Using GridSpec with custom wspace doesn't work with tight_layout - matplotlib

The final goal I'm trying to achieve here is to have a figure saved as a .pdf with a certain size ([5,2] in the example code below), with no padding outside the axis labels/tick labels.
I usually achieve this by creating a figure using a combination of figsize and setting the padding to zero via tight_layout (I added the grey background color to show the edges/padding better):
fig = plt.figure(
figsize = [5,2],
tight_layout = {'pad': 0}
)
t = np.arange(0.0, 2.0, 0.01)
s = 1 + np.sin(2*np.pi*t)
plt.plot(t, s)
plt.savefig('figure.pdf', facecolor = (0.7,0.7,0.7))
This creates a nice pdf with size 5x2.
But I'm having trouble doing this with a figure where I'm using GridSpec to create subplots. The strange thing is that the problem is only apparent when setting a custom wspace for the GridSpec.
Example without wspace
fig, (ax0, ax1) = plt.subplots(
nrows = 1, ncols = 2,
gridspec_kw = {'width_ratios' : [3,2]},
tight_layout = {'pad': 0},
figsize = [5,2]
)
t = np.arange(0.0, 2.0, 0.01)
s = 1 + np.sin(2*np.pi*t)
ax0.plot(t, s)
ax1.plot(t, s)
ax1.yaxis.tick_right()
ax0.set_xlim([0, 2.25])
ax1.set_xlim([-0.25, 2])
plt.savefig('figure.pdf')
Example with wspace
I add some wspace to have some space between the subplots, since they are so close together in the example above
fig, (ax0, ax1) = plt.subplots(
nrows = 1, ncols = 2,
gridspec_kw = {'width_ratios' : [3,2], 'wspace' : 0.1},
tight_layout = {'pad': 0},
figsize = [5,2]
)
t = np.arange(0.0, 2.0, 0.01)
s = 1 + np.sin(2*np.pi*t)
ax0.plot(t, s)
ax1.plot(t, s)
ax1.yaxis.tick_right()
ax0.set_xlim([0, 2.25])
ax1.set_xlim([-0.25, 2])
plt.savefig('figure.pdf', facecolor = (0.7,0.7,0.7))
(the only change from above is the added wspace to the gridspec_kw dict)
This gives me an error in the savefig command
C:\Users\<username>\Anaconda3\lib\site-packages\matplotlib\figure.py:1744:
UserWarning: This figure includes Axes that are not compatible with
tight_layout, so its results might be incorrect.
warnings.warn("This figure includes Axes that are not "
# the warning is cut off here for some reason
and produces the following image, clearly not using tight_layout
Does anyone know of a way to get around this issue, or a better way to do what I'm trying?

If the aim is to save the image, you may leave out the tight_layout argument to the figure, and use the arguments bbox_inches='tight', pad_inches=0 when savng the figure:
plt.savefig('figure.pdf', bbox_inches='tight', pad_inches=0)

