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

# # Siemens Star
# 
# The [Siemens Star](https://en.wikipedia.org/wiki/Siemens_star) is a radial starburst pattern commonly used to adjust internal focus settings in camera lens and for measuring camera resolution. This notebook produces a Siemens Star test chart in the form in [Scalable Vector Graphics (svg)[(https://en.wikipedia.org/wiki/Scalable_Vector_Graphics) that can be rendered by most modern web browsers.  The idea for this notebook was motivated by this [post](http://www.dpreview.com/forums/post/57422062) on a forum at [Digital Photography Review (DPReview)](http://www.dpreview.com/).
# 
# ## References
# 
# * [Digital Camera Resolution Measurement Using Sinusoidal Siemens Stars](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.470.2385&rep=rep1&type=pdf)
# * [Wikipedia: Siemens star](https://en.wikipedia.org/wiki/Siemens_star)
# * [Image Engineering: Resolution measurement with siemens stars](https://github.com/jckantor/Siemens-Star)
# * [A/D Photography: Resolution Test Chart – Siemens star](https://claclaclack.wordpress.com/2015/05/17/resolution/)
# * [Lens Rentals: Setting Up an Optical Testing Station](https://www.lensrentals.com/blog/2014/02/setting-up-an-optical-testing-station/)
# * [Imatest: Star Chart](http://www.imatest.com/docs/starchart/)
# 
# 
# ## Usage
# 
# This is a [Jupyter notebook](http://jupyter.org/) containing Python functions. An executable version of this notebook is available from the [http://mybinder.org/](http://mybinder.org/) by clicking on the following button.  There may be a longish pause as the notebook loads.
# 
# [![Binder](http://mybinder.org/badge.svg)](http://mybinder.org/repo/jckantor/Siemens-Star)
# 
# To use the notebook after it has been loaded in an executable environment:
# 
# 1. First run the code in the following cell. Do this by clicking in the cell to highlight it, then entering 'shift-return' from the keyboard, or clicking on the run button in the toolbar menu (looks like >|), or the 'Cell>Run Cells' menu item.
# 2. Execute the second cell below to create the desired chart interactively. The controls adjust the colors and number of spokes displayed in the chart.

# ## Imports

# In[10]:


get_ipython().system('pip install svglib')


# ## Function Definitions
# 
# The following cell defines functions that create SVG markup. Run this cell first!

# In[11]:


from math import pi, sin, cos, sqrt

# page width
page_width = 900

# xrite passport rgb color table 
# https://xritephoto.com/ph_product_overview.aspx?ID=820&Action=support&SupportID=5159
rgb = [
    [115, 82, 68], #  1. dark skin
    [194,150,130], #  2. light skin
    [ 98,122,157], #  3. blue sky
    [ 87,108, 67], #  4. folliage
    [133,128,177], #  5. blue flower
    [103,189,170], #  6. bluish green
    [214,126, 44], #  7. orange
    [ 80, 91,166], #  8. purplish blue
    [193, 90, 99], #  9. moderate red
    [ 94, 60,108], # 10. purple
    [157,188, 64], # 11. yellow green
    [224,163, 46], # 12. orange yellow
    [ 56, 61,150], # 13. blue
    [ 70,148, 73], # 14. green
    [175, 54, 60], # 15. red
    [231,199, 31], # 16. yellow
    [187, 86,149], # 17. magenta
    [  8,133,161], # 18. cyan
    [243,243,242], # 19. white (0.05*)
    [200,200,200], # 20. neutral 8 (0.23*)
    [160,160,160], # 21. neutral 6.5 (0.44*)
    [122,122,121], # 22. neutral 5 (0.70*)
    [ 85, 85, 85], # 23. neutral 3.5 (1.05*)
    [ 52, 52, 52], # 24. black (1.50*)
]

def star(xc, yc, radius, cycles=72, colors=['black', 'white']):
    """Return an svg string containing of polygons in the form of a star."""
    phi = pi/cycles/len(colors)
    xy = [xc, yc, xc - radius*sin(phi), yc + radius*cos(phi), xc + radius*sin(phi), yc + radius*cos(phi)]
    fmt = '<polygon points = "{:.3f},{:.3f} {:.3f},{:.3f} {:.3f},{:.3f}"'.format(*xy) \
          + ' style = "fill:{0}" transform = "rotate({1:.3f},' \
          + ' {:.3f}, {:.3f})"/>\n'.format(xc, yc)
    return ''.join([fmt.format(colors[k], 360.0*(n + float(k)/len(colors))/cycles) 
                    for n in range(0, int(cycles)) for k in range(0, len(colors))])
    
