[PyQt] QImage with a trapezoid draw result

Sergi Blanch i Torné sbt at ya.com
Tue Apr 22 15:27:21 BST 2008

Hi again,

I have new information over the trapezoidal problem. The ccd camera is giving 
the images on 12 bits and it means this has to be an unsigned short image and 
the conversion to unsigned char breaks the rows and columns.

As I read in the QImage class documentation the 12 bit grayscale is not 
supported. Do you have an idea or suggestion how to rid it?

Sano kaj liber!


On Wednesday 16 April 2008 10:57:05 Sergi Blanch i Torné wrote:
> Hi!
> I'm try to show an image on a widget but the image appears distorted. This
> widget is receiving images by events with a method where the dimensions has
> also to be sent:
> 	def eventReceived(self, EventSource, EventType, EventValue):
> 		self._imagedata = array.array('B',EventValue.value).tostring()
> 		self._imagedim = [EventValue.dim_x, EventValue.dim_y]
> 		self.ImageResize()
> 		self.emit(QtCore.SIGNAL('newImage()'))
> As this function says (or this is what I try), the image is composed by
> unsigned short values (it's grayscale). Then I have a method where the
> QImage object is created and resized:
> 	def ImageResize(self):
> 		self._image = QtGui.QImage(self._imagedata,
> 					self._imagedim[0],self._imagedim[1],
> 					QtGui.QImage.Format_Indexed8)
> 		width,height = [self.width(),self.height()]
> 		self._image = self._image.scaled(width,height,
> 					Qt.Qt.IgnoreAspectRatio,
> 					Qt.Qt.FastTransformation)
> The image show on the screen looks trapezoidal like if the width hadn't
> been well calculated. I try closing a plus minus value to fix this
> inclination but without success.
> I explain the same but with image samples where:
> http://cryptosynchrotron.blogspot.com/2008/04/pyqt-qimage-problem.html
> And there you can found a link to the widget current code.
> Sano kaj liber!
> /Sergi.
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