I am struggling to make a pie chart with only three color variations according to correlation values between two quantities, the color only varies between red(-1 peak), white (0), and blue(+1 peak). this is my code, I copied some parts from StackOverflow.
import NumPy as np
import matplotlib.pyplot as plt
def mypie(slices, labels, colors, val):
colordict = {}
for l, c in zip(labels, colors):
colordict[l] = c
fig = plt.figure(figsize=[10, 10])
ax = fig.add_subplot(111)
# , autopct=make_autopct(slices))
pie_wedge_collection = ax.pie(slices, labels=labels, labeldistance=1.05)
for pie_wedge in pie_wedge_collection[0]:
pie_wedge.set_edgecolor('white')
pie_wedge.set_facecolor(colordict[pie_wedge.get_label()])
titlestring = val
ax.set_title(titlestring)
return fig, ax, pie_wedge_collection
for idx,val in enumerate(pf.index):
slices = np.abs(pf.iloc[idx,:])
labels = oct12.columns
label_df = pd.DataFrame(labels, columns=['labels'])
label_df['slices'] = slices
label_df['label'] = label_df['labels'] + ': ' + label_df['slices'].apply(lambda x: '{:.2g}'.format(x))
# sort by slices
label_df = label_df.sort_values(by='slices', ascending=False)
cmap = plt.cm.prism
colors = cmap(np.linspace(1.024, 0.004, len(slices)))
labels = oct12.columns
sizes = [30 for i in range(len(oct12.columns))]
fig, ax, pie_wedge_collection = mypie(sizes, label_df.label, colors, val)
plt.show()
This is what I am getting, here I am hardcoding the colors, however, I need to have color variations between [red, white, blue] according to the variations in correlation in slices variable.
However, I want something like below:
Related
Matplotlib can convert a plot/figure into a RGB array as follows:
import matplotlib.pyplot as plt
import numpy as np
import io
fig, ax = plt.subplots()
n=256
I, J = np.indices((n, n))
im = ax.imshow((I | J) % 19, interpolation='none')
fig.colorbar(im, ax=ax)
#Convert fig to a RGB array
io_buf = io.BytesIO()
fig.savefig(io_buf, format='raw')
io_buf.seek(0)
fig_arr = np.reshape(np.frombuffer(io_buf.getvalue(), dtype=np.uint8),
newshape=(int(fig.bbox.bounds[3]), int(fig.bbox.bounds[2]), -1))
print(f"The shape of the rgb array: {fig_arr.shape}")
plt.show()
It displays:
The shape of the rgb array: (480, 640, 4)
Is it possible to convert similarly a Plots plot into a Matrix{RGB{N0f8}}?
The first part:
using Plots
n = 255
I = [i for i in 0:n, j in 0:n]
h = heatmap(mod.((I .| I'), 19), c= :deep, yflip=true, size=(400, 400), aspect_ratio=:equal)
I searched for Julia equivalent of numpy.frombuffer, but no result has been returned
With h holding the plot, as the code in the OP has described. The following:
using FileIO
io = IOBuffer()
show(io, MIME("image/png"), h);
strm = Stream(format"PNG", io)
img = load(strm)
leaves img with the Matrix{RGB{...}}.
This is my code it shows all color spaces except YCBCR ,,
Notation:ConvertLayer converts color space of image
fig=plt.figure(figsize=(9, 9))
for images, labels in train_ds.take(1):
for i in range(16):
plt.subplot(5, 5, i + 1)
color_space = COLOR_SPACES[i%5]
image = tf.expand_dims(images[i//5] ,axis=0)
image = augmentation(NormalLayer(color_space)(tf.cast(image,tf.float32)))
if color_space=="YCBCR":
image = tf.cast(image, tf.uint8)
image = ConvertLayer(color_space)(image)
#image = tf.cast(image * 255.0, tf.uint8)
lbl = "{}({})".format(class_names[labels[i//4].numpy().argmax()] , color_space )
plt.imshow(tf.squeeze(image))
plt.title(lbl)
plt.axis("off")
break
I need to visualize it just in matplotlib.
