UIImage+RCTCompress.m
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//
// UIImage+RCTCompress.m
// RCTWeChat
//
// Created by admin on 2021/2/26.
// Copyright © 2021 WeFlex. All rights reserved.
//
#import "UIImage+RCTCompress.h"
@implementation UIImage (RCTCompress)
-(NSData *)compressWithLengthLimit:(NSUInteger)maxLength{
// Compress by quality
CGFloat compression = 1;
NSData *data = UIImageJPEGRepresentation(self, compression);
//NSLog(@"Before compressing quality, image size = %ld KB",data.length/1024);
if (data.length < maxLength) return data;
CGFloat max = 1;
CGFloat min = 0;
for (int i = 0; i < 6; ++i) {
compression = (max + min) / 2;
data = UIImageJPEGRepresentation(self, compression);
//NSLog(@"Compression = %.1f", compression);
//NSLog(@"In compressing quality loop, image size = %ld KB", data.length / 1024);
if (data.length < maxLength * 0.9) {
min = compression;
} else if (data.length > maxLength) {
max = compression;
} else {
break;
}
}
//NSLog(@"After compressing quality, image size = %ld KB", data.length / 1024);
if (data.length < maxLength) return data;
UIImage *resultImage = [UIImage imageWithData:data];
// Compress by size
NSUInteger lastDataLength = 0;
while (data.length > maxLength && data.length != lastDataLength) {
lastDataLength = data.length;
CGFloat ratio = (CGFloat)maxLength / data.length;
//NSLog(@"Ratio = %.1f", ratio);
CGSize size = CGSizeMake((NSUInteger)(resultImage.size.width * sqrtf(ratio)),
(NSUInteger)(resultImage.size.height * sqrtf(ratio))); // Use NSUInteger to prevent white blank
UIGraphicsBeginImageContext(size);
[resultImage drawInRect:CGRectMake(0, 0, size.width, size.height)];
resultImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
data = UIImageJPEGRepresentation(resultImage, compression);
//NSLog(@"In compressing size loop, image size = %ld KB", data.length / 1024);
}
//NSLog(@"After compressing size loop, image size = %ld KB", data.length / 1024);
return data;
}
- (NSData *)compressQualityWithLengthLimit:(NSInteger)maxLength {
CGFloat compression = 1;
NSData *data = UIImageJPEGRepresentation(self, compression);
while (data.length > maxLength && compression > 0) {
compression -= 0.02;
data = UIImageJPEGRepresentation(self, compression); // When compression less than a value, this code dose not work
}
return data;
}
-(NSData *)compressMidQualityWithLengthLimit:(NSInteger)maxLength{
CGFloat compression = 1;
NSData *data = UIImageJPEGRepresentation(self, compression);
if (data.length < maxLength) return data;
CGFloat max = 1;
CGFloat min = 0;
for (int i = 0; i < 6; ++i) {
compression = (max + min) / 2;
data = UIImageJPEGRepresentation(self, compression);
if (data.length < maxLength * 0.9) {
min = compression;
} else if (data.length > maxLength) {
max = compression;
} else {
break;
}
}
return data;
}
-(NSData *)compressBySizeWithLengthLimit:(NSUInteger)maxLength{
UIImage *resultImage = self;
NSData *data = UIImageJPEGRepresentation(resultImage, 1);
NSUInteger lastDataLength = 0;
while (data.length > maxLength && data.length != lastDataLength) {
lastDataLength = data.length;
CGFloat ratio = (CGFloat)maxLength / data.length;
CGSize size = CGSizeMake((NSUInteger)(resultImage.size.width * sqrtf(ratio)),
(NSUInteger)(resultImage.size.height * sqrtf(ratio))); // Use NSUInteger to prevent white blank
UIGraphicsBeginImageContext(size);
// Use image to draw (drawInRect:), image is larger but more compression time
// Use result image to draw, image is smaller but less compression time
[resultImage drawInRect:CGRectMake(0, 0, size.width, size.height)];
resultImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
data = UIImageJPEGRepresentation(resultImage, 1);
}
return data;
}
@end