Something error with GPUImageGaussianBlurFilter?

[Shun87]

Hello BradLarson, I found there are still something wrong. When I run FilterShowcase demo, I made a change to the newFrameReadyAtTime function of GPUImageFilter class like this, change all value in imageVertices from 1.0 to 0.5:
static const GLfloat imageVertices[] = {
-0.5f, -0.5f,
0.5f, -0.5f,
-0.5f, 0.5f,
0.5f, 0.5f,
};
The result texture rendered on screen in gaussianBlur demo was ## 1/16 size of view port, I think it should be 1/4, the result x or y is only 0.25, not 0.5, what's wrong? Other filter works well, for example gray scale.