WIP in case my local computer combusts

I promise to revise history soon 😬

astrowidgets/bqplot.py

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+import numpy as np
+from bqplot import Figure, LinearScale, Axis, ColorScale, PanZoom
+from bqplot_image_gl import ImageGL
+from bqplot_image_gl.interacts import (MouseInteraction,
+                                       keyboard_events, mouse_events)
+
+import ipywidgets as ipw
+import traitlets as trait
+
+# Allowed locations for cursor display
+ALLOWED_CURSOR_LOCATIONS = ['top', 'bottom', None]
+
+# List of marker names that are for internal use only
+RESERVED_MARKER_SET_NAMES = ['all']
+
+
+class _AstroImage(ipw.VBox):
+    """
+    Encapsulate an image as a bqplot figure inside a box.
+
+    bqplot is involved for its pan/zoom capabilities, and it presents as
+    a box to obscure the usual bqplot properties and methods.
+    """
+    def __init__(self, image_data=None,
+                 display_width=500,
+                 viewer_aspect_ratio=1.0):
+        super().__init__()
+
+        self._viewer_aspect_ratio = viewer_aspect_ratio
+
+        self._display_width = display_width
+        self._display_height = self._viewer_aspect_ratio * self._display_width
+
+
+        layout = ipw.Layout(width=f'{self._display_width}px',
+                            height=f'{self._display_height}px',
+                            justify_content='center')
+
+        self._figure_layout = layout
+
+        scale_x = LinearScale(min=0, max=1, #self._image_shape[1],
+                              allow_padding=False)
+        scale_y = LinearScale(min=0, max=1, #self._image_shape[0],
+                              allow_padding=False)
+        self._scales = {'x': scale_x, 'y': scale_y}
+        axis_x = Axis(scale=scale_x, visible=False)
+        axis_y = Axis(scale=scale_y, orientation='vertical', visible=False)
+        scales_image = {'x': scale_x, 'y': scale_y,
+                        'image': ColorScale(max=1.114, min=2902,
+                                            scheme='Greys')}
+
+        self._figure = Figure(scales=self._scales, axes=[axis_x, axis_y],
+                              fig_margin=dict(top=0, left=0,
+                                              right=0, bottom=0),
+                              layout=layout)
+
+        self._image = ImageGL(scales=scales_image)
+
+        self._figure.marks = (self._image, )
+
+        panzoom = PanZoom(scales={'x': [scales_image['x']],
+                                  'y': [scales_image['y']]})
+        interaction = MouseInteraction(x_scale=scales_image['x'],
+                                       y_scale=scales_image['y'],
+                                       move_throttle=70, next=panzoom,
+                                       events=keyboard_events + mouse_events)
+
+        self._figure.interaction = interaction
+
+        if image_data:
+            self.set_data(image_data, reset_view=True)
+
+        self.children = (self._figure, )
+
+    @property
+    def data_aspect_ratio(self):
+        """
+        Aspect ratio of the image data, horizontal size over vertical size.
+        """
+        return self._image_shape[0] / self._image_shape[1]
+
+    def reset_scale_to_fit_image(self):
+        wide = self.data_aspect_ratio < 1
+        tall = self.data_aspect_ratio > 1
+        square = self.data_aspect_ratio == 1
+
+        if wide:
+            self._scales['x'].min = 0
+            self._scales['x'].max = self._image_shape[1]
+            self._set_scale_aspect_ratio_to_match_viewer()
+        elif tall or square:
+            self._scales['y'].min = 0
+            self._scales['y'].max = self._image_shape[0]
+            self._set_scale_aspect_ratio_to_match_viewer(reset_scale='x')
+
+        # Great, now let's center
+        self.center = (self._image_shape[1]/2,
+                       self._image_shape[0]/2)
+
+
+    def _set_scale_aspect_ratio_to_match_viewer(self,
+                                                reset_scale='y'):
+        # Set the scales so that they match the aspect ratio
+        # of the viewer, preserving the current image center.
+        width_x, width_y = self.scale_widths
+        frozen_width = dict(y=width_x, x=width_y)
+        scale_aspect = width_x / width_y
+        figure_x = float(self._figure.layout.width[:-2])
+        figure_y = float(self._figure.layout.height[:-2])
+        figure_aspect = figure_x / figure_y
+        current_center = self.center
+        if abs(figure_aspect - scale_aspect) > 1e-4:
+            # Make the scale aspect ratio match the
+            # figure layout aspect ratio
+            if reset_scale == 'y':