Related

Matplotlib - Change the white space between specific subplots in a grid grid

I have a grid of subplots and I would like to adjust the white space between only two of them such that the shared x labels are centred without overlapping either graph.
This question has a solution for when these are the only two subplots. However I'm struggling to adjust this to two specific subplots in a grid of many.
This code can be used to illustrate my problem.
In [1]
fig = plt.figure(figsize = (15, 10))
gs = fig.add_gridspec(2,4)
ax1 = fig.add_subplot(gs[0, 0])
ax2 = fig.add_subplot(gs[0, 1:3])
ax3 = fig.add_subplot(gs[0, 3])
ax4 = fig.add_subplot(gs[1, 0])
ax5 = fig.add_subplot(gs[1, 1])
ax6 = fig.add_subplot(gs[1, 2])
ax7 = fig.add_subplot(gs[1, 3])
np.random.seed(19680801)
# Example data
people = ('Really Really Long Name', 'Another Long Name', 'Short Name', 'Name', 'N')
y_pos = np.arange(len(people))
performance = 3 + 10 * np.random.rand(len(people))
ax5.barh(y_pos, performance, align='center')
ax5.set_yticks(y_pos, labels=people)
ax5.invert_xaxis()
ax5.set_xlabel('Label')
ax5.set_title('Bar 1')
ax6.barh(y_pos, performance, align='center')
ax6.set_yticks(y_pos, labels=people)
ax6.set_xlabel('Label')
ax6.set_title('Bar 2')
Out [1]
If I apply the solution to the linked question here then every subplot's white space is effected. I know this is because it calls on fig.dpi_scale_trans which effects the whole figure but I'm new to transforms and can't work out what to use in its place
In [2]
fig.tight_layout()
fig.subplots_adjust(wspace=0.7)
plt.setp(axes[0].yaxis.get_majorticklabels(), ha='center')
# Create offset transform by some points in x direction
dx = 60 / 72.
dy = 0 / 72.
offset = mlb.transforms.ScaledTranslation(dx, dy, fig.dpi_scale_trans)
# apply offset transform to all y ticklabels.
for label in ax6.yaxis.get_majorticklabels():
label.set_transform(label.get_transform() + offset)
Out [2]
I figured out how to solve this so posting my own answer in case anybody has a similar problem in the future.
This question and answer from 7 years ago contained the necessary help to solve the problem.
Essentially you must plot and position different GridSpecs in the figure using GridSpec from matplotlib.gridspec rather than calling one with fig.add_gridspec()
Link to GridSpec documentation
Following on from my example above I wanted to create a 2x4 grid. To do that we can plot the following grids in set positions of the figure:
Left: 1x2
Top Centre: 1x1
Bottom Centre: 2x1
Right: 1x2
In [1]:
from matplotlib.gridspec import GridSpec
fig = plt.figure(figsize = (15, 10))
# Example Data
people = ('Really Really Long Name', 'Another Long Name', 'Short Name', 'Name',
'N')
y_pos = np.arange(len(people))
performance = 3 + 10 * np.random.rand(len(people))
# Left portion of grid (2x1).
# 'left' and 'right' tell the grid where it should start and finish
gs1 = GridSpec(2, 1)
gs1.update(left = 0, right = 0.2)
# Plotting empty subplots for illustration purposes
for i in gs1:
ax = plt.subplot(i)
# Mirroring on the right portion of the grid
gs2 = GridSpec(2, 1)
gs2.update(left = 0.8, right = 1)
for i in gs2:
ax = plt.subplot(i)
# Plotting in top center
# Note here we only need to plot a 1x1
gs3 = GridSpec(1, 1)
gs3.update(left = 0.25, right = 0.75, bottom = 0.53) #0.53 aligns with sides
ax3 = plt.subplot(gs3[0])
# Plotting the barh in the bottom center
# wsapce only adjusts this grid not the entire figure
gs4 = GridSpec(1, 2)
gs4.update(left = 0.2, right = 0.8, top = 0.45, wspace = 0.75)
# Left barh
ax5 = plt.subplot(gs4[0])
ax5.barh(y_pos, performance, align='center')
ax5.set_yticks([])
ax5.invert_xaxis()
ax5.set_xlabel('Label')
ax5.set_title('Bar 1')
# Right barh
ax6 = plt.subplot(gs4[1])
ax6.barh(y_pos, performance, align='center')
ax6.set_yticks(y_pos, labels=people)
ax6.set_xlabel('Label')
ax6.set_title('Bar 2')
plt.show()
Out [1]:

y and x axis subplots matplotlib

A quite basic question about ticks' labels for x and y-axis. According to this code
fig, axes = plt.subplots(6,12, figsize=(50, 24), constrained_layout=True, sharex=True , sharey=True)
fig.subplots_adjust(hspace = .5, wspace=.5)
custom_xlim = (-1, 1)
custom_ylim = (-0.2,0.2)
for i in range(72):
x_data = ctheta[i]
y_data = phi[i]
y_err = err_phi[i]
ax = fig.add_subplot(6, 12, i+1)
ax.plot(x_data_new, bspl(x_data_new))
ax.axis('off')
ax.errorbar(x_data,y_data, yerr=y_err, fmt="o")
ax.set_xlim(custom_xlim)
ax.set_ylim(custom_ylim)
I get the following output:
With y labels for plots on the first column and x labels for theone along the last line, although I call them off.
Any idea?
As #BigBen wrote in their comment, your issue is caused by you adding axes to your figure twice, once via fig, axes = plt.subplots() and then once again within your loop via fig.add_subplot(). As a result, the first set of axes is still visible even after you applied .axis('off') to the second set.
Instead of the latter, you could change your loop to:
for i in range(6):
for j in range(12):
ax = axes[i,j] # these are the axes created via plt.subplots(6,12,...)
ax.axis('off')
# … your other code here

