PocketMatrix

Hi,
i am programming for iPhone, i want to scale an image, based on user's touch (touch one corner of image and drag it).
how can i scale the image.
i tried the following, but it displays nothing:

//member variables declaration part
E2DBLTFX bltfx;

//constructor
bltfx.xscale = 3;
bltfx.yscale = 3;

//OnNextFrame function
display -> BltFx(10, 10, image, &rect, &bltfx);


But there wsa no problem with rendering the image normally:
display -> BltFast(100, 100, image, &rect)
the above statement displays the image properly.