Improve buttons

Now, starting up the buttons DOESN'T block until ImageJ is ready!

Also, we switch to icons only since it's more napari-like

src/napari_imagej/widget_IJ2.py

@@ -1,42 +1,61 @@
 from enum import Enum
+from threading import Thread
 from typing import List
 
 from magicgui.widgets import request_values
 from napari import Viewer
+from napari._qt.qt_resources import QColoredSVGIcon
 from napari.layers import Layer
 from qtpy.QtCore import Qt
 from qtpy.QtGui import QIcon, QPixmap
-from qtpy.QtWidgets import QMessageBox, QPushButton, QVBoxLayout, QWidget
+from qtpy.QtWidgets import QHBoxLayout, QMessageBox, QPushButton, QWidget
 
 from napari_imagej._module_utils import _get_layers_hack
-from napari_imagej.setup_imagej import ij, jc, running_headless
+from napari_imagej.setup_imagej import ensure_jvm_started, ij, jc, running_headless
 
 
 class GUIWidget(QWidget):
     def __init__(self, viewer: Viewer):
         super().__init__()
-        self.setLayout(QVBoxLayout())
+        self.setLayout(QHBoxLayout())
+
+        self.from_ij: FromIJButton = FromIJButton(viewer)
+        self.layout().addWidget(self.from_ij)
+
+        self.to_ij: ToIJButton = ToIJButton(viewer)
+        self.layout().addWidget(self.to_ij)
 
         self.gui_button: GUIButton = GUIButton()
         self.layout().addWidget(self.gui_button)
 
-        self.to_ij: ToIJButton = ToIJButton()
-        self.layout().addWidget(self.to_ij)
+        if running_headless():
+            self.gui_button.clicked.connect(self.gui_button.disable_popup)
+        else:
+            self.gui_button.clicked.connect(self._showUI)
+            self.gui_button.clicked.connect(lambda: self.to_ij.setEnabled(True))
+            self.gui_button.clicked.connect(lambda: self.from_ij.setEnabled(True))
 
-        self.from_ij: FromIJButton = FromIJButton(viewer)
-        self.layout().addWidget(self.from_ij)
-        if not running_headless():
-            self.gui_button.clicked.connect(lambda: self.to_ij.setHidden(False))
-            self.gui_button.clicked.connect(lambda: self.from_ij.setHidden(False))
+    def _showUI(self):
+        """
+        NB: This must be its own function to prevent premature calling of ij()
+        """
+        ensure_jvm_started()
+        ij().ui().showUI()
 
 
 class ToIJButton(QPushButton):
-    def __init__(self):
+    def __init__(self, viewer):
         super().__init__()
-        self.setHidden(True)
-        self.setText("Send layers to ImageJ2")
+        self.setEnabled(False)
+        icon = QColoredSVGIcon.from_resources("long_right_arrow")
+        self.setIcon(icon.colored(theme=viewer.theme))
+        self.setToolTip("Send layers to ImageJ2")
         self.clicked.connect(self.send_layers)
 
+    def _set_icon(self, path: str):
+        icon: QIcon = QIcon(QPixmap(path))
+        self.setIcon(icon)
+
     def send_layers(self):
         layers: dict = request_values(
             title="Send layers to ImageJ2",
@@ -55,10 +74,16 @@ def __init__(self, viewer: Viewer):
         super().__init__()
         self.viewer = viewer
 
-        self.setHidden(True)
-        self.setText("Get layers from ImageJ2")
+        self.setEnabled(False)
+        icon = QColoredSVGIcon.from_resources("long_left_arrow")
+        self.setIcon(icon.colored(theme=viewer.theme))
+        self.setToolTip("Get layers from ImageJ2")
         self.clicked.connect(self.get_layers)
 
+    def _set_icon(self, path: str):
+        icon: QIcon = QIcon(QPixmap(path))
+        self.setIcon(icon)
+
     def _get_objects(self, t):
         compatibleInputs = ij().convert().getCompatibleInputs(t)
         compatibleInputs.addAll(ij().object().getObjects(t))
@@ -87,28 +112,30 @@ def get_layers(self) -> List[Layer]:
 class GUIButton(QPushButton):
     def __init__(self):
         super().__init__()
-        self._text = "Display ImageJ2 GUI"
-
-        if running_headless():
-            self._setup_headless()
-        else:
+        running_headful = not running_headless()
+        self.setEnabled(False)
+        if running_headful:
             self._setup_headful()
+        else:
+            self._setup_headless()
 
     def _set_icon(self, path: str):
         icon: QIcon = QIcon(QPixmap(path))
         self.setIcon(icon)
 
