func Grid(canvas *pdf.Canvas, x, y, w, h, step float64) {
canvas.Push()
canvas.SetColor(0.75, 0.75, 0.75)
canvas.Translate(unit(x), unit(y))
rowCount := int(math.Floor(h / step))
for row := 0; row < rowCount; row++ {
bottom := float64(row) * step
top := bottom + step
start := 0.0
if row%2 == 0 {
start += step
}
for left := start; left < w; left += (2 * step) {
right := left + step
bottomLeft := point(left, bottom)
topRight := point(right, top)
path := new(pdf.Path)
path.Rectangle(pdf.Rectangle{bottomLeft, topRight})
canvas.Fill(path)
}
}
canvas.Pop()
}
func traceCurve(a, b, c, d pdf.Point, canvas *pdf.Canvas) {
path := new(pdf.Path)
path.Move(a)
path.Curve(b, c, d)
canvas.Stroke(path)
}
func EngraveStaff(origin pdf.Point, width, height, lineWidth pdf.Unit, canvas *pdf.Canvas) {
path := new(pdf.Path)
noteHeight := pdf.Unit(height / 4)
for i := 0; i < 5; i++ {
path.Move(origin)
path.Line(pdf.Point{origin.X + width, origin.Y})
origin.Y = origin.Y + noteHeight
}
canvas.Push()
canvas.SetLineWidth(lineWidth)
canvas.Stroke(path)
canvas.Pop()
}
func EngraveSurrogateNoteHead(origin pdf.Point, size pdf.Unit, canvas *pdf.Canvas) {
outline := new(pdf.Path)
topRight := pdf.Point{origin.X + size, origin.Y + size}
outline.Rectangle(pdf.Rectangle{origin, topRight})
mid := pdf.Point{origin.X + pdf.Unit(size/2), origin.Y + pdf.Unit(size/2)}
midPoints := new(pdf.Path)
midPoints.Move(pdf.Point{mid.X, origin.Y})
midPoints.Line(pdf.Point{mid.X, origin.Y + size})
midPoints.Move(pdf.Point{origin.X, mid.Y})
midPoints.Line(pdf.Point{origin.X + size, mid.Y})
canvas.Push()
canvas.SetColor(0.6, 0.6, 0.6)
canvas.Fill(outline)
canvas.SetLineWidth(pdf.Unit(0.1))
canvas.Stroke(midPoints)
canvas.Pop()
}
