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Change mouse event behaviour for point outside canvas

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This commit is contained in:
Adwait Bhope 2020-05-05 22:44:50 +05:30 committed by darrenl
parent 5816f71157
commit 9bebf84986
1 changed files with 10 additions and 29 deletions
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39
libs/canvas.py
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@ -124,8 +124,12 @@ class Canvas(QWidget):
color = self.drawingLineColor
if self.outOfPixmap(pos):
# Don't allow the user to draw outside the pixmap.
# Project the point to the pixmap's edges.
pos = self.intersectionPoint(self.current[-1], pos)
# Clip the coordinates to 0 or max,
# if they are outside the range [0, max]
size = self.pixmap.size()
clipped_x = min(max(0, pos.x()), size.width())
clipped_y = min(max(0, pos.y()), size.height())
pos = QPointF(clipped_x, clipped_y)
elif len(self.current) > 1 and self.closeEnough(pos, self.current[0]):
# Attract line to starting point and colorise to alert the
# user:
@ -350,7 +354,10 @@ class Canvas(QWidget):
index, shape = self.hVertex, self.hShape
point = shape[index]
if self.outOfPixmap(pos):
pos = self.intersectionPoint(point, pos)
size = self.pixmap.size()
clipped_x = min(max(0, pos.x()), size.width())
clipped_y = min(max(0, pos.y()), size.height())
pos = QPointF(clipped_x, clipped_y)
if self.drawSquare:
opposite_point_index = (index + 2) % 4
@ -528,32 +535,6 @@ class Canvas(QWidget):
# print "d %.2f, m %d, %.2f" % (d, m, d - m)
return distance(p1 - p2) < self.epsilon
def intersectionPoint(self, p1, p2):
# Cycle through each image edge in clockwise fashion,
# and find the one intersecting the current line segment.
# http://paulbourke.net/geometry/lineline2d/
size = self.pixmap.size()
points = [(0, 0),
(size.width(), 0),
(size.width(), size.height()),
(0, size.height())]
x1, y1 = p1.x(), p1.y()
x2, y2 = p2.x(), p2.y()
d, i, (x, y) = min(self.intersectingEdges((x1, y1), (x2, y2), points))
x3, y3 = points[i]
x4, y4 = points[(i + 1) % 4]
if (x, y) == (x1, y1):
# Handle cases where previous point is on one of the edges.
if x3 == x4:
return QPointF(x3, min(max(0, y2), max(y3, y4)))
else: # y3 == y4
return QPointF(min(max(0, x2), max(x3, x4)), y3)
# Ensure the labels are within the bounds of the image. If not, fix them.
x, y, _ = self.snapPointToCanvas(x, y)
return QPointF(x, y)
def intersectingEdges(self, x1y1, x2y2, points):
"""For each edge formed by `points', yield the intersection
with the line segment `(x1,y1) - (x2,y2)`, if it exists.