qpainter

问题 I am trying to learn PyQt vector painting. Currently I am stuck in trying to pass information to paintEvent() method which I guess, should call other methods: I am trying to paint different numbers to a fundamental block (here drawFundBlock() method, which should draw some lines). The code is trying to check if right arrow is pressed-> drawFundamental block and if number is pressed (now trying to simply draw "5"), it will draw that number on a certain area on that fundamental block. But I can

问题 I have created a widget using Qt Creator such a way that it has two sub windows inside a main window and some push buttons to load, save images, set pen width and color to paint on the window. But when i start to paint it gives me error saying QWidget::paintEngine: Should no longer be called QPainter::begin: Paint device returned engine == 0, type: 1 QPainter::setPen: Painter not active QPainter::drawPoints: Painter not active Does anyone know what mistake i am doing, i checked threads

问题 I have created a widget using Qt Creator such a way that it has two sub windows inside a main window and some push buttons to load, save images, set pen width and color to paint on the window. But when i start to paint it gives me error saying QWidget::paintEngine: Should no longer be called QPainter::begin: Paint device returned engine == 0, type: 1 QPainter::setPen: Painter not active QPainter::drawPoints: Painter not active Does anyone know what mistake i am doing, i checked threads

问题 This question already has answers here : paintEvent in QTableView derived class: Paint device returned engine == 0, type: 1 (1 answer) Warning QPainter inside paintEvent [duplicate] (1 answer) Closed 2 years ago . I have a class, MyTree , which derived from QTreeWidget and void MyTree::paintEvent(QPaintEvent *event) { QPainter painter(this); } causes to raise the following issue, QWidget::paintEngine: Should no longer be called QPainter::begin: Paint device returned engine == 0, type: 1 Could

问题 I am trying to draw a simple two dimensional figure in a QWidget window. There is a paintEvent defined and a painter object of the QPainter class is also defined. My drawing contains elements which I need to draw more than once at various locations, such as lines, text etc. For this purpose, I am using functions to draw these lines with varying positions. Similarly for text. In order to make the program shorter, also modular. The paintEvent function is calling functions which are used to

问题 Am trying to follow the documentation for printing a QWidet and am getting an error. When I run the following code I get QPaintDevice: Cannot destroy paint device that is being painted . import sys from PyQt4 import QtGui, QtCore class SampleApp(QtGui.QDialog): def __init__(self): super().__init__() layout = QtGui.QVBoxLayout() self.setLayout(layout) text_editor = QtGui.QTextEdit() layout.addWidget(text_editor) button = QtGui.QPushButton("Print") layout.addWidget(button) button.clicked

问题 I am able to read ECG signals and plot the wave using QPainter. But the resulting wave is formed by removing the first coordinate and appending the new coordinates as the last point. So this gives a scrolling effect to the wave. I wanted to know if there was any way to paint the wave like how a patient monitoring system does (a black bar running the length of the wave and updating the wave like this). Code examples or snippets will be very helpful.Thanks. 回答1: Here is a quick example in a few

问题 I use QPainter::setRenderHint(QPainter::Antialiasing, true) to tell Qt that I want it to antialias any drawing I do (in this case, text drawn with drawText() ). This works fine and the text looks good, until I want to rotate the pixmap I'm drawing to e.g. Painter.translate(0, height()); Painter.rotate(-90); (to rotate the QPainter 90 degrees counterclockwise and bring it back into view) The call to rotate() seems to disable antialiasing for any text drawn - the text is drawn at the correct

问题 I have a list of points. For example, points = [[160, 75], [115, 567]] . How to draw a line in PyQt4, so it would be something like this: Thanks in advance. EDIT: For the record, I'm trying to implement Bezier Curves, so it looked like this: Here is the code I have at the moment: from PyQt4.QtGui import QWidget, QPolygonF, QPainter, QPen, QBrush, QColor, \ QApplication, QIcon, QVBoxLayout, QSlider, QHBoxLayout, QPushButton, QLCDNumber from PyQt4.QtCore import QObject, SIGNAL, SLOT, QPointF,

问题 I want to draw a rectangle with rounded corners (border radius same for all 4 corners) with a specific color filling the entire rectangle, and a separate border color (say border is 1 px wide). From my observation, Qt provides three methods - fillRect and drawRect and drawRoundedRect . I have tried them, they don't work like I want to. There is no method like fillRoundedRect . Which means that I can draw a rounded rectangle but it won't be filled with the color I want. How do I do it? And