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Action:
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Scales a single element of an existing pattern.
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Filename:
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kern/kern_scm/pattern_scm.cxx
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Syntax:
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(pattern:scale-element pat coords scale root)
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Arg Types:
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pat
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pattern
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coords
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real
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scale
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real | gvector
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root
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position
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Returns:
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pattern
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Description:
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Scales the element specified by
coords of an existing pattern about the position root by an amount
scale.
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pat specifies a pattern.
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coords identify the element in the pattern.
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scale argument specifies the scale value to be applied. The
scale may be a real number, for uniform scaling, or a vector, for non-uniform scaling.
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root specifies the neutral point about which the scaling takes place (i.e., the point on the seed entity that remains fixed while the entity's dimensions are altered).
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Example:
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; pattern:scale-element
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; make a prism
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(define height 1)
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;; height
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(define maj_rad 1)
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;; maj_rad
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(define min_rad 0.5)
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;; min_rad
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(define num_sides 3)
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;; num_sides
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(define prism (solid:prism height maj_rad min_rad num_sides))
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;; prism
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; position the prism
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(define origin (position 1 2 3))
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;; origin
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(define trans (entity:transform prism
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(transform:axes origin
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(gvector 1 0 0) (gvector 0 1 0))))
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;; trans
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; make a pattern
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(define center origin)
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;; center
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(define normal (gvector 0 0 1))
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;; normal
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(define num-radial 4)
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;; num-radial
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(define num-angular 5)
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;; num-angular
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(define spacing 3)
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;; spacing
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(define pat (pattern:radial center normal
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num-radial num-angular spacing))
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;; pat
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; modify the pattern
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(define scaling 2)
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;; scaling
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(define root origin)
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;; root
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(set! pat (pattern:scale-element pat
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(list 0 0) scaling root))
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;; #[pattern
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;; trans-vec:
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"DOMAIN(VEC(-1,0,0)*COS
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;; (1.256637061435917*X2)*3*X+VEC
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;; (0,-1,0)*SIN(1.256637061435917*X2)
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;; *3*X+VEC (1,2,3),0,3,0,4)"
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;; x-vec:
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"VEC(-1,0,0)*COS
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;; (1.256637061435917*X2)+VEC
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;; (0,-1,0)*SIN(1.256637061435917*X2)"
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;; y-vec:
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"VEC(0,0,1)"
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;; z-vec:
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"null_law"
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;; scale:
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"null_law"
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;; keep:
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"PIECEWISE(X>0,X,X2<1)"
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;; [list]]
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; apply the pattern to the prism
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(define body (entity:pattern prism pat))
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;; body
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(law:equal-test (length (entity:vertices body)) 96)
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;; #t
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