def point(path, t, segments=None):
"""Returns coordinates for point at t on the path.
Gets the length of the path, based on the length
of each curve and line in the path.
Determines in what segment t falls.
Gets the point on that segment.
When you supply the list of segment lengths yourself,
as returned from length(path, segmented=True),
point() works about thirty times faster in a for-loop,
since it doesn't need to recalculate the length
during each iteration. Note that this has been deprecated:
the BezierPath now caches the segment lengths the moment you use
them.
>>> path = BezierPath(None)
>>> point(path, 0.0)
Traceback (most recent call last):
...
NodeBoxError: The given path is empty
>>> path.moveto(0, 0)
>>> point(path, 0.0)
Traceback (most recent call last):
...
NodeBoxError: The given path is empty
>>> path.lineto(100, 0)
>>> point(path, 0.0)
PathElement(LINETO, ((0.0, 0.0),))
>>> point(path, 0.1)
PathElement(LINETO, ((10.0, 0.0),))
"""
if len(path) == 0:
raise NodeBoxError, "The given path is empty"
i, t, closeto = _locate(path, t, segments=segments)
x0, y0 = path[i].x, path[i].y
p1 = path[i + 1]
if p1.cmd == CLOSE:
x, y = linepoint(t, x0, y0, closeto.x, closeto.y)
return PathElement(LINETO, ((x, y), ))
elif p1.cmd == LINETO:
x1, y1 = p1.x, p1.y
x, y = linepoint(t, x0, y0, x1, y1)
return PathElement(LINETO, ((x, y), ))
elif p1.cmd == CURVETO:
x3, y3, x1, y1, x2, y2 = p1.x, p1.y, p1.ctrl1.x, p1.ctrl1.y, p1.ctrl2.x, p1.ctrl2.y
x, y, c1x, c1y, c2x, c2y = curvepoint(t, x0, y0, x1, y1, x2, y2, x3,
y3)
return PathElement(CURVETO, ((c1x, c1y), (c2x, c2y), (x, y)))
else:
raise NodeBoxError, "Unknown cmd for p1 %s" % p1
def draw_freehand(self):
""" Freehand sketching.
"""
if _ctx._ns["mousedown"]:
x, y = mouse()
if self.show_grid:
x, y = self.grid.snap(x, y)
if self.freehand_move == True:
cmd = MOVETO
self.freehand_move = False
else:
cmd = LINETO
# Add a new LINETO to the path,
# except when starting to draw,
# then a MOVETO is added to the path.
pt = PathElement()
if cmd != MOVETO:
pt.freehand = True # Used when mixed with curve drawing.
else:
pt.freehand = False
pt.cmd = cmd
pt.x = x
pt.y = y
pt.ctrl1 = Point(x,y)
pt.ctrl2 = Point(x,y)
self._points.append(pt)
# Draw the current location of the cursor.
r = 4
_ctx.nofill()
_ctx.stroke(self.handle_color)
_ctx.oval(pt.x-r, pt.y-r, r*2, r*2)
_ctx.fontsize(9)
_ctx.fill(self.handle_color)
_ctx.text(" ("+str(int(pt.x))+", "+str(int(pt.y))+")", pt.x+r, pt.y)
self._dirty = True
else:
# Export the updated drawing,
# remember to do a MOVETO on the next interaction.
self.freehand_move = True
if self._dirty:
self._points[-1].freehand = False
self.export_svg()
self._dirty = False
def draw_freehand(self):
""" Freehand sketching.
"""
if _ctx._ns["mousedown"]:
x, y = mouse()
if self.show_grid:
x, y = self.grid.snap(x, y)
if self.freehand_move == True:
cmd = MOVETO
self.freehand_move = False
else:
cmd = LINETO
# Add a new LINETO to the path,
# except when starting to draw,
# then a MOVETO is added to the path.
pt = PathElement()
if cmd != MOVETO:
pt.freehand = True # Used when mixed with curve drawing.
else:
pt.freehand = False
pt.cmd = cmd
pt.x = x
pt.y = y
pt.ctrl1 = Point(x,y)
pt.ctrl2 = Point(x,y)
self._points.append(pt)
# Draw the current location of the cursor.
r = 4
_ctx.nofill()
_ctx.stroke(self.handle_color)
_ctx.oval(pt.x-r, pt.y-r, r*2, r*2)
_ctx.fontsize(9)
_ctx.fill(self.handle_color)
_ctx.text(" ("+str(int(pt.x))+", "+str(int(pt.y))+")", pt.x+r, pt.y)
self._dirty = True
else:
# Export the updated drawing,
# remember to do a MOVETO on the next interaction.
self.freehand_move = True
if self._dirty:
self._points[-1].freehand = False
self.export_svg()
self._dirty = False
def update(self):
""" Update runs each frame to check for mouse interaction.
Alters the path by allowing the user to add new points,
drag point handles and move their location.
Updates are automatically stored as SVG
in the given filename.
"""
x, y = mouse()
if self.show_grid:
x, y = self.grid.snap(x, y)
if _ctx._ns["mousedown"] \
and not self.freehand:
self._dirty = True
# Handle buttons first.
# When pressing down on a button, all other action halts.
# Buttons appear near a point being edited.
# Once clicked, actions are resolved.
if self.edit != None \
and not self.drag_point \
and not self.drag_handle1 \
and not self.drag_handle2:
pt = self._points[self.edit]
dx = pt.x+self.btn_x
dy = pt.y+self.btn_y
# The delete button
if self.overlap(dx, dy, x, y, r=self.btn_r):
self.delete = self.edit
return
# The moveto button,
# active on the last point in the path.
dx += self.btn_r*2 + 2
if self.edit == len(self._points) -1 and \
self.overlap(dx, dy, x, y, r=self.btn_r):
self.moveto = self.edit
return
if self.insert:
self.inserting = True
return
# When not dragging a point or the handle of a point,
# i.e. the mousebutton was released and then pressed again,
# check to see if a point on the path is pressed.
# When this point is not the last new point,
# enter edit mode.
if not self.drag_point and \
not self.drag_handle1 and \
not self.drag_handle2:
self.editing = False
indices = range(len(self._points))
indices.reverse()
for i in indices:
pt = self._points[i]
if pt != self.new \
and self.overlap(x, y, pt.x, pt.y) \
and self.new == None:
# Don't select a point if in fact
# it is at the same location of the first handle
# of the point we are currently editing.
if self.edit == i+1 \
and self.overlap(self._points[i+1].ctrl1.x,
self._points[i+1].ctrl1.y, x, y):
continue
else:
self.edit = i
self.editing = True
break
# When the mouse button is down,
# edit mode continues as long as
# a point or handle is dragged.
# Else, stop editing and switch to add-mode
# (the user is clicking somewhere on the canvas).
if not self.editing:
if self.edit != None:
pt = self._points[self.edit]
if self.overlap(pt.ctrl1.x, pt.ctrl1.y, x, y) or \
self.overlap(pt.ctrl2.x, pt.ctrl2.y, x, y):
self.editing = True
else:
self.edit = None
# When not in edit mode, there are two options.
# Either no new point is defined and the user is
# clicking somewhere on the canvas (add a new point)
# or the user is dragging the handle of the new point.
# Adding a new point is a fluid click-to-locate and
# drag-to-curve action.
if self.edit == None:
if self.new == None:
# A special case is when the used clicked
# the moveto button on the last point in the path.
# This indicates a gap (i.e. MOVETO) in the path.
self.new = PathElement()
if self.moveto == True \
or len(self._points) == 0:
cmd = MOVETO
self.moveto = None
self.last_moveto = self.new
else:
cmd = CURVETO
self.new.cmd = cmd
self.new.x = x
self.new.y = y
self.new.ctrl1 = Point(x, y)
self.new.ctrl2 = Point(x, y)
