How to check uiimage is empty or blank - uiimage

Question

I am using following code to save uiimage. Before saving the image, i want to check the image is empty or blank.
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Note :
UIImage, check if contain image
How to check if a uiimage is blank? (empty, transparent)
I couldn't find solution in the above link. Thanks!!!

Answer 1

I found a solution for the above problem. This may help anyone in future. This below function works perfectly for even PNG transparent image.
-(BOOL)isBlankImage:(UIImage *)myImage
{
typedef struct
{
uint8_t red;
uint8_t green;
uint8_t blue;
uint8_t alpha;
} MyPixel_T;
CGImageRef myCGImage = [myImage CGImage];
//Get a bitmap context for the image
CGContextRef bitmapContext = CGBitmapContextCreate(NULL, CGImageGetWidth(myCGImage), CGImageGetHeight(myCGImage),
CGImageGetBitsPerComponent(myCGImage), CGImageGetBytesPerRow(myCGImage),
CGImageGetColorSpace(myCGImage), CGImageGetBitmapInfo(myCGImage));
//Draw the image into the context
CGContextDrawImage(bitmapContext, CGRectMake(0, 0, CGImageGetWidth(myCGImage), CGImageGetHeight(myCGImage)), myCGImage);
//Get pixel data for the image
MyPixel_T *pixels = CGBitmapContextGetData(bitmapContext);
size_t pixelCount = CGImageGetWidth(myCGImage) * CGImageGetHeight(myCGImage);
for(size_t i = 0; i < pixelCount; i++)
{
MyPixel_T p = pixels[i];
//Your definition of what's blank may differ from mine
if(p.red > 0 || p.green > 0 || p.blue > 0 || p.alpha > 0)
return NO;
}
return YES;
}