CGImageSourceRef imageSource = CGImageSourceCreateWithURL returns NULL

问题

I want to get the Size of the image without loading it so i am using the below code

-(float)gettingimagedimensions:(NSString*)url{
    NSURL *imageFileURL = [NSURL fileURLWithPath:url];
    //CGImageSourceRef imageSource = CGImageSourceCreateWithURL(imageFileURL, NULL);
    CGImageSourceRef imageSource = CGImageSourceCreateWithURL((__bridge CFURLRef)imageFileURL, NULL);
    if (imageSource == NULL) {
        // Error loading image

        return 0;
    }

    CGFloat width = 0.0f, height = 0.0f;
    CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, NULL);
    if (imageProperties != NULL) {
        CFNumberRef widthNum  = CFDictionaryGetValue(imageProperties, kCGImagePropertyPixelWidth);
        if (widthNum != NULL) {
            CFNumberGetValue(widthNum, kCFNumberFloatType, &width);
        }

        CFNumberRef heightNum = CFDictionaryGetValue(imageProperties, kCGImagePropertyPixelHeight);
        if (heightNum != NULL) {
            CFNumberGetValue(heightNum, kCFNumberFloatType, &height);
        }

        CFRelease(imageProperties);
    }

    NSLog(@"Image dimensions: %.0f x %.0f px", width, height);

    return height;
}

The Problem is that imageSource is always NULL Does any body has any idea , why it is not working !!

Please Note that URL are Valid links to images JPG or PNG

回答1:

Do you have ARC enabled? I don't and my working code is as follows:

NSURL * imageFileURL = [NSURL fileURLWithPath:fp];
CGImageSourceRef imageSource = CGImageSourceCreateWithURL((CFURLRef)imageFileURL, NULL);

Note the absence of __bridge. I call CFRelease on imageSource when done btw.

来源：https://stackoverflow.com/questions/16713610/cgimagesourceref-imagesource-cgimagesourcecreatewithurl-returns-null

标签

objective-c

cgimagesource