def lphcircles(xc, yc, radius, cycles, colors, bb_height):
    lph = [10, 20, 50, 100, 200, 500, 1000, 2000, 5000]
    r = [bb_height*cycles*len(colors)/(2*pi*lph) for lph in lph]           
    fmt = '<circle cx="{0:.3f}" cy="{1:.3f}" r="{2:.3f}" stroke="black" stroke-width="1" fill-opacity="0"/>\n' +\
          '<text x="{3:.3f}" y="{4:.3f}" fill="red" font-weight="bold" text-align="center">{5:4.0f}</text>'
    return '\n'.join([fmt.format(xc, yc, r, xc+r*cos(13*pi/8), yc + r*sin(13*pi/8), lph) 
                      for (lph,r) in zip(lph,r) if 10 < r < radius]) + '\n'

def colorchecker(bw, bh):
    return ''.join(['<rect width="{0}" height="{1}" '.format(bw, bh) + 
                    ' x="{0}" y="{1}"'.format(bw*((0.5+col) + 15*(col>1)), bh*(7+row)) + 
                    ' style="fill:rgb({0},{1},{2});stroke-width:2;stroke:black"/>\n'.format(*rgb[row + 6*col])
                    for col in range(0,4) for row in range (0,6)])

def SiemensStar(cycles=144, aspect=4/3, colors=['black','white'], colorcheck='True', cstars='True', lph='True'):
    bb_width = page_width
    bb_height = bb_width/aspect
    r = bb_height*min(0.5, (sqrt(1+aspect**2))/4)
    svg = '<svg xmlns="https://www.w3.org/2000/svg"' + \
          ' width="{0}" height="{1}" style="border:solid 1px" >\n'.format(bb_width, bb_height)   
    svg += star(bb_width/2, bb_height/2, r, cycles, colors) 
    svg += lphcircles(0.5*bb_width, 0.5*bb_height, r, cycles, colors, bb_height) if lph else ''
    if cstars:
        for x,y in [(x,y) for x in (0, bb_width) for y in (0, bb_height)]:
            svg += star(x, y, r, cycles, colors)
            svg += lphcircles(x, y, r, cycles, colors, bb_height) if lph else ''
    svg += colorchecker(0.05*bb_width, 0.05*bb_height) if colorcheck else ''
    return svg + '</svg>'


# ## Manually Create and Display the Siemens Star
# 
# The following cell creates a simple resolution chart consisting of a central Siemens Star and additional elements. The central star consists of alternating radial spokes of color from a specified list `colors`. If omitted, the default is black and white. The list may contain two or more colors. The list of colors is repeated a number of times as determined by the parameter `cycles`.
# 
# A list of svg commands is generated, stored in a file [star.svf](star.svg), and displayed as an inline graphic within the notebook. To download the resulting file, right click on the link and choose the `Save Link As ...` option.

# In[14]:


from IPython.display import SVG
from svglib.svglib import svg2rlg
from reportlab.graphics import renderPDF, renderPM

svg = SiemensStar(cycles=144, colors = ['blue', 'yellow'])
with open('star.svg', 'w') as f:
    f.write(svg)

chart = svg2rlg('star.svg')
renderPDF.drawToFile(chart, 'star.pdf')
renderPM.drawToFile(chart, 'star.png', fmt='PNG')

SVG(svg)


# ## Interactively Create and Display Siemens Star
# 
# The following interactive cell creates a simple resolution chart consisting of a central Siemens Star and additional elements. Use the dropdown menus to set the colors of the radial spokes, and the cycles slider to set the number of spokes.
# 
# A list of svg commands is generated and stored in a file [star.html](star.html). To download the resulting file, right click on the link and choose the `Save Link As ...` option.

# In[15]:


from IPython.display import SVG
from ipywidgets import interact, Dropdown, IntSlider, Checkbox
from IPython.display import display

svg_colors = ['black', 'white', 'red', 'blue', 'green', 'cyan', 'yellow', 'magenta']

def makestar(cycles, aspect, color1, color2, colorcheck, cstars, clines):
    svg = SiemensStar(cycles, aspect=eval(aspect), colors=[color1,color2], colorcheck=colorcheck, cstars=cstars, lph=clines)
    display(SVG(svg))
    with open('star.html','w') as f:
        f.write(svg)
    
interact(makestar, 
         cycles = IntSlider(min=12, max=600, value = 144, step=2, description='Color Cycles'), \
         aspect = Dropdown(options=['16/9', '3/2', '4/3', '1/1'], value='4/3', description='Aspect Ratio'), \
         color1 = Dropdown(options=svg_colors, value='black', description='Color A'), \
         color2 = Dropdown(options=svg_colors, value='white', description='Color B'), \
         colorcheck = Checkbox(value=True, description='Color Checker'), \
         cstars = Checkbox(value=True, description='Corner Stars'), \
         clines = Checkbox(value=True, description='LPH Lines'))


# In[ ]: