Create color_dialog.py

DataAnnotation/labelme/labelme/widgets/color_dialog.py

+from qtpy import QtWidgets
+
+
+class ColorDialog(QtWidgets.QColorDialog):
+
+    def __init__(self, parent=None):
+        super(ColorDialog, self).__init__(parent)
+        self.setOption(QtWidgets.QColorDialog.ShowAlphaChannel)
+        # The Mac native dialog does not support our restore button.
+        self.setOption(QtWidgets.QColorDialog.DontUseNativeDialog)
+        # Add a restore defaults button.
+        # The default is set at invocation time, so that it
+        # works across dialogs for different elements.
+        self.default = None
+        self.bb = self.layout().itemAt(1).widget()
+        self.bb.addButton(QtWidgets.QDialogButtonBox.RestoreDefaults)
+        self.bb.clicked.connect(self.checkRestore)
+
+    def getColor(self, value=None, title=None, default=None):
+        self.default = default
+        if title:
+            self.setWindowTitle(title)
+        if value:
+            self.setCurrentColor(value)
+        return self.currentColor() if self.exec_() else None
+
+    def checkRestore(self, button):
+        if self.bb.buttonRole(button) & \
+                QtWidgets.QDialogButtonBox.ResetRole and self.default:
+            self.setCurrentColor(self.default)