There are so many options provided by Python to develop GUI application and PyQt5 is one of them. PyQt5 is cross-platform GUI toolkit, a set of python bindings for Qt v5. One can develop an interactive desktop application with so much ease because of the tools and simplicity provided by this library.
In this tutorial we’ll take a look how to save canvas in pyqt5. We draw things on canvas using QPainter class.
QPainter : Qt’s painting system is able to render vector graphics, images, and outline font-based text with sub-pixel accuracy using anti-aliasing to improve rendering quality.
In this article, we create a canvas and will draw a line on it and see how to save that canvas as image file at desired location on the system. Below is the implementation.
Python3
# importing modulesfrom PyQt5.QtWidgets import *from PyQt5.QtGui import *from PyQt5.QtCore import * import sys# creating class for windowclass Window(QMainWindow): def __init__(self): super().__init__() title = "Paint and save Application" top = 400 left = 400 width = 800 height = 600 # setting title of window self.setWindowTitle(title) # setting geometry self.setGeometry(top, left, width, height) # creating canvas self.image = QImage(self.size(), QImage.Format_RGB32) # setting canvas color to white self.image.fill(Qt.white) # creating menu bar mainMenu = self.menuBar() # adding file menu in it fileMenu = mainMenu.addMenu("File") # creating save action saveAction = QAction("Save", self) # setting save action shortcut saveAction.setShortcut("Ctrl + S") # adding save action to filemenu fileMenu.addAction(saveAction) # setting triggered method saveAction.triggered.connect(self.save) # calling draw_something method self.draw_something() # paintEvent for creating blank canvas def paintEvent(self, event): canvasPainter = QPainter(self) canvasPainter.drawImage(self.rect(), self.image, self.image.rect()) # this method will draw a line def draw_something(self): painter = QPainter(self.image) painter.setPen(QPen(Qt.black, 5, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin)) # drawing a line painter.drawLine(100, 100, 300, 300) # updating it to canvas self.update() # save method def save(self): # selecting file path filePath, _ = QFileDialog.getSaveFileName(self, "Save Image", "", "PNG(*.png);;JPEG(*.jpg *.jpeg);;All Files(*.*) ") # if file path is blank return back if filePath == "": return # saving canvas at desired path self.image.save(filePath)# main methodif __name__ == "__main__": app = QApplication(sys.argv) window = Window() window.show() # looping for window sys.exit(app.exec()) |
Output :
After running the code window will appear with a canvas of white color on which line is drawn.
After clicking on the file menu save button will appear.
When save button is pressed it will ask for the location and name and image will get saved at desirable location.
This code will save the canvas in png format at the desired location.
