Overlay two pixmaps with alpha value using QPainter
1
I'm trying to overlay 2 pixmaps and convert them into a single pixmap in a QGraphics scene. Both pixmaps are transparent at certain locations. I want to combine the maps using the 'SourceOver' blend type listed here: I have a simple toy example below to illustrate my issue where I have created two dummy transparent pixmaps, one green and one blue. In reality, these maps are loaded from images and painted over, but this example reproduces the problem. Based on this How to add an image on the top of another image?, the approach I tried (4 lines commented out) was to create a QPainter with one of the pixmaps and then draw the other pixmap on top of it, however that crashes the program. Any ideas on how to fix this? I eventually want to be able to save the combined pixmap.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtGui import QPixmap, QPainter, QPen, QBrush, QPainterPath
from PyQt5.QtCore import (QLineF, QPointF, QRectF, Qt)
class Viewer(QtWidgets.QGraphicsView):
def __init__(self, parent):
super(Viewer, self).__init__(parent)
self._scene = QtWidgets.QGraphicsScene(self)
self.photo = QtWidgets.QGraphicsPixmapItem()
self.label = QtWidgets.QGraphicsPixmapItem()
self._scene.addItem(self.photo)
self._scene.addItem(self.label)
self.setScene(self._scene)
def overlayMaps(self):
blue = QtGui.QPixmap(600, 600)
blue.fill(QtGui.QColor(0,0,255,0))
p = QPainter(blue)
self.pen = QPen()
self.pen.setColor(QtGui.QColor(0,0,255,255))
self.pen.setWidth(10)
p.setPen(self.pen)
p.drawLine(0,0,600,600)
green = QtGui.QPixmap(600, 600)
green.fill(QtGui.QColor(0,255,0,0))
p = QPainter(green)
self.pen = QPen()
self.pen.setColor(QtGui.QColor(0,255,0,255))
self.pen.setWidth(10)
p.setPen(self.pen)
p.drawLine(600,0,0,600)
self.photo.setPixmap(blue)
self.label.setPixmap(green)
resultPixmap = QtGui.QPixmap(self.photo.pixmap().width(), self.photo.pixmap().height())
# resultPainter = QtGui.QPainter(resultPixmap)
# resultPainter.setCompositionMode(QtGui.QPainter.CompositionMode_SourceOver)
# resultPainter.drawPixmap(300,300, self.photo.pixmap())
# resultPainter.drawPixmap(300,300, self.label.pixmap())
def saveOverlayMap(self):
pass
class Window(QtWidgets.QWidget):
def __init__(self):
super(Window, self).__init__()
self.viewer = Viewer(self)
self.viewer.overlayMaps()
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
window = Window()
window.setGeometry(500, 300, 600, 600)
window.show()
sys.exit(app.exec_())
python pyqt pyqt5 qpainter qpixmap
edited Mar 10 at 5:11
eyllanesc
82.5k103360
asked Nov 21 '18 at 21:38
CSforStructuralEngineerCSforStructuralEngineer
737
add a comment |
1
I'm trying to overlay 2 pixmaps and convert them into a single pixmap in a QGraphics scene. Both pixmaps are transparent at certain locations. I want to combine the maps using the 'SourceOver' blend type listed here: I have a simple toy example below to illustrate my issue where I have created two dummy transparent pixmaps, one green and one blue. In reality, these maps are loaded from images and painted over, but this example reproduces the problem. Based on this How to add an image on the top of another image?, the approach I tried (4 lines commented out) was to create a QPainter with one of the pixmaps and then draw the other pixmap on top of it, however that crashes the program. Any ideas on how to fix this? I eventually want to be able to save the combined pixmap.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtGui import QPixmap, QPainter, QPen, QBrush, QPainterPath
