draw2d/path_converter.go
Stani d47e08f7c9 Preparing for pdf backend
- make PathStorage Commands and Vertices public, so they can be accessed by the pdf backend
- start every path with MoveTo (also before ArcTo)
2015-06-27 01:03:41 +02:00

173 lines
4.9 KiB
Go

// Copyright 2010 The draw2d Authors. All rights reserved.
// created: 06/12/2010 by Laurent Le Goff
package draw2d
import (
"math"
)
type PathConverter struct {
converter VertexConverter
ApproximationScale, AngleTolerance, CuspLimit float64
startX, startY, x, y float64
}
func NewPathConverter(converter VertexConverter) *PathConverter {
return &PathConverter{converter, 1, 0, 0, 0, 0, 0, 0}
}
func (c *PathConverter) Convert(paths ...*PathStorage) {
for _, path := range paths {
j := 0
for _, cmd := range path.Commands {
j = j + c.ConvertCommand(cmd, path.Vertices[j:]...)
}
c.converter.NextCommand(VertexStopCommand)
}
}
func (c *PathConverter) ConvertCommand(cmd PathCmd, vertices ...float64) int {
switch cmd {
case MoveTo:
c.x, c.y = vertices[0], vertices[1]
c.startX, c.startY = c.x, c.y
c.converter.NextCommand(VertexStopCommand)
c.converter.NextCommand(VertexStartCommand)
c.converter.Vertex(c.x, c.y)
return 2
case LineTo:
c.x, c.y = vertices[0], vertices[1]
if c.startX == c.x && c.startY == c.y {
c.converter.NextCommand(VertexCloseCommand)
}
c.converter.Vertex(c.x, c.y)
c.converter.NextCommand(VertexJoinCommand)
return 2
case QuadCurveTo:
quadraticBezier(c.converter, c.x, c.y, vertices[0], vertices[1], vertices[2], vertices[3], c.ApproximationScale, c.AngleTolerance)
c.x, c.y = vertices[2], vertices[3]
if c.startX == c.x && c.startY == c.y {
c.converter.NextCommand(VertexCloseCommand)
}
c.converter.Vertex(c.x, c.y)
return 4
case CubicCurveTo:
cubicBezier(c.converter, c.x, c.y, vertices[0], vertices[1], vertices[2], vertices[3], vertices[4], vertices[5], c.ApproximationScale, c.AngleTolerance, c.CuspLimit)
c.x, c.y = vertices[4], vertices[5]
if c.startX == c.x && c.startY == c.y {
c.converter.NextCommand(VertexCloseCommand)
}
c.converter.Vertex(c.x, c.y)
return 6
case ArcTo:
c.x, c.y = arc(c.converter, vertices[0], vertices[1], vertices[2], vertices[3], vertices[4], vertices[5], c.ApproximationScale)
if c.startX == c.x && c.startY == c.y {
c.converter.NextCommand(VertexCloseCommand)
}
c.converter.Vertex(c.x, c.y)
return 6
case Close:
c.converter.NextCommand(VertexCloseCommand)
c.converter.Vertex(c.startX, c.startY)
return 0
}
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.NextCommand(VertexStopCommand)
c.converter.NextCommand(VertexStartCommand)
c.converter.Vertex(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
if c.startX == c.x && c.startY == c.y {
c.converter.NextCommand(VertexCloseCommand)
}
c.converter.Vertex(c.x, c.y)
c.converter.NextCommand(VertexJoinCommand)
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 {
quadraticBezier(c.converter, c.x, c.y, cx, cy, x, y, c.ApproximationScale, c.AngleTolerance)
c.x, c.y = x, y
if c.startX == c.x && c.startY == c.y {
c.converter.NextCommand(VertexCloseCommand)
}
c.converter.Vertex(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 {
cubicBezier(c.converter, c.x, c.y, cx1, cy1, cx2, cy2, x, y, c.ApproximationScale, c.AngleTolerance, c.CuspLimit)
c.x, c.y = x, y
if c.startX == c.x && c.startY == c.y {
c.converter.NextCommand(VertexCloseCommand)
}
c.converter.Vertex(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)
if c.startX == c.x && c.startY == c.y {
c.converter.NextCommand(VertexCloseCommand)
}
c.converter.Vertex(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.NextCommand(VertexCloseCommand)
c.converter.Vertex(c.startX, c.startY)
return c
}