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rui/path.go

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5.2 KiB
Go

package rui
// Path is a path interface
type Path interface {
// Reset erases the Path
Reset()
// MoveTo begins a new sub-path at the point specified by the given (x, y) coordinates
MoveTo(x, y float64)
// LineTo adds a straight line to the current sub-path by connecting
// the sub-path's last point to the specified (x, y) coordinates
LineTo(x, y float64)
// ArcTo adds a circular arc to the current sub-path, using the given control points and radius.
// The arc is automatically connected to the path's latest point with a straight line, if necessary.
// x0, y0 - coordinates of the first control point;
// x1, y1 - coordinates of the second control point;
// radius - the arc's radius. Must be non-negative.
ArcTo(x0, y0, x1, y1, radius float64)
// Arc adds a circular arc to the current sub-path.
// x, y - coordinates of the arc's center;
// radius - the arc's radius. Must be non-negative;
// startAngle - the angle at which the arc starts, measured clockwise from the positive
// x-axis and expressed in radians.
// endAngle - the angle at which the arc ends, measured clockwise from the positive
// x-axis and expressed in radians.
// clockwise - if true, causes the arc to be drawn clockwise between the start and end angles,
// otherwise - counter-clockwise
Arc(x, y, radius, startAngle, endAngle float64, clockwise bool)
// BezierCurveTo adds a cubic Bézier curve to the current sub-path. The starting point is
// the latest point in the current path.
// cp0x, cp0y - coordinates of the first control point;
// cp1x, cp1y - coordinates of the second control point;
// x, y - coordinates of the end point.
BezierCurveTo(cp0x, cp0y, cp1x, cp1y, x, y float64)
// QuadraticCurveTo adds a quadratic Bézier curve to the current sub-path.
// cpx, cpy - coordinates of the control point;
// x, y - coordinates of the end point.
QuadraticCurveTo(cpx, cpy, x, y float64)
// Ellipse adds an elliptical arc to the current sub-path
// x, y - coordinates of the ellipse's center;
// radiusX - the ellipse's major-axis radius. Must be non-negative;
// radiusY - the ellipse's minor-axis radius. Must be non-negative;
// rotation - the rotation of the ellipse, expressed in radians;
// startAngle - the angle at which the ellipse starts, measured clockwise
// from the positive x-axis and expressed in radians;
// endAngle - the angle at which the ellipse ends, measured clockwise
// from the positive x-axis and expressed in radians.
// clockwise - if true, draws the ellipse clockwise, otherwise draws counter-clockwise
Ellipse(x, y, radiusX, radiusY, rotation, startAngle, endAngle float64, clockwise bool)
// Close adds a straight line from the current point to the start of the current sub-path.
// If the shape has already been closed or has only one point, this function does nothing.
Close()
create(session Session)
}
type pathElement struct {
funcName string
args []any
}
type pathData struct {
elements []pathElement
}
// NewPath creates a new empty Path
func NewPath() Path {
path := new(pathData)
path.Reset()
return path
}
func (path *pathData) Reset() {
path.elements = []pathElement{
pathElement{funcName: "beginPath", args: []any{}},
}
}
func (path *pathData) MoveTo(x, y float64) {
path.elements = append(path.elements, pathElement{funcName: "moveTo", args: []any{x, y}})
}
func (path *pathData) LineTo(x, y float64) {
path.elements = append(path.elements, pathElement{funcName: "lineTo", args: []any{x, y}})
}
func (path *pathData) ArcTo(x0, y0, x1, y1, radius float64) {
if radius > 0 {
path.elements = append(path.elements, pathElement{funcName: "arcTo", args: []any{x0, y0, x1, y1, radius}})
}
}
func (path *pathData) Arc(x, y, radius, startAngle, endAngle float64, clockwise bool) {
if radius > 0 {
if !clockwise {
path.elements = append(path.elements, pathElement{funcName: "arc", args: []any{x, y, radius, startAngle, endAngle, true}})
} else {
path.elements = append(path.elements, pathElement{funcName: "arc", args: []any{x, y, radius, startAngle, endAngle}})
}
}
}
func (path *pathData) BezierCurveTo(cp0x, cp0y, cp1x, cp1y, x, y float64) {
path.elements = append(path.elements, pathElement{funcName: "bezierCurveTo", args: []any{cp0x, cp0y, cp1x, cp1y, x, y}})
}
func (path *pathData) QuadraticCurveTo(cpx, cpy, x, y float64) {
path.elements = append(path.elements, pathElement{funcName: "quadraticCurveTo", args: []any{cpx, cpy, x, y}})
}
func (path *pathData) Ellipse(x, y, radiusX, radiusY, rotation, startAngle, endAngle float64, clockwise bool) {
if radiusX > 0 && radiusY > 0 {
if !clockwise {
path.elements = append(path.elements, pathElement{funcName: "ellipse", args: []any{x, y, radiusX, radiusY, rotation, startAngle, endAngle, true}})
} else {
path.elements = append(path.elements, pathElement{funcName: "ellipse", args: []any{x, y, radiusX, radiusY, rotation, startAngle, endAngle}})
}
}
}
func (path *pathData) Close() {
path.elements = append(path.elements, pathElement{funcName: "close", args: []any{}})
}
func (path *pathData) create(session Session) {
for _, element := range path.elements {
session.callCanvasFunc(element.funcName, element.args...)
}
}