Merge pull request #1558 from pllim/blink-back-to-the-future

Allow Shift+b to blink backwards

Author: pllim

CHANGES.rst

@@ -18,8 +18,12 @@ Imviz
 
 - Auto-populate simple aperture photometry values if JWST data is loaded into viewer. [#1549]
 
+- Pressing Shift+b now blinks backwards. Right-clicking on the image while Blink tool
+  is active on the toolbar also blinks backwards. [#1558]
+
 Mosviz
 ^^^^^^
+
 - NIRISS parser now sorts FITS files by header instead of file name. [#819]
 
 Specviz

docs/imviz/displayimages.rst

@@ -156,8 +156,10 @@ Blinking
 Blinking is an Imviz-specific functionality that allows a user to quickly switch
 between viewing two or more images, as long as they are linked (see :ref:`imviz_pan_zoom` for
 more on linking behavior). This can be done by selecting the |icon-blink| icon and
-then clicking on the image. You can also blink by pressing the "b" key on your
-keyboard while moused over the image.
+then left-clicking on the image to blink forward; right-clicking would blink backwards.
+
+You can also blink forward by pressing the "b" key on your keyboard while moused over the image.
+If you press Shift + "b" ("B"), you may blink backwards.
 
 From the API
 ------------
@@ -167,6 +169,10 @@ From the API within the Jupyter notebook::
     viewer = imviz.default_viewer
     viewer.blink_once()
 
+And to blink backwards::
+
+    viewer.blink_once(reversed=True)
+
 Contrast/Bias
 =============
 

jdaviz/configs/imviz/plugins/tools.py

@@ -102,17 +102,17 @@ class BlinkOnce(CheckableTool):
     icon = os.path.join(ICON_DIR, 'blink.svg')
     tool_id = 'jdaviz:blinkonce'
     action_text = 'Go to next image'
-    tool_tip = ('Click on the viewer to display the next image, '
-                'or you can also press the "b" key anytime')
+    tool_tip = ('Click on the viewer or press "b" to display the next image, '
+                'or right-click or press "B" to display the previous')
 
     def activate(self):
-        self.viewer.add_event_callback(self.on_click, events=['click'])
+        self.viewer.add_event_callback(self.on_click, events=['click', 'contextmenu'])
 
     def deactivate(self):
         self.viewer.remove_event_callback(self.on_click)
 
     def on_click(self, data):
-        self.viewer.blink_once()
+        self.viewer.blink_once(reversed=data['event']=='contextmenu')  # noqa: E225
 
         # Also update the coordinates display.
         data['event'] = 'mousemove'

jdaviz/configs/imviz/plugins/viewers.py

@@ -151,8 +151,8 @@ def on_mouse_or_key_event(self, data):
         elif data['event'] == 'keydown':
             key_pressed = data['key']
 
-            if key_pressed == 'b':
-                self.blink_once()
+            if key_pressed in ('b', 'B'):
+                self.blink_once(reversed=key_pressed=='B')  # noqa: E225
 
                 # Also update the coordinates display.
                 data['event'] = 'mousemove'
@@ -171,7 +171,7 @@ def on_mouse_or_key_event(self, data):
                 self.line_profile_xy.selected_viewer = self.reference_id
                 self.line_profile_xy.vue_draw_plot()
 
-    def blink_once(self):
+    def blink_once(self, reversed=False):
         # Simple blinking of images - this will make it so that only one
         # layer is visible at a time and cycles through the layers.
 
@@ -198,7 +198,11 @@ def blink_once(self):
                                       color='warning', sender=self)
                 self.session.hub.broadcast(msg)
             elif n_visible > 0:
-                next_layer = valid[(valid.index(visible[-1]) + 1) % n_layers]
+                if not reversed:
+                    delta = 1
+                else:
+                    delta = -1
+                next_layer = valid[(valid.index(visible[-1]) + delta) % n_layers]
                 self.state.layers[next_layer].visible = True
 
                 for ilayer in (set(valid) - set([next_layer])):

jdaviz/configs/imviz/tests/test_linking.py

@@ -151,7 +151,8 @@ def test_wcslink_affine_with_extras(self):
 
         # blink image through clicking with blink tool
         self.viewer.toolbar_nested.active_tool_id = 'jdaviz:blinkonce'
-        self.viewer.toolbar_nested.active_tool.on_click({'domain': {'x': 0, 'y': 0}})
+        self.viewer.toolbar_nested.active_tool.on_click(
+            {'event': 'click', 'domain': {'x': 0, 'y': 0}})
         assert self.viewer.label_mouseover.pixel == 'x=00.0 y=00.0'
         assert self.viewer.label_mouseover.value == '+1.00000e+00 '
         assert self.viewer.label_mouseover.world_ra_deg == '337.5202808000'

jdaviz/configs/imviz/tests/test_tools.py

@@ -1,3 +1,5 @@
+import numpy as np
+
 from jdaviz.configs.imviz.tests.utils import BaseImviz_WCS_WCS
 
 
@@ -32,3 +34,29 @@ def test_zoom_tools(self):
         v.toolbar_nested.tools['jdaviz:prevzoom'].activate()
         assert (v.state.x_min, v.state.x_max, v.state.y_min, v.state.y_max) == (1, 8, 1, 8)
         assert (v2.state.x_min, v2.state.x_max, v2.state.y_min, v2.state.y_max) == (1, 8, 1, 8)
+
+
+def test_blink(imviz_helper):
+    viewer = imviz_helper.default_viewer
+
+    for i in range(3):
+        imviz_helper.load_data(np.zeros((2, 2)) + i, data_label=f'image_{i}')
+
+    # Last loaded is shown first. So, blinking will take you back to the first one.
+    # Blink forward. The event will also initialize viewer.label_mouseover .
+    viewer.on_mouse_or_key_event({'event': 'keydown', 'key': 'b', 'domain': {'x': 0, 'y': 0}})
+    assert viewer.label_mouseover.value == '+0.00000e+00 '
+
+    # Blink forward again and update coordinates info panel.
+    viewer.blink_once()
+    viewer.on_mouse_or_key_event({'event': 'mousemove', 'domain': {'x': 0, 'y': 0}})
+    assert viewer.label_mouseover.value == '+1.00000e+00 '
+
+    # Blink backward.
+    viewer.blink_once(reversed=True)
+    viewer.on_mouse_or_key_event({'event': 'mousemove', 'domain': {'x': 0, 'y': 0}})
+    assert viewer.label_mouseover.value == '+0.00000e+00 '
+
+    # Blink backward again.
+    viewer.on_mouse_or_key_event({'event': 'keydown', 'key': 'B', 'domain': {'x': 0, 'y': 0}})
+    assert viewer.label_mouseover.value == '+2.00000e+00 '