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// Copyright 2010 The draw2d Authors. All rights reserved.
// created: 21/11/2010 by Laurent Le Goff
package draw2d
import (
"fmt"
"math"
)
type PathCmd int
const (
MoveTo PathCmd = iota
LineTo
QuadCurveTo
CubicCurveTo
ArcTo
Close
)
type PathStorage struct {
commands []PathCmd
vertices []float64
x, y float64
}
func NewPathStorage() (p *PathStorage) {
p = new(PathStorage)
p.commands = make([]PathCmd, 0, 256)
p.vertices = make([]float64, 0, 256)
return
}
func (p *PathStorage) Clear() {
p.commands = p.commands[0:0]
p.vertices = p.vertices[0:0]
return
}
func (p *PathStorage) appendToPath(cmd PathCmd, vertices ...float64) {
if cap(p.vertices) <= len(p.vertices)+6 {
a := make([]PathCmd, len(p.commands), cap(p.commands)+256)
b := make([]float64, len(p.vertices), cap(p.vertices)+256)
copy(a, p.commands)
p.commands = a
copy(b, p.vertices)
p.vertices = b
}
p.commands = p.commands[0 : len(p.commands)+1]
p.commands[len(p.commands)-1] = cmd
copy(p.vertices[len(p.vertices):len(p.vertices)+len(vertices)], vertices)
p.vertices = p.vertices[0 : len(p.vertices)+len(vertices)]
}
func (src *PathStorage) Copy() (dest *PathStorage) {
dest = new(PathStorage)
dest.commands = make([]PathCmd, len(src.commands))
copy(dest.commands, src.commands)
dest.vertices = make([]float64, len(src.vertices))
copy(dest.vertices, src.vertices)
return dest
}
func (p *PathStorage) LastPoint() (x, y float64) {
return p.x, p.y
}
func (p *PathStorage) IsEmpty() bool {
return len(p.commands) == 0
}
func (p *PathStorage) Close() *PathStorage {
p.appendToPath(Close)
return p
}
func (p *PathStorage) MoveTo(x, y float64) *PathStorage {
p.appendToPath(MoveTo, x, y)
p.x = x
p.y = y
return p
}
func (p *PathStorage) RMoveTo(dx, dy float64) *PathStorage {
x, y := p.LastPoint()
p.MoveTo(x+dx, y+dy)
return p
}
func (p *PathStorage) LineTo(x, y float64) *PathStorage {
p.appendToPath(LineTo, x, y)
p.x = x
p.y = y
return p
}
func (p *PathStorage) RLineTo(dx, dy float64) *PathStorage {
x, y := p.LastPoint()
p.LineTo(x+dx, y+dy)
return p
}
func (p *PathStorage) QuadCurveTo(cx, cy, x, y float64) *PathStorage {
p.appendToPath(QuadCurveTo, cx, cy, x, y)
p.x = x
p.y = y
return p
}
func (p *PathStorage) RQuadCurveTo(dcx, dcy, dx, dy float64) *PathStorage {
x, y := p.LastPoint()
p.QuadCurveTo(x+dcx, y+dcy, x+dx, y+dy)
return p
}
func (p *PathStorage) CubicCurveTo(cx1, cy1, cx2, cy2, x, y float64) *PathStorage {
p.appendToPath(CubicCurveTo, cx1, cy1, cx2, cy2, x, y)
p.x = x
p.y = y
return p
}
func (p *PathStorage) RCubicCurveTo(dcx1, dcy1, dcx2, dcy2, dx, dy float64) *PathStorage {
x, y := p.LastPoint()
p.CubicCurveTo(x+dcx1, y+dcy1, x+dcx2, y+dcy2, x+dx, y+dy)
return p
}
func (p *PathStorage) ArcTo(cx, cy, rx, ry, startAngle, angle float64) *PathStorage {
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
if len(p.commands) > 0 {
p.LineTo(startX, startY)
} else {
p.MoveTo(startX, startY)
}
p.appendToPath(ArcTo, cx, cy, rx, ry, startAngle, angle)
p.x = cx + math.Cos(endAngle)*rx
p.y = cy + math.Sin(endAngle)*ry
return p
}
func (p *PathStorage) RArcTo(dcx, dcy, rx, ry, startAngle, angle float64) *PathStorage {
x, y := p.LastPoint()
p.ArcTo(x+dcx, y+dcy, rx, ry, startAngle, angle)
return p
}
func (p *PathStorage) String() string {
s := ""
j := 0
for _, cmd := range p.commands {
switch cmd {
case MoveTo:
s += fmt.Sprintf("MoveTo: %f, %f\n", p.vertices[j], p.vertices[j+1])
j = j + 2
case LineTo:
s += fmt.Sprintf("LineTo: %f, %f\n", p.vertices[j], p.vertices[j+1])
j = j + 2
case QuadCurveTo:
s += fmt.Sprintf("QuadCurveTo: %f, %f, %f, %f\n", p.vertices[j], p.vertices[j+1], p.vertices[j+2], p.vertices[j+3])
j = j + 4
case CubicCurveTo:
s += fmt.Sprintf("CubicCurveTo: %f, %f, %f, %f, %f, %f\n", p.vertices[j], p.vertices[j+1], p.vertices[j+2], p.vertices[j+3], p.vertices[j+4], p.vertices[j+5])
j = j + 6
case ArcTo:
s += fmt.Sprintf("ArcTo: %f, %f, %f, %f, %f, %f\n", p.vertices[j], p.vertices[j+1], p.vertices[j+2], p.vertices[j+3], p.vertices[j+4], p.vertices[j+5])
j = j + 6
case Close:
s += "Close\n"
}
}
return s
}
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