self.new.freehand = False
# Don't forget to map the point's ctrl1 handle
# to the ctrl2 handle of the previous point.
# This makes for smooth, continuous paths.
if len(self._points) > 0:
prev = self._points[-1]
rx, ry = self.reflect(prev.x, prev.y, prev.ctrl2.x, prev.ctrl2.y)
self.new.ctrl1 = Point(rx, ry)
self._points.append(self.new)
else:
# Illustrator-like behavior:
# when the handle is dragged downwards,
# the path bulges upwards.
rx, ry = self.reflect(self.new.x, self.new.y, x, y)
self.new.ctrl2 = Point(rx, ry)
# Edit mode
elif self.new == None:
pt = self._points[self.edit]
# The user is pressing the mouse on a point,
# enter drag-point mode.
if self.overlap(pt.x, pt.y, x, y) \
and not self.drag_handle1 \
and not self.drag_handle2 \
and not self.new != None:
self.drag_point = True
self.drag_handle1 = False
self.drag_handle2 = False
# The user is pressing the mouse on a point's handle,
# enter drag-handle mode.
if self.overlap(pt.ctrl1.x, pt.ctrl1.y, x, y) \
and pt.cmd == CURVETO \
and not self.drag_point \
and not self.drag_handle2:
self.drag_point = False
self.drag_handle1 = True
self.drag_handle2 = False
if self.overlap(pt.ctrl2.x, pt.ctrl2.y, x, y) \
and pt.cmd == CURVETO \
and not self.drag_point \
and not self.drag_handle1:
self.drag_point = False
self.drag_handle1 = False
self.drag_handle2 = True
# In drag-point mode,
# the point is located at the mouse coordinates.
# The handles move relatively to the new location
# (e.g. they are retained, the path does not distort).
# Modify the ctrl1 handle of the next point as well.
if self.drag_point == True:
dx = x - pt.x
dy = y - pt.y
pt.x = x
pt.y = y
pt.ctrl2.x += dx
pt.ctrl2.y += dy
if self.edit < len(self._points)-1:
rx, ry = self.reflect(pt.x, pt.y, x, y)
next = self._points[self.edit+1]
next.ctrl1.x += dx
next.ctrl1.y += dy
# In drag-handle mode,
# set the path's handle to the mouse location.
# Rotate the handle of the next or previous point
# to keep paths smooth - unless the user is pressing "x".
if self.drag_handle1 == True:
pt.ctrl1 = Point(x, y)
if self.edit > 0 \
and self.last_key != "x":
prev = self._points[self.edit-1]
d = self.distance(prev.x, prev.y, prev.ctrl2.x, prev.ctrl2.y)
a = self.angle(prev.x, prev.y, pt.ctrl1.x, pt.ctrl1.y)
prev.ctrl2 = self.coordinates(prev.x, prev.y, d, a+180)
if self.drag_handle2 == True:
pt.ctrl2 = Point(x, y)
if self.edit < len(self._points)-1 \
and self.last_key != "x":
next = self._points[self.edit+1]
d = self.distance(pt.x, pt.y, next.ctrl1.x, next.ctrl1.y)
a = self.angle(pt.x, pt.y, pt.ctrl2.x, pt.ctrl2.y)
next.ctrl1 = self.coordinates(pt.x, pt.y, d, a+180)
elif not self.freehand:
# The mouse button is released
# so we are not dragging anything around.
self.new = None
self.drag_point = False
self.drag_handle1 = False
self.drag_handle2 = False
# The delete button for a point was clicked.
if self.delete != None and len(self._points) > 0:
i = self.delete
cmd = self._points[i].cmd
del self._points[i]
if 0 < i < len(self._points):
prev = self._points[i-1]
rx, ry = self.reflect(prev.x, prev.y, prev.ctrl2.x, prev.ctrl2.y)
self._points[i].ctrl1 = Point(rx, ry)
