cocoa - 如何将 NSImage 保存为新文件

Question

如何将 NSImage 保存为某个目录中的新文件(png、jpg...)？

Answer 1

你可以像这样向 NSImage 添加一个类别

@interface NSImage(saveAsJpegWithName)
- (void) saveAsJpegWithName:(NSString*) fileName;
@end

@implementation NSImage(saveAsJpegWithName)

- (void) saveAsJpegWithName:(NSString*) fileName
{
    // Cache the reduced image
    NSData *imageData = [self TIFFRepresentation];
    NSBitmapImageRep *imageRep = [NSBitmapImageRep imageRepWithData:imageData];
    NSDictionary *imageProps = [NSDictionary dictionaryWithObject:[NSNumber numberWithFloat:1.0] forKey:NSImageCompressionFactor];
    imageData = [imageRep representationUsingType:NSJPEGFileType properties:imageProps];
    [imageData writeToFile:fileName atomically:NO];        
}

@end

对“TIFFRepresentation”的调用至关重要，否则您可能无法获得有效的图像。