有没有办法防止矩形pyqtgraph ROI不左右移动

Question

我有一段代码片段，它来自我正在使用pyqtgraph ROI编写的代码的一部分。我还设置了ROI不能在所有方面交叉的边界。当我移动任何一个垂直刻度手柄时，如果点击ROI内部，它就会给ROI一个左右移动的机会。有办法防止这种情况发生吗？我只想让它上下移动。这有点像根据当前X开始位置和X停止位置在ROI的原始边界内设置另一个边界。

我尝试使用信号修改ROI类中的self.maxBound变量，但它变得很乱，ROI一直忽略右边界。

任何帮助都会得到的大力支持

from PyQt5.QtWidgets import (
QApplication,
QMainWindow,
QGridLayout,
QWidget)
import pyqtgraph as pg
import sys
import numpy as np
from PyQt5.QtCore import QRectF, QRect

class TestROI(QMainWindow):
imageWidth = 1000
imageHardLimitTop = 1048
imageHardLimitBottom = 2047
shallowestPixel = 1400
deepestPixel = 1699
ROITopBottomMargin = 20
shaderDarkness = 185
shaderColor = (0, 0, 50, shaderDarkness)
imageHardLimitDepth = imageHardLimitBottom - imageHardLimitTop + 1
def __init__(self):
super(TestROI, self).__init__()
self.mainWidget = QWidget()
self.imagePlotCanvas = pg.GraphicsLayoutWidget()
self.graphGridLayout = QGridLayout(self.mainWidget)
self.graphGridLayout.addWidget(self.imagePlotCanvas)
self.setCentralWidget(self.mainWidget)
self.showMaximized()
# Place for 2D images:
self.plotArea = self.imagePlotCanvas.addPlot()
self.plotArea.setRange(
QRect(0, self.imageHardLimitTop, self.imageWidth, self.imageHardLimitDepth))
self.plotArea.setLimits(xMin=-1000, xMax=2000)
self.plotArea.setAspectLocked(True)
self.plotArea.invertY(b=True)
self.plotArea.showGrid(x=True, y=True, alpha=1.0)
self.plotArea.showButtons()
self.twoDImageROI = pg.ROI(pos=[0, self.shallowestPixel],
size=[
self.imageWidth, self.deepestPixel - self.shallowestPixel + 1],
removable=False,
maxBounds=QRectF(-1, self.imageHardLimitTop-1,
self.imageWidth + 2, self.imageHardLimitDepth+1),
scaleSnap=False, translateSnap=False)
self.twoDImageROI.setZValue(20)

self.shadedTopRegion = pg.LinearRegionItem(
[self.imageHardLimitTop, self.shallowestPixel], orientation=pg.LinearRegionItem.Horizontal, movable=False)
self.shadedTopRegion.setBrush(color=self.shaderColor)
self.shadedTopRegion.setZValue(10)
self.plotArea.addItem(self.shadedTopRegion)
self.shadedBottomRegion = pg.LinearRegionItem(
[self.deepestPixel + 1, self.imageHardLimitBottom+1], orientation=pg.LinearRegionItem.Horizontal, movable=False)
self.shadedBottomRegion.setBrush(color=self.shaderColor)
self.shadedBottomRegion.setZValue(10)
self.plotArea.addItem(self.shadedBottomRegion)
# self.twoDImageROI.setAcceptedMouseButtons(Qt.LeftButton)
self.twoDImageROI.sigRegionChanged.connect(self.imageROIChanged)
# Shaded Region on the left and right to cover up the above two vertical lines when out of image bound.
self.shadedLeftRegion = pg.LinearRegionItem(
[-1000, 0], orientation=pg.LinearRegionItem.Vertical, movable=False)
self.shadedLeftRegion.setBrush(color=(0, 0, 0))
self.shadedLeftRegion.setZValue(20)
self.plotArea.addItem(self.shadedLeftRegion)
self.shadedRightRegion = pg.LinearRegionItem(
[1000, 2000], orientation=pg.LinearRegionItem.Vertical, movable=False)
self.shadedRightRegion.setBrush(color=(0, 0, 0))
self.shadedRightRegion.setZValue(20)
self.plotArea.addItem(self.shadedRightRegion)
self.twoDImageROI.addScaleHandle([0.5, 0.0], [0.5, 1.0], index=0)
self.twoDImageROI.addScaleHandle([0.5, 1.0], [0.5, 0.0], index=1)
self.twoDImageROI.addScaleHandle([1.0, 0.5], [0.5, 0.5])
self.twoDImageROI.addScaleHandle([0.0, 0.5], [0.5, 0.5])
self.twoDOCMImage = pg.ImageItem(border='c')
self.twoDOCMImage.setParentItem(self.plotArea)
self.plotArea.addItem(self.twoDOCMImage)
self.plotArea.addItem(self.twoDImageROI)
zeroImage = np.zeros(self.imageWidth * self.imageHardLimitDepth)
.reshape((self.imageWidth, self.imageHardLimitDepth))
self.twoDOCMImage.setImage(zeroImage)
startingRect = QRect(0, self.imageHardLimitTop,
self.imageWidth, self.imageHardLimitDepth)
self.twoDOCMImage.setRect(startingRect)
def imageROIChanged(self):
x, top = self.twoDImageROI.pos()
top = int(round(top, 0))
w, h = self.twoDImageROI.size()
h = int(round(h, 0))
bot = top + h - 1
self.shallowestPixel = top
self.deepestPixel = bot
self.updateLinearRegion()
def updateLinearRegion(self):
x, top = self.twoDImageROI.pos()
top = int(round(top, 0))
w, h = self.twoDImageROI.size()
h = int(round(h, 0))
bot = top + h - 1
self.shadedTopRegion.setRegion([self.imageHardLimitTop, top])
self.shadedBottomRegion.setRegion([bot, self.imageHardLimitBottom+1])

if __name__ == '__main__':
app = QApplication(sys.argv)
main_window = TestROI()
main_window.show()
sys.exit(app.exec_())

Answer 1

我相信你所说的问题是在上下移动ROI时，从左到右的1px摆动。这种效果是由于将真实ROI位置转换为绘图X、Y值。总是会有四舍五入，因此ROI总是会左右摆动一点。

为了防止这种情况，您可以手动设置ROI的恒定x位置。为此，您必须覆盖ROI类的setPos。

以下是ROI类的示例，您可以使用：

class ConstantXROI(ROI):
constant_x = 0
def setPos(self, pos, y=None, update=True, finish=True):
pos.setX(self.constant_x)
super().setPos(pos, y=y, update=update, finish=finish)

然后在您的代码中，只需使用：

self.twoDImageROI = ConstantXROI(...)