Zoomable spectrum plot in the Spectrum Viewer (#2133)

docs/release_notes/next/feature-2133-zoomable-spectrum-plot

@@ -0,0 +1 @@
+#2133: The Spectrum plot in the Spectrum Viewer can be zoomed via a click and drag zoom-box

mantidimaging/gui/widgets/mi_mini_image_view/view.py

@@ -36,12 +36,16 @@ class MIMiniImageView(GraphicsLayout, BadDataOverlay, AutoColorMenu):
     bright_levels: None | list[int] = None
     levels: list[float]
 
-    def __init__(self, name: str = "MIMiniImageView", parent: QWidget | None = None, recon_mode: bool = False):
+    def __init__(self,
+                 name: str = "MIMiniImageView",
+                 parent: QWidget | None = None,
+                 recon_mode: bool = False,
+                 view_box_type: type[ViewBox] = ViewBox):
         super().__init__()
 
         self.name = name.title()
         self.im = ImageItem()
-        self.vb = ViewBox(invertY=True, lockAspect=True, name=name)
+        self.vb = view_box_type(invertY=True, lockAspect=True, name=name)
         self.vb.addItem(self.im)
         self.hist = HistogramLUTItem(self.im)
         graveyard.append(self.vb)

mantidimaging/gui/windows/spectrum_viewer/spectrum_widget.py

@@ -7,6 +7,7 @@
 from PyQt5.QtCore import pyqtSignal, Qt, QSignalBlocker
 from PyQt5.QtGui import QColor
 from PyQt5.QtWidgets import QColorDialog, QAction, QMenu, QSplitter, QWidget, QVBoxLayout
+
 from pyqtgraph import ROI, GraphicsLayoutWidget, LinearRegionItem, PlotItem, mkPen, ViewBox
 
 from mantidimaging.core.utility.close_enough_point import CloseEnoughPoint
@@ -257,6 +258,49 @@ def rename_roi(self, old_name: str, new_name: str) -> None:
             self.roi_dict[new_name].rename_roi(new_name)
 
 
+class CustomViewBox(ViewBox):
+
+    def __init__(self, *args, **kwds):
+        #kwds['enableMenu'] = False
+        ViewBox.__init__(self, *args, **kwds)
+        self.setMouseMode(self.PanMode)
+
+    def keyPressEvent(self, event):
+        if event.key() == Qt.Key_Control:
+            self.setMouseMode(self.RectMode)
+            for child in self.allChildren():
+                if isinstance(child, LinearRegionItem):
+                    child.setMovable(False)
+                elif isinstance(child, SpectrumROI):
+                    child.translatable = False
+
+    def keyReleaseEvent(self, event):
+        if event.key() == Qt.Key_Control:
+            self.rbScaleBox.hide()
+            self.setMouseMode(self.PanMode)
+            for child in self.allChildren():
+                if isinstance(child, LinearRegionItem):
+                    child.setMovable(True)
+                elif isinstance(child, SpectrumROI):
+                    child.translatable = True
+
+    ## reimplement right-click to zoom out
+    def mouseClickEvent(self, ev):
+        if ev.button() == Qt.MouseButton.RightButton and not self.menuEnabled():
+            self.autoRange()
+        else:
+            ViewBox.mouseClickEvent(self, ev)
+
+    ## reimplement mouseDragEvent to disable continuous axis zoom
+    def mouseDragEvent(self, ev, axis=None):
+        if axis is not None and ev.button() == Qt.MouseButton.RightButton:
+            ev.ignore()
+        elif ev.button() == Qt.MouseButton.LeftButton:
+            ViewBox.mouseDragEvent(self, ev)
+        else:
+            ViewBox.mouseDragEvent(self, ev, axis=axis)
+
+
 class SpectrumPlotWidget(GraphicsLayoutWidget):
 
     spectrum: PlotItem
@@ -268,8 +312,8 @@ class SpectrumPlotWidget(GraphicsLayoutWidget):
     def __init__(self) -> None:
         super().__init__()
 
-        self.vb = ViewBox()
-        self.spectrum = self.addPlot(viewbox=self.vb)
+        self.spectrum_viewbox = CustomViewBox(enableMenu=True)
+        self.spectrum = self.addPlot(viewBox=self.spectrum_viewbox)
         self.nextRow()
         self._tof_range_label = self.addLabel()
         self.nextRow()
@@ -309,7 +353,6 @@ class SpectrumProjectionWidget(GraphicsLayoutWidget):
 
     def __init__(self) -> None:
         super().__init__()
-
-        self.image = MIMiniImageView(name="Projection")
+        self.image = MIMiniImageView(name="Projection", view_box_type=CustomViewBox)
         self.addItem(self.image, 0, 0)
         self.ci.layout.setRowStretchFactor(0, 3)

mantidimaging/gui/windows/spectrum_viewer/view.py

@@ -90,7 +90,7 @@ def __init__(self, main_window: MainWindowView):
         self.spectrum_widget.roi_changed.connect(self.presenter.handle_roi_moved)
         self.spectrum_widget.roiColorChangeRequested.connect(self.presenter.change_roi_colour)
 
-        self.spectrum_right_click_menu = self.spectrum_widget.spectrum_plot_widget.spectrum.vb.menu
+        self.spectrum_right_click_menu = self.spectrum.spectrum_viewbox.menu
         self.units_menu = self.spectrum_right_click_menu.addMenu("Units")
         self.tof_mode_select_group = QActionGroup(self)