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49 lines
1.8 KiB
Python

import ctypes
from .backend_cairo import cairo, FigureCanvasCairo, RendererCairo
from .backend_qt5 import QtCore, QtGui, _BackendQT5, FigureCanvasQT
from .qt_compat import QT_API
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 = dpi_ratio * self.width()
height = 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
if hasattr(qimage, 'setDevicePixelRatio'):
# Not available on Qt4 or some older Qt5.
qimage.setDevicePixelRatio(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