iOS iPhone CGImage Memory problems - iphone

Question

I'm trying to create a visual representation of some data I have.
The function I have works and creates the image perfectly (and VERY quickly) but under instruments the Real Memory usage rockets and eventually crashes the app.
I have replaced my function with a return [UIImage imageNamed:#"blah"]; and the memory problems vanish completely.
Was wondering if someone could see why and where the memory is being taken up and how I could possibly free it again?
I have run in instruments under the allocations and leaks tool but nothing shows up in there.
The function is...
- (UIImage*)imageOfMapWithDeadColor:(UIColor *)deadColor aliveColor:(UIColor *)aliveColor
{
//translate colours into rgb components
if ([deadColor isEqual:[UIColor whiteColor]]) {
dr = dg = db = 255;
} else if ([deadColor isEqual:[UIColor blackColor]]) {
dr = dg = db = 0;
} else {
[deadColor getRed:&drf green:&dgf blue:&dbf alpha:&blah];
dr = drf * 255;
dg = dgf * 255;
db = dbf * 255;
}
if ([aliveColor isEqual:[UIColor whiteColor]]) {
ar = ag = ab = 255;
} else if ([aliveColor isEqual:[UIColor blackColor]]) {
ar = ag = ab = 0;
} else {
[aliveColor getRed:&arf green:&agf blue:&abf alpha:&blah];
ar = arf * 255;
ag = agf * 255;
ab = abf * 255;
}
//create bytes of image from the cell map
int yRef, cellRef;
unsigned char *cell_ptr = cells;
for (int y=0; y<self.height; y++)
{
yRef = y * (self.width * 4);
int x = 0;
do
{
cellRef = yRef + 4 * x;
if (*cell_ptr & 0x01) {
//alive colour
buffer[cellRef] = ar;
buffer[cellRef + 1] = ag;
buffer[cellRef + 2] = ab;
buffer[cellRef + 3] = 255;
} else {
//dead colour
buffer[cellRef] = dr;
buffer[cellRef + 1] = dg;
buffer[cellRef + 2] = db;
buffer[cellRef + 3] = 255;
}
cell_ptr++;
} while (++x < self.width);
}
//create image
imageRef = CGImageCreate(self.width, self.height, 8, 32, 4 * self.width, CGColorSpaceCreateDeviceRGB(), kCGBitmapByteOrderDefault, provider, NULL, NO, kCGRenderingIntentDefault);
UIImage *image = [UIImage imageWithCGImage:imageRef];
//return image
return image;
}
a few notes...
buffer is an ivar GLubyte malloc-ed in the init.
cells is the original unsigned char array that I'm taking the data from.
Like I said, the function works perfectly (creating the image etc...) I just get a massive usage of memory.
Oh... this function is called LOTS, like 30 times a second or more (which I know will make a difference).
Thanks for any help.

Answer 1

You use CGImageCreate and the docs say :
Return Value
A new Quartz bitmap image. You are responsible for releasing this object by calling CGImageRelease.