#!/usr/bin/env python
# coding: utf-8

# # Customize Legend Appearance

# In[1]:


from IPython.display import Image

import pandas as pd

from lets_plot import *


# In[2]:


LetsPlot.setup_html()


# In[3]:


display(Image("images/theme_legend_scheme.png"))


# In[4]:


df = pd.read_csv("https://raw.githubusercontent.com/JetBrains/lets-plot-docs/master/data/mpg.csv")
print(df.shape)
df.head()


# ## Legend Position
# 
# Parameters to customize the legend position and justification:
# 
# - `legend_position` - the position of legends;
# 
# - `legend_justification` - anchor point for positioning legend;
# 
# - `legend_direction` - layout of items in legends.

# In[5]:


p1 = ggplot(df, aes("displ", "hwy")) + geom_point(aes(color="cty", shape="drv"), size=5)
p1


# In[6]:


# Draw legend below the plot area
p1 + theme(legend_position='bottom')


# In[7]:


# Specify position, justification and orientation
p1 + theme(legend_position=[1, 1], legend_justification=[1, 1], legend_direction='horizontal')


# ## Legend Spacing and Margins
# 
# Parameters to customize the legend spacing and margins:
# 
# - `legend_box` - arrangement of multiple legends ("horizontal" or "vertical");
# 
# - `legend_box_just` - justification of each legend within the overall bounding box ("top", "bottom", "left", "right", "center");
# 
# - `legend_box_spacing` - spacing between plotting area and legend box;
# 
# - `legend_margin` - margin around each legend;
# 
# - `legend_spacing` - spacing between legends, `legend_spacing_x`/`legend_spacing_y` - in the horizontal/vertical direction.

# In[8]:


p2 = ggplot(df, aes('displ', 'cty')) + \
    geom_point(aes(fill='drv', size='hwy'), shape=21) + \
    scale_size(range=[1, 10], breaks=[15, 30, 40]) + \
    theme(legend_position='bottom', legend_background=element_rect(size=1))
p2


# In[9]:


# legend_margin
p2 + theme(legend_margin=[10, 20])


# In[10]:


# legend_box
p2 + theme(legend_box='horizontal')


# In[11]:


# legend_box_just
p2 + theme(legend_box_just='center')


# In[12]:


# legend_box_spacing
p2 + theme(legend_box='horizontal',  legend_box_spacing=50)


# In[13]:


# legend_spacing
p2 + theme(legend_box='horizontal', legend_spacing_x=50)


# ## Legend Key Parameters
# 
# Parameters to customize the legend key:
# 
# - `legend_key` - background underneath legend keys, set with `element_rect()`;
# 
# - `legend_key_size` - size of legend keys;
# 
# - `legend_key_width` - key background width;
# 
# - `legend_key_height` - key background height;
# 
# - `legend_key_spacing` - spacing between legend keys;
# 
# - `legend_key_spacing_x` - spacing in the horizontal direction;
# 
# - `legend_key_spacing_y` - spacing in the vertical direction.

# In[14]:


p3 = ggplot(df, aes(x='hwy')) + \
    geom_dotplot(aes(fill='class'), color='pen') + \
    theme(legend_background=element_rect(size=0.5))
p3


# Add background underneath legend keys:

# In[15]:


p4 = p3 + theme(legend_key=element_rect(fill='#efedf5', color='#756bb1'))
p4


# Change size of legend keys:

# In[16]:


p4 + theme(legend_key_size=30)


# In[17]:


p5 = p4 + theme(legend_key_width=80, legend_key_height=20)
p5


# Add spacing between legend keys:

# In[18]:


p5 + theme(legend_key_spacing_y=10)