With the following code I was able to visualize the image in matplotlib.
import matplotlib.pyplot as plt
import numpy as np
x=plt.imread("/content/car.jpeg")
y=rgb2ycbcr(x)
fig = plt.figure(figsize=(10, 7))
rows = 1
columns = 2
fig.add_subplot(rows, columns, 1)
plt.imshow(x)
plt.axis('off')
plt.title("RGB")
fig.add_subplot(rows, columns, 2)
plt.imshow(y)
plt.axis('off')
plt.title("YCBCR")
def rgb2ycbcr(im):
xform = np.array([[.299, .587, .114], [-.1687, -.3313, .5], [.5, -.4187, -.0813]])
ycbcr = im.dot(xform.T)
ycbcr[:,:,[1,2]] += 128
return np.uint8(ycbcr)
Output:
I have a Seaborn displot with a hued variable:
For each hued variable, I want to extract the mode of the density estimate and then plot each hue variable versus its mode, like so:
How do I do this?
You can use scipy.stats.gaussian_kde to create the density estimation function. And then call that function on an array of x-values to calculate its maximum.
import matplotlib.pyplot as plt
import seaborn as sns
import pandas as pd
import numpy as np
df = pd.DataFrame({'x': np.random.normal(0.001, 1, 1300).cumsum() + 30,
'hue': np.repeat(np.arange(0.08, 0.20001, 0.01), 100).round(2)})
g = sns.displot(df, x='x', hue='hue', palette='turbo', kind='kde', fill=True, height=6, aspect=1.5)
plt.show()
from scipy.stats import gaussian_kde
from matplotlib.cm import ScalarMappable
fig, ax = plt.subplots(figsize=(10, 6))
hues = df['hue'].unique()
num_hues = len(hues)
colors = sns.color_palette('turbo', num_hues)
xmin, xmax = df['x'].min(), df['x'].max()
xs = np.linspace(xmin, xmax, 500)
for hue, color in zip(hues, colors):
data = df[df['hue'] == hue]['x'].values
kde = gaussian_kde(data)
mode_index = np.argmax(kde(xs))
mode_x = xs[mode_index]
sns.scatterplot(x=[hue], y=[mode_x], color=color, s=50, ax=ax)
cmap = sns.color_palette('turbo', as_cmap=True)
norm = plt.Normalize(hues.min(), hues.max())
plt.colorbar(ScalarMappable(cmap=cmap, norm=norm), ax=ax, ticks=hues)
plt.show()
Here is another approach, extracting the kde curves. It uses the legend of the kde plot to get the correspondence between the curves and the hue values. sns.kdeplot is the axes-level function used by sns.displot(kind='kde'). fill=False creates lines instead of filled polygons for the curves, for which the values are easier to extract. (ax1.fill_between can fill the curves during a second pass). The x and y axes of the second plot are switched to align the x-axes of both plots.
import matplotlib.pyplot as plt
import seaborn as sns
import pandas as pd
import numpy as np
df = pd.DataFrame({'x': np.random.normal(0.007, 0.1, 1300).cumsum() + 30,
'hue': np.repeat(np.arange(0.08, 0.20001, 0.01), 100).round(2)})
fig, (ax1, ax2) = plt.subplots(nrows=2, figsize=(12, 10), sharex=True)
sns.kdeplot(data=df, x='x', hue='hue', palette='turbo', fill=False, ax=ax1)
hues = [float(txt.get_text()) for txt in ax1.legend_.get_texts()]
ax2.set_yticks(hues)
ax2.set_ylabel('hue')
for hue, line in zip(hues, ax1.lines[::-1]):
color = line.get_color()
x = line.get_xdata()
y = line.get_ydata()
ax1.fill_between(x, y, color=color, alpha=0.3)
mode_ind = np.argmax(y)
mode_x = x[mode_ind]
sns.scatterplot(x=[mode_x], y=hue, color=color, s=50, ax=ax2)
sns.despine()
plt.tight_layout()
plt.show()
I've to plot multiple scatter and table in a grid space and I'm having a couple of issues with the relative position but most important with defining and maintaining the aspect ratio of the scatter plot.
I've written a script with "fake" data on it to describe my problem and a minimum "not working" example below.
What I have is a dataframe with x, and y positions of objects, and what I want to do is to put the corresponding image below.
Since the image can have an arbitrary aspect ratio I need to read the aspect ratio and construct the scatter plot in that way but I'm unable to make it work.
Another problem is connected with the invert_xaxis and invert_yaxis that don't work (I need that command since the scatter data are inverted.
