_y = int(dataPos[0]), int(dataPos[1])
+        x_start = max((0, idx_x - roi_size[1]))
+        x_end = min((idx_x + roi_size[1], data.shape[1]))
+        y_start = max((0, idx_y - roi_size[0]))
+        y_end = min((idx_y + roi_size[0], data.shape[0]))
+
+        data_values = data[y_start:y_end, x_start:x_end]
+        vmin, vmax = min_max(data_values)
+        bb_x = (x_start, x_start, x_end, x_end)
+        bb_y = (y_start, y_end, y_end, y_start)
+        return vmin, vmax, bb_x, bb_y
+
+    def handleEvent(self, eventName, *args, **kwargs):
+        super().handleEvent(eventName, *args, **kwargs)
+
+        try:
+            x, y = args[:2]
+        except ValueError:
+            return
+
+        # Get data
+        result = self.plot._pickTopMost(x, y, lambda i: isinstance(i, items.ImageBase))
+        if result is None:
+            return
+        else:
+            item = result.getItem()
+        colormap = item.getColormap()
+        dataPos = self.plot.pixelToData(x, y)
+        data = item.getData()
+
+        # Extract ROI min and max
+        vmin, vmax, bb_x, bb_y = self._compute_vmin_vmax(data, dataPos)
+
+        # Add a blue rectangle that shows the ROI
+        self.plot.addShape(
+            bb_x,
+            bb_y,
+            legend="ColorMap reference",
+            replace=False,
+            fill=False,
+            color=self.COLOR,
+            gapcolor=None,
+            linestyle=self.LINESTYLE,
+            overlay=True,
+            z=1,
+        )
+
+        # Set new min and max
+        colormap.setVRange(vmin, vmax)
+        item.setColormap(colormap)
+
+
 # Interaction mode control ####################################################
 
 # Mapping of draw modes: event handler
@@ -1795,6 +1864,9 @@ def _getInteractiveMode(self):
         elif isinstance(self._eventHandler, PanAndSelect):
             return {"mode": "pan"}
 
+        elif isinstance(self._eventHandler, DynamicColormapMode):
+            return {"mode": "dynamic_colormap"}
+
         else:
             return {"mode": "select"}
 
@@ -1824,8 +1896,14 @@ def _setInteractiveMode(
         :param str label: Only for 'draw' mode.
         :param float width: Width of the pencil. Only for draw pencil mode.
         """
-        assert mode in ("draw", "pan", "select", "select-draw", "zoom")
-
+        assert mode in (
+            "draw",
+            "pan",
+            "select",
+            "select-draw",
+            "zoom",
+            "dynamic_colormap",
+        )
         plotWidget = self.parent()
         assert plotWidget is not None
 
@@ -1848,6 +1926,10 @@ def _setInteractiveMode(
             self._eventHandler = ZoomAndSelect(plotWidget, color)
             self._eventHandler.zoomEnabledAxes = self.getZoomEnabledAxes()
 
+        elif mode == "dynamic_colormap":
+            self._eventHandler.cancel()
+            self._eventHandler = DynamicColormapMode(plotWidget)
+
         else:  # Default mode: interaction with plot objects
             # Ignores color, shape and label
             self._eventHandler.cancel()

src/silx/gui/plot/PlotWidget.py

@@ -332,6 +332,13 @@ class PlotWidget(qt.QMainWindow):
     It provides the source as passed to :meth:`setInteractiveMode`.
     """
 
+    # sigDynamicColormapModeChanged = qt.Signal(object)
+    # """
+    # Signal emitted when the dynamic colormap changed
+
+    # It provides the source as passed to :meth:`setInteractiveMode`.
+    # """
+
     sigItemAdded = qt.Signal(items.Item)
     """Signal emitted when an item was just added to the plot
 
@@ -3667,7 +3674,7 @@ def getInteractiveMode(self):
         """Returns the current interactive mode as a dict.
 
         The returned dict contains at least the key 'mode'.
-        Mode can be: 'draw', 'pan', 'select', 'select-draw', 'zoom'.
+        Mode can be: 'draw', 'pan', 'select', 'select-draw', 'zoom', 'dynamic_colormap'.
         It can also contains extra keys (e.g., 'color') specific to a mode
         as provided to :meth:`setInteractiveMode`.
         """
@@ -3695,7 +3702,7 @@ def setInteractiveMode(
         """Switch the interactive mode.
 