Creating figure with exact size and no padding (and legend outside the axes)

I am trying to make some figures for a scientific article, so I want my figures to have a specific size. I also see that Matplotlib by default adds a lot of padding on the border of the figures, which I don't need (since the figures will be on a white background anyway).
To set a specific figure size I simply use plt.figure(figsize = [w, h]), and I add the argument tight_layout = {'pad': 0} to remove the padding. This works perfectly, and even works if I add a title, y/x-labels etc. Example:
fig = plt.figure(
figsize = [3,2],
tight_layout = {'pad': 0}
)
ax = fig.add_subplot(111)
plt.title('title')
ax.set_ylabel('y label')
ax.set_xlabel('x label')
plt.savefig('figure01.pdf')
This creates a pdf file with exact size 3x2 (inches).
The issue I have is that when I for example add a text box outside the axis (typically a legend box), Matplotlib does not make room for the text box like it does when adding titles/axis labels. Typically the text box is cut off, or does not show in the saved figure at all. Example:
plt.close('all')
fig = plt.figure(
figsize = [3,2],
tight_layout = {'pad': 0}
)
ax = fig.add_subplot(111)
plt.title('title')
ax.set_ylabel('y label')
ax.set_xlabel('x label')
t = ax.text(0.7, 1.1, 'my text here', bbox = dict(boxstyle = 'round'))
plt.savefig('figure02.pdf')
A solution I found elsewhere on SO was to add the argument bbox_inches = 'tight' to the savefig command. The text box is now included like I wanted, but the pdf is now the wrong size. It seems like Matplotlib just makes the figure bigger, instead of reducing the size of the axes like it does when adding titles and x/y-labels.
Example:
plt.close('all')
fig = plt.figure(
figsize = [3,2],
tight_layout = {'pad': 0}
)
ax = fig.add_subplot(111)
plt.title('title')
ax.set_ylabel('y label')
ax.set_xlabel('x label')
t = ax.text(0.7, 1.1, 'my text here', bbox = dict(boxstyle = 'round'))
plt.savefig('figure03.pdf', bbox_inches = 'tight')
(This figure is 3.307x2.248)
Is there any solution to this that covers most cases with a legend just outside the axes?
So the requirements are:
Having a fixed, predefined figure size
Adding a text label or legend outside the axes
Axes and text cannot overlap
The axes, together with the title and axis labels, sits tightly agains the figure border.
So tight_layout with pad = 0, solves 1. and 4. but contradicts 2.
One could think on setting pad to a larger value. This would solve 2. However, since it's is symmetric in all directions, it would contradict 4.
Using bbox_inches = 'tight' changes the figure size. Contradicts 1.
So I think there is no generic solution to this problem.
Something I can come up with is the following: It sets the text in figure coordinates and then resizes the axes either in horizontal or in vertical direction such that there is no overlap between the axes and the text.
import matplotlib.pyplot as plt
import matplotlib.transforms
fig = plt.figure(figsize = [3,2])
ax = fig.add_subplot(111)
plt.title('title')
ax.set_ylabel('y label')
ax.set_xlabel('x label')
def text_legend(ax, x0, y0, text, direction = "v", padpoints = 3, margin=1.,**kwargs):
ha = kwargs.pop("ha", "right")
va = kwargs.pop("va", "top")
t = ax.figure.text(x0, y0, text, ha=ha, va=va, **kwargs)
otrans = ax.figure.transFigure
plt.tight_layout(pad=0)
ax.figure.canvas.draw()
plt.tight_layout(pad=0)
offs = t._bbox_patch.get_boxstyle().pad * t.get_size() + margin # adding 1pt
trans = otrans + \
matplotlib.transforms.ScaledTranslation(-offs/72.,-offs/72.,fig.dpi_scale_trans)
t.set_transform(trans)
ax.figure.canvas.draw()