I've used the following commands, and as far as I've understood each of them should block the aspect ratio of the scatter plot to the same ratio of the figure but they do not work.
The aspect ratio becomes corrected only when the figure is plotted but that eliminates the effect of axis inversion.
I've had a similar problem with setting the aspect ratio of plots without the addition of a figure, sometimes it worked but not with tight_layout.
It is obvious that I'm missing something important....but I'm unable to figure it out.
This is the fake data code:
###############################################################################
# fake data
#general data aspect ratio
image_height= 5 #4270
image_width = 10 # 8192
pix2scale = 0.3125
data_AR = image_height / image_width
#random data generation
data_width = image_width* pix2scale
data_height = image_height * pix2scale
data1x = np.random.uniform(-data_width/2, data_width/2, size=(40))
data1y = np.random.uniform(-data_height/2, data_height/2, size=(40))
data2x = np.random.uniform(-data_width/2, data_width/2, size=(40))
data2y = np.random.uniform(-data_height/2,data_height/2, size=(40))
temp_df1 = pd.DataFrame([data1x,data1y,['random1']*40],index = ['x','y','label']).T
temp_df2 = pd.DataFrame([data2x,data2y,['random2']*40],index = ['x','y','label']).T
df = pd.concat([temp_df1,temp_df2],axis = 0, ignore_index = True)
del temp_df1, temp_df2
#sample image generation of variable aspect ratio
img_size = (image_height, image_width)
R_layer = np.ones(shape= img_size)*0.50
G_layer = np.ones(shape= img_size)*0.50
B_layer = np.ones(shape= img_size)*0.50
A_layer = np.ones(shape= img_size)
img = np.dstack([R_layer,G_layer,B_layer,A_layer])
#add a mark at the top left of the image
for k in range(0,3):
for i in range(0,int(image_width*0.2*data_AR)):
for j in range(0,int(image_width*0.2)):
img[i,j,k] = 0
#add a mark at the center of the image
# get center coordinates of the image
center = [[2, 4], [2, 5]]
for k in range(0,3):
for point in center:
if k == 0:
img[point[0],point[1],k] = 1
else:
img[point[0],point[1],k] = 0
#show image
fig, ax = plt.subplots()
ax.imshow(img)
###############################################################################
this is the code that generates the image:
#%%
# sample code
# at this point Iìve already loaded the image, the pix2scale value
# and the df containing data points
#read image aspect ratio
img_AR = img.shape[0]/img.shape[1]
pixel_width = img.shape[1]
pixel_height = img.shape[0]
# each pixel correspond to 0.3125 unit (mm)
pix2scale = 0.3125
#define image position
#the center of the image need to be placed at (0,0)
#bottom left corner
left = - (pixel_width * pix2scale)/2
bottom = - (pixel_height * pix2scale)/2
right = left + (pixel_width * pix2scale)
top = bottom + (pixel_height * pix2scale)
extent = [left,right,bottom,top]
#figure definition
figure_width = 15 #inch
figure_AR = 1
scatter_AR = img_AR
#initialize figure
fig_s= plt.figure(figsize = (figure_width,figure_width*figure_AR))
gs = plt.GridSpec (3,3)
#scatter plot in ax1
ax1 = fig_s.add_subplot(gs[:2,:2])
g = sns.scatterplot( data = df,
x = 'x',
y = 'y',
hue = 'label',
ax =ax1
)
ax1.invert_xaxis()
ax1.invert_yaxis()
#resize the figure box
box = ax1.get_position()
ax1.set_position([box.x0,box.y0,box.width*0.4,box.width*0.4*scatter_AR])
ax1.legend(loc = 'center left', bbox_to_anchor = (1,0.5))
ax1.set_title('Inclusions Scatter Plot')
ax1.set_aspect(scatter_AR)
#plt image
ax1.imshow(img,extent = extent)
#scatter plot
ax2 = fig_s.add_subplot(gs[2,:2])
g = sns.scatterplot( data = df,
x = 'x',
y = 'y',
hue = 'label',
ax =ax2
)
#resize the figure box
box = ax2.get_position()
ax2.set_position([box.x0,box.y0,box.width*0.4,box.width*0.4*scatter_AR])
ax2.legend(loc = 'center left', bbox_to_anchor = (1,0.5))
ax2.set_title('Inclusions Scatter Plot')
ax2.set_aspect(scatter_AR)
ax2.imshow(img,extent = extent)
#scatter plot
ax3 = fig_s.add_subplot(gs[1,2])
g = sns.scatterplot( data = df,
x = 'x',
y = 'y',
hue = 'label',
ax =ax3
)
#resize the figure box
box = ax3.get_position()
ax3.set_position([box.x0,box.y0,box.width*0.4,box.width*0.4*scatter_AR])
ax3.legend(loc = 'center left', bbox_to_anchor = (1,0.5))
ax3.set_title('Inclusions Scatter Plot')
ax3.set_aspect(scatter_AR)
ax3.imshow(img,extent = extent)
#add suptitle to figure
fig_s.suptitle('my title',fontsize= 22)
fig_s.subplots_adjust(top=0.85)
# #make it fancy
for i in range(3):
fig_s.tight_layout()
plt.pause(0.2)
I've plotted multiple grid because I wanted to test the tight_layout().
