91 lines
2.3 KiB
Go
91 lines
2.3 KiB
Go
|
package drawing
|
||
|
|
|
||
|
|
// Liner receive segment definition
|
||
|
|
type Liner interface {
|
||
|
|
// LineTo Draw a line from the current position to the point (x, y)
|
||
|
|
LineTo(x, y float64)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Flattener receive segment definition
|
||
|
|
type Flattener interface {
|
||
|
|
// MoveTo Start a New line from the point (x, y)
|
||
|
|
MoveTo(x, y float64)
|
||
|
|
// LineTo Draw a line from the current position to the point (x, y)
|
||
|
|
LineTo(x, y float64)
|
||
|
|
// LineJoin add the most recent starting point to close the path to create a polygon
|
||
|
|
LineJoin()
|
||
|
|
// Close add the most recent starting point to close the path to create a polygon
|
||
|
|
Close()
|
||
|
|
// End mark the current line as finished so we can draw caps
|
||
|
|
End()
|
||
|
|
}
|
||
|
|
|
||
|
|
// Flatten convert curves into straight segments keeping join segments info
|
||
|
|
func Flatten(path *Path, flattener Flattener, scale float64) {
|
||
|
|
// First Point
|
||
|
|
var startX, startY float64 = 0, 0
|
||
|
|
// Current Point
|
||
|
|
var x, y float64 = 0, 0
|
||
|
|
i := 0
|
||
|
|
for _, cmp := range path.Components {
|
||
|
|
switch cmp {
|
||
|
|
case MoveToComponent:
|
||
|
|
x, y = path.Points[i], path.Points[i+1]
|
||
|
|
startX, startY = x, y
|
||
|
|
if i != 0 {
|
||
|
|
flattener.End()
|
||
|
|
}
|
||
|
|
flattener.MoveTo(x, y)
|
||
|
|
i += 2
|
||
|
|
case LineToComponent:
|
||
|
|
x, y = path.Points[i], path.Points[i+1]
|
||
|
|
flattener.LineTo(x, y)
|
||
|
|
flattener.LineJoin()
|
||
|
|
i += 2
|
||
|
|
case QuadCurveToComponent:
|
||
|
|
TraceQuad(flattener, path.Points[i-2:], 0.5)
|
||
|
|
x, y = path.Points[i+2], path.Points[i+3]
|
||
|
|
flattener.LineTo(x, y)
|
||
|
|
i += 4
|
||
|
|
case CubicCurveToComponent:
|
||
|
|
TraceCubic(flattener, path.Points[i-2:], 0.5)
|
||
|
|
x, y = path.Points[i+4], path.Points[i+5]
|
||
|
|
flattener.LineTo(x, y)
|
||
|
|
i += 6
|
||
|
|
case ArcToComponent:
|
||
|
|
x, y = TraceArc(flattener, path.Points[i], path.Points[i+1], path.Points[i+2], path.Points[i+3], path.Points[i+4], path.Points[i+5], scale)
|
||
|
|
flattener.LineTo(x, y)
|
||
|
|
i += 6
|
||
|
|
case CloseComponent:
|
||
|
|
flattener.LineTo(startX, startY)
|
||
|
|
flattener.Close()
|
||
|
|
}
|
||
|
|
}
|
||
|
|
flattener.End()
|
||
|
|
}
|
||
|
|
|
||
|
|
type SegmentedPath struct {
|
||
|
|
Points []float64
|
||
|
|
}
|
||
|
|
|
||
|
|
func (p *SegmentedPath) MoveTo(x, y float64) {
|
||
|
|
p.Points = append(p.Points, x, y)
|
||
|
|
// TODO need to mark this point as moveto
|
||
|
|
}
|
||
|
|
|
||
|
|
func (p *SegmentedPath) LineTo(x, y float64) {
|
||
|
|
p.Points = append(p.Points, x, y)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (p *SegmentedPath) LineJoin() {
|
||
|
|
// TODO need to mark the current point as linejoin
|
||
|
|
}
|
||
|
|
|
||
|
|
func (p *SegmentedPath) Close() {
|
||
|
|
// TODO Close
|
||
|
|
}
|
||
|
|
|
||
|
|
func (p *SegmentedPath) End() {
|
||
|
|
// Nothing to do
|
||
|
|
}
|