Thanks to visit codestin.com
Credit goes to github.com

Skip to content

Don't call draw() twice when Qt canvas first appears. #9103

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Aug 28, 2017
Merged

Don't call draw() twice when Qt canvas first appears. #9103

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 13 additions & 0 deletions lib/matplotlib/backends/backend_qt5.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -249,6 +249,15 @@ def __init__(self, figure):
# Key auto-repeat enabled by default
self._keyautorepeat = True

# In cases with mixed resolution displays, we need to be careful if the
# dpi_ratio changes - in this case we need to resize the canvas
# accordingly. We could watch for screenChanged events from Qt, but
# the issue is that we can't guarantee this will be emitted *before*
# the first paintEvent for the canvas, so instead we keep track of the
# dpi_ratio value here and in paintEvent we resize the canvas if
# needed.
self._dpi_ratio_prev = None

@property
def _dpi_ratio(self):
# Not available on Qt4 or some older Qt5.
Expand Down Expand Up @@ -342,6 +351,10 @@ def keyAutoRepeat(self, val):
self._keyautorepeat = bool(val)

def resizeEvent(self, event):
# _dpi_ratio_prev will be set the first time the canvas is painted, and
# the rendered buffer is useless before anyways.
if self._dpi_ratio_prev is None:
return
w = event.size().width() * self._dpi_ratio
h = event.size().height() * self._dpi_ratio
dpival = self.figure.dpi
Expand Down
29 changes: 11 additions & 18 deletions lib/matplotlib/backends/backend_qt5agg.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@

from .backend_agg import FigureCanvasAgg
from .backend_qt5 import (
QtCore, QtGui, _BackendQT5, FigureCanvasQT, FigureManagerQT,
QtCore, QtGui, QtWidgets, _BackendQT5, FigureCanvasQT, FigureManagerQT,
NavigationToolbar2QT, backend_version)
from .qt_compat import QT_API

Expand All @@ -38,15 +38,6 @@ def __init__(self, figure):
self._bbox_queue = []
self._drawRect = None

# In cases with mixed resolution displays, we need to be careful if the
# dpi_ratio changes - in this case we need to resize the canvas
# accordingly. We could watch for screenChanged events from Qt, but
# the issue is that we can't guarantee this will be emitted *before*
# the first paintEvent for the canvas, so instead we keep track of the
# dpi_ratio value here and in paintEvent we resize the canvas if
# needed.
self._dpi_ratio_prev = None

def drawRectangle(self, rect):
if rect is not None:
self._drawRect = [pt / self._dpi_ratio for pt in rect]
Expand All @@ -66,18 +57,13 @@ def paintEvent(self, e):
shown onscreen.
"""

# 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

# As described in __init__ above, we need to be careful in cases with
# mixed resolution displays if dpi_ratio is changing between painting
# events.
if (self._dpi_ratio_prev is None or
self._dpi_ratio != self._dpi_ratio_prev):
if self._dpi_ratio != self._dpi_ratio_prev:
# We need to update the figure DPI
self._update_figure_dpi()
self._dpi_ratio_prev = self._dpi_ratio
# The easiest way to resize the canvas is to emit a resizeEvent
# since we implement all the logic for resizing the canvas for
# that event.
Expand All @@ -86,7 +72,14 @@ def paintEvent(self, e):
# since the latter doesn't guarantee that the event will be emitted
# straight away, and this causes visual delays in the changes.
self.resizeEvent(event)
self._dpi_ratio_prev = self._dpi_ratio
QtWidgets.QApplication.instance().processEvents()
# resizeEvent triggers a paintEvent itself, so we exit this one.
return

# 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)

Expand Down