Modifying contours

Modifying a ShapeContour

sub()

A contour can be cut into a shorter contour using ShapeContour.sub().

../media/shapes-005.png

import offset.offset
import org.openrndr.application
import org.openrndr.color.ColorRGBa
import org.openrndr.extra.composition.composition
import org.openrndr.extra.composition.drawComposition
import org.openrndr.extra.noise.shapes.uniform
import org.openrndr.extra.noise.uniform
import org.openrndr.extra.shapes.hobbycurve.hobbyCurve
import org.openrndr.extra.shapes.operators.roundCorners
import org.openrndr.math.transforms.transform
import org.openrndr.shape.Circle
import org.openrndr.shape.Rectangle
import org.openrndr.shape.ShapeContour

fun main() = application {
    program {
        val cc = List(100) {
            val t = Double.uniform(0.0, 1.0)
            Circle(drawer.bounds.center, 10.0 + it * 2.0).contour.sub(t, t + 0.25)
        }
        val myDesign = drawComposition {
            contours(cc)
        }
        extend {
            drawer.clear(ColorRGBa.WHITE)
            drawer.composition(myDesign)
        }
    }
}

offset()

The function ShapeContour.offset can be used to create an offset version of a contour. This can be useful to create thicker lines for the pen plotter.

../media/shapes-101.png

import offset.offset
import org.openrndr.application
import org.openrndr.color.ColorRGBa
import org.openrndr.extra.composition.composition
import org.openrndr.extra.composition.drawComposition
import org.openrndr.extra.noise.shapes.uniform
import org.openrndr.extra.noise.uniform
import org.openrndr.extra.shapes.hobbycurve.hobbyCurve
import org.openrndr.extra.shapes.operators.roundCorners
import org.openrndr.math.transforms.transform
import org.openrndr.shape.Circle
import org.openrndr.shape.Rectangle
import org.openrndr.shape.ShapeContour

fun main() = application {
    program {
        val cc = List(20) {
            Rectangle.fromCenter(drawer.bounds.center, 200.0).contour.offset(it * 1.0)
        }
        val myDesign = drawComposition {
            contours(cc)
        }
        extend {
            drawer.clear(ColorRGBa.WHITE)
            drawer.composition(myDesign)
        }
    }
}

ShapeContour.offset can also be used to offset curved contours. The following demonstration shows a 10 point hobby curve offset 12 times.

../media/shapes-100.png

import offset.offset
import org.openrndr.application
import org.openrndr.color.ColorRGBa
import org.openrndr.extra.composition.composition
import org.openrndr.extra.composition.drawComposition
import org.openrndr.extra.noise.shapes.uniform
import org.openrndr.extra.noise.uniform
import org.openrndr.extra.shapes.hobbycurve.hobbyCurve
import org.openrndr.extra.shapes.operators.roundCorners
import org.openrndr.math.transforms.transform
import org.openrndr.shape.Circle
import org.openrndr.shape.Rectangle
import org.openrndr.shape.ShapeContour

fun main() = application {
    program {
        val c = hobbyCurve(List(10) {
            drawer.bounds.offsetEdges(-100.0).uniform()
        }, false)
        val myDesign = drawComposition {
            repeat(12) {
                contour(c.offset(it * 3.0))
            }
        }
        extend {
            drawer.clear(ColorRGBa.WHITE)
            drawer.composition(myDesign)
        }
    }
}

ShapeContour.reversed can be used to reverse a contour. This can be useful to draw lines two times in opposing directions to make sure ink is applied on the paper at every point of the line.

../media/reversed-100.png

import offset.offset
import org.openrndr.application
import org.openrndr.color.ColorRGBa
import org.openrndr.extra.composition.composition
import org.openrndr.extra.composition.drawComposition
import org.openrndr.extra.noise.shapes.uniform
import org.openrndr.extra.noise.uniform
import org.openrndr.extra.shapes.hobbycurve.hobbyCurve
import org.openrndr.extra.shapes.operators.roundCorners
import org.openrndr.math.transforms.transform
import org.openrndr.shape.Circle
import org.openrndr.shape.Rectangle
import org.openrndr.shape.ShapeContour

fun main() = application {
    program {
        val c = hobbyCurve(List(10) {
            drawer.bounds.offsetEdges(-150.0).uniform()
        }, false)
        val myDesign = drawComposition {
            contour(c)
            contour(c.reversed)
        }
        extend {
            drawer.clear(ColorRGBa.WHITE)
            drawer.composition(myDesign)
        }
    }
}

ShapeContour.roundCorners() can be used to round sharp corners of a contour.

../media/rounded-100.png

import offset.offset
import org.openrndr.application
import org.openrndr.color.ColorRGBa
import org.openrndr.extra.composition.composition
import org.openrndr.extra.composition.drawComposition
import org.openrndr.extra.noise.shapes.uniform
import org.openrndr.extra.noise.uniform
import org.openrndr.extra.shapes.hobbycurve.hobbyCurve
import org.openrndr.extra.shapes.operators.roundCorners
import org.openrndr.math.transforms.transform
import org.openrndr.shape.Circle
import org.openrndr.shape.Rectangle
import org.openrndr.shape.ShapeContour

fun main() = application {
    program {
        val c = ShapeContour.fromPoints(List(12) {
            drawer.bounds.offsetEdges(-52.0).uniform()
        }, false)
        val myDesign = drawComposition {
            contour(c.roundCorners(25.0))
        }
        extend {
            drawer.clear(ColorRGBa.WHITE)
            drawer.composition(myDesign)
        }
    }
}

ShapeContour.transform() can be used to apply translations, rotations and scaling to a contour:

../media/contour-transform-100.png

import offset.offset
import org.openrndr.application
import org.openrndr.color.ColorRGBa
import org.openrndr.extra.composition.composition
import org.openrndr.extra.composition.drawComposition
import org.openrndr.extra.noise.shapes.uniform
import org.openrndr.extra.noise.uniform
import org.openrndr.extra.shapes.hobbycurve.hobbyCurve
import org.openrndr.extra.shapes.operators.roundCorners
import org.openrndr.math.transforms.transform
import org.openrndr.shape.Circle
import org.openrndr.shape.Rectangle
import org.openrndr.shape.ShapeContour

fun main() = application {
    program {
        val c = ShapeContour.fromPoints(List(12) {
            drawer.bounds.offsetEdges(-50.0).uniform()
        }, false).roundCorners(25.0)
        
        val myDesign = drawComposition {
            repeat(10) {
                // create a transformation matrix rotating
                // around the center of the window
                val rotation = transform {
                    translate(drawer.bounds.center)
                    rotate(1.0 * it)
                    translate(-drawer.bounds.center)
                }
                // Use isolated to avoid accumulating transformations
                // (like pushMatrix / popMatrix in other frameworks)
                contour(c.transform(rotation))
            }
        }
        extend {
            drawer.clear(ColorRGBa.WHITE)
            drawer.composition(myDesign)
        }
    }
}

Find more ways to transform contours by typing . after an instance of ShapeContour, for example c., and exploring the list of suggested methods.

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