"""
Render to qt from agg.
"""
import ctypes
from matplotlib.transforms import Bbox
from .qt_compat import QT_API, _enum
from .backend_agg import FigureCanvasAgg
from .backend_qt import QtCore, QtGui, _BackendQT, FigureCanvasQT
from .backend_qt import ( # noqa: F401 # pylint: disable=W0611
FigureManagerQT, NavigationToolbar2QT)
class FigureCanvasQTAgg(FigureCanvasAgg, FigureCanvasQT):
def paintEvent(self, event):
"""
Copy the image from the Agg canvas to the qt.drawable.
In Qt, all drawing should be done inside of here when a widget is
shown onscreen.
"""
self._draw_idle() # Only does something if a draw is pending.
# If the canvas does not have a renderer, then give up and wait for
# FigureCanvasAgg.draw(self) to be called.
if not hasattr(self, 'renderer'):
return
painter = QtGui.QPainter(self)
try:
# See documentation of QRect: bottom() and right() are off
# by 1, so use left() + width() and top() + height().
rect = event.rect()
# scale rect dimensions using the screen dpi ratio to get
# correct values for the Figure coordinates (rather than
# QT5's coords)
width = rect.width() * self.device_pixel_ratio
height = rect.height() * self.device_pixel_ratio
left, top = self.mouseEventCoords(rect.topLeft())
# shift the "top" by the height of the image to get the
# correct corner for our coordinate system
bottom = top - height
# same with the right side of the image
right = left + width
# create a buffer using the image bounding box
bbox = Bbox([[left, bottom], [right, top]])
buf = memoryview(self.copy_from_bbox(bbox))
if QT_API == "PyQt6":
from PyQt6 import sip
ptr = int(sip.voidptr(buf))
else:
ptr = buf
painter.eraseRect(rect) # clear the widget canvas
qimage = QtGui.QImage(ptr, buf.shape[1], buf.shape[0],
_enum("QtGui.QImage.Format").Format_RGBA8888)
qimage.setDevicePixelRatio(self.device_pixel_ratio)
# set origin using original QT coordinates
origin = QtCore.QPoint(rect.left(), rect.top())
painter.drawImage(origin, qimage)
# Adjust the buf reference count to work around a memory
# leak bug in QImage under PySide.
if QT_API == "PySide2" and QtCore.__version_info__ < (5, 12):
ctypes.c_long.from_address(id(buf)).value = 1
self._draw_rect_callback(painter)
finally:
painter.end()
def print_figure(self, *args, **kwargs):
super().print_figure(*args, **kwargs)
self.draw()
@_BackendQT.export
class _BackendQTAgg(_BackendQT):
FigureCanvas = FigureCanvasQTAgg