from PyQt5.QtCore import (QLineF, QPointF, QRectF, Qt)
class Viewer(QtWidgets.QGraphicsView):
def __init__(self, parent):
super(Viewer, self).__init__(parent)
self._scene = QtWidgets.QGraphicsScene(self)
self.photo = QtWidgets.QGraphicsPixmapItem()
self.label = QtWidgets.QGraphicsPixmapItem()
self._scene.addItem(self.photo)
self._scene.addItem(self.label)
self.setScene(self._scene)
def overlayMaps(self):
blue = QtGui.QPixmap(600, 600)
blue.fill(QtGui.QColor(0,0,255,0))
p = QPainter(blue)
self.pen = QPen()
self.pen.setColor(QtGui.QColor(0,0,255,255))
self.pen.setWidth(10)
p.setPen(self.pen)
p.drawLine(0,0,600,600)
green = QtGui.QPixmap(600, 600)
green.fill(QtGui.QColor(0,255,0,0))
p = QPainter(green)
self.pen = QPen()
self.pen.setColor(QtGui.QColor(0,255,0,255))
self.pen.setWidth(10)
p.setPen(self.pen)
p.drawLine(600,0,0,600)
self.photo.setPixmap(blue)
self.label.setPixmap(green)
resultPixmap = QtGui.QPixmap(self.photo.pixmap().width(), self.photo.pixmap().height())
# resultPainter = QtGui.QPainter(resultPixmap)
# resultPainter.setCompositionMode(QtGui.QPainter.CompositionMode_SourceOver)
# resultPainter.drawPixmap(300,300, self.photo.pixmap())
# resultPainter.drawPixmap(300,300, self.label.pixmap())
def saveOverlayMap(self):
pass
class Window(QtWidgets.QWidget):
def __init__(self):
super(Window, self).__init__()
self.viewer = Viewer(self)
self.viewer.overlayMaps()
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
window = Window()
window.setGeometry(500, 300, 600, 600)
window.show()
sys.exit(app.exec_())
python pyqt pyqt5 qpainter qpixmap
edited Mar 10 at 5:11
eyllanesc
82.5k103360
asked Nov 21 '18 at 21:38
CSforStructuralEngineerCSforStructuralEngineer
737
The code snippet is just to illustrate the issue. In my full code, the pixmaps are different.
– CSforStructuralEngineer
Nov 21 '18 at 22:14
Okay, edited the question and code
– CSforStructuralEngineer
Nov 21 '18 at 22:18
I modified the pixmaps and the question. The pixmaps are actually from images over which some shapes have been painted. This toy example reproduces the same error simply using lines.
– CSforStructuralEngineer
Nov 21 '18 at 22:34
Thanks so much! Your code works! I'm still not yet sure what I did wrong though
– CSforStructuralEngineer
Nov 21 '18 at 22:58
add a comment |
1
1
1
1
I'm trying to overlay 2 pixmaps and convert them into a single pixmap in a QGraphics scene. Both pixmaps are transparent at certain locations. I want to combine the maps using the 'SourceOver' blend type listed here: I have a simple toy example below to illustrate my issue where I have created two dummy transparent pixmaps, one green and one blue. In reality, these maps are loaded from images and painted over, but this example reproduces the problem. Based on this How to add an image on the top of another image?, the approach I tried (4 lines commented out) was to create a QPainter with one of the pixmaps and then draw the other pixmap on top of it, however that crashes the program. Any ideas on how to fix this? I eventually want to be able to save the combined pixmap.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtGui import QPixmap, QPainter, QPen, QBrush, QPainterPath
from PyQt5.QtCore import (QLineF, QPointF, QRectF, Qt)
