[英]Matplotlib / PyQT4: transparent figure
我在PyQt4中使用Python,我想在GUI中嵌入一個matplotlib圖。 對我來說重要的是, Figure
的背景與GUI的背景顏色相匹配。 (實際情節周圍沒有灰色背景)
我的部分解決方案是使用以下代碼使Figure
透明:
...
fig.patch.set_alpha(0.5)
...
這在pylab模式下繪圖時效果很好,但是當在PyQt4中嵌入時,重新渲染不會清除舊圖形,而是將其添加到我給出的透明度的頂部。 如下面的示例所示,這是調整窗口大小的結果:
將樣品使用所產生的從matplotlib網站碼與添加set_alpha(0.5)
在管線__init__
的語句MyMplCanvas
。
您在matplotlib
發現了一個有趣的錯誤。 Qt4
后端不會清除重繪前用於顯示圖形的qImage
,因此您可以看到陰影的原因。 通過向matplotlib.backends.backed_qt4Agg.FigureCanvasQTAgg.paintEvent
添加幾行可以很容易地解決這個問題。
def paintEvent(self, e):
"""
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.
"""
#FigureCanvasQT.paintEvent(self, e)
if DEBUG:
print('FigureCanvasQtAgg.paintEvent: ', self,
self.get_width_height())
if self.blitbox is None:
# matplotlib is in rgba byte order. QImage wants to put the bytes
# into argb format and is in a 4 byte unsigned int. Little endian
# system is LSB first and expects the bytes in reverse order
# (bgra).
if QtCore.QSysInfo.ByteOrder == QtCore.QSysInfo.LittleEndian:
stringBuffer = self.renderer._renderer.tostring_bgra()
else:
stringBuffer = self.renderer._renderer.tostring_argb()
refcnt = sys.getrefcount(stringBuffer)
qImage = QtGui.QImage(stringBuffer, self.renderer.width,
self.renderer.height,
QtGui.QImage.Format_ARGB32)
rect = qImage.rect() ### <-- added this line
p = QtGui.QPainter(self)
p.eraseRect(rect) ### <-- added this line
p.drawPixmap(QtCore.QPoint(0, 0), QtGui.QPixmap.fromImage(qImage))
# draw the zoom rectangle to the QPainter
if self.drawRect:
p.setPen(QtGui.QPen(QtCore.Qt.black, 1, QtCore.Qt.DotLine))
p.drawRect(self.rect[0], self.rect[1],
self.rect[2], self.rect[3])
p.end()
# This works around a bug in PySide 1.1.2 on Python 3.x,
# where the reference count of stringBuffer is incremented
# but never decremented by QImage.
# TODO: revert PR #1323 once the issue is fixed in PySide.
del qImage
if refcnt != sys.getrefcount(stringBuffer):
_decref(stringBuffer)
else:
bbox = self.blitbox
l, b, r, t = bbox.extents
w = int(r) - int(l)
h = int(t) - int(b)
t = int(b) + h
reg = self.copy_from_bbox(bbox)
stringBuffer = reg.to_string_argb()
qImage = QtGui.QImage(stringBuffer, w, h,
QtGui.QImage.Format_ARGB32)
pixmap = QtGui.QPixmap.fromImage(qImage)
p = QtGui.QPainter(self)
p.drawPixmap(QtCore.QPoint(l, self.renderer.height-t), pixmap)
p.end()
self.blitbox = None
self.drawRect = False
差異形式的變化:
diff --git a/lib/matplotlib/backends/backend_qt4agg.py b/lib/matplotlib/backends/backend_qt4agg.py
index 8433731..718d352 100644
--- a/lib/matplotlib/backends/backend_qt4agg.py
+++ b/lib/matplotlib/backends/backend_qt4agg.py
@@ -118,7 +118,9 @@ class FigureCanvasQTAgg(FigureCanvasQT, FigureCanvasAgg):
qImage = QtGui.QImage(stringBuffer, self.renderer.width,
self.renderer.height,
QtGui.QImage.Format_ARGB32)
+ rect = qImage.rect()
p = QtGui.QPainter(self)
+ p.eraseRect(rect)
p.drawPixmap(QtCore.QPoint(0, 0), QtGui.QPixmap.fromImage(qImage))
# draw the zoom rectangle to the QPainter
您可以修改本地安裝,也可以在代碼中修補它。
PR#2449已合並,將在1.3.1中
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