[Add feature] Change brightness based on color segment in rendering

[paduLAB]

I would suggest to add a function to render the pen according both the name of layer and the color of the pen.
So for example, if you choose to have a red layer "#red":

• black pen will give a dark red colour;
• grey pen will give the colour you chose;
• white pen will give a light red coulor.

To achieve this I have added some code in render.py
This function is used to get darker or lighter a color: Bleach power >=1 has a bleach effect, <1 and >0 has a darker effect

def _bleach_color(color,bleach_power):
    COEFF=1.04
    OFFSET=0.1
    red = (COEFF*color.red+OFFSET)*bleach_power
    green = (COEFF*color.green+OFFSET)*bleach_power
    blue = (COEFF*color.blue+OFFSET)*bleach_power
    new_color = (red,green,blue)
    return _get_color(new_color)

I also edited a part of _render_rm_file, adding a piece of code that choose a darker or lighter color based on segment color

segment_blackDistance=colors.colorDistance(segment_color,colors.black)
    if layer_colors[layer] is None:
        segment_colors.append(segment_color)
    elif segment_blackDistance<0.75:  #black
        segment_colors.append(_bleach_color(layer_colors[layer],0.5))
    elif segment_blackDistance>1: #white
        segment_colors.append(_bleach_color(layer_colors[layer],5))
    else: #grey
        segment_colors.append(layer_colors[layer])

I hope my little work was useful.

Regards

[peerdavid]

Very nice idea. Thanks a lot also for the code. I will include this soon :)