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timhoffmtimhoffm
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DOC: add index labels
1 parent e461640 commit 285c8d2

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Lines changed: 79 additions & 15 deletions

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‎tutorials/intermediate/imshow_extent.py‎

Lines changed: 79 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -20,6 +20,66 @@
2020
from matplotlib.gridspec import GridSpec
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def index_to_coordinate(index, extent, origin):
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"""Return the pixel center of an index."""
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left, right, bottom, top = extent
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hshift = 0.5 * np.sign(right - left)
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left, right = left + hshift, right - hshift
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vshift = 0.5 * np.sign(top - bottom)
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bottom, top = bottom + vshift, top - vshift
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if origin == 'upper':
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bottom, top = top, bottom
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return {
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"[0, 0]": (left, bottom),
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"[N', 0]": (left, top),
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"[0, M']": (right, bottom),
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"[N', M']": (right, top),
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}[index]
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def get_index_label_pos(index, extent, origin, inverted_xindex):
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"""
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Return the desired position and horizontal alignment of an index label.
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"""
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if extent is None:
48+
extent = lookup_extent(origin)
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left, right, bottom, top = extent
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x, y = index_to_coordinate(index, extent, origin)
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is_x0 = index[-2:] == "0]"
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halign = 'left' if is_x0 ^ inverted_xindex else 'right'
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hshift = 0.5 * np.sign(left - right)
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x += hshift * (1 if is_x0 else -1)
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return x, y, halign
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def get_color(index, data, cmap):
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"""Return the data color of an index."""
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val = {
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"[0, 0]": data[0, 0],
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"[0, M']": data[0, -1],
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"[N', 0]": data[-1, 0],
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"[N', M']": data[-1, -1],
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}[index]
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return cmap(val / data.max())
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def lookup_extent(origin):
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"""Return extent for label positioning when not given explicitly."""
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if origin == 'lower':
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return (-0.5, 6.5, -0.5, 5.5)
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else:
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return (-0.5, 6.5, 5.5, -0.5)
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def set_extent_None_text(ax):
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ax.text(3, 2.5, 'equals\nextent=None', size='large',
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ha='center', va='center', color='w')
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def generate_imshow_demo_grid(extents, auto_limits):
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N = len(extents)
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fig = plt.figure(tight_layout=True)
@@ -37,18 +97,6 @@ def generate_imshow_demo_grid(extents, auto_limits):
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im = ax.imshow(d, origin=origin, extent=extent)
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left, right, bottom, top = im.get_extent()
40-
arrow_style = {'arrowprops': {'arrowstyle': '-|>',
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'shrinkA': 0,
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'color': '0.5',
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'linewidth': 3}}
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ax.annotate('',
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(left, bottom + 2*np.sign(top - bottom)),
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(left, bottom),
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**arrow_style)
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ax.annotate('',
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(left + 2*np.sign(right - left), bottom),
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(left, bottom),
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**arrow_style)
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if auto_limits or top > bottom:
54102
upper_string, lower_string = 'top', 'bottom'
@@ -57,8 +105,10 @@ def generate_imshow_demo_grid(extents, auto_limits):
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if auto_limits or left < right:
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port_string, starboard_string = 'left', 'right'
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inverted_xindex = False
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else:
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port_string, starboard_string = 'right', 'left'
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inverted_xindex = True
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bbox_kwargs = {'fc': 'w', 'alpha': .75, 'boxstyle': "round4"}
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ann_kwargs = {'xycoords': 'axes fraction',
@@ -78,6 +128,13 @@ def generate_imshow_demo_grid(extents, auto_limits):
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ax.set_title('origin: {origin}'.format(origin=origin))
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131+
for index in ["[0, 0]", "[0, M']", "[N', 0]", "[N', M']"]:
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tx, ty, halign = get_index_label_pos(index, extent, origin,
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inverted_xindex)
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facecolor = get_color(index, d, im.get_cmap())
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ax.text(tx, ty, index, color='white', ha=halign, va='center',
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bbox={'boxstyle': 'square', 'facecolor': facecolor})
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81138
if not auto_limits:
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ax.set_xlim(-1, 7)
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ax.set_ylim(-1, 6)
@@ -89,7 +146,7 @@ def generate_imshow_demo_grid(extents, auto_limits):
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'xy': (1, .5)}
90147
if extent is None:
91148
ax.annotate('None', **text_kwargs)
92-
ax.set_title('`extent=`')
149+
ax.set_title('extent=')
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else:
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left, right, bottom, top = extent
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text = ('left: {left:0.1f}\nright: {right:0.1f}\n' +
@@ -98,6 +155,7 @@ def generate_imshow_demo_grid(extents, auto_limits):
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ax.annotate(text, **text_kwargs)
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ax.axis('off')
158+
return columns
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103161
extents = (None,
@@ -106,6 +164,8 @@ def generate_imshow_demo_grid(extents, auto_limits):
106164
(6.5, -0.5, -0.5, 5.5),
107165
(6.5, -0.5, 5.5, -0.5))
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167+
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###############################################################################
110170
#
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#
@@ -153,7 +213,9 @@ def generate_imshow_demo_grid(extents, auto_limits):
153213
# may invert the axis so they do not increase in the 'natural' direction.
154214
#
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156-
generate_imshow_demo_grid(extents[1:], auto_limits=True)
216+
columns = generate_imshow_demo_grid(extents[1:], auto_limits=True)
217+
set_extent_None_text(columns['upper'][1])
218+
set_extent_None_text(columns['lower'][0])
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###############################################################################
@@ -170,4 +232,6 @@ def generate_imshow_demo_grid(extents, auto_limits):
170232
# - The 'left-right' and 'top-bottom' sense of the image is uncoupled from
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# the orientation on the screen.
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173-
generate_imshow_demo_grid(extents, auto_limits=False)
235+
columns = generate_imshow_demo_grid(extents, auto_limits=False)
236+
set_extent_None_text(columns['upper'][2])
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set_extent_None_text(columns['lower'][1])

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