         :param mode: The name of the interactive mode.
-                     In 'draw', 'pan', 'select', 'select-draw', 'zoom'.
+                     In 'draw', 'pan', 'select', 'select-draw', 'zoom', 'dynamic_colormap'.
         :param color: Only for 'draw' and 'zoom' modes.
                       Color to use for drawing selection area. Default black.
         :type color: Color description: The name as a str or
@@ -3719,7 +3726,7 @@ def setInteractiveMode(
         finally:
             self.__isInteractionSignalForwarded = True
 
-        if mode in ["pan", "zoom"]:
+        if mode in ["pan", "zoom", "dynamic_colormap"]:
             self._previousDefaultMode = mode, zoomOnWheel
 
         self.notify("interactiveModeChanged", source=source)
@@ -3785,6 +3792,12 @@ def keyPressEvent(self, event):
             # that even if mouse didn't move on the screen, it moved relative
             # to the plotted data.
             self.__simulateMouseMove()
+        elif key == qt.Qt.Key_W:
+            self.setInteractiveMode("dynamic_colormap")
+        elif key == qt.Qt.Key_P:
+            self.setInteractiveMode("pan")
+        elif key == qt.Qt.Key_Z:
+            self.setInteractiveMode("zoom")
         else:
             # Only call base class implementation when key is not handled.
             # See QWidget.keyPressEvent for details.

src/silx/gui/plot/actions/mode.py

@@ -137,3 +137,39 @@ def _actionTriggered(self, checked=False):
         plot = self.plot
         if plot is not None:
             plot.setInteractiveMode("pan", source=self)
+
+
+class DynamicColormapAction(PlotAction):
+    """QAction controlling the colormap mode of a :class:`.PlotWidget`.
+    This mode adjusts the colormap based on a small region around the 
+    mouse position in the plot.
+
+    :param plot: :class:`.PlotWidget` instance on which to operate
+    :param parent: See :class:`QAction`
+    """
+
+    def __init__(self, plot, parent=None):
+        super().__init__(
+            plot,
+            icon="dynamic_colormap",  # TODO: add a dedicated icon
+            text="Dynamic Colormap mode",
+            tooltip="Update the colormap according to the mouse position in the plot",
+            triggered=self._actionTriggered,
+            checkable=True,
+            parent=parent,
+        )
+        # Listen to mode change
+        self.plot.sigInteractiveModeChanged.connect(self._modeChanged)
+        # Init the state
+        self._modeChanged(None)
+
+    def _modeChanged(self, source):
+        modeDict = self.plot.getInteractiveMode()
+        old = self.blockSignals(True)
+        self.setChecked(modeDict["mode"] == "dynamic_colormap")
+        self.blockSignals(old)
+
+    def _actionTriggered(self, checked=False):
+        plot = self.plot
+        if plot is not None:
+            plot.setInteractiveMode("dynamic_colormap", source=self)

src/silx/gui/plot/test/test_plotinteraction.py

@@ -28,10 +28,12 @@
 __date__ = "01/09/2017"
 
 import pytest
-
+import numpy
 from silx.gui import qt
 from silx.gui.plot import PlotWidget
 from .utils import PlotWidgetTestCase
+from silx.gui.plot.PlotInteraction import  DynamicColormapMode
+
 
 
 class _SignalDump:
@@ -49,6 +51,33 @@ def received(self):
         return list(self._received)
 
 
+class TestSelectDynamicColormap():
+
+    def test_dynamic_colormap_interaction(self):
+        """Test correct interaction mode."""
+        plot = PlotWidget()
+        plot.setInteractiveMode("dynamic_colormap", shape="rectangle", label="test")
+
+        interaction = plot.getInteractiveMode()
+        assert interaction["mode"] == "dynamic_colormap"
+        assert isinstance(plot.interaction()._eventHandler, DynamicColormapMode)
+
+    def test_dynamic_colormap_vmin_vmax_calculation(self):
+        """Test vmin/vmax calculation for dynamic colormap"""
+        # Test with a rectangle
+        roi = numpy.arange(484).reshape((22,22))
+        vmin, vmax, bb_x, bb_y = DynamicColormapMode._compute_vmin_vmax(roi,(11,11))
+        assert vmin == 23 and vmax == 460 and bb_x == (1,1,21,21) and bb_y == (1,21,21,1)
+
+        roi = numpy.arange(484).reshape((22,22))
+        vmin, vmax, bb_x, bb_y = DynamicColormapMode._compute_vmin_vmax(roi,(0,0))
+        assert vmin == 0 and vmax == 207 and bb_x == (0,0,10,10) and bb_y == (0,10,10,0)
+
+        roi = numpy.arange(484).reshape((22,22))
+        vmin, vmax, bb_x, bb_y = DynamicColormapMode._compute_vmin_vmax(roi,(21,21))
+        assert vmin == 253 and vmax == 483 and bb_x == (11,11,22,22) and bb_y == (11,22,22,11)
+
+
 class TestSelectPolygon(PlotWidgetTestCase):
     """Test polygon selection interaction"""
 

src/silx/gui/plot/tools/toolbars.py

@@ -53,6 +53,11 @@ def __init__(self, parent=None, plot=None, title="Plot Interaction"):
         self._panModeAction = actions.mode.PanModeAction(parent=self, plot=plot)
         self.addAction(self._panModeAction)
 
+        self._dynamicColormapAction = actions.mode.DynamicColormapAction(
+            parent=self, plot=plot
+        )
+        self.addAction(self._dynamicColormapAction)
+
     def getZoomModeAction(self):
         """Returns the zoom mode QAction.
 
@@ -67,6 +72,9 @@ def getPanModeAction(self):
         """
         return self._panModeAction
 
+    def getDynamicColormapAction(self):
+        return self._dynamicColormapAction
+
 
 class OutputToolBar(qt.QToolBar):
     """Toolbar providing icons to copy, save and print a PlotWidget