draw2d/path_converter.go

// Copyright 2010 The draw2d Authors. All rights reserved.
// created: 06/12/2010 by Laurent Le Goff

package draw2d

import (
	"github.com/llgcode/draw2d/curve"
	"math"
)

type PathConverter struct {
	converter            LineBuilder
	ApproximationScale   float64
	startX, startY, x, y float64
}

func NewPathConverter(converter LineBuilder) *PathConverter {
	return &PathConverter{converter, 1, 0, 0, 0, 0}
}

func (c *PathConverter) Convert(paths ...*Path) {
	for _, path := range paths {
		i := 0
		for _, cmd := range path.commands {
			switch cmd {
			case MoveTo:
				c.x, c.y = path.vertices[i], path.vertices[i+1]
				c.startX, c.startY = c.x, c.y
				if i != 0 {
					c.converter.End()
				}
				c.converter.MoveTo(c.x, c.y)
				i += 2
			case LineTo:
				c.x, c.y = path.vertices[i], path.vertices[i+1]
				c.converter.LineTo(c.x, c.y)
				c.converter.LineJoin()
				i += 2
			case QuadCurveTo:
				curve.TraceQuad(c.converter, path.vertices[i-2:], 0.5)
				c.x, c.y = path.vertices[i+2], path.vertices[i+3]
				c.converter.LineTo(c.x, c.y)
				i += 4
			case CubicCurveTo:
				curve.TraceCubic(c.converter, path.vertices[i-2:], 0.5)
				c.x, c.y = path.vertices[i+4], path.vertices[i+5]
				c.converter.LineTo(c.x, c.y)
				i += 6
			case ArcTo:
				c.x, c.y = arc(c.converter, path.vertices[i], path.vertices[i+1], path.vertices[i+2], path.vertices[i+3], path.vertices[i+4], path.vertices[i+5], c.ApproximationScale)
				c.converter.LineTo(c.x, c.y)
				i += 6
			case Close:
				c.converter.LineTo(c.startX, c.startY)
				c.converter.Close()
			}
		}
		c.converter.End()
	}
}

func (c *PathConverter) convertCommand(cmd PathCmd, vertices ...float64) int {
	return 0
}

func (c *PathConverter) MoveTo(x, y float64) *PathConverter {
	c.x, c.y = x, y
	c.startX, c.startY = c.x, c.y
	c.converter.End()
	c.converter.MoveTo(c.x, c.y)
	return c
}

func (c *PathConverter) RMoveTo(dx, dy float64) *PathConverter {
	c.MoveTo(c.x+dx, c.y+dy)
	return c
}

func (c *PathConverter) LineTo(x, y float64) *PathConverter {
	c.x, c.y = x, y
	c.converter.LineTo(c.x, c.y)
	c.converter.LineJoin()
	return c
}

func (c *PathConverter) RLineTo(dx, dy float64) *PathConverter {
	c.LineTo(c.x+dx, c.y+dy)
	return c
}

func (c *PathConverter) QuadCurveTo(cx, cy, x, y float64) *PathConverter {
	curve.TraceQuad(c.converter, []float64{c.x, c.y, cx, cy, x, y}, 0.5)
	c.x, c.y = x, y
	c.converter.LineTo(c.x, c.y)
	return c
}

func (c *PathConverter) RQuadCurveTo(dcx, dcy, dx, dy float64) *PathConverter {
	c.QuadCurveTo(c.x+dcx, c.y+dcy, c.x+dx, c.y+dy)
	return c
}

func (c *PathConverter) CubicCurveTo(cx1, cy1, cx2, cy2, x, y float64) *PathConverter {
	curve.TraceCubic(c.converter, []float64{c.x, c.y, cx1, cy1, cx2, cy2, x, y}, 0.5)
	c.x, c.y = x, y
	c.converter.LineTo(c.x, c.y)
	return c
}

func (c *PathConverter) RCubicCurveTo(dcx1, dcy1, dcx2, dcy2, dx, dy float64) *PathConverter {
	c.CubicCurveTo(c.x+dcx1, c.y+dcy1, c.x+dcx2, c.y+dcy2, c.x+dx, c.y+dy)
	return c
}

func (c *PathConverter) ArcTo(cx, cy, rx, ry, startAngle, angle float64) *PathConverter {
	endAngle := startAngle + angle
	clockWise := true
	if angle < 0 {
		clockWise = false
	}
	// normalize
	if clockWise {
		for endAngle < startAngle {
			endAngle += math.Pi * 2.0
		}
	} else {
		for startAngle < endAngle {
			startAngle += math.Pi * 2.0
		}
	}
	startX := cx + math.Cos(startAngle)*rx
	startY := cy + math.Sin(startAngle)*ry
	c.MoveTo(startX, startY)
	c.x, c.y = arc(c.converter, cx, cy, rx, ry, startAngle, angle, c.ApproximationScale)
	c.converter.LineTo(c.x, c.y)
	return c
}

func (c *PathConverter) RArcTo(dcx, dcy, rx, ry, startAngle, angle float64) *PathConverter {
	c.ArcTo(c.x+dcx, c.y+dcy, rx, ry, startAngle, angle)
	return c
}

func (c *PathConverter) Close() *PathConverter {
	c.converter.Close()
	return c
}