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"""Simple example items.
These items are used in various tests.
"""
from math import pi
from gaphas.connector import Handle
from gaphas.item import NW, Element, Matrices
class Box(Element):
"""A Box has 4 handles (for a start):
NW +---+ NE SW +---+ SE
"""
def __init__(self, connections, width=10, height=10):
super().__init__(connections, width, height)
def draw(self, context):
c = context.cairo
nw = self._handles[NW].pos
c.rectangle(nw.x, nw.y, self.width, self.height)
if context.hovered:
c.set_source_rgba(0.8, 0.8, 1, 0.8)
else:
c.set_source_rgba(1, 1, 1, 0.8)
c.fill_preserve()
c.set_source_rgb(0, 0, 0.8)
c.stroke()
class Text(Matrices):
"""Simple item showing some text on the canvas."""
def __init__(self, text=None, plain=False, multiline=False, align_x=1, align_y=-1):
super().__init__()
self.text = "Hello" if text is None else text
self.plain = plain
self.multiline = multiline
self.align_x = align_x
self.align_y = align_y
def handles(self):
return []
def ports(self):
return []
def point(self, x, y):
return 0
def draw(self, context):
cr = context.cairo
if self.multiline:
text_multiline(cr, 0, 0, self.text)
elif self.plain:
cr.show_text(self.text)
else:
text_align(cr, 0, 0, self.text, self.align_x, self.align_y)
class Circle(Matrices):
def __init__(self):
super().__init__()
self._handles = [Handle(), Handle()]
h1, h2 = self._handles
h1.movable = False
@property
def radius(self):
h1, h2 = self._handles
p1, p2 = h1.pos, h2.pos
return ((p2.x - p1.x) ** 2 + (p2.y - p1.y) ** 2) ** 0.5
@radius.setter
def radius(self, r):
h1, h2 = self._handles
h2.pos.x = r
h2.pos.y = r
def handles(self):
return self._handles
def ports(self):
return []
def point(self, x, y):
h1, _ = self._handles
p1 = h1.pos
dist = ((x - p1.x) ** 2 + (y - p1.y) ** 2) ** 0.5
return dist - self.radius
def draw(self, context):
cr = context.cairo
path_ellipse(cr, 0, 0, 2 * self.radius, 2 * self.radius)
cr.stroke()
def text_align(cr, x, y, text, align_x=0, align_y=0, padding_x=0, padding_y=0):
"""Draw text relative to (x, y).
x, y - coordinates
text - text to print (utf8)
align_x - -1 (top), 0 (middle), 1 (bottom)
align_y - -1 (left), 0 (center), 1 (right)
padding_x - padding (extra offset), always > 0
padding_y - padding (extra offset), always > 0
"""
if not text:
return
x_bear, y_bear, w, h, _x_adv, _y_adv = cr.text_extents(text)
if align_x == 0:
x = 0.5 - (w / 2 + x_bear) + x
elif align_x < 0:
x = -(w + x_bear) + x - padding_x
else:
x = x + padding_x
if align_y == 0:
y = 0.5 - (h / 2 + y_bear) + y
elif align_y < 0:
y = -(h + y_bear) + y - padding_y
else:
y = -y_bear + y + padding_y
cr.move_to(x, y)
cr.show_text(text)
def text_multiline(cr, x, y, text):
"""Draw a string of text with embedded newlines.
cr - cairo context
x - leftmost x
y - topmost y
text - text to draw
"""
if not text:
return
for line in text.split("\n"):
_x_bear, _y_bear, _w, h, _x_adv, _y_adv = cr.text_extents(text)
y += h
cr.move_to(x, y)
cr.show_text(line)
def path_ellipse(cr, x, y, width, height, angle=0):
"""Draw an ellipse.
x - center x
y - center y
width - width of ellipse (in x direction when angle=0)
height - height of ellipse (in y direction when angle=0)
angle - angle in radians to rotate, clockwise
"""
cr.save()
cr.translate(x, y)
cr.rotate(angle)
cr.scale(width / 2.0, height / 2.0)
cr.move_to(1.0, 0.0)
cr.arc(0.0, 0.0, 1.0, 0.0, 2.0 * pi)
cr.restore()
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