将NSView保存到PNG文件？

Question

我正在制作一个简单的程序，为我玩的游戏创造游戏卡。我已经把它寄给了我的一些朋友进行测试，但他们真的希望它保存图像，而不仅仅是打印它们。我试图使它另存为.png文件。我在这里有问题。

• 如何使其将我的视图保存为.png文件，包括所有视图的nsimagewells。

• 如何将nspopupbutton添加到NSSavePanel以允许用户选择格式？

  任何帮助非常感谢。

Answer 1

First create a TIFF representation of your view:

// Get the data into a bitmap.
[self lockFocus];
rep = [[NSBitmapImageRep alloc] initWithFocusedViewRect:[self bounds]];
[self unlockFocus];
data = [rep TIFFRepresentation];

To support multiple file types, use:

data = [rep representationUsingType:(NSBitmapImageFileType)storageType
properties:(NSDictionary *)properties];

NSBitmapImageFileType is an enum constant specifying a file type for bitmap images. It can be NSBMPFileType, NSGIFFileType, NSJPEGFileType, NSPNGFileType, or NSTIFFFileType.

If you need to customize the NSSavePanel, look into accessory views: http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/AppFileMgmt/Articles/ManagingAccessoryViews.html

Answer 2

// Get the data into a bitmap.
[viewBarChart lockFocus];
NSBitmapImageRep *rep = [[NSBitmapImageRep alloc] initWithFocusedViewRect:[viewBarChart bounds]];
[viewBarChart unlockFocus];
NSData *exportedData = [rep representationUsingType:NSJPEGFileType properties:nil];

NSSavePanel *savepanel = [NSSavePanel savePanel];
savepanel.title = @"Save chart";

[savepanel setAllowedFileTypes:[NSArray arrayWithObject:@"jpg"]];

[savepanel beginSheetModalForWindow:self.view.window completionHandler:^(NSInteger result)
 {
     if (NSFileHandlingPanelOKButton == result)
     {
         NSURL* fileURL = [savepanel URL];

         if ([fileURL.pathExtension isEqualToString:@""])
             fileURL = [fileURL URLByAppendingPathExtension:@"jpg"];

         [exportedData writeToURL:fileURL atomically:YES];
     }

     [rep release];
 }];