I am currently having issues understanding the behavior of QGraphicsAnchorLayout within a QGraphicsScene. I create 4 boxes and anchor the corners of each, but no anchors appear to be applied properly, or at least the way I believed they would be.
The yellow box should be on the top left of the QGraphicsScene at all times, even when the GraphicsView is expanded. The blue box is anchored to appear adjacent to the yellow box on the right, with its top the coinciding with the top of the QGraphicsScene/viewport.
The top left corner of the green box is anchored to the bottom right of the blue box and likewise for the red box to the green box. But this is what I am getting:
I expect the yellow box to be at the top of the graphics scene/viewport at all times. And I would like for it always to remain visible even when scrolled right, but I believe that probably would be a separate issue. However, when I expand the window vertically, all the boxes are centered, including the yellow box which I expected to remain at top.
The blue, green and red boxes seem to bear no resemblance to the anchors I applied.
Following is the code I used to generate this. How do these anchors work and what can I do to correct this?
import numpy as np
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import Qt
from debug_utils import *
from PyQt5.QtWidgets import QGraphicsAnchorLayout, QGraphicsWidget, QGraphicsLayoutItem
def qp(p):
return "({}, {})".format(p.x(), p.y())
class box(QtWidgets.QGraphicsWidget):
pressed = QtCore.pyqtSignal()
def __init__(self, rect, color, parent=None):
super(box, self).__init__(parent)
self.raw_rect = rect
self.rect = QtCore.QRectF(rect[0], rect[1], rect[2], rect[3])
self.color = color
def boundingRect(self):
pen_adj = 0
return self.rect.normalized().adjusted(-pen_adj, -pen_adj, pen_adj, pen_adj)
def paint(self, painter, option, widget):
r = self.boundingRect()
brush = QtGui.QBrush()
brush.setColor(QtGui.QColor(self.color))
brush.setStyle(Qt.SolidPattern)
#rect = QtCore.QRect(0, 0, painter.device().width(), painter.device().height())
painter.fillRect(self.boundingRect(), brush)
painter.setRenderHint(QtGui.QPainter.Antialiasing)
painter.setPen(Qt.darkGray)
painter.drawRect(self.boundingRect())
#painter.drawRect(0, 0, max_time*char_spacing, self.bar_height)
def mousePressEvent(self, ev):
self.pressed.emit()
self.update()
def mouseReleaseEvent(self, ev):
self.update()
class GraphicsView(QtWidgets.QGraphicsView):
def __init__(self, parent=None):
super(GraphicsView, self).__init__(parent)
scene = QtWidgets.QGraphicsScene(self)
self.setScene(scene)
self.numbers = []
self.setMouseTracking(True)
l = QGraphicsAnchorLayout()
l.setSpacing(0)
w = QGraphicsWidget()
#painter = QtGui.QPainter(self)
w.setPos(0, 0)
w.setLayout(l)
scene.addItem(w)
self.main_widget = w
self.main_layout = l
self.makeBoxs()
def makeBoxs(self):
rect = [0, 0, 600, 250]
blue_box = box(rect, QtGui.QColor(0, 0, 255, 128))
green_box = box(rect, QtGui.QColor(0, 255, 0, 128))
red_box = box([0, 0, 200, 50], QtGui.QColor(255, 0, 0, 128))
yellow_box_left = box([0, 0, 75, 600], QtGui.QColor(255, 255, 0, 128))
#self.scene().setSceneRect(blue_box.rect)
#self.scene().setSceneRect(bar_green.rect)
# Adding anchors adds the item to the layout which is part of the scene
self.main_layout.addCornerAnchors(yellow_box_left, Qt.TopLeftCorner, self.main_layout, Qt.TopLeftCorner)
self.main_layout.addCornerAnchors(blue_box, Qt.TopLeftCorner, yellow_box_left, Qt.TopRightCorner)
self.main_layout.addCornerAnchors(green_box, Qt.TopLeftCorner, blue_box, Qt.BottomRightCorner)
self.main_layout.addCornerAnchors(red_box, Qt.TopLeftCorner, green_box, Qt.BottomRightCorner)
#self.main_layout.addAnchor(bar_green, Qt.AnchorTop, blue_box, Qt.AnchorBottom)
#self.main_layout.addAnchor(bar_green, Qt.AnchorLeft, blue_box, Qt.AnchorRight)
def printStatus(self, pos):
msg = "Viewport Position: " + str(qp(pos))
v = self.mapToScene(pos)
v = QtCore.QPoint(v.x(), v.y())
msg = msg + ", Mapped to Scene: " + str(qp(v))
v = self.mapToScene(self.viewport().rect()).boundingRect()
msg = msg + ", viewport Mapped to Scene: " + str(qp(v))
v2 = self.mapToScene(QtCore.QPoint(0, 0))
msg = msg + ", (0, 0) to scene: " + qp(v2)
self.parent().statusBar().showMessage(msg)
def mouseMoveEvent(self, event):
pos = event.pos()
self.printStatus(pos)
super(GraphicsView, self).mouseMoveEvent(event)
def resizeEvent(self, event):
self.printStatus(QtGui.QCursor().pos())
h = self.mapToScene(self.viewport().rect()).boundingRect().height()
r = self.sceneRect()
r.setHeight(h)
height = self.viewport().height()
for item in self.items():
item_height = item.boundingRect().height()
super(GraphicsView, self).resizeEvent(event)
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super(MainWindow, self).__init__(parent)
gv = GraphicsView()
self.setCentralWidget(gv)
self.setGeometry(475, 250, 600, 480)
scene = self.scene = gv.scene()
sb = self.statusBar()
def main():
import sys
app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()
EDIT: Adding expected output Based on how the anchors are defined, I expect the output to look something like the following. Since I can't yet actually create what I need, I have created this in PowerPoint. But, of course, in addition to getting this to work, I'm hoping to understand how to use anchors in a more general sense as well.
EDIT 2: Thank you again for updating. It's not quite what I was expecting, and there is a strange artifact when I scroll. Just to clarify,
- I expect the yellow widget to be visible at all times, top left of viewport with the highest z-order. I think you provided that.
- All the other widgets should scroll, maintaining their relative anchors. I removed the blue box's anchor to the yellow box, but then all boxes align left.
- In your current implementation, the non-yellow boxes do not scroll, but when I resize or move the scroll bar right and back left I see this artifact:
