如何在不影响质量的情况下以编程方式缩小图像。
捕获图像后,我想在不改变 objective-c 质量的情况下减小该图像的大小。
最佳答案
这是我用来压缩图片的代码
代码:
-(UIImage *)compressImage:(UIImage *)image{
NSData *imgData = UIImageJPEGRepresentation(image, 1); //1 it represents the quality of the image.
NSLog(@"Size of Image(bytes):%ld",(unsigned long)[imgData length]);
float actualHeight = image.size.height;
float actualWidth = image.size.width;
float maxHeight = 600.0;
float maxWidth = 800.0;
float imgRatio = actualWidth/actualHeight;
float maxRatio = maxWidth/maxHeight;
float compressionQuality = 0.5;//50 percent compression
if (actualHeight > maxHeight || actualWidth > maxWidth){
if(imgRatio < maxRatio){
//adjust width according to maxHeight
imgRatio = maxHeight / actualHeight;
actualWidth = imgRatio * actualWidth;
actualHeight = maxHeight;
}
else if(imgRatio > maxRatio){
//adjust height according to maxWidth
imgRatio = maxWidth / actualWidth;
actualHeight = imgRatio * actualHeight;
actualWidth = maxWidth;
}
else{
actualHeight = maxHeight;
actualWidth = maxWidth;
}
}
CGRect rect = CGRectMake(0.0, 0.0, actualWidth, actualHeight);
UIGraphicsBeginImageContext(rect.size);
[image drawInRect:rect];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
NSData *imageData = UIImageJPEGRepresentation(img, compressionQuality);
UIGraphicsEndImageContext();
NSLog(@"Size of Image(bytes):%ld",(unsigned long)[imageData length]);
return [UIImage imageWithData:imageData];
}
所以这是使用上面的代码
UIImage *org = [UIImage imageNamed:@"MacLehose Stage 7 Stunning Natural Sceneries.jpg"];
UIImage *imgCompressed = [self compressImage:org];
如果要压缩更多
NSData *dataImage = UIImageJPEGRepresentation(imgCompressed, 0.0);
NSLog(@"Size of Image(bytes):%ld",(unsigned long)[dataImage length]);
通过上述方式,我能够将图像从 2 MB 压缩到接近 50 KB。
关于ios - 在不影响 objective-c 质量的情况下缩小图像,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/40129215/