ppar = [0,-padpoints/72.] if direction == "v" else [-padpoints/72.,0]
trans2 = matplotlib.transforms.ScaledTranslation(ppar[0],ppar[1],fig.dpi_scale_trans) + \
ax.figure.transFigure.inverted()
tbox = trans2.transform(t._bbox_patch.get_window_extent())
bbox = ax.get_position()
if direction=="v":
ax.set_position([bbox.x0, bbox.y0,bbox.width, tbox[0][1]-bbox.y0])
else:
ax.set_position([bbox.x0, bbox.y0,tbox[0][0]-bbox.x0, bbox.height])
# case 1: place text label at top right corner of figure (1,1). Adjust axes height.
#text_legend(ax, 1,1, 'my text here', bbox = dict(boxstyle = 'round'), )
# case 2: place text left of axes, (1, y), direction=="v"
text_legend(ax, 1., 0.8, 'my text here', margin=2., direction="h", bbox = dict(boxstyle = 'round') )
plt.savefig(__file__+'.pdf')
plt.show()
case 1 (left) and case 2 (right):
Doin the same with a legend is slightly easier, because we can directly use the bbox_to_anchor argument and don't need to control the fancy box around the legend.
import matplotlib.pyplot as plt
import matplotlib.transforms
fig = plt.figure(figsize = [3.5,2])
ax = fig.add_subplot(111)
ax.set_title('title')
ax.set_ylabel('y label')
ax.set_xlabel('x label')
ax.plot([1,2,3], marker="o", label="quantity 1")
ax.plot([2,1.7,1.2], marker="s", label="quantity 2")
def legend(ax, x0=1,y0=1, direction = "v", padpoints = 3,**kwargs):
otrans = ax.figure.transFigure
t = ax.legend(bbox_to_anchor=(x0,y0), loc=1, bbox_transform=otrans,**kwargs)
plt.tight_layout(pad=0)
ax.figure.canvas.draw()
plt.tight_layout(pad=0)
ppar = [0,-padpoints/72.] if direction == "v" else [-padpoints/72.,0]
trans2=matplotlib.transforms.ScaledTranslation(ppar[0],ppar[1],fig.dpi_scale_trans)+\
ax.figure.transFigure.inverted()
tbox = t.get_window_extent().transformed(trans2 )
bbox = ax.get_position()
if direction=="v":
ax.set_position([bbox.x0, bbox.y0,bbox.width, tbox.y0-bbox.y0])
else:
ax.set_position([bbox.x0, bbox.y0,tbox.x0-bbox.x0, bbox.height])
# case 1: place text label at top right corner of figure (1,1). Adjust axes height.
#legend(ax, borderaxespad=0)
# case 2: place text left of axes, (1, y), direction=="h"
legend(ax,y0=0.8, direction="h", borderaxespad=0.2)
plt.savefig(__file__+'.pdf')
plt.show()
Why 72? The 72 is the number of points per inch (ppi). This is a fixed typographic unit e.g. fontsizes are always given in points (like 12pt). Because matplotlib defines the padding of the text box in units relative to fontsize, which is points, we need to use 72 to transform back to inches (and then to display coordinates). The default dots per inch (dpi) is not touched here, but is accounted for in fig.dpi_scale_trans. If you want to change dpi you need to make sure the figure dpi is set when creating the figure as well as when saving it (use dpi=.. in the call to plt.figure() as well as plt.savefig()).
As of matplotlib==3.1.3, you can use constrained_layout=True to achieve the desired result. This is currently experimental, but see the docs for a very helpful guide (and the section specifically on legends). Note that the legend will steal space from the plot, but this is unavoidable. I've found that as long as the legend does not take up too much space relative to the size of the plot, then the figure gets saved without cropping anything.
import matplotlib.pyplot as plt
fig, ax = plt.subplots(figsize=(3, 2), constrained_layout=True)
ax.set_title('title')
ax.set_ylabel('y label')
ax.set_xlabel('x label')
ax.plot([0,1], [0,1], label='my text here')
ax.legend(loc='center left', bbox_to_anchor=(1.1, 0.5))
fig.savefig('figure03.pdf')

multiple matplotlib gridspec's in single figure BUT each one with their own common title

