[英]PyQt5 triggering a paintEvent() with keyPressEvent()
我正在尝试学习PyQt矢量绘画。 目前,我一直在尝试将信息传递给paintEvent()方法,我猜应该调用其他方法:
我正在尝试将不同的数字绘制到基本块(此处为drawFundBlock()方法,该方法应绘制一些线)。 该代码试图检查是否按下了右箭头-> drawFundamental块,并且如果按下了数字(现在试图简单地绘制“ 5”),它将在该基本块的某个区域上绘制该数字。 但是我似乎无法使QPainter正常工作。 似乎现在两次调用paintEvent()覆盖方法(为什么?)。 有人建议使用update()方法,但我不知道如何仍然将任何参数传递给paintEvent(),后者应确定是绘制“ fundblock”还是“ number”。 现在,代码使用update()进行演示,但这只是移动了行-但已经添加的行应该保留!
有什么帮助吗?
# Test QPainter etc.
from PyQt5.QtWidgets import QWidget, QApplication
from PyQt5.QtGui import QPainter, QPen, QColor, QFont
from PyQt5.QtCore import Qt, QPoint, pyqtSignal, QRect
import sys
class Example(QWidget):
paintTrigger = pyqtSignal()
def __init__(self):
super().__init__()
self.initUI()
self.ydist = 15
self.eveType = "drawBlock"
self.currentRegion = QRect(50,50,50,80)
#self.paintTrigger[self.eveType].connect(lambda:self.paintEvent())
self.x0=5
self.x1=25
self.y0=5
self.y1=25
def initUI(self):
self.setGeometry(300,300,280,270)
self.setWindowTitle('Painter training')
self.show()
# How to pass info here, which type of drawing should be done (block or number)?
def paintEvent(self,event):
qp = QPainter(self)
qp.begin(self)
self.drawFundBlock(qp)
qp.end()
def drawFundBlock(self,qp):
pen = QPen(Qt.black, 2, Qt.SolidLine)
pen.setStyle(Qt.DashLine)
qp.setPen(pen)
for i in range(1,10):
#qp.drawLine(0,i*self.ydist,40,i*self.ydist)
qp.drawLine(self.x0,i*self.y0,self.x1,self.y0*i)
#notePoint=QPoint(200,200)
#qp.drawText(notePoint,"5")
def drawNumber(self,qp,notePoint):
pen = QPen(Qt.black,2,Qt.SolidLine)
#qp.setPen(QColor(200,200,200))
qp.setPen(pen)
qp.setFont(QFont('Arial', 10))
qp.drawText(notePoint,"5")
def nextRegion(self):
self.x0=self.x0+30
self.x1=self.x1+30
self.y0=self.y0+30
self.y1=self.y1+30
def keyPressEvent(self,event):
# Did the user press a button??
gey=event.key()
if gey == Qt.Key_M:
print("Key 'm' pressed!")
elif gey == Qt.Key_Right:
print("Right key pressed!, call drawFundBlock()")
#self.paintTrigger["drawBlock"].emit()
#self.paintEvent()
self.update()
self.nextRegion()
elif gey == Qt.Key_5:
print("#5 pressed, call drawNumber()")
#self.paintTrigger["drawNo"].emit()
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
QPaintEvent
不应直接调用,我们必须通过update()
,这将在必要时进行内部调用。
每次调用QPaintEvent
时, QPaintEvent
在此干净的空间中进行绘制,因此不会节省以前的图形的内存,一种简单的解决方案是首先绘制一个QPixmap
,它将存储您先前绘制的内容,然后使用那个QPixmap
。
另一件事是,以下2条指令是等效的:
1。
painter = QPainter(some_QPaintDevice)
2。
painter = QPainter()
painter.begin(some_QPaintDevice)
这两种方法都将对象传递到将要绘制对象的位置,在您的情况下,您将分配相同的小部件2倍。
为了方便绘图,我提出了方法drawBackground
,该方法需要用self.func
填充,第一个参数必须是函数的名称,第二个参数是具有字典的字典,除了QPainter
之外,还需要其他参数。
码
class Example(QWidget):
def __init__(self):
super().__init__()
self.mModified = True
self.initUI()
self.currentRegion = QRect(50, 50, 50, 80)
self.x0 = 5
self.x1 = 25
self.y0 = 5
self.y1 = 25
self.mPixmap = QPixmap()
self.func = (None, None)
def initUI(self):
self.setGeometry(300, 300, 280, 270)
self.setWindowTitle('Painter training')
self.show()
def paintEvent(self, event):
if self.mModified:
pixmap = QPixmap(self.size())
pixmap.fill(Qt.white)
painter = QPainter(pixmap)
painter.drawPixmap(0, 0, self.mPixmap)
self.drawBackground(painter)
self.mPixmap = pixmap
self.mModified = False
qp = QPainter(self)
qp.drawPixmap(0, 0, self.mPixmap)
def drawBackground(self, qp):
func, kwargs = self.func
if func is not None:
kwargs["qp"] = qp
func(**kwargs)
def drawFundBlock(self, qp):
pen = QPen(Qt.black, 2, Qt.SolidLine)
pen.setStyle(Qt.DashLine)
qp.setPen(pen)
for i in range(1, 10):
qp.drawLine(self.x0, i * self.y0, self.x1, self.y0 * i)
def drawNumber(self, qp, notePoint):
pen = QPen(Qt.black, 2, Qt.SolidLine)
qp.setPen(pen)
qp.setFont(QFont('Arial', 10))
qp.drawText(notePoint, "5")
def nextRegion(self):
self.x0 += 30
self.x1 += 30
self.y0 += 30
self.y1 += 30
def keyPressEvent(self, event):
gey = event.key()
self.func = (None, None)
if gey == Qt.Key_M:
print("Key 'm' pressed!")
elif gey == Qt.Key_Right:
print("Right key pressed!, call drawFundBlock()")
self.func = (self.drawFundBlock, {})
self.mModified = True
self.update()
self.nextRegion()
elif gey == Qt.Key_5:
print("#5 pressed, call drawNumber()")
self.func = (self.drawNumber, {"notePoint": QPoint(100, 100)})
self.mModified = True
self.update()
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