可以在uiimage的分类中加入下面的代码,并且引入系统的imageio.framework
我要评论/**
根据图片的url获取尺寸
@param url url
@return cgsize
*/
+ (cgsize)getimagesizewithurl:(id)url;
/**
* 根据图片url获取图片尺寸
*/
+ (cgsize)getimagesizewithurl:(id)url{
nsurl * url = nil;
if ([url iskindofclass:[nsurl class]]) {
url = url;
}
if ([url iskindofclass:[nsstring class]]) {
url = [nsurl urlwithstring:url];
}
if (!url) {
return cgsizezero;
}
cgimagesourceref imagesourceref = cgimagesourcecreatewithurl((cfurlref)url, null);
cgfloat width = 0, height = 0;
if (imagesourceref) {
cfdictionaryref imageproperties = cgimagesourcecopypropertiesatindex(imagesourceref, 0, null);
if (imageproperties != null) {
cfnumberref widthnumberref = cfdictionarygetvalue(imageproperties, kcgimagepropertypixelwidth);
if (widthnumberref != null) {
cfnumbergetvalue(widthnumberref, kcfnumberfloat64type, &width);
}
cfnumberref heightnumberref = cfdictionarygetvalue(imageproperties, kcgimagepropertypixelheight);
if (heightnumberref != null) {
cfnumbergetvalue(heightnumberref, kcfnumberfloat64type, &height);
}
cfrelease(imageproperties);
}
cfrelease(imagesourceref);
}
return cgsizemake(width, height);
}
实践证明,网上的另外一种方法是不可行存在问题的,贴上所示的图片url:http://xs3.op.xywy.com/club.xywy.com/doc/20181017/0fd2a51f9435a4.jpg
// 根据图片url获取图片尺寸
-(cgsize)getimagesizewithurl:(id)imageurl
{
nsurl* url = nil;
if([imageurl iskindofclass:[nsurl class]]){
url = imageurl;
}
if([imageurl iskindofclass:[nsstring class]]){
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];
}
else if([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)
{
int w1 = 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)];
int w = (w1 << 24) + (w2 << 16) + (w3 << 8) + w4;
int h1 = 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)];
int h = (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)
{
short w1 = 0, w2 = 0;
[data getbytes:&w1 range:nsmakerange(0, 1)];
[data getbytes:&w2 range:nsmakerange(1, 1)];
short w = w1 + (w2 << 8);
short h1 = 0, h2 = 0;
[data getbytes:&h1 range:nsmakerange(2, 1)];
[data getbytes:&h2 range:nsmakerange(3, 1)];
short h = 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
short w1 = 0, w2 = 0;
[data getbytes:&w1 range:nsmakerange(0x60, 0x1)];
[data getbytes:&w2 range:nsmakerange(0x61, 0x1)];
short w = (w1 << 8) + w2;
short h1 = 0, h2 = 0;
[data getbytes:&h1 range:nsmakerange(0x5e, 0x1)];
[data getbytes:&h2 range:nsmakerange(0x5f, 0x1)];
short h = (h1 << 8) + h2;
return cgsizemake(w, h);
} else {
short word = 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
short w1 = 0, w2 = 0;
[data getbytes:&w1 range:nsmakerange(0xa5, 0x1)];
[data getbytes:&w2 range:nsmakerange(0xa6, 0x1)];
short w = (w1 << 8) + w2;
short h1 = 0, h2 = 0;
[data getbytes:&h1 range:nsmakerange(0xa3, 0x1)];
[data getbytes:&h2 range:nsmakerange(0xa4, 0x1)];
short h = (h1 << 8) + h2;
return cgsizemake(w, h);
} else {// 一个dqt字段
short w1 = 0, w2 = 0;
[data getbytes:&w1 range:nsmakerange(0x60, 0x1)];
[data getbytes:&w2 range:nsmakerange(0x61, 0x1)];
short w = (w1 << 8) + w2;
short h1 = 0, h2 = 0;
[data getbytes:&h1 range:nsmakerange(0x5e, 0x1)];
[data getbytes:&h2 range:nsmakerange(0x5f, 0x1)];
short h = (h1 << 8) + h2;
return cgsizemake(w, h);
}
} else {
return cgsizezero;
}
}
}
源自:https://www.jianshu.com/p/9984c37f3f54
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