I know I can use update to adjust the parameters of a GridSpec instance in a matplotlib figure, allowing to arrange multiple gridspec's in a single figure. Much as in this example taken from the matplotlib doc
gs1 = gridspec.GridSpec(3, 3)
gs1.update(left=0.05, right=0.48, wspace=0.05)
ax1 = plt.subplot(gs1[:-1, :])
ax2 = plt.subplot(gs1[-1, :-1])
ax3 = plt.subplot(gs1[-1, -1])
gs2 = gridspec.GridSpec(3, 3)
gs2.update(left=0.55, right=0.98, hspace=0.05)
ax4 = plt.subplot(gs2[:, :-1])
ax5 = plt.subplot(gs2[:-1, -1])
ax6 = plt.subplot(gs2[-1, -1])
But how can I give both gs1 and gs2 their own common title? Using suptitle I only get a common title for the whole figure at once.
I can think of four ways, all quite ugly. I do not know if there are any automatic way of setting such things.
The four ugly ways are:
1) Set the title to the "top" axis-object in each group with ax.set_title() (in your case ax1 and ax4). It works great on the left group, but horrible for the right group...
2) Set one title with fig.suptitle, but make a lot of spaces inside the title, and use horizontalalignment='center'.
3) Set a text-object manually for each title... (not in the example below, but just look at matplotlib.text)
4) Create ghost axes, hide everything on them and just use them to set their title...
Below is some example code
import matplotlib.pyplot as plt
import matplotlib.gridspec as gridspec
fig = plt.figure()
gs1 = gridspec.GridSpec(3, 3)
gs1.update(left=0.05, right=0.48, wspace=0.05)
ax1 = fig.add_subplot(gs1[:-1, :])
ax2 = fig.add_subplot(gs1[-1, :-1])
ax3 = fig.add_subplot(gs1[-1, -1])
ax1.set_title('Left group title') # Alternative 1)
gs2 = gridspec.GridSpec(3, 3)
gs2.update(left=0.55, right=0.98, hspace=0.05)
ax4 = fig.add_subplot(gs2[:, :-1])
ax5 = fig.add_subplot(gs2[:-1, -1])
ax6 = fig.add_subplot(gs2[-1, -1])
ax4.set_title('Right group title') # Alternative 1)
# Alternative 2. Note the many white-spaces
fig.suptitle('figure title left figure title right', horizontalalignment='center')
# Alternative 4)
rect_left = 0, 0, 0.5, 0.8 # lower, left, width, height (I use a lower height than 1.0, to place the title more visible)
rect_right = 0.5, 0, 0.5, 0.8
ax_left = fig.add_axes(rect_left)
ax_right = fig.add_axes(rect_right)
ax_left.set_xticks([])
ax_left.set_yticks([])
ax_left.spines['right'].set_visible(False)
ax_left.spines['top'].set_visible(False)
ax_left.spines['bottom'].set_visible(False)
ax_left.spines['left'].set_visible(False)
ax_left.set_axis_bgcolor('none')
ax_right.set_xticks([])
ax_right.set_yticks([])
ax_right.spines['right'].set_visible(False)
ax_right.spines['top'].set_visible(False)
ax_right.spines['bottom'].set_visible(False)
ax_right.spines['left'].set_visible(False)
ax_right.set_axis_bgcolor('none')
ax_left.set_title('Ghost left title')
ax_right.set_title('Ghost right title')
plt.show()
Way too late, but just found this thread when searching for the exact same thing, so just leaving this for anyone stumbling across it.
I think #pathoren's Alternative 4) is the way to go, but you can reuse the existing gridspec to create your ghost axis such that it exactly matches the existing ones:
import matplotlib.pyplot as plt
import matplotlib.gridspec as gridspec
fig = plt.figure()
gs1 = gridspec.GridSpec(3, 3)
gs1.update(left=0.05, right=0.48, wspace=0.05)
ax1 = fig.add_subplot(gs1[:-1, :])
ax2 = fig.add_subplot(gs1[-1, :-1])
ax3 = fig.add_subplot(gs1[-1, -1])
gs2 = gridspec.GridSpec(3, 3)
gs2.update(left=0.55, right=0.98, hspace=0.05)
ax4 = fig.add_subplot(gs2[:, :-1])
ax5 = fig.add_subplot(gs2[:-1, -1])
ax6 = fig.add_subplot(gs2[-1, -1])
# Add ghost axes and titles on gs1 and gs2
ax_left = fig.add_subplot(gs1[:])
ax_left.axis('off')
ax_left.set_title('Left title')
ax_right = fig.add_subplot(gs2[:])
ax_right.axis('off')
ax_right.set_title('Right title')
plt.show()
Resulting layout:

How do I extend the margin at the bottom of a figure in Matplotlib?

The following screenshot shows my x-axis.
I added some labels and rotated them by 90 degrees in order to better read them. However, pyplot truncates the bottom such that I'm not able to completely read the labels.
How do I extend the bottom margin in order to see the complete labels?
Two retroactive ways:
fig, ax = plt.subplots()
# ...
fig.tight_layout()
Or
fig.subplots_adjust(bottom=0.2) # or whatever
Here's a subplots_adjust example: http://matplotlib.org/examples/pylab_examples/subplots_adjust.html
(but I prefer tight_layout)
A quick one-line solution that has worked for me is to use pyplot's auto tight_layout method directly, available in Matplotlib v1.1 onwards:
plt.tight_layout()
This can be invoked immediately before you show the plot (plt.show()), but after your manipulations on the axes (e.g. ticklabel rotations, etc).
This convenience method avoids manipulating individual figures of subplots.
Where plt is the standard pyplot from:
import matplotlib.pyplot as plt
fig.savefig('name.png', bbox_inches='tight')
works best for me, since it doesn't reduce the plot size compared to
fig.tight_layout()
Subplot-adjust did not work for me, since the whole figure would just resize with the labels still out of bounds.
A workaround I found was to keep the y-axis always a certain margin over the highest or minimum y-values:
x1,x2,y1,y2 = plt.axis()
plt.axis((x1,x2,y1 - 100 ,y2 + 100))
fig, ax = plt.subplots(tight_layout=True)
This is rather complicated, but it gives a general and neat solution.
import numpy as np
value1 = 3
xvalues = [0, 1, 2, 3, 4]
line1 = [2.0, 3.0, 2.0, 5.0, 4.0]
stdev1 = [0.1, 0.2, 0.1, 0.4, 0.3]
line2 = [1.7, 3.1, 2.5, 4.8, 4.2]
stdev2 = [0.12, 0.18, 0.12, 0.3, 0.35]
max_times = [max(line1+stdev1),max(line2+stdev2)]
min_times = [min(line1+stdev1),min(line2+stdev2)]
font_size = 25
max_total = max(max_times)
min_total = min(min_times)
max_minus_min = max_total - min_total
step_size = max_minus_min/10
head_space = (step_size*3)
plt.figure(figsize=(15, 15))
plt.errorbar(xvalues, line1, yerr=stdev1, fmt='', color='b')
plt.errorbar(xvalues, line2, yerr=stdev2, fmt='', color='r')
plt.xlabel("xvalues", fontsize=font_size)
plt.ylabel("lines 1 and 2 Test "+str(value1), fontsize=font_size)
plt.title("Let's leave space for the legend Experiment"+ str(value1), fontsize=font_size)
plt.legend(("Line1", "Line2"), loc="upper left", fontsize=font_size)
plt.tick_params(labelsize=font_size)
plt.yticks(np.arange(min_total, max_total+head_space, step=step_size) )
plt.grid()
plt.tight_layout()
Result: