I am writing a program using PyQt4 for front-end GUI and this program accesses a back-end database (which can be either MySQL or SQLite). I need to store some image data in the database and below is the Python code I use to import image files (in JPEG format) to a blob data field in the database:
def dump_image(imgfile):i = open(imgfile, 'rb')i.seek(0)w = i.read()i.close()return cPickle.dumps(w,1)blob = dump_image(imgfile)
hex_str = blob.encode('hex')
# x"%s"%hex_str will be the string inserted into the SQL command
This part works fine. My question is about how to create a QPixmap object from the image data stored in the database in PyQt4. My current approach involves the following steps:
(1) Hex str in database -- cPickle&StringIO --> PIL Image Object
def load_image(s):o = cPickle.loads(s)c = StringIO.StringIO()c.write(o)c.seek(0)im = Image.open(c)return im
(2) PIL Image Object -->Temporary image file
(3) Temporary image file --> QPixmap
This approach also works fine. But it would be better if I don't have to write/read temporary image files which may slow down the program response to user interactions. I guess I could use QPixmap::loadFromData() to directly load from the blob data stored in the database and hope someone here could show me an example on how to use this function.
TIA,
Bing