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Thread: SVG Weave/Crosshatching Pattern Generator

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      Hai-Etlik is offline
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    Post SVG Weave/Crosshatching Pattern Generator

    A crosshatching type pattern that resembles weaving. I've seen it used in a few places and decided to make my own. And being lazy, I got the computer to do it for me by writing a Ruby script.

    Here's the code.

    Code:
    require 'matrix'
    
    class Vector
      def pair_mult(v)
        map2(v) do |x1, x2|
          x1*x2
        end
      end
    end
    
    
    BOX_SIZE=Vector[10,10]
    BOX_COUNT=Vector[8,8]
    BOX_SHIFT=Vector[1.5,1.5]
    PATTERN_SIZE=BOX_SIZE.pair_mult(BOX_COUNT)
    LINES=4
    
    
    def moveto(p)
      "M #{p[0]} #{p[1]}"
    end
    
    def lineto(p)
      "L #{p[0]} #{p[1]}"
    end
    
    
    
    def envelope_lines(a,b,c,d,lines)
      step1=(b-a)*(1.0/(lines+1))
      step2=(d-c)*(1.0/(lines+1))
    
      result=[]
      
      lines.times do |i|
        result<< moveto(a+step1*(i+1))
        result<< lineto(c+step2*(i+1))
      end
      return result.join " "
    end
    
    
    
    points=Array.new(BOX_COUNT[1]) do |j|
      row=Array.new(BOX_COUNT[0]) do |i|
    
        Vector[i,j].pair_mult(BOX_SIZE)+Vector[2*rand-1, 2*rand-1].pair_mult(BOX_SHIFT)
      end
      row<< row[0]+Vector[PATTERN_SIZE[0],0] # Last point is the first point shifted by the width of the whole pattern
    end
    # Last row is the first row shifted by the height of the whole pattern
    points<< points[0].map {|p| p+Vector[0,PATTERN_SIZE[1]]}
    
    result=""
    
    BOX_COUNT[1].times do |j|
      BOX_COUNT[0].times do |i|
        a=points[j][i]
        b=points[j][i+1]
        c=points[j+1][i]
        d=points[j+1][i+1]
    
        a,b,c,d=a,c,b,d if (i+j)%2==0 # Swap vertical and horizontal in alternating boxes
    
        result+=envelope_lines(a,b,c,d,LINES)
      end
    end
    
    
    puts <<EOS
    <?xml version="1.0" standalone="no"?>
    <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" 
      "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
    <svg width="4cm" height="4cm" viewBox="0 0 #{PATTERN_SIZE[0]} #{PATTERN_SIZE[1]} "
         xmlns="http://www.w3.org/2000/svg" version="1.1">
        <defs>
    <pattern id="weave" patternUnits="userSpaceOnUse"
                 x="0" y="0" width="#{PATTERN_SIZE[0]}" height="#{PATTERN_SIZE[1]}">
        <path stroke="black" d="#{result}" stroke-width="1" />
          
        </pattern> 
      </defs>
      <rect fill="url(#weave)" x="0" y="0" width="#{PATTERN_SIZE[0]}" height="#{PATTERN_SIZE[1]}" />
    </svg>
    EOS
    The pattern itself is zipped because the forum is stupid.
    Attached Thumbnails Attached Thumbnails SVG Weave/Crosshatching Pattern Generator-weave.png  
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