     def _setup_headful(self):
-        self._set_icon("resources/16x16-flat.png")
-        self.setText(self._text)
-        self.setToolTip("Open ImageJ2 in a new window!")
-        self.clicked.connect(ij().ui().showUI)
+        self._set_icon("resources/16x16-flat-disabled.png")
+        self.setToolTip("Display ImageJ2 GUI (loading)")
+        def post_setup():
+            ensure_jvm_started()
+            self._set_icon("resources/16x16-flat.png")
+            self.setEnabled(True)
+            self.setToolTip("Display ImageJ2 GUI")
+        Thread(target=post_setup).start()
 
     def _setup_headless(self):
         self._set_icon("resources/16x16-flat-disabled.png")
-        self.setText(self._text + " (disabled)")
-        self.setToolTip("Not available when running PyImageJ headlessly!")
-        self.clicked.connect(self.disable_popup)
+        self.setToolTip("ImageJ2 GUI unavailable!")
 
     def disable_popup(self):
         msg: QMessageBox = QMessageBox()

tests/test_IJ2GUIWidget.py

@@ -4,7 +4,7 @@
 from napari.viewer import current_viewer
 from qtpy.QtCore import Qt, QTimer
 from qtpy.QtGui import QPixmap
-from qtpy.QtWidgets import QApplication, QDialog, QMessageBox, QPushButton, QVBoxLayout
+from qtpy.QtWidgets import QApplication, QDialog, QMessageBox, QPushButton, QHBoxLayout
 
 from napari_imagej.setup_imagej import JavaClasses, running_headless
 from napari_imagej.widget_IJ2 import FromIJButton, GUIButton, GUIWidget, ToIJButton
@@ -62,10 +62,10 @@ def test_widget_layout(gui_widget: GUIWidget):
     """Tests the number and expected order of imagej_widget children"""
     subwidgets = gui_widget.children()
     assert len(subwidgets) == 4
-    assert isinstance(subwidgets[0], QVBoxLayout)
-    assert isinstance(subwidgets[1], GUIButton)
+    assert isinstance(subwidgets[0], QHBoxLayout)
+    assert isinstance(subwidgets[1], FromIJButton)
     assert isinstance(subwidgets[2], ToIJButton)
-    assert isinstance(subwidgets[3], FromIJButton)
+    assert isinstance(subwidgets[3], GUIButton)
 
 
 @pytest.mark.skipif(
@@ -79,10 +79,9 @@ def test_GUIButton_layout_headful(qtbot, ij, gui_widget: GUIWidget):
     actual: QPixmap = button.icon().pixmap(expected.size())
     assert expected.toImage() == actual.toImage()
 
-    expected_text = "Display ImageJ2 GUI"
-    assert expected_text == button.text()
+    assert "" == button.text()
 
-    expected_toolTip = "Open ImageJ2 in a new window!"
+    expected_toolTip = "Display ImageJ2 GUI"
     assert expected_toolTip == button.toolTip()
 
     # Test showing UI
@@ -102,11 +101,10 @@ def test_GUIButton_layout_headless(qtbot, gui_widget: GUIWidget):
     actual: QPixmap = button.icon().pixmap(expected.size())
     assert expected.toImage() == actual.toImage()
 
-    expected_text = "Display ImageJ2 GUI (disabled)"
-    assert expected_text == button.text()
+    assert "" == button.text()
 
-    expected_toolTip = "Not available when running PyImageJ headlessly!"
-    assert expected_toolTip == button.toolTip()
+    expected_text = "ImageJ2 GUI unavailable!"
+    assert expected_text == button.toolTip()
 
     # Test popup when running headlessly
     def handle_dialog():
@@ -137,11 +135,11 @@ def handle_dialog():
 )
 def test_data_to_ImageJ(qtbot, ij, gui_widget: GUIWidget):
     button: ToIJButton = gui_widget.to_ij
-    assert button.isHidden()
+    assert not button.isEnabled()
 
     # Show the button
     qtbot.mouseClick(gui_widget.gui_button, Qt.LeftButton, delay=1)
-    qtbot.waitUntil(lambda: not button.isHidden())
+    qtbot.waitUntil(lambda: button.isEnabled())
 
     # Add some data to the viewer
     sample_data = numpy.ones((100, 100, 3))
@@ -174,11 +172,11 @@ def handle_dialog():
 )
 def test_data_from_ImageJ(qtbot, ij, gui_widget: GUIWidget):
     button: FromIJButton = gui_widget.from_ij
-    assert button.isHidden()
+    assert not button.isEnabled()
 
     # Show the button
     qtbot.mouseClick(gui_widget.gui_button, Qt.LeftButton, delay=1)
-    qtbot.waitUntil(lambda: not button.isHidden())
+    qtbot.waitUntil(lambda: button.isEnabled())
 
     # Add some data to ImageJ
     sample_data = jc.ArrayImgs.bytes(10, 10, 10)