Reading and Writing Font Data

Font information is stored on the font pasteboard as an attribute of RTF data from an attributed string. To copy and paste a font, therefore, you need to respectively create an attributed string with the appropriate attribute and unpack the information from an attributed string.

Writing Font Data

You copy a font using the pasteboard named NSFontPboard. You must first get the pasteboard, then declare the appropriate type—NSFontPboardType. To create the data to place on the pasteboard, you create an instance of NSAttributedString; the string itself is arbitrary, but you must specify an attribute dictionary that contains the key NSFontAttributeName and the corresponding value the font that you want to write to the pasteboard. You then create from the string an NSData object to represent the RTF data and set that as the data on the pasteboard for the NSFontPboardType.

The following code example illustrates how to write font information to the font pasteboard. The example uses a statically-defined font; in your code you typically find the font of the currently-selected text item and use that.

NSPasteboard *pb = [NSPasteboard pasteboardWithName:NSFontPboard];
[pb declareTypes:[NSArray arrayWithObject:NSFontPboardType] owner:self];
 
NSFont *font = [NSFont fontWithName:@"Helvetica" size:12.0];
NSDictionary *attributes = [NSDictionary dictionaryWithObject:font forKey:NSFontAttributeName];
 
NSAttributedString *aString = [[NSAttributedString alloc] initWithString:@"a" attributes:attributes];
NSRange aRange = NSMakeRange(0, 1);
 
NSData *aStringData = [aString RTFFromRange:aRange documentAttributes:nil];
[aString release];
 
[pb setData:aStringData forType:NSFontPboardType];

Reading Font Data

You read a font using the pasteboard named NSFontPboard. You must first get the pasteboard, then ask the pasteboard for the appropriate type—NSFontPboardType. The font data is in the form of RTF data created from an attributed string. You therefore create an instance of NSAttributedString from this data, then get the font attribute from the attributed string.

The following code example illustrates how to read font information from the font pasteboard.

NSPasteboard *pb = [NSPasteboard pasteboardWithName:NSFontPboard];
NSString *bestType = [pb availableTypeFromArray:
                             [NSArray arrayWithObject:NSFontPboardType]];
NSFont *font;
 
if (bestType != nil) {
 
    NSData *data = [pb dataForType:NSFontPboardType];
    NSAttributedString *aString =
            [[NSAttributedString alloc] initWithRTF:data documentAttributes:NULL];
 
    if (aString != nil) {
        font = [aString attribute:NSFontAttributeName atIndex:0 effectiveRange:NULL];
        NSLog(@"font: %@", [font description]);
    }
    else {
        NSLog(@"couldn't get attributed string");
    }
    [aString release];
}
else {
    NSLog(@"couldn't get NSFontPboardType");
}


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