class Viewer(QtWidgets.QGraphicsView):
def __init__(self, parent):
super(Viewer, self).__init__(parent)
self._scene = QtWidgets.QGraphicsScene(self)
self.photo = QtWidgets.QGraphicsPixmapItem()
self.label = QtWidgets.QGraphicsPixmapItem()
self._scene.addItem(self.photo)
self._scene.addItem(self.label)
self.setScene(self._scene)
def overlayMaps(self):
blue = QtGui.QPixmap(600, 600)
blue.fill(QtGui.QColor(0,0,255,0))
p = QPainter(blue)
self.pen = QPen()
self.pen.setColor(QtGui.QColor(0,0,255,255))
self.pen.setWidth(10)
p.setPen(self.pen)
p.drawLine(0,0,600,600)
green = QtGui.QPixmap(600, 600)
green.fill(QtGui.QColor(0,255,0,0))
p = QPainter(green)
self.pen = QPen()
self.pen.setColor(QtGui.QColor(0,255,0,255))
self.pen.setWidth(10)
p.setPen(self.pen)
p.drawLine(600,0,0,600)
self.photo.setPixmap(blue)
self.label.setPixmap(green)
resultPixmap = QtGui.QPixmap(self.photo.pixmap().width(), self.photo.pixmap().height())
# resultPainter = QtGui.QPainter(resultPixmap)
# resultPainter.setCompositionMode(QtGui.QPainter.CompositionMode_SourceOver)
# resultPainter.drawPixmap(300,300, self.photo.pixmap())
# resultPainter.drawPixmap(300,300, self.label.pixmap())
def saveOverlayMap(self):
pass
class Window(QtWidgets.QWidget):
def __init__(self):
super(Window, self).__init__()
self.viewer = Viewer(self)
self.viewer.overlayMaps()
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
window = Window()
window.setGeometry(500, 300, 600, 600)
window.show()
sys.exit(app.exec_())
python pyqt pyqt5 qpainter qpixmap
edited Mar 10 at 5:11
eyllanesc
82.5k103360
asked Nov 21 '18 at 21:38
CSforStructuralEngineerCSforStructuralEngineer
737
I'm trying to overlay 2 pixmaps and convert them into a single pixmap in a QGraphics scene. Both pixmaps are transparent at certain locations. I want to combine the maps using the 'SourceOver' blend type listed here: I have a simple toy example below to illustrate my issue where I have created two dummy transparent pixmaps, one green and one blue. In reality, these maps are loaded from images and painted over, but this example reproduces the problem. Based on this How to add an image on the top of another image?, the approach I tried (4 lines commented out) was to create a QPainter with one of the pixmaps and then draw the other pixmap on top of it, however that crashes the program. Any ideas on how to fix this? I eventually want to be able to save the combined pixmap.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtGui import QPixmap, QPainter, QPen, QBrush, QPainterPath
from PyQt5.QtCore import (QLineF, QPointF, QRectF, Qt)
class Viewer(QtWidgets.QGraphicsView):
def __init__(self, parent):
super(Viewer, self).__init__(parent)
self._scene = QtWidgets.QGraphicsScene(self)
self.photo = QtWidgets.QGraphicsPixmapItem()
self.label = QtWidgets.QGraphicsPixmapItem()
self._scene.addItem(self.photo)
self._scene.addItem(self.label)
self.setScene(self._scene)
def overlayMaps(self):
blue = QtGui.QPixmap(600, 600)
blue.fill(QtGui.QColor(0,0,255,0))
p = QPainter(blue)
self.pen = QPen()
self.pen.setColor(QtGui.QColor(0,0,255,255))
self.pen.setWidth(10)
p.setPen(self.pen)
p.drawLine(0,0,600,600)
green = QtGui.QPixmap(600, 600)
green.fill(QtGui.QColor(0,255,0,0))
p = QPainter(green)
self.pen = QPen()
self.pen.setColor(QtGui.QColor(0,255,0,255))
self.pen.setWidth(10)
p.setPen(self.pen)
p.drawLine(600,0,0,600)
self.photo.setPixmap(blue)
