Convert PyQt to PIL image

Question

I have an image in a QImage and I want to process it in PIL before I display it. While the ImageQT class lets me convert a PIL Image to a QImage, there doesn't appear to anything to go from a QImage to a PIL Image.

Answer 1

You can convert a QImage into a Python string:

>>> image = QImage(256, 256, QImage.Format_ARGB32)
>>> bytes = image.bits().asstring(image.numBytes())
>>> len(bytes)
262144

Converting from this to PIL should be easy.

Answer 2

I convert it from QImage to PIL with this code:

img = QImage("/tmp/example.png")
buffer = QBuffer()
buffer.open(QIODevice.ReadWrite)
img.save(buffer, "PNG")

strio = cStringIO.StringIO()
strio.write(buffer.data())
buffer.close()
strio.seek(0)
pil_im = Imagen.open(strio)

I lost a full morning searching a correct way to do this.

Answer 3

Another route would be:

1. Load the image data into a numpy array (example code using PIL)
2. Manipulate the image using numpy, scipy or scikits.image
3. Load the data into a QImage (example: browse the scikits.image archive (linked in 1) and look on line 45 of qt_plugin.py -- sorry, stackoverflow doesn't allow me to post more links yet)

As Virgil mentions, the data must be 32-bit (or 4-byte) aligned, which means you need to remember to specify the strides in step 3 (as shown in the snippet).

Answer 4

hi...

can u please provide the full coding for this converter cause i'm a beginner and its difficult for me to understand....

thank u in advance...

Answer 5

from PyQt4 import QtGui, QtCore

img = QtGui.QImage("greyScaleImage.png")

bytes=img.bits().asstring(img.numBytes())

from PIL import Image

pilimg = Image.frombuffer("L",(img.width(),img.height()),bytes,'raw', "L", 0, 1)

pilimg.show()

Thanks Eli Bendersky, your code was helpful.

-Chenna

Answer 6

#Code for converting grayscale QImage to PIL image

from PyQt4 import QtGui, QtCore
qimage1 = QtGui.QImage("t1.png")
bytes=qimage1.bits().asstring(qimage1.numBytes())
from PIL import Image
pilimg = Image.frombuffer("L",(qimage1.width(),qimage1.height()),bytes,'raw', "L", 0, 1)
pilimg.show()