一：根据url，获取网络图片的尺寸大小：
+(CGSize)getImageSizeWithURL:(id)imageURL
{
NSURL* URL = nil;
if([imageURL isKindOfClass:[NSURLclass]]){
URL = imageURL;
}
if([imageURL isKindOfClass:[NSStringclass]]){
URL = [NSURL URLWithString:imageURL];
}
if(URL == nil)
return CGSizeZero;// url不正确返回CGSizeZero
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:URL];
NSString* pathExtendsion = [URL.pathExtension lowercaseString];
CGSize size = CGSizeZero;
if([pathExtendsion isEqualToString:@"png"]){
size = [self getPNGImageSizeWithRequest:request];
}
elseif([pathExtendsion isEqual:@"gif"])
{
size = [self getGIFImageSizeWithRequest:request];
}
else{
size = [self getJPGImageSizeWithRequest:request];
}
if(CGSizeEqualToSize(CGSizeZero, size))// 如果获取文件头信息失败,发送异步请求请求原图 {
NSData* data = [NSURLConnection sendSynchronousRequest:[NSURLRequest requestWithURL:URL] returningResponse:nil error:nil];
UIImage* image = [UIImage imageWithData:data];
if(image)
{
size = image.size;
}
}
return size;
}
// 获取PNG图片的大小
+(CGSize)getPNGImageSizeWithRequest:(NSMutableURLRequest*)request
{
[request setValue:@"bytes=16-23"forHTTPHeaderField:@"Range"];
NSData* data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
if(data.length ==8)
{
intw1 =0, w2 =0, w3 =0, w4 =0;
[data getBytes:&w1 range:NSMakeRange(0,1)];
[data getBytes:&w2 range:NSMakeRange(1,1)];
[data getBytes:&w3 range:NSMakeRange(2,1)];
[data getBytes:&w4 range:NSMakeRange(3,1)];
intw = (w1 <<24) + (w2 <<16) + (w3 <<8) + w4;
inth1 =0, h2 =0, h3 =0, h4 =0;
[data getBytes:&h1 range:NSMakeRange(4,1)];
[data getBytes:&h2 range:NSMakeRange(5,1)];
[data getBytes:&h3 range:NSMakeRange(6,1)];
[data getBytes:&h4 range:NSMakeRange(7,1)];
inth = (h1 <<24) + (h2 <<16) + (h3 <<8) + h4;
return CGSizeMake(w, h);
}
return CGSizeZero;
}
// 获取gif图片的大小
+(CGSize)getGIFImageSizeWithRequest:(NSMutableURLRequest*)request
{
[request setValue:@"bytes=6-9"forHTTPHeaderField:@"Range"];
NSData* data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
if(data.length ==4)
{
shortw1 =0, w2 =0;
[data getBytes:&w1 range:NSMakeRange(0,1)];
[data getBytes:&w2 range:NSMakeRange(1,1)];
shortw = w1 + (w2 <<8);
shorth1 =0, h2 =0;
[data getBytes:&h1 range:NSMakeRange(2,1)];
[data getBytes:&h2 range:NSMakeRange(3,1)];
shorth = h1 + (h2 <<8);
return CGSizeMake(w, h);
}
return CGSizeZero;
}
//
获取jpg图片的大小
+(CGSize)getJPGImageSizeWithRequest:(NSMutableURLRequest*)request
{
[request setValue:@"bytes=0-209"forHTTPHeaderField:@"Range"];
NSData* data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
if([data length] <=0x58) {
return CGSizeZero;
}
if([data length] <210) {// 肯定只有一个DQT字段shortw1 =0, w2 =0;
[data getBytes:&w1 range:NSMakeRange(0x60,0x1)];
[data getBytes:&w2 range:NSMakeRange(0x61,0x1)];
shortw = (w1 <<8) + w2;
shorth1 =0, h2 =0;
[data getBytes:&h1 range:NSMakeRange(0x5e,0x1)];
[data getBytes:&h2 range:NSMakeRange(0x5f,0x1)];
shorth = (h1 <<8) + h2;
return CGSizeMake(w, h);
} else {
shortword =0x0;
[data getBytes:&word range:NSMakeRange(0x15,0x1)];
if(word ==0xdb) {
[data getBytes:&word range:NSMakeRange(0x5a,0x1)];
if(word ==0xdb) {// 两个DQT字段shortw1 =0, w2 =0;
[data getBytes:&w1 range:NSMakeRange(0xa5,0x1)];
[data getBytes:&w2 range:NSMakeRange(0xa6,0x1)];
shortw = (w1 <<8) + w2;
shorth1 =0, h2 =0;
[data getBytes:&h1 range:NSMakeRange(0xa3,0x1)];
[data getBytes:&h2 range:NSMakeRange(0xa4,0x1)];
shorth = (h1 <<8) + h2;
return CGSizeMake(w, h);
} else{// 一个DQT字段shortw1 =0, w2 =0;
[data getBytes:&w1 range:NSMakeRange(0x60,0x1)];
[data getBytes:&w2 range:NSMakeRange(0x61,0x1)];
shortw = (w1 <<8) + w2;
shorth1 =0, h2 =0;
[data getBytes:&h1 range:NSMakeRange(0x5e,0x1)];
[data getBytes:&h2 range:NSMakeRange(0x5f,0x1)];
shorth = (h1 <<8) + h2;
return CGSizeMake(w, h);
}
} else {
return CGSizeZero;
}
}
}
二：获取本地图片：
在获取本地的图片的时候，要注意一个问题，就是该图片是本地已经有的，还是本地没有，通过下载来的。两种情况。
1.本地已经存在的获取图片尺寸的方法：
CGSize size = [UIImage imageNamed:@"regStep2_sex"].size;
2.通过先下载到本地，在获取图片尺寸的，要先找到图片的路径，在获取尺寸,如果直接获取，则会导致程序奔溃，因为找不到图片路径：
NSString *documentPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
NSString *path1 = [documentPath stringByAppendingPathComponent:@"ss.png"];
UIImage *image1=[UIImage imageWithContentsOfFile:path1];
CGSize size=image1.size;
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