在iPhone应用程序中存储图像时压缩/缩小尺寸/调整图像大小

Question

要了解我的问题,请通过以下方式:

• 在我的应用程序中,用户首先点击一个按钮.
• 显示图像选择器控制器
• 用户从中选择图像/图像.
• 所有图像必须保存到我的iPhone应用程序.

我已经实现了这一点,为此,我实现了以下代码.

 -(IBAction)setPhoto:(id)sender {
    facPhotoPicker=[[UIImagePickerController alloc]init];
    facPhotoPicker.delegate=self;
    facPhotoPicker.sourceType=UIImagePickerControllerSourceTypePhotoLibrary;
    facPhotoPicker.allowsImageEditing=YES;
    facPhotoPicker.navigationBar.barStyle=UIBarStyleBlackOpaque;
    [self presentModalViewController:facPhotoPicker animated:YES];
}

-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary*)info {
    NSData *imgData=UIImageJPEGRepresentation([info objectForKey:@"UIImagePickerControllerOriginalImage"],1);
    UIImage *img=[[UIImage alloc] initWithData:imgData];
    facImgView.image=img;
    [img release];
    NSString *str=[NSString stringWithFormat:@"%i.jpg",[currentFaculty facultyNo]];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *path = [NSString stringWithFormat:@"%@/%@", [paths objectAtIndex:0], str];
    [imgData writeToFile:path atomically:YES];
    [picker dismissModalViewControllerAnimated:YES];
}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
    [picker dismissModalViewControllerAnimated:YES];
}

但问题是用户的iPhone可能有更大的图像.

我不想在应用程序中存储那些大图像.例如

• 用户选择尺寸为1200 x 800的图像

• 但我只想要80 x 80尺寸的图像

  1. 所选图像的尺寸应根据我的要求/ 8 mb图像减小到500 kb以下
  2. 如何在资源目录中存储图像而不是存储在文档目录中？

Answer 1

这解决了.

缩小规模的关键.我将图像缩小到116 kb.

NSData *imgData=UIImageJPEGRepresentation([info objectForKey:@"UIImagePickerControllerOriginalImage"],compressionRatio);
while ([imgData length]>50000) { 
    compressionRatio=compressionRatio*0.5;
    imgData=UIImageJPEGRepresentation([info objectForKey:@"UIImagePickerControllerOriginalImage"],compressionRatio);
}

-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary*)info
{
double compressionRatio=1;
NSData *imgData=UIImageJPEGRepresentation([info objectForKey:@"UIImagePickerControllerOriginalImage"],compressionRatio);
while ([imgData length]>50000) { 
    compressionRatio=compressionRatio*0.5;
    imgData=UIImageJPEGRepresentation([info objectForKey:@"UIImagePickerControllerOriginalImage"],compressionRatio);
}
UIImage *img=[[UIImage alloc] initWithData:imgData];
facImgView.image=img;
NSLog(@"%@",[info objectForKey:@"UIImagePickerControllerOriginalImage"],3);
[img release];


NSString *str=[NSString stringWithFormat:@"%i.jpg",[currentFaculty facultyNo]];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *path = [NSString stringWithFormat:@"%@", [paths objectAtIndex:0]];
path=[path stringByDeletingLastPathComponent];
path=[NSString stringWithFormat:@"%@/%@",path,str];
[imgData writeToFile:path atomically:YES];
[picker dismissModalViewControllerAnimated:YES];
}