Day002Albers.sagews

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Author:  Vincent J. Matsko<br />
Date:    4 September 2015, Day002<br />
Post:    Josef Albers and Interaction of Color

Author: Vincent J. Matsko
Date: 4 September 2015, Day002
Post: Josef Albers and Interaction of Color

Interact: please open in CoCalc

# This code snippet explores the color contrast of Josef Albers.
# Slide the r, g, and b controls to change color of the interior rectangles.
# Slide the deltar, deltag, and deltab controls to change the colors of the exterior rectangles.
# Note how the colors are defined for S1 and S2!
# To use, place your cursor anyone in the code, then hit shift+enter - hold down the shift key, and while you're holding it, hit the enter key.
# Hitting shift and enter separately won't work!
#
# NOTE:  To get an "Albers" effect, make sure your delta values aren't too large.  See the blog post for more comments.

# Negative RGB values become 0, and values greater than 1 are truncated to 1.
def RGBValue (value): 
    if value < 0:
        return 0
    else:
        if value > 1:
            return 1
        else:
            return value
        
# Changing "True" to "False" in the next line will allow you change ALL the sliders and then press an Update button.
# However, the most recent image disappears when you do this.        
@interact(auto_update=True)
def _(r=slider(0, 1.0, default=0.5, step_size=0.01, width=30), # Will default to neutral gray.
      g=slider(0, 1.0, default=0.5, step_size=0.01, width=30),
      b=slider(0, 1.0, default=0.5, step_size=0.01, width=30),
      deltar=slider(0, 1.0, default=0, step_size=0.01, width=30),
      deltag=slider(0, 1.0, default=0, step_size=0.01, width=30),
      deltab=slider(0, 1.0, default=0, step_size=0.01, width=30)):
        P1 = plot(polygon2d([[0.15,0.15],[0.15,0.85],[0.35,0.85],[0.35,0.15]], rgbcolor=(r,g,b)))
        P2 = plot(polygon2d([[0.65,0.15],[0.65,0.85],[0.85,0.85],[0.85,0.15]], rgbcolor=(r,g,b)))
        S1 = plot(polygon2d([[0,0],[0,1],[0.5,1],[0.5,0]], rgbcolor=(RGBValue(r - deltar), RGBValue(g - deltag), RGBValue(b - deltab))))
        S2 = plot(polygon2d([[0.5,0],[0.5,1],[1,1],[1,0]], rgbcolor=(RGBValue(r + deltar), RGBValue(g + deltag), RGBValue(b + deltab))))
        show(S1 + S2 + P1 + P2, aspect_ratio=1, axes=False)

Interact: please open in CoCalc