draw2d/draw2dpdf/path_converter.go
2015-07-11 18:39:51 +02:00

60 lines
1.6 KiB
Go

// Copyright 2015 The draw2d Authors. All rights reserved.
// created: 26/06/2015 by Stani Michiels
package draw2dpdf
import (
"math"
"github.com/llgcode/draw2d"
)
const deg = 180 / math.Pi
// PathConverter converts the paths to the pdf api
type PathConverter struct {
pdf Vectorizer
}
// NewPathConverter constructs a PathConverter from a pdf vectorizer
func NewPathConverter(pdf Vectorizer) *PathConverter {
return &PathConverter{pdf: pdf}
}
// Convert converts the paths to the pdf api
func (c *PathConverter) Convert(paths ...*draw2d.PathStorage) {
for _, path := range paths {
j := 0
for _, cmd := range path.Commands {
j = j + c.ConvertCommand(cmd, path.Vertices[j:]...)
}
}
}
// ConvertCommand converts a single path segment to the pdf api
func (c *PathConverter) ConvertCommand(cmd draw2d.PathCmd, vertices ...float64) int {
switch cmd {
case draw2d.MoveTo:
c.pdf.MoveTo(vertices[0], vertices[1])
return 2
case draw2d.LineTo:
c.pdf.LineTo(vertices[0], vertices[1])
return 2
case draw2d.QuadCurveTo:
c.pdf.CurveTo(vertices[0], vertices[1], vertices[2], vertices[3])
return 4
case draw2d.CubicCurveTo:
c.pdf.CurveBezierCubicTo(vertices[0], vertices[1], vertices[2], vertices[3], vertices[4], vertices[5])
return 6
case draw2d.ArcTo:
// draw2d: angles clockwise, fpdf angles counter clockwise
c.pdf.ArcTo(vertices[0], vertices[1], vertices[2], vertices[3],
0, // degRotate
-vertices[4]*deg, // degStart = -startAngle
(-vertices[4]-vertices[5])*deg) // degEnd = -startAngle-angle
return 6
default: // case draw2d.Close:
c.pdf.ClosePath()
return 0
}
}