Testing QWebEngineView rendering

webengineview_pixel_color.py

try:
    from PySide2.QtWebEngineWidgets import QWebEngineView
    from PySide2.QtCore import QObject, Signal, Slot, QTimer, QEventLoop, QPoint
    from PySide2.QtWidgets import QLabel, QWidget
    from PySide2.QtGui import QImage, QRegion
except ModuleNotFoundError:
    from PySide6.QtWebEngineWidgets import QWebEngineView
    from PySide6.QtCore import QObject, Signal, Slot, QTimer, QEventLoop, QPoint
    from PySide6.QtWidgets import QLabel, QWidget
    from PySide6.QtGui import QImage, QPainter, QRegion, QPixmap
import sys

class WebEngineViewTester(QObject):
    sample_webview_color_finished = Signal()
    
    def __init__(self, parent=None):
        super().__init__(parent)
        self.TEST_COLOR = "#FF00FF" # %237f7f7f
        self._webview = QWebEngineView()
        self._sample_webview_color_result = None
        self.event_loop = QEventLoop()

    def _load_webview(self):
        self._webview.load("data:text/html,<style>body{background-color:" + self.TEST_COLOR.replace(r"#", "%23") + ";}</style>")

    @Slot()
    def _sample_webview_color(self):
        screen = self._webview.screen()
        win_id = self._webview.window().windowHandle().winId()
        webview_pixmap = screen.grabWindow(win_id)
        pixel_color = webview_pixmap.toImage().pixelColor(webview_pixmap.width()/2,webview_pixmap.height()/2).name()
        if pixel_color == self.TEST_COLOR:
            print("QWebEngineView rendered properly.")
        self._webview.close()
        self._sample_webview_color_result = pixel_color
        self.sample_webview_color_finished.emit()
        
    def test_basic_render(self):
        self._load_webview()
        self._webview.setGeometry(0, 0, 100, 100)
        self._webview.show()
        self.sample_webview_color_finished.connect(self.event_loop.quit)
        QTimer.singleShot(500, self._sample_webview_color)
        self.event_loop.exec()
        if self._sample_webview_color_result is None:
            print("Error: WebEngineViewTester.test_basic_render didn't finish with result", file=sys.stderr)
        else:
            print(f"WebEngineViewTester.test_basic_render { 'PASSED' if self._sample_webview_color_result == self.TEST_COLOR else 'FAILED'}")


    def _sample_webview_color_two(self, ok):
        if ok:
            page = self._webview.page()
            size = page.contentsSize().toSize()
            w = size.width()
            h = size.height()
            image = QImage(w, h, QImage.Format_ARGB32)
            painter = QPainter(image)
            print(f"painter type: {type(painter)}")
            self._webview.render(painter, QPoint())
            painter.end()
            label = QLabel()
            label.setPixmap(QPixmap(image))
            label.show()
            pixel_color = image.pixelColor(w/2, h/2).name().upper()
        else:
            pixel_color = None
            
        if pixel_color and pixel_color == self.TEST_COLOR:
            print("QWebEngineView rendered properly.")
        else:
            print(f"QWebEngineView failed to render properly, expected {self.TEST_COLOR}, got {pixel_color}")
        self._sample_webview_color_result = pixel_color
        self.sample_webview_color_finished.emit()

    @Slot()
    def _save_loadFinished_result_start_timer(self, loadOk):
        # Still need a small delay after the load is finished before content shows on the view.
        QTimer.singleShot(500, lambda: self._sample_webview_color_two(loadOk))

    def test_basic_renderTwo(self):
        self._load_webview()
        self._webview.setGeometry(0, 0, 100, 100)
        self._webview.show()
        self._webview.loadFinished.connect(self._save_loadFinished_result_start_timer)
        self.sample_webview_color_finished.connect(self.event_loop.quit)
        QTimer.singleShot(5000, lambda: print("test_basic_renderTwo timed out.") or self.event_loop.quit() if self.event_loop.isRunning() else None)
        self.event_loop.exec()
        if self._sample_webview_color_result is None:
            print("Error: WebEngineViewTester.test_basic_render didn't finish with result", file=sys.stderr)
        else:
            print(f"WebEngineViewTester.test_basic_render { 'PASSED' if self._sample_webview_color_result == self.TEST_COLOR else 'FAILED'}")

tester = WebEngineViewTester()
tester.test_basic_renderTwo()