I'm working on a rewrite of my app in Swift from an older mixed C/C++/Objective-C version, and I'm getting a crash when trying to create a drag image from an NSTextView. I have a custom view containing an NSTextView which is set up like this:
let textView = NSTextView(frame: textRect)
textView.drawsBackground = false
textView.isEditable = false
textView.isSelectable = false
textView.isVerticallyResizable = false
textView.isHorizontallyResizable = false
textView.selectedTextAttributes = [:]
addSubview(textView)(I have tried isSelectable true and false, without change of behaviour). In the mouseDragged(with:) function, I have this code:
textView.setSelectedRange(NSMakeRange(0, textView.textStorage!.length))
let dragImage = textView.dragImageForSelection(with: event, origin: nil)
let dragItem = NSDraggingItem(pasteboardWriter: self)
dragItem.setDraggingFrame(NSMakeRect(0.0, 0.0, theRect.size.width, theRect.size.height), contents: dragImage)
beginDraggingSession(with: [dragItem], event: event, source: self)I always get a crash in the call to dragImageForSelection(with:origin:):
2019-04-29 09:16:38.291806+0300 MyApp[61986:7244166] [General] Cannot lock focus on image <NSImage 0x6000018c4a80 Size={0, 0} Reps=(
) flipped:YES (flippedness is deprecated)>, because it is size zero.
2019-04-29 09:16:38.293248+0300 Ukelele Swift[61986:7244166] [General] (
0 CoreFoundation 0x00007fff3f3b5cf9 __exceptionPreprocess + 256
1 libobjc.A.dylib 0x00007fff69f4aa17 objc_exception_throw + 48
2 CoreFoundation 0x00007fff3f3b5b2b +[NSException raise:format:] + 201
3 AppKit 0x00007fff3caa9f17 -[NSImage _lockFocusOnRepresentation:rect:context:hints:flipped:] + 316
4 AppKit 0x00007fff3caa9dd1 __51-[NSImage lockFocusWithRect:context:hints:flipped:]_block_invoke + 68
5 AppKit 0x00007fff3ca3aa7b -[NSImage _usingBestRepresentationForRect:context:hints:body:] + 156
6 AppKit 0x00007fff3caa9d83 -[NSImage lockFocusWithRect:context:hints:flipped:] + 141
7 AppKit 0x00007fff3cbabfe5 -[NSImage lockFocusFlipped:] + 111
8 AppKit 0x00007fff3d1dfcdb -[NSTextView(NSDragging) dