我想获取图像的大小而不加载它,所以我使用下面的代码
-(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;
}
问题是imageSource始终为NULL 有没有人知道,为什么它不起作用!!
请注意,URL是JPG或PNG图像的有效链接
答案 0 :(得分:1)
您是否启用了ARC?我没有,我的工作代码如下:
NSURL * imageFileURL = [NSURL fileURLWithPath:fp];
CGImageSourceRef imageSource = CGImageSourceCreateWithURL((CFURLRef)imageFileURL, NULL);
请注意缺少__bridge
。完成btw后,我在CFRelease
上致电imageSource
。