Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/matplotlib/backends/backend_qt5cairo.py

@@ -0,0 +1,46 @@
+import ctypes
+
+from .backend_cairo import cairo, FigureCanvasCairo, RendererCairo
+from .backend_qt5 import QtCore, QtGui, _BackendQT5, FigureCanvasQT
+from .qt_compat import QT_API, _setDevicePixelRatioF
+
+
+class FigureCanvasQTCairo(FigureCanvasQT, FigureCanvasCairo):
+    def __init__(self, figure):
+        super().__init__(figure=figure)
+        self._renderer = RendererCairo(self.figure.dpi)
+        self._renderer.set_width_height(-1, -1)  # Invalid values.
+
+    def draw(self):
+        if hasattr(self._renderer.gc, "ctx"):
+            self.figure.draw(self._renderer)
+        super().draw()
+
+    def paintEvent(self, event):
+        self._update_dpi()
+        dpi_ratio = self._dpi_ratio
+        width = int(dpi_ratio * self.width())
+        height = int(dpi_ratio * self.height())
+        if (width, height) != self._renderer.get_canvas_width_height():
+            surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
+            self._renderer.set_ctx_from_surface(surface)
+            self._renderer.set_width_height(width, height)
+            self.figure.draw(self._renderer)
+        buf = self._renderer.gc.ctx.get_target().get_data()
+        qimage = QtGui.QImage(buf, width, height,
+                              QtGui.QImage.Format_ARGB32_Premultiplied)
+        # Adjust the buf reference count to work around a memory leak bug in
+        # QImage under PySide on Python 3.
+        if QT_API == 'PySide':
+            ctypes.c_long.from_address(id(buf)).value = 1
+        _setDevicePixelRatioF(qimage, dpi_ratio)
+        painter = QtGui.QPainter(self)
+        painter.eraseRect(event.rect())
+        painter.drawImage(0, 0, qimage)
+        self._draw_rect_callback(painter)
+        painter.end()
+
+
+@_BackendQT5.export
+class _BackendQT5Cairo(_BackendQT5):
+    FigureCanvas = FigureCanvasQTCairo