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

# # Using "Exponent Format"
# 
# The `exponent_format` parameter in the `theme(...)` function can be used to configure the way "exponent notation" looks like on plot.  
# Available values:
# - `'e'` for E notation, for example, 1.23e+3, which is the default format.
# - `'pow'` for superscript power notation.
# 
# The "exponent format" is automatically applied to each value formatted in scientific notation, regardless whether the format is user-defined or chosen automatically based on the data. This format affects every part of a plot, including geoms, scales, labels, and tooltips.
# 
# > #### Note:
# >
# > Do NOT(!) use `exponent_format='pow'` if you are planning to export plot to a raster format (PNG,PDF).
# > 
# > The `CairoSVG` library (which is under the hood of our `ggsave()` function) does not handre `tspan` element properly end breaks superscript notation when transforming SVG to PNG/PDF.
# >
# > More details: https://github.com/Kozea/CairoSVG/issues/317

# In[1]:


from lets_plot import *
import numpy as np


# In[2]:


LetsPlot.setup_html()


# #### Set `exponent_format='pow'` for all plots in the notebook
# Each plot still can be cofigured individually: `p + theme(exponent_format='e'))`

# In[3]:


# LetsPlot.set_theme(theme(exponent_format='pow'))


# In[4]:


n = 10
data = {
    'x': list(range(n)),
    'y': [(i + 1 + 0.025 * i) * 10**(-5) for i in range(n)],
    'c': [i * 10**(10) for i in range(n)]
}

p = ggplot(data, mapping=aes(x='x', y='y', fill='c')) + geom_bar(stat='identity')


# In[5]:


pow_theme = theme(exponent_format='pow')


# #### 1. E-notation vs. Superscript Power Notation
# 
# In this example "scientific notation" formatting for the guides is chosen automatically, basing on the data.

# In[6]:


gggrid([p + ggtitle("E-notation (default)"),
        p + pow_theme + ggtitle("Superscript Power")])


# #### 2. Formatting in `geom_text()` and `geom_label()`
# 
# By default, values in `geom_text()` and `geom_label()` are always shown in standard notation. 
# 
# Thus by default, the `'pow'` in `theme()` doesn't affect numbers in `geom_text()` and `geom_label()` (see the chart on the left) unless <br>
# you specify a scientific notation formatting explicitly via the `label_format` parameter (see the chart on the right).
# 

# In[7]:


left  = p + geom_label(aes(label='y'), alpha=0.8, fill='white')
right = p + geom_label(aes(label='y'), alpha=0.8, fill='white', label_format='.2~e')

gggrid([left, right]) + pow_theme