# Also delete all the freehand points
# prior to this point.
start_i = i
while i > 1:
i -= 1
pt = self._points[i]
if pt.freehand:
del self._points[i]
elif i < start_i-1 and pt.freehand == False:
if pt.cmd == MOVETO:
del self._points[i]
break
# When you delete a MOVETO point,
# the last moveto (the one where the dashed line points to)
# needs to be updated.
if len(self._points) > 0 \
and (cmd == MOVETO or i == 0):
self.last_moveto = self._points[0]
for pt in self._points:
if pt.cmd == MOVETO:
self.last_moveto = pt
self.delete = None
self.edit = None
# The moveto button for the last point
# in the path was clicked.
elif isinstance(self.moveto, int):
self.moveto = True
self.edit = None
# We are not editing a node and
# the mouse is hovering over the path outline stroke:
# it is possible to insert a point here.
elif self.edit == None \
and self.contains_point(x, y, d=2):
self.insert = True
else:
self.insert = False
# Commit insert of new point.
if self.inserting \
and self.contains_point(x, y, d=2):
self.insert_point(x, y)
self.insert = False
self.inserting = False
# No modifications are being made right now
# and the SVG file needs to be updated.
if self._dirty == True:
self.export_svg()
self._dirty = False
# Keyboard interaction.
if _ctx._ns["keydown"]:
self.last_key = _ctx._ns["key"]
self.last_keycode = _ctx._ns["keycode"]
if not _ctx._ns["keydown"] and self.last_key != None:
# If the TAB-key is pressed,
# switch the magnetic grid either on or off.
if self.last_keycode == KEY_TAB:
self.show_grid = not self.show_grid
# When "f" is pressed, switch freehand mode.
if self.last_key == "f":
self.edit = None
self.freehand = not self.freehand
if self.freehand:
self.msg = "freehand"
else:
self.msg = "curves"
# When ESC is pressed exit edit mode.
if self.last_keycode == KEY_ESC:
self.edit = None
# When BACKSPACE is pressed, delete current point.
if self.last_keycode == _ctx.KEY_BACKSPACE \
and self.edit != None:
self.delete = self.edit
self.last_key = None
self.last_code = None
# Using the keypad you can scroll the screen.
if _ctx._ns["keydown"]:
dx = 0
dy = 0
keycode = _ctx._ns["keycode"]
if keycode == _ctx.KEY_LEFT:
dx = -10
elif keycode == _ctx.KEY_RIGHT:
dx = 10
if keycode == _ctx.KEY_UP:
dy = -10
elif keycode == _ctx.KEY_DOWN:
dy = 10
if dx != 0 or dy != 0:
for pt in self._points:
pt.x += dx
pt.y += dy
pt.ctrl1.x += dx
pt.ctrl1.y += dy
pt.ctrl2.x += dx
pt.ctrl2.y += dy
def insert_point(self, x, y):
""" Inserts a point on the path at the mouse location.
We first need to check if the mouse location is on the path.
Inserting point is time intensive and experimental.
"""
try:
bezier = _ctx.ximport("bezier")
except:
from nodebox.graphics import bezier
# Do a number of checks distributed along the path.
# Keep the one closest to the actual mouse location.
# Ten checks works fast but leads to imprecision in sharp corners
# and curves closely located next to each other.
# I prefer the slower but more stable approach.
n = 100
closest = None
dx0 = float(INFINITY)
dy0 = float(INFINITY)
for i in range(n):
t = float(i)/n
pt = self.path.point(t)
dx = abs(pt.x-x)
dy = abs(pt.y-y)
if dx+dy <= dx0+dy0:
