Creating multicolored circle

Comments

• gerhono

  March 2019

  Hello Zgolot,

  This is an in-line script that does most of the job. You will have to adapt the colors according to your need and keep in mind that each of the 3 RGB parameters must be in the range 0-255.

  

  Best,

  Gérard
• zgolot

  March 2019

  Thank you very much, that was very helpful.

  Best,

  Zgolot.
• zgolot

  March 2019 edited March 2019

  Hello again, I managed to create the circle I wanted but now I've got another issue. So on this screenshot, you can see what I managed to do. For the task, the filled bar changes color in real time according to mouse angle from the center. So when the mouse is on the circle it's fine but when it's not, the filled bar still changes color and I'd like to avoid that and make it so it only changes color when mouse hovers the circle. My problem is that I don't know how to determine whether the mouse is on the circle or not.

  

  Thanks for your help,

  Best,

  Zgolot.
• zgolot

  March 2019 edited March 2019

  I have found a solution to my above problem. I named each line of the color circle by its color (so each line is called "rgb(xx.xx%,xx.xx%,xx.xx%"). And then I used this small code to check whether the mouse is on an element that has "rgb" in it:

  check=self.c.elements_at(x,y)
  if any("rgb" in ch for ch in check):
    """ change color and do stuff"""
  

  I guess there is a better and cleaner way to do that, but so far I haven't encountered any bug.

  Best,

  Zgolot
• tcar

  April 2020

  Hi zgolot,

  that looks great! I am currently trying to implement something related: I want to draw part of a circle, i.e. a circular line with a start and end point. So far I managed to just occlude part of the circle which I don't want to show, but this workaround has its limits. Could you maybe share your solution for the multicolored circle above?
• eduard

  May 2020

  Hi Tcar,

  If I understand right, you could do 2 things:

  1) Use the background color for the part of the circle that you want to omit, so that it won't be visible.

  2) Break the loop once you have drawn the part of the circle that you want to see.

  Either one is fine.

  Eduard

  
• tcar

  May 2020 edited May 2020

  Hi eduard,

  I found a solution to my problem by creating a polygon with many edges which follow the outline of a partial circle. See code for this below.

  Have a nice weekend!

  
  

  from math import sin, cos
  
  
  def arc_xy(start_angle, end_angle, radius = 100, width = 10, x = 0, y = 0):
  
     
  
    innerEdge = []
  
    outerEdge = []
  
     
  
    # Simple fix, if start angle > end angle, then reverse the two!
  
    if start_angle > end_angle:
  
      start_angle, end_angle = end_angle, start_angle 
  
       
  
     
  
    for angle in range(start_angle,end_angle + 1):
  
      
  
     # Rotating, so that everything starts from the bottom
  
       angle += 180
  
       
  
     # Preparing inner edge 
  
       
  
       cx = int(round((radius - width) * sin(angle * 0.0174532925),0))
  
       cy = int(round((radius - width) * -cos(angle * 0.0174532925),0)) 
  
       
  
       innerEdge.append([x + cx,y + cy])
  
       
  
     # Preparing outer edge
  
       cx = int(round((radius + width) * sin((start_angle + end_angle - angle) * 0.0174532925),0))
  
       cy = int(round((radius + width) * -cos((start_angle + end_angle - angle) * 0.0174532925),0)) 
  
      
  
       outerEdge.append([x + cx,y + cy])
  
       
  
    allEdge = innerEdge + outerEdge
  
     
  
    return allEdge
  
     
  
  
  
  
  
  
  
  
  
  
  c = Canvas()
  
  c.polygon(arc_xy(start_angle = 340, end_angle = 60, x = 15), color = (80,80,80), fill = True)
  
  c.show()