//转化为jpg图片并压缩方法：
UIImageJPEGRepresentation(image, compression);
/**
压图片质量
@param image image
*/
- (NSData *)zipImageWithImage:(UIImage *)image
{
if (!image) {
return nil;
}
CGFloat maxFileSize = 500*1024;
CGFloat compression = 0.9f;
NSData *compressedData = UIImageJPEGRepresentation(image, compression);
while ([compressedData length] > maxFileSize) {
compression *= 0.9;
compressedData = UIImageJPEGRepresentation([self compressImage:image newWidth:image.size.width*compression], compression);
}
return compressedData;
}
/**
* 等比缩放本图片大小
* @param newImageWidth 缩放后图片宽度，像素为单位
* @return self-->(image)
*/
- (UIImage *)compressImage:(UIImage *)image newWidth:(CGFloat)newImageWidth
{
if (!image) return nil;
float imageWidth = image.size.width;
float imageHeight = image.size.height;
float width = newImageWidth;
float height = image.size.height/(image.size.width/width);
float widthScale = imageWidth /width;
float heightScale = imageHeight /height;
// 创建一个bitmap的context
// 并把它设置成为当前正在使用的context
UIGraphicsBeginImageContext(CGSizeMake(width, height));
if (widthScale > heightScale) {
[image drawInRect:CGRectMake(0, 0, imageWidth /heightScale , height)];
}
else {
[image drawInRect:CGRectMake(0, 0, width , imageHeight /widthScale)];
}
// 从当前context中创建一个改变大小后的图片
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
// 使当前的context出堆栈
UIGraphicsEndImageContext();
return newImage;
}