self.label.setPixmap(green)
resultPixmap = QtGui.QPixmap(self.photo.pixmap().width(), self.photo.pixmap().height())
# resultPainter = QtGui.QPainter(resultPixmap)
# resultPainter.setCompositionMode(QtGui.QPainter.CompositionMode_SourceOver)
# resultPainter.drawPixmap(300,300, self.photo.pixmap())
# resultPainter.drawPixmap(300,300, self.label.pixmap())
def saveOverlayMap(self):
pass
class Window(QtWidgets.QWidget):
def __init__(self):
super(Window, self).__init__()
self.viewer = Viewer(self)
self.viewer.overlayMaps()
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
window = Window()
window.setGeometry(500, 300, 600, 600)
window.show()
sys.exit(app.exec_())
python pyqt pyqt5 qpainter qpixmap
python pyqt pyqt5 qpainter qpixmap
edited Mar 10 at 5:11
eyllanesc
82.5k103360
asked Nov 21 '18 at 21:38
CSforStructuralEngineerCSforStructuralEngineer
737
edited Mar 10 at 5:11
eyllanesc
82.5k103360
asked Nov 21 '18 at 21:38
CSforStructuralEngineerCSforStructuralEngineer
737
edited Mar 10 at 5:11
eyllanesc
82.5k103360
edited Mar 10 at 5:11
eyllanesc
82.5k103360
edited Mar 10 at 5:11
eyllanesc
82.5k103360
82.5k103360
asked Nov 21 '18 at 21:38
CSforStructuralEngineerCSforStructuralEngineer
737
asked Nov 21 '18 at 21:38
CSforStructuralEngineerCSforStructuralEngineer
737
asked Nov 21 '18 at 21:38
CSforStructuralEngineerCSforStructuralEngineer
737
737
The code snippet is just to illustrate the issue. In my full code, the pixmaps are different.
– CSforStructuralEngineer
Nov 21 '18 at 22:14
Okay, edited the question and code
– CSforStructuralEngineer
Nov 21 '18 at 22:18
I modified the pixmaps and the question. The pixmaps are actually from images over which some shapes have been painted. This toy example reproduces the same error simply using lines.
– CSforStructuralEngineer
Nov 21 '18 at 22:34
Thanks so much! Your code works! I'm still not yet sure what I did wrong though
– CSforStructuralEngineer
Nov 21 '18 at 22:58
add a comment |
The code snippet is just to illustrate the issue. In my full code, the pixmaps are different.
– CSforStructuralEngineer
Nov 21 '18 at 22:14
Okay, edited the question and code
– CSforStructuralEngineer
Nov 21 '18 at 22:18
I modified the pixmaps and the question. The pixmaps are actually from images over which some shapes have been painted. This toy example reproduces the same error simply using lines.
– CSforStructuralEngineer
Nov 21 '18 at 22:34
Thanks so much! Your code works! I'm still not yet sure what I did wrong though
– CSforStructuralEngineer
Nov 21 '18 at 22:58
The code snippet is just to illustrate the issue. In my full code, the pixmaps are different.
– CSforStructuralEngineer
Nov 21 '18 at 22:14
The code snippet is just to illustrate the issue. In my full code, the pixmaps are different.
– CSforStructuralEngineer
Nov 21 '18 at 22:14
Okay, edited the question and code
– CSforStructuralEngineer
Nov 21 '18 at 22:18
Okay, edited the question and code
– CSforStructuralEngineer
Nov 21 '18 at 22:18
I modified the pixmaps and the question. The pixmaps are actually from images over which some shapes have been painted. This toy example reproduces the same error simply using lines.
– CSforStructuralEngineer
Nov 21 '18 at 22:34
I modified the pixmaps and the question. The pixmaps are actually from images over which some shapes have been painted. This toy example reproduces the same error simply using lines.
