from math import hypot
from .. import functions as fn
from ..Qt import QtGui, QtWidgets
__all__ = ['ArrowItem']
[docs]
class ArrowItem(QtWidgets.QGraphicsPathItem):
"""
For displaying scale-invariant arrows.
For arrows pointing to a location on a curve, see CurveArrow
"""
[docs]
def __init__(self, parent=None, **opts):
"""
Arrows can be initialized with any keyword arguments accepted by
the setStyle() method.
"""
self.opts = {}
QtWidgets.QGraphicsPathItem.__init__(self, parent)
if 'size' in opts:
opts['headLen'] = opts['size']
if 'width' in opts:
opts['headWidth'] = opts['width']
pos = opts.pop('pos', (0, 0))
defaultOpts = {
'pxMode': True,
'angle': -150, ## If the angle is 0, the arrow points left
'headLen': 20,
'headWidth': None,
'tipAngle': 25,
'baseAngle': 0,
'tailLen': None,
'tailWidth': 3,
'pen': (200,200,200),
'brush': (50,50,200),
}
defaultOpts.update(opts)
self.setStyle(**defaultOpts)
# for backward compatibility
self.setPos(*pos)
[docs]
def setStyle(self, **opts):
"""
Changes the appearance of the arrow.
All arguments are optional:
====================== =================================================
**Keyword Arguments:**
angle Orientation of the arrow in degrees. Default is
0; arrow pointing to the left.
headLen Length of the arrow head, from tip to base.
default=20
headWidth Width of the arrow head at its base. If
headWidth is specified, it overrides tipAngle.
tipAngle Angle of the tip of the arrow in degrees. Smaller
values make a 'sharper' arrow. default=25
baseAngle Angle of the base of the arrow head. Default is
0, which means that the base of the arrow head
is perpendicular to the arrow tail.
tailLen Length of the arrow tail, measured from the base
of the arrow head to the end of the tail. If
this value is None, no tail will be drawn.
default=None
tailWidth Width of the tail. default=3
pen The pen used to draw the outline of the arrow.
brush The brush used to fill the arrow.
pxMode If True, then the arrow is drawn as a fixed size
regardless of the scale of its parents (including
the ViewBox zoom level).
====================== =================================================
"""
arrowOpts = ['headLen', 'tipAngle', 'baseAngle', 'tailLen', 'tailWidth', 'headWidth']
allowedOpts = ['angle', 'pen', 'brush', 'pxMode'] + arrowOpts
needUpdate = False
for k,v in opts.items():
if k not in allowedOpts:
raise KeyError('Invalid arrow style option "%s"' % k)
if self.opts.get(k) != v:
needUpdate = True
self.opts[k] = v
if not needUpdate:
return
opt = dict([(k,self.opts[k]) for k in arrowOpts if k in self.opts])
tr = QtGui.QTransform()
tr.rotate(self.opts['angle'])
self.path = tr.map(fn.makeArrowPath(**opt))
self.setPath(self.path)
self.setPen(fn.mkPen(self.opts['pen']))
self.setBrush(fn.mkBrush(self.opts['brush']))
if self.opts['pxMode']:
self.setFlags(self.flags() | self.GraphicsItemFlag.ItemIgnoresTransformations)
else:
self.setFlags(self.flags() & ~self.GraphicsItemFlag.ItemIgnoresTransformations)
def paint(self, p, *args):
p.setRenderHint(QtGui.QPainter.RenderHint.Antialiasing)
super().paint(p, *args)
#p.setPen(fn.mkPen('r'))
#p.setBrush(fn.mkBrush(None))
#p.drawRect(self.boundingRect())
def shape(self):
#if not self.opts['pxMode']:
#return QtWidgets.QGraphicsPathItem.shape(self)
return self.path
## dataBounds and pixelPadding methods are provided to ensure ViewBox can
## properly auto-range
def dataBounds(self, ax, frac, orthoRange=None):
pw = 0
pen = self.pen()
if not pen.isCosmetic():
pw = pen.width() * 0.7072
if self.opts['pxMode']:
return [0,0]
else:
br = self.boundingRect()
if ax == 0:
return [br.left()-pw, br.right()+pw]
else:
return [br.top()-pw, br.bottom()+pw]
def pixelPadding(self):
pad = 0
if self.opts['pxMode']:
br = self.boundingRect()
pad += hypot(br.width(), br.height())
pen = self.pen()
if pen.isCosmetic():
pad += max(1, pen.width()) * 0.7072
return pad
