Objective c Photoshop的OSX脚本桥选项

我正试图将Adobe Photoshop中的图像保存为PNG，我用以下代码实现了这一点

AdobePhotoshopApplication* psApp = [SBApplication applicationWithBundleIdentifier:@"com.adobe.Photoshop"];
AdobePhotoshopDocument *curDoc   = [psApp currentDocument];
AdobePhotoshopDocument *temp     = [curDoc saveIn:[NSURL URLWithString:[path stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]] as:AdobePhotoshopSvFmPNG copying:YES appending:AdobePhotoshopE300LowercaseExtension withOptions:nil];

这里唯一的问题是，即使是一个简单的图像也需要4-5MB。现在我想在

saveIn:as:copying:appending:withOptions:

我可以在选项中提供压缩值，如中所示

// Settings related to saving a PNG document
@interface AdobePhotoshopPNGSaveOptions : AdobePhotoshopSaveOptions    
@property NSInteger compression;  // compression used on the image. ( 0 - 9; default: 0 )
@property BOOL interlaced;  // should rows be interlaced? ( default: false )    
@end

问题是，当我创建选项并将其传递给

saveIn

方法时，我得到以下错误

*** NSForwarding: warning: object 0x618000030280 of class '__NSMessageBuilder' does not implement doesNotRecognizeSelector: -- abort

我创建了

AdobePhotoshopPNGSaveOptions

AdobePhotoshopPNGSaveOptions *options = [[psApp classForScriptingClass:@"PNG save options"] new];

我不知道从这里到哪里去