dx0 = dx
dy0 = dy
closest = t
# Next, scan the area around the approximation.
# If the closest point is located at 0.2 on the path,
# we need to scan between 0.1 and 0.3 for a better
# approximation. If 1.5 was the best guess, scan
# 1.40, 1.41 ... 1.59 and so on.
# Each decimal precision takes 20 iterations.
decimals = [3,4]
for d in decimals:
d = 1.0/pow(10,d)
for i in range(20):
t = closest-d + float(i)*d*0.1
if t < 0.0: t = 1.0+t
if t > 1.0: t = t-1.0
pt = self.path.point(t)
dx = abs(pt.x-x)
dy = abs(pt.y-y)
if dx <= dx0 and dy <= dy0:
dx0 = dx
dy0 = dy
closest_precise = t
closest = closest_precise
# Update the points list with the inserted point.
p = bezier.insert_point(self.path, closest_precise)
i, t, pt = bezier._locate(self.path, closest_precise)
i += 1
pt = PathElement()
pt.cmd = p[i].cmd
pt.x = p[i].x
pt.y = p[i].y
pt.ctrl1 = Point(p[i].ctrl1.x, p[i].ctrl1.y)
pt.ctrl2 = Point(p[i].ctrl2.x, p[i].ctrl2.y)
pt.freehand = False
self._points.insert(i, pt)
self._points[i-1].ctrl1 = Point(p[i-1].ctrl1.x, p[i-1].ctrl1.y)
self._points[i+1].ctrl1 = Point(p[i+1].ctrl1.x, p[i+1].ctrl1.y)
self._points[i+1].ctrl2 = Point(p[i+1].ctrl2.x, p[i+1].ctrl2.y)
def insert_point(self, x, y):
""" Inserts a point on the path at the mouse location.
We first need to check if the mouse location is on the path.
Inserting point is time intensive and experimental.
"""
try:
bezier = _ctx.ximport("bezier")
except:
from nodebox.graphics import bezier
# Do a number of checks distributed along the path.
# Keep the one closest to the actual mouse location.
# Ten checks works fast but leads to imprecision in sharp corners
# and curves closely located next to each other.
# I prefer the slower but more stable approach.
n = 100
closest = None
dx0 = float(INFINITY)
dy0 = float(INFINITY)
for i in range(n):
t = float(i) / n
pt = self.path.point(t)
dx = abs(pt.x - x)
dy = abs(pt.y - y)
if (dx + dy) <= (dx0 + dy0):
dx0 = dx
dy0 = dy
closest = t
# Next, scan the area around the approximation.
# If the closest point is located at 0.2 on the path,
# we need to scan between 0.1 and 0.3 for a better
# approximation. If 1.5 was the best guess, scan
# 1.40, 1.41 ... 1.59 and so on.
# Each decimal precision takes 20 iterations.
decimals = [3,4]
for d in decimals:
d = 1.0 / pow(10, d)
for i in range(20):
t = (closest - d) + (float(i) * d * 0.1)
if t < 0.0: t = 1.0+t
if t > 1.0: t = t-1.0
pt = self.path.point(t)
dx = abs(pt.x - x)
dy = abs(pt.y - y)
if dx <= dx0 and dy <= dy0:
dx0 = dx
dy0 = dy
closest_precise = t
closest = closest_precise
# Update the points list with the inserted point.
p = bezier.insert_point(self.path, closest_precise)
i, t, pt = bezier._locate(self.path, closest_precise)
i += 1
pt = PathElement()
pt.cmd = p[i].cmd
pt.x = p[i].x
pt.y = p[i].y
pt.ctrl1 = Point(p[i].ctrl1.x, p[i].ctrl1.y)
pt.ctrl2 = Point(p[i].ctrl2.x, p[i].ctrl2.y)
pt.freehand = False
self._points.insert(i, pt)
self._points[i-1].ctrl1 = Point(p[i-1].ctrl1.x, p[i-1].ctrl1.y)
self._points[i+1].ctrl1 = Point(p[i+1].ctrl1.x, p[i+1].ctrl1.y)
self._points[i+1].ctrl2 = Point(p[i+1].ctrl2.x, p[i+1].ctrl2.y)
