PySide: showing an base64 image on a QMainWindow [Resolved]

kamalakshantv

[quote author="VCsala" date="1293047083"]I do not know how it works in python but in C++ I would just read it to a QByteArray, decode to raw data, load from it (with loadFromData) to QPixmap and show it on a QLabel.[/quote]

Yes, you are right as mentioned in "this":http://www.qtcentre.org/threads/25186-Encode-decode-base-64-images thread

grizmio

thanks for the guide

I read http://www.qtcentre.org/threads/25186-Encode-decode-base-64-images
and I tried to mod the following example/code to work in pyside:

@
QByteArray by = QByteArray::fromBase64("iV...........AABAgQIECBAgAABAgQIECBwrQLfmeUk6E23pFsAAAAASUVORK5CYII=");
QImage image = QImage::fromData(by, "PNG");
QLabel label;
label.setPixmap(QPixmap::fromImage(image));
label.show();
@

First, I created the call.base64 using:
@
<?php
$imgfile = "call.png";
$handle = fopen($imgfile, "r");
$imgbinary = fread(fopen($imgfile, "r"), filesize($imgfile));
$fw = fopen('call.base64', 'w');
print_r(base64_encode($imgbinary));
fwrite($fw, base64_encode($imgbinary));
fclose($fw);
//echo '<img />';
?>
@

then using pyside:
@
imagen64 = open('call.base64','r').read()
imagen = QtGui.QImage()
bytearr = QtCore.QByteArray(imagen64)
print "devuelta:", imagen.loadFromData( bytearr, 'PNG' )
self.label.setPixmap( QtGui.QPixmap.fromImage(imagen) )
print self.label.pixmap()
@

but, doesn't this display anything.
if I set a text first in the label, it disappear when setting the pixmap

when the next gets executed:
@print "devuelta:", imagen.loadFromData( bytearr, 'PNG' )@
it returns "devuelta: False"

even if I use:
@
bytearr = QtCore.QByteArray("iV...........AABAgQIECBAgAABAgQIECBwrQLfmeUk6E23pFsAAAAASUVORK5CYII=")
@

doesn't work.
thanks for your time and help

[EDIT: added @-tags for code formatting, Volker]

goetz

grizmio, please add @-tags around your code or use the icon in the editor. It makes your code much more easier to read.

grizmio

Thanks Volker, it looks really nice now, lesson learned :)

goetz

Just checked the code now: In your pyside code, you do not decode the base64 encoded data. Instead you feed the base64 characters into the image. I'm not familiar with PySide, but there should be a fromBase64 method too.

grizmio

yes, you are righ there is a fromBase64 method, but even if I change it, still don't work.
maybe I'm using a bad encoded image.
Now I'm using:
@
bytearr.fromBase64( imagen64 )
@

if I run it, the print bytearr.length() prints 0
here's the actual method:
@
def getImage(self):
imagen64 = open('call.base64','r').read()
print "#############################"

    imagen = QtGui.QImage()
    bytearr = QtCore.QByteArray()
    bytearr.fromBase64(  imagen64  ) 
    pprint.pprint( bytearr.length() )
    print imagen.loadFromData(   bytearr, 'PNG'   )
    self.label.setPixmap(    QtGui.QPixmap.fromImage(imagen)   )
    print self.label.pixmap()
    self.label.show()
    # self.label.setAlignment(QtCore.Qt.AlignBottom | QtCore.Qt.AlignRight)
    print "DONE"

@
here is the photo/image, maybe someone could encode it just for check:
!http://img543.imageshack.us/img543/5513/callq.png!
here you could find the magic string
"image in base64 with php":http://pastebin.com/raw.php?i=agGhq88V

any ideas?anything will be appreciate :)

[EDIT: fixed image tag, Volker]

goetz

In C++ Qt fromBase64() is a static function, i.e. it returns a the decoded data, but does not manipulate the data of an instance. Maybe there is something similar in Python, I don't know.

Naively I would try

@
bytearr = QtCore.QByteArray.fromBase64( imagen64 )
@

but I don't know if this is valid Python syntax.

grizmio

genius!!! that is my mistake! now it works!
I think it's time to study about static functions.

really really thank you!
:):):):)

EOF

goetz

You're welcome. I'm glad that it helped - I never did anything with Python, so this was just a blind guess :-)

grizmio

a nice blind guess!

if someone else wants to do the same, or is searching for an example:
@
def getImage(self):
imagen64 = open('call.base64','r').read()
imagen = QtGui.QImage()
bytearr = QtCore.QByteArray.fromBase64( imagen64 )
imagen.loadFromData( bytearr, 'PNG' )
self.label.setPixmap( QtGui.QPixmap.fromImage(imagen) )
@
where:
call.base64 is a file containing the base64 string with no CR nor LF, with a string of length:1888
encoded using php:
@
$imgfile = "call.png";
$handle = fopen($imgfile, "r");
$imgbinary = fread(fopen($imgfile, "r"), filesize($imgfile));
$fw = fopen('call.base64', 'w');
fwrite($fw, base64_encode($imgbinary));
fclose($fw);
@
with imports:
@
from PySide import QtCore, QtGui
@