QWMatrix::mapRect

[Pharell]

Hello all,

I am fighting with a problem regarding mapping a rectangle which is not of

QRect type. I want to rotate the rectangle 90 degree counterclockwise and

I just did it as follow but the result is not what I want.Instead the rectangle

gets larger in size. Can someone give me suggestions how to solve this problem?


QWMatrix matrixWorld;
QRect newRect;
double rotateDegree = 90.0;

newRect.setRect(myRect.Left(), myRect.Top(), myRect.Width(), myRect.Height());
matrixWorld.rotate(rotateDegree);
newRect = matrixWorld.mapRect(newRect);
myRect.Rect(newRect.left(), newRect.top(), newRect.width(), newRect.height());

[aamer4yu]

What is QWMatrix ???

[Pharell]

The QWMatrix class specifies 2D transformations of a coordinate system.
The standard coordinate system of a paint device has the origin located at the top-left position. X values increase to the right; Y values increase downward.

[Pharell]

Anyone knows how to solve this problem?? :confused:

[spirit]

in Qt I found only QMatrix and there are some small examples with rotation. the interafe of this class very similar to class which you was describe.

[jacek]

You can do the 90 degrees rotation without any matrices. Just swap coordinates and multiply one of them by -1.