– CSforStructuralEngineer
Nov 21 '18 at 22:34
Thanks so much! Your code works! I'm still not yet sure what I did wrong though
– CSforStructuralEngineer
Nov 21 '18 at 22:58
Thanks so much! Your code works! I'm still not yet sure what I did wrong though
– CSforStructuralEngineer
Nov 21 '18 at 22:58
add a comment |
1 Answer
1
active
oldest
votes
3
I have implemented a function that performs the action of joining depending on the mode, for a better appreciation I have moved the items.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
def join_pixmap(p1, p2, mode=QtGui.QPainter.CompositionMode_SourceOver):
s = p1.size().expandedTo(p2.size())
result = QtGui.QPixmap(s)
result.fill(QtCore.Qt.transparent)
painter = QtGui.QPainter(result)
painter.setRenderHint(QtGui.QPainter.Antialiasing)
painter.drawPixmap(QtCore.QPoint(), p1)
painter.setCompositionMode(mode)
painter.drawPixmap(result.rect(), p2, p2.rect())
painter.end()
return result
class Viewer(QtWidgets.QGraphicsView):
def __init__(self, parent=None):
super(Viewer, self).__init__(parent)
self._scene = QtWidgets.QGraphicsScene(self)
self.setScene(self._scene)
blue = QtGui.QPixmap(100, 100)
blue.fill(QtCore.Qt.transparent)
p = QtGui.QPainter(blue)
pen = QtGui.QPen(QtGui.QBrush(QtGui.QColor(0,0,255)), 10)
p.setPen(pen)
p.drawLine(0, 0, 100, 100)
p.end()
self.photo = self._scene.addPixmap(blue)
green = QtGui.QPixmap(100, 100)
green.fill(QtCore.Qt.transparent)
p = QtGui.QPainter(green)
pen = QtGui.QPen(QtGui.QBrush(QtGui.QColor(0, 255, 0, 255)), 10)
p.setPen(pen)
p.drawLine(100, 0, 0, 100)
p.end()
self.label = self._scene.addPixmap(green)
self.label.setPos(200, 0)
self.overlayMaps()
def overlayMaps(self):
p1 = QtGui.QPixmap(self.photo.pixmap())
p2 = QtGui.QPixmap(self.label.pixmap())
result_pixmap = join_pixmap(self.photo.pixmap(), self.label.pixmap())
self.result_item = self._scene.addPixmap(result_pixmap)
self.result_item.setPos(100, 200)
result_pixmap.save("result_pixmap.png")
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
window = Viewer()
window.resize(640, 480)
window.show()
sys.exit(app.exec_())
result_pixmap.png
answered Nov 21 '18 at 22:50
eyllanesceyllanesc
82.5k103360
add a comment |
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1 Answer
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1 Answer
1
active
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votes
active
oldest
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active
oldest
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3
I have implemented a function that performs the action of joining depending on the mode, for a better appreciation I have moved the items.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
def join_pixmap(p1, p2, mode=QtGui.QPainter.CompositionMode_SourceOver):
s = p1.size().expandedTo(p2.size())
result = QtGui.QPixmap(s)
result.fill(QtCore.Qt.transparent)
painter = QtGui.QPainter(result)
painter.setRenderHint(QtGui.QPainter.Antialiasing)
painter.drawPixmap(QtCore.QPoint(), p1)
painter.setCompositionMode(mode)
painter.drawPixmap(result.rect(), p2, p2.rect())
painter.end()
return result
class Viewer(QtWidgets.QGraphicsView):
def __init__(self, parent=None):
super(Viewer, self).__init__(parent)
self._scene = QtWidgets.QGraphicsScene(self)
self.setScene(self._scene)
blue = QtGui.QPixmap(100, 100)
blue.fill(QtCore.Qt.transparent)
p = QtGui.QPainter(blue)
pen = QtGui.QPen(QtGui.QBrush(QtGui.QColor(0,0,255)), 10)
p.setPen(pen)
p.drawLine(0, 0, 100, 100)
p.end()
self.photo = self._scene.addPixmap(blue)
green = QtGui.QPixmap(100, 100)
green.fill(QtCore.Qt.transparent)
p = QtGui.QPainter(green)
pen = QtGui.QPen(QtGui.QBrush(QtGui.QColor(0, 255, 0, 255)), 10)
p.setPen(pen)
p.drawLine(100, 0, 0, 100)
p.end()
self.label = self._scene.addPixmap(green)
self.label.setPos(200, 0)
self.overlayMaps()
def overlayMaps(self):
p1 = QtGui.QPixmap(self.photo.pixmap())
p2 = QtGui.QPixmap(self.label.pixmap())
result_pixmap = join_pixmap(self.photo.pixmap(), self.label.pixmap())
self.result_item = self._scene.addPixmap(result_pixmap)
self.result_item.setPos(100, 200)
