Imviz: API for center_on and offset_to in pixels

spacetelescope · Jun 17, 2021 · e1e8906 · e1e8906
1 parent d8fad81
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diff --git a/jdaviz/configs/imviz/helper.py b/jdaviz/configs/imviz/helper.py
@@ -2,6 +2,9 @@
 import re
 from copy import deepcopy
 
+from astropy.coordinates import SkyCoord
+from echo import delay_callback
+
 from jdaviz.core.helpers import ConfigHelper
 
 __all__ = ['Imviz']
@@ -79,6 +82,57 @@ def load_data(self, data, parser_reference=None, **kwargs):
             self.app.load_data(
                 data, parser_reference=parser_reference, **kwargs)
 
+    def center_on(self, point):
+        """Centers the view on a particular point.
+
+        Parameters
+        ----------
+        point : tuple or `~astropy.coordinates.SkyCoord`
+            If tuple of ``(X, Y)`` is given, it is assumed
+            to be in data coordinates and 0-indexed.
+
+        """
+        viewer = self.app.get_viewer("viewer-1")
+
+        if isinstance(point, SkyCoord):
+            raise NotImplementedError
+        else:
+            with delay_callback(viewer.state, 'x_min', 'x_max', 'y_min', 'y_max'):
+                width = viewer.state.x_max - viewer.state.x_min
+                height = viewer.state.y_max - viewer.state.y_min
+                viewer.state.x_min = point[0] - (width * 0.5)
+                viewer.state.y_min = point[1] - (height * 0.5)
+                viewer.state.x_max = viewer.state.x_min + width
+                viewer.state.y_max = viewer.state.y_min + height
+
+    def offset_to(self, dx, dy, skycoord_offset=False):
+        """Move the center to a point that is given offset
+        away from the current center.
+
+        Parameters
+        ----------
+        dx, dy : float
+            Offset value. Unit is assumed based on
+            ``skycoord_offset``.
+
+        skycoord_offset : bool
+            If `True`, offset must be given in degrees.
+            Otherwise, they are in pixel values.
+
+        """
+        viewer = self.app.get_viewer("viewer-1")
+
+        if skycoord_offset:
+            raise NotImplementedError
+        else:
+            with delay_callback(viewer.state, 'x_min', 'x_max', 'y_min', 'y_max'):
+                width = viewer.state.x_max - viewer.state.x_min
+                height = viewer.state.y_max - viewer.state.y_min
+                viewer.state.x_min += dx
+                viewer.state.y_min += dy
+                viewer.state.x_max = viewer.state.x_min + width
+                viewer.state.y_max = viewer.state.y_min + height
+
 
 def split_filename_with_fits_ext(filename):
     """Split a ``filename[ext]`` input into filename and FITS extension.

diff --git a/notebooks/ImvizExample.ipynb b/notebooks/ImvizExample.ipynb
@@ -2,13 +2,15 @@
  "cells": [
   {
    "cell_type": "markdown",
+   "id": "17b4af6f",
    "metadata": {},
    "source": [
     "# Proof of concept of Imviz requirements using glupyter/bqplot"
    ]
   },
   {
    "cell_type": "markdown",
+   "id": "3b0f5142",
    "metadata": {},
    "source": [
     "We start off by silencing warnings that can happen when loading data as well as deprecation warnings, for clarity:"
@@ -17,6 +19,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "a4b3aee3",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -27,6 +30,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "bccca7f4",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -38,6 +42,7 @@
   },
   {
    "cell_type": "markdown",
+   "id": "0ec7c554",
    "metadata": {},
    "source": [
     "We start off by looking at some of the basic features:"
@@ -46,6 +51,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "77c97590",
    "metadata": {
     "scrolled": false
    },
@@ -88,6 +94,7 @@
   },
   {
    "cell_type": "markdown",
+   "id": "1abb759e",
    "metadata": {},
    "source": [
     "Panning and zooming is possible by showing the viewer toolbar and clicking on the '+'-shaped icon, then dragging around in the image and using scrolling to zoom in and out. To change the stretch and colormap, show the **Layer** options accessible through the last icon in the viewer toolbar.\n",
@@ -98,6 +105,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "d76b335d",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -106,6 +114,7 @@
   },
   {
    "cell_type": "markdown",
+   "id": "11888383",
    "metadata": {},
    "source": [
     "the colormap:"
@@ -114,6 +123,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "fec4de61",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -122,6 +132,7 @@
   },
   {
    "cell_type": "markdown",
+   "id": "def18589",
    "metadata": {},
    "source": [
     "the limits via the percentile option:"
@@ -130,6 +141,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "7c41f17a",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -138,6 +150,7 @@
   },
   {
    "cell_type": "markdown",
+   "id": "c59d150e",
    "metadata": {},
    "source": [
     "or the limits directly:"
@@ -146,6 +159,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "2a3ac022",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -155,13 +169,15 @@
   },
   {
    "cell_type": "markdown",
+   "id": "2f25ccd8",
    "metadata": {},
    "source": [
     "Note also that in the above example there are mouse-over coordinates visible by default."
    ]
   },
   {
    "cell_type": "markdown",
+   "id": "5a7848d0",
    "metadata": {},
    "source": [
     "It possible to make selections/regions in images and export these to astropy regions. Click on the viewer toolbar then click on the circular selection tool, and drag and click to select an interesting region on the sky. We can then export this region with:"
@@ -170,6 +186,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "1e369edd",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -179,6 +196,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "a0385234",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -187,6 +205,7 @@
   },
   {
    "cell_type": "markdown",
+   "id": "11afa633",
    "metadata": {},
    "source": [
     "Since the region is an astropy region, we can e.g. convert it to a mask:"
@@ -195,6 +214,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "71e2191b",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -204,6 +224,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "0a4e02ef",
    "metadata": {},
    "outputs": [],
    "source": [
@@ -213,15 +234,47 @@
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "164a1a40",
    "metadata": {},
    "outputs": [],
    "source": [
     "plt.imshow(mask.to_image(data.shape), origin='lower')"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "99766ca8",
+   "metadata": {},
+   "source": [
+    "You can also programmatically control the viewer."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "5e908421",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Center the image on given pixel position.\n",
+    "imviz.center_on((10, 20))  # X=10,Y=20 (0-indexed)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "e68b6306",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Move the image with the given pixel offsets.\n",
+    "imviz.offset_to(-10, 10)  # dX, dY"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
+   "id": "e0f3845a",
    "metadata": {},
    "outputs": [],
    "source": []
@@ -243,7 +296,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.3"
+   "version": "3.9.5"
   }
  },
  "nbformat": 4,