+                scale_factor = 1/ figure_aspect
+            else:
+                scale_factor = figure_aspect
+
+            self._scales[reset_scale].min = 0
+            self._scales[reset_scale].max = frozen_width[reset_scale] * scale_factor
+            self.center = current_center
+
+    def set_data(self, image_data, reset_view=True):
+        self._image_shape = image_data.shape
+
+        if reset_view:
+            self.reset_scale_to_fit_image()
+
+        # Set the image data and map it to the bqplot figure so that
+        # cursor location corresponds to the underlying array index.
+        self._image.image = image_data
+        self._image.x = [0, self._image_shape[1]]
+        self._image.y = [0, self._image_shape[0]]
+
+    @property
+    def center(self):
+        """
+        Center of current view in pixels in x, y.
+        """
+        x_center = (self._scales['x'].min + self._scales['x'].max) / 2
+        y_center = (self._scales['y'].min + self._scales['y'].max) / 2
+        return (x_center, y_center)
+
+    @property
+    def scale_widths(self):
+        width_x = self._scales['x'].max - self._scales['x'].min
+        width_y = self._scales['y'].max - self._scales['y'].min
+        return (width_x, width_y)
+
+    @center.setter
+    def center(self, value):
+        x_c, y_c = value
+
+        width_x, width_y = self.scale_widths
+        self._scales['x'].max = x_c + width_x / 2
+        self._scales['x'].min = x_c - width_x / 2
+        self._scales['y'].max = y_c + width_y / 2
+        self._scales['y'].min = y_c - width_y / 2
+
+    def set_color(self, colors):
+        # colors here means a list of hex colors
+        self._image.scales['image'].colors = colors
+
+
+def bqcolors(colormap, reverse=False):
+    from matplotlib import cm as cmp
+    from matplotlib.colors import to_hex
+
+    # bqplot-image-gl has 256 levels
+    LEVELS = 256
+
+    # Make a matplotlib colormap object
+    mpl = cmp.get_cmap(colormap, LEVELS)
+
+    # Get RGBA colors
+    mpl_colors = mpl(np.linspace(0, 1, LEVELS))
+
+    # Convert RGBA to hex
+    bq_colors = [to_hex(mpl_colors[i, :]) for i in range(LEVELS)]
+
+    if reverse:
+        bq_colors = bq_colors[::-1]
+
+    return bq_colors
+
+"""
+next(iter(imviz.app._viewer_store.values())).figure
+"""
+
+
+class ImageWidget(ipw.VBox):
+    click_center = trait.Bool(default_value=False).tag(sync=True)
+    click_drag = trait.Bool(default_value=False).tag(sync=True)
+    scroll_pan = trait.Bool(default_value=False).tag(sync=True)
+    image_width = trait.Int(help="Width of the image (not viewer)").tag(sync=True)
+    image_height = trait.Int(help="Height of the image (not viewer)").tag(sync=True)
+    zoom_level = trait.Float(help="Current zoom of the view").tag(sync=True)
+    marker = trait.Any(help="Markers").tag(sync=True)
+    cuts = trait.Tuple(help="Cut levels").tag(sync=True)
+    stretch = trait.Unicode(help='Stretch algorithm name').tag(sync=True)
+
+    def __init__(self, *args, image_width=500, image_height=500):
+        super().__init__(*args)
+        self.image_width = image_width
+        self.image_height = image_height
+        self._astro_im = _AstroImage()
+
+    # The methods, grouped loosely by purpose
+
+    # Methods for loading data
+    # @abstractmethod
+    # def load_fits(self, file):
+    #     raise NotImplementedError
+
+    def load_array(self, array):
+        raise NotImplementedError
+
+    # @abstractmethod
+    # def load_nddata(self, data):
+    #     raise NotImplementedError
+
+    # Saving contents of the view and accessing the view
+    @abstractmethod
+    def save(self, filename):
+        raise NotImplementedError
+
+    # Marker-related methods
+    @abstractmethod
+    def start_marking(self):
+        raise NotImplementedError
+
+    @abstractmethod
+    def stop_marking(self):
+        raise NotImplementedError
+
+    @abstractmethod
+    def add_markers(self):
+        raise NotImplementedError
+
+    @abstractmethod
+    def get_markers(self):
+        raise NotImplementedError
+
+    @abstractmethod
+    def remove_markers(self):
+        raise NotImplementedError
+
+    # @abstractmethod
+    # def get_all_markers(self):
+    #     raise NotImplementedError
+
+    # @abstractmethod
+    # def get_markers_by_name(self, marker_name=None):
+    #     raise NotImplementedError
+
+    # Methods that modify the view
+    @abstractmethod
+    def center_on(self):
+        raise NotImplementedError
+
+    @abstractmethod
+    def offset_to(self):
+        raise NotImplementedError
+
+    @abstractmethod
+    def zoom(self):
+        raise NotImplementedError