result_pixmap.save("result_pixmap.png")
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
window = Viewer()
window.resize(640, 480)
window.show()
sys.exit(app.exec_())
result_pixmap.png
answered Nov 21 '18 at 22:50
eyllanesceyllanesc
82.5k103360
add a comment |
3
I have implemented a function that performs the action of joining depending on the mode, for a better appreciation I have moved the items.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
def join_pixmap(p1, p2, mode=QtGui.QPainter.CompositionMode_SourceOver):
s = p1.size().expandedTo(p2.size())
result = QtGui.QPixmap(s)
result.fill(QtCore.Qt.transparent)
painter = QtGui.QPainter(result)
painter.setRenderHint(QtGui.QPainter.Antialiasing)
painter.drawPixmap(QtCore.QPoint(), p1)
painter.setCompositionMode(mode)
painter.drawPixmap(result.rect(), p2, p2.rect())
painter.end()
return result
class Viewer(QtWidgets.QGraphicsView):
def __init__(self, parent=None):
super(Viewer, self).__init__(parent)
self._scene = QtWidgets.QGraphicsScene(self)
self.setScene(self._scene)
blue = QtGui.QPixmap(100, 100)
blue.fill(QtCore.Qt.transparent)
p = QtGui.QPainter(blue)
pen = QtGui.QPen(QtGui.QBrush(QtGui.QColor(0,0,255)), 10)
p.setPen(pen)
p.drawLine(0, 0, 100, 100)
p.end()
self.photo = self._scene.addPixmap(blue)
green = QtGui.QPixmap(100, 100)
green.fill(QtCore.Qt.transparent)
p = QtGui.QPainter(green)
pen = QtGui.QPen(QtGui.QBrush(QtGui.QColor(0, 255, 0, 255)), 10)
p.setPen(pen)
p.drawLine(100, 0, 0, 100)
p.end()
self.label = self._scene.addPixmap(green)
self.label.setPos(200, 0)
self.overlayMaps()
def overlayMaps(self):
p1 = QtGui.QPixmap(self.photo.pixmap())
p2 = QtGui.QPixmap(self.label.pixmap())
result_pixmap = join_pixmap(self.photo.pixmap(), self.label.pixmap())
self.result_item = self._scene.addPixmap(result_pixmap)
self.result_item.setPos(100, 200)
result_pixmap.save("result_pixmap.png")
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
window = Viewer()
window.resize(640, 480)
window.show()
sys.exit(app.exec_())
result_pixmap.png
answered Nov 21 '18 at 22:50
eyllanesceyllanesc
82.5k103360
add a comment |
3
3
3
I have implemented a function that performs the action of joining depending on the mode, for a better appreciation I have moved the items.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
def join_pixmap(p1, p2, mode=QtGui.QPainter.CompositionMode_SourceOver):
s = p1.size().expandedTo(p2.size())
result = QtGui.QPixmap(s)
result.fill(QtCore.Qt.transparent)
painter = QtGui.QPainter(result)
painter.setRenderHint(QtGui.QPainter.Antialiasing)
painter.drawPixmap(QtCore.QPoint(), p1)
painter.setCompositionMode(mode)
painter.drawPixmap(result.rect(), p2, p2.rect())
painter.end()
return result
class Viewer(QtWidgets.QGraphicsView):
def __init__(self, parent=None):
super(Viewer, self).__init__(parent)
self._scene = QtWidgets.QGraphicsScene(self)
self.setScene(self._scene)
blue = QtGui.QPixmap(100, 100)
blue.fill(QtCore.Qt.transparent)
p = QtGui.QPainter(blue)
pen = QtGui.QPen(QtGui.QBrush(QtGui.QColor(0,0,255)), 10)
p.setPen(pen)
p.drawLine(0, 0, 100, 100)
p.end()
self.photo = self._scene.addPixmap(blue)
green = QtGui.QPixmap(100, 100)
green.fill(QtCore.Qt.transparent)
p = QtGui.QPainter(green)
pen = QtGui.QPen(QtGui.QBrush(QtGui.QColor(0, 255, 0, 255)), 10)
p.setPen(pen)
p.drawLine(100, 0, 0, 100)
p.end()
self.label = self._scene.addPixmap(green)
self.label.setPos(200, 0)
self.overlayMaps()
def overlayMaps(self):
p1 = QtGui.QPixmap(self.photo.pixmap())
p2 = QtGui.QPixmap(self.label.pixmap())
result_pixmap = join_pixmap(self.photo.pixmap(), self.label.pixmap())
self.result_item = self._scene.addPixmap(result_pixmap)
self.result_item.setPos(100, 200)
result_pixmap.save("result_pixmap.png")
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
window = Viewer()
window.resize(640, 480)
window.show()
sys.exit(app.exec_())
result_pixmap.png
answered Nov 21 '18 at 22:50
eyllanesceyllanesc
82.5k103360
I have implemented a function that performs the action of joining depending on the mode, for a better appreciation I have moved the items.
