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typesetting/pitfall/pdfkit/lib/path.coffee

327 lines
6.9 KiB
CoffeeScript

class SVGPath
@apply: (doc, path) ->
commands = parse path
apply commands, doc
parameters =
A: 7
a: 7
C: 6
c: 6
H: 1
h: 1
L: 2
l: 2
M: 2
m: 2
Q: 4
q: 4
S: 4
s: 4
T: 2
t: 2
V: 1
v: 1
Z: 0
z: 0
parse = (path) ->
ret = []
args = []
curArg = ""
foundDecimal = no
params = 0
for c in path
if parameters[c]?
params = parameters[c]
if cmd # save existing command
args[args.length] = +curArg if curArg.length > 0
ret[ret.length] = {cmd,args}
args = []
curArg = ""
foundDecimal = no
cmd = c
else if c in [" ", ","] or (c is "-" and curArg.length > 0 and curArg[curArg.length - 1] isnt 'e') or (c is "." and foundDecimal)
continue if curArg.length is 0
if args.length is params # handle reused commands
ret[ret.length] = {cmd,args}
args = [+curArg]
# handle assumed commands
cmd = "L" if cmd is "M"
cmd = "l" if cmd is "m"
else
args[args.length] = +curArg
foundDecimal = (c is ".")
# fix for negative numbers or repeated decimals with no delimeter between commands
curArg = if c in ['-', '.'] then c else ''
else
curArg += c
foundDecimal = true if c is '.'
# add the last command
if curArg.length > 0
if args.length is params # handle reused commands
ret[ret.length] = {cmd, args}
args = [+curArg]
# handle assumed commands
cmd = "L" if cmd is "M"
cmd = "l" if cmd is "m"
else
args[args.length] = +curArg
ret[ret.length] = {cmd,args}
return ret
cx = cy = px = py = sx = sy = 0
apply = (commands, doc) ->
# current point, control point, and subpath starting point
cx = cy = px = py = sx = sy = 0
# run the commands
for c, i in commands
runners[c.cmd]?(doc, c.args)
cx = cy = px = py = 0
runners =
M: (doc, a) ->
cx = a[0]
cy = a[1]
px = py = null
sx = cx
sy = cy
doc.moveTo cx, cy
m: (doc, a) ->
cx += a[0]
cy += a[1]
px = py = null
sx = cx
sy = cy
doc.moveTo cx, cy
C: (doc, a) ->
cx = a[4]
cy = a[5]
px = a[2]
py = a[3]
doc.bezierCurveTo a...
c: (doc, a) ->
doc.bezierCurveTo a[0] + cx, a[1] + cy, a[2] + cx, a[3] + cy, a[4] + cx, a[5] + cy
px = cx + a[2]
py = cy + a[3]
cx += a[4]
cy += a[5]
S: (doc, a) ->
if px is null
px = cx
py = cy
doc.bezierCurveTo cx-(px-cx), cy-(py-cy), a[0], a[1], a[2], a[3]
px = a[0]
py = a[1]
cx = a[2]
cy = a[3]
s: (doc, a) ->
if px is null
px = cx
py = cy
doc.bezierCurveTo cx-(px-cx), cy-(py-cy), cx + a[0], cy + a[1], cx + a[2], cy + a[3]
px = cx + a[0]
py = cy + a[1]
cx += a[2]
cy += a[3]
Q: (doc, a) ->
px = a[0]
py = a[1]
cx = a[2]
cy = a[3]
doc.quadraticCurveTo(a[0], a[1], cx, cy)
q: (doc, a) ->
doc.quadraticCurveTo(a[0] + cx, a[1] + cy, a[2] + cx, a[3] + cy)
px = cx + a[0]
py = cy + a[1]
cx += a[2]
cy += a[3]
T: (doc, a) ->
if px is null
px = cx
py = cy
else
px = cx-(px-cx)
py = cy-(py-cy)
doc.quadraticCurveTo(px, py, a[0], a[1])
px = cx-(px-cx)
py = cy-(py-cy)
cx = a[0]
cy = a[1]
t: (doc, a) ->
if px is null
px = cx
py = cy
else
px = cx-(px-cx)
py = cy-(py-cy)
doc.quadraticCurveTo(px, py, cx + a[0], cy + a[1])
cx += a[0]
cy += a[1]
A: (doc, a) ->
solveArc(doc, cx, cy, a)
cx = a[5]
cy = a[6]
a: (doc, a) ->
a[5] += cx
a[6] += cy
solveArc(doc, cx, cy, a)
cx = a[5]
cy = a[6]
L: (doc, a) ->
cx = a[0]
cy = a[1]
px = py = null
doc.lineTo(cx, cy)
l: (doc, a) ->
cx += a[0]
cy += a[1]
px = py = null
doc.lineTo(cx, cy)
H: (doc, a) ->
cx = a[0]
px = py = null
doc.lineTo(cx, cy)
h: (doc, a) ->
cx += a[0]
px = py = null
doc.lineTo(cx, cy)
V: (doc, a) ->
cy = a[0]
px = py = null
doc.lineTo(cx, cy)
v: (doc, a) ->
cy += a[0]
px = py = null
doc.lineTo(cx, cy)
Z: (doc) ->
doc.closePath()
cx = sx
cy = sy
z: (doc) ->
doc.closePath()
cx = sx
cy = sy
solveArc = (doc, x, y, coords) ->
[rx,ry,rot,large,sweep,ex,ey] = coords
segs = arcToSegments(ex, ey, rx, ry, large, sweep, rot, x, y)
for seg in segs
bez = segmentToBezier seg...
