Thank You for this explanation. As suggested by Krzysztof I changed the matrix to be an identity one, but then why can't I see any changes in the application. I mean nothing is happening by changing it to identity matrix. But as told, _doc2dt represents the mapping of co-ordinates of two spaces, the thing must show change after changing this matrix to an identity one. I can only report that previously this was the matrix(1,0,0,-1,0,document->height) and i changed it to (1,0,0,1,0,document->height); I hope I did it correctly.I did this change just in the local copy of _doc2dt and nothing happened.

2010/3/29 Krzysztof KosiƄski <>
2010/3/28 Abhishek Sharma <>:
> So this neat trick actually has to do with translations and efficiency, now
> I get it. May some one also kindly specify the reason I was suggested to
> modify the matrix to an identity one. I mean how would changing _doc2dt to
> an identity matrix help in the bug reduction(I am asking this not to comment
> or question anybody, I am just unaware...).

There are two coordinate spaces: the document space, which corresponds
to the SVG specification, and the desktop space, which is the same
except it has the Y axis flipped, and is used to position items on the
canvas. What we want is to change the desktop space to be identical to
the desktop space. _doc2dt determines the mapping between the document
space and desktop space, so we need to change it to the identity
matrix to make those two spaces identical.

Regards, Krzysztof

Abhishek Sharma
B-Tech Information Technology
Indian Institute of Information Technology(Amethi Campus)