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
def join_pixmap(p1, p2, mode=QtGui.QPainter.CompositionMode_SourceOver):
s = p1.size().expandedTo(p2.size())
result = QtGui.QPixmap(s)
result.fill(QtCore.Qt.transparent)
painter = QtGui.QPainter(result)
painter.setRenderHint(QtGui.QPainter.Antialiasing)
painter.drawPixmap(QtCore.QPoint(), p1)
painter.setCompositionMode(mode)
painter.drawPixmap(result.rect(), p2, p2.rect())
painter.end()
return result
class Viewer(QtWidgets.QGraphicsView):
def __init__(self, parent=None):
super(Viewer, self).__init__(parent)
self._scene = QtWidgets.QGraphicsScene(self)
self.setScene(self._scene)
blue = QtGui.QPixmap(100, 100)
blue.fill(QtCore.Qt.transparent)
p = QtGui.QPainter(blue)
pen = QtGui.QPen(QtGui.QBrush(QtGui.QColor(0,0,255)), 10)
p.setPen(pen)
p.drawLine(0, 0, 100, 100)
p.end()
self.photo = self._scene.addPixmap(blue)
green = QtGui.QPixmap(100, 100)
green.fill(QtCore.Qt.transparent)
p = QtGui.QPainter(green)
pen = QtGui.QPen(QtGui.QBrush(QtGui.QColor(0, 255, 0, 255)), 10)
p.setPen(pen)
p.drawLine(100, 0, 0, 100)
p.end()
self.label = self._scene.addPixmap(green)
self.label.setPos(200, 0)
self.overlayMaps()
def overlayMaps(self):
p1 = QtGui.QPixmap(self.photo.pixmap())
p2 = QtGui.QPixmap(self.label.pixmap())
result_pixmap = join_pixmap(self.photo.pixmap(), self.label.pixmap())
self.result_item = self._scene.addPixmap(result_pixmap)
self.result_item.setPos(100, 200)
result_pixmap.save("result_pixmap.png")
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
window = Viewer()
window.resize(640, 480)
window.show()
sys.exit(app.exec_())
result_pixmap.png
answered Nov 21 '18 at 22:50
eyllanesceyllanesc
82.5k103360
answered Nov 21 '18 at 22:50
eyllanesceyllanesc
82.5k103360
answered Nov 21 '18 at 22:50
eyllanesceyllanesc
82.5k103360
answered Nov 21 '18 at 22:50
eyllanesceyllanesc
82.5k103360
82.5k103360
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The code snippet is just to illustrate the issue. In my full code, the pixmaps are different.
– CSforStructuralEngineer
Nov 21 '18 at 22:14
Okay, edited the question and code
– CSforStructuralEngineer
Nov 21 '18 at 22:18
I modified the pixmaps and the question. The pixmaps are actually from images over which some shapes have been painted. This toy example reproduces the same error simply using lines.
– CSforStructuralEngineer
Nov 21 '18 at 22:34
Thanks so much! Your code works! I'm still not yet sure what I did wrong though
– CSforStructuralEngineer
Nov 21 '18 at 22:58