[enter image description here][2]
I wish to appear a figure (and certain text) as if they are printed on a page of an open book. Is it possible to transform an jpg image programmatically or in matplotlib to have such an effect?
You can use a background axis along with an open source book image to do something like this,
import numpy as np
import matplotlib.pyplot as plt
fig = plt.figure()
ax1 = fig.add_axes([0.1, 0.1, 0.8, 0.8])
ax2 = fig.add_axes([0.2, 0.3, 0.25, 0.3])
#Plot page from a book
im = plt.imread("./book_page.jpg")
implot = ax1.imshow(im, origin='lower')
# Plot a graph and set background to transparent
x = np.linspace(0,4.*np.pi,40)
y = np.sin(x)
ax2.plot(x,y,'-ro',alpha=0.5)
ax2.set_ylim([-1.1,1.1])
ax2.patch.set_alpha(0.0)
from matplotlib import rc
rc('text', usetex=True)
margin = im.shape[0]*0.075
ytext = im.shape[1]/2.+10
ax1.text(margin, ytext, "The following text is an example")
ax1.text(margin, 90, "Figure 1. Showing a sine function")
plt.show()
Which looks like this,
where I used the following book image.
UPDATE: Added non-affine transformation based on scikit-image warp example, but with Maxwell distribution. The solution saves the matplotlib line as an image in order to apply a pointwise transform. Mapping for vector graphics may be possible but I think this will be more complicated...
import numpy as np
import matplotlib.pyplot as plt
def maxwellian_transform_image(image):
from skimage.transform import PiecewiseAffineTransform, warp
rows, cols = image.shape[0], image.shape[1]
src_cols = np.linspace(0, cols, 20)
src_rows = np.linspace(0, rows, 10)
src_rows, src_cols = np.meshgrid(src_rows, src_cols)
src = np.dstack([src_cols.flat, src_rows.flat])[0]
# add maxwellian to row coordinates
x = np.linspace(0, 3., src.shape[0])
dst_rows = src[:, 1] + (np.sqrt(2/np.pi)*x**2 * np.exp(-x**2/2)) * 50
dst_cols = src[:, 0]
dst_rows *= 1.5
dst_rows -= 1.0 * 50
dst = np.vstack([dst_cols, dst_rows]).T
tform = PiecewiseAffineTransform()
tform.estimate(src, dst)
out_rows = image.shape[0] - 1.5 * 50
out_cols = cols
out = warp(image, tform, output_shape=(out_rows, out_cols))
return out
#Create the new figure
fig = plt.figure()
ax = fig.add_axes([0.1, 0.1, 0.8, 0.8])
#Plot page from a book
im = plt.imread("./book_page.jpg")
implot = ax.imshow(im, origin='lower')
# Plot and save graph as image, will need some manipulation of location
temp, at = plt.subplots()
margin = im.shape[0]*0.1
x = np.linspace(margin,im.shape[0]/2.,40)
y = im.shape[1]/3. + 0.1*im.shape[1]*np.sin(12.*np.pi*x/im.shape[0])
at.plot(x,y,'-ro',alpha=0.5)
temp.savefig("lineplot.png",transparent=True)
#Read in plot as an image and apply transform
plot = plt.imread("./lineplot.png")
out = maxwellian_transform_image(plot)
ax.imshow(out, extent=[0,im.shape[1],0,im.shape[0]])
plt.show()
The figure now looks like,