QGLShaderProgram::setUniformValue(int location, const QSize& size) method sends (width, width) to shader instead or (width, height).

The method QGLShaderProgram::setUniformValue(int location, const QSize& size) sends the values (width, width) to the shader instead of sending (width, height).

See http://qt.gitorious.org/qt/qt/blobs/4.7/src/opengl/qglshaderprogram.cpp, line 2124. (Compare with line 2153 or 2066, the equivalent methods with QSizeF and QPoint arguments.)