doc.bezierCurveTo bez...
# from Inkscape svgtopdf, thanks!
arcToSegments = (x, y, rx, ry, large, sweep, rotateX, ox, oy) ->
th = rotateX * (Math.PI/180)
sin_th = Math.sin(th)
cos_th = Math.cos(th)
rx = Math.abs(rx)
ry = Math.abs(ry)
px = cos_th * (ox - x) * 0.5 + sin_th * (oy - y) * 0.5
py = cos_th * (oy - y) * 0.5 - sin_th * (ox - x) * 0.5
pl = (px*px) / (rx*rx) + (py*py) / (ry*ry)
if pl > 1
pl = Math.sqrt(pl)
rx *= pl
ry *= pl
a00 = cos_th / rx
a01 = sin_th / rx
a10 = (-sin_th) / ry
a11 = (cos_th) / ry
x0 = a00 * ox + a01 * oy
y0 = a10 * ox + a11 * oy
x1 = a00 * x + a01 * y
y1 = a10 * x + a11 * y
d = (x1-x0) * (x1-x0) + (y1-y0) * (y1-y0)
sfactor_sq = 1 / d - 0.25
sfactor_sq = 0 if sfactor_sq < 0
sfactor = Math.sqrt(sfactor_sq)
sfactor = -sfactor if sweep is large
xc = 0.5 * (x0 + x1) - sfactor * (y1-y0)
yc = 0.5 * (y0 + y1) + sfactor * (x1-x0)
th0 = Math.atan2(y0-yc, x0-xc)
th1 = Math.atan2(y1-yc, x1-xc)
th_arc = th1-th0
if th_arc < 0 && sweep is 1
th_arc += 2*Math.PI
else if th_arc > 0 && sweep is 0
th_arc -= 2 * Math.PI
segments = Math.ceil(Math.abs(th_arc / (Math.PI * 0.5 + 0.001)))
result = []
for i in [0...segments]
th2 = th0 + i * th_arc / segments
th3 = th0 + (i+1) * th_arc / segments
result[i] = [xc, yc, th2, th3, rx, ry, sin_th, cos_th]
return result
segmentToBezier = (cx, cy, th0, th1, rx, ry, sin_th, cos_th) ->
a00 = cos_th * rx
a01 = -sin_th * ry
a10 = sin_th * rx
a11 = cos_th * ry
th_half = 0.5 * (th1 - th0)
t = (8 / 3) * Math.sin(th_half * 0.5) * Math.sin(th_half * 0.5) / Math.sin(th_half)
x1 = cx + Math.cos(th0) - t * Math.sin(th0)
y1 = cy + Math.sin(th0) + t * Math.cos(th0)
x3 = cx + Math.cos(th1)
y3 = cy + Math.sin(th1)
x2 = x3 + t * Math.sin(th1)
y2 = y3 - t * Math.cos(th1)
return [
a00 * x1 + a01 * y1, a10 * x1 + a11 * y1,
a00 * x2 + a01 * y2, a10 * x2 + a11 * y2,
a00 * x3 + a01 * y3, a10 * x3 + a11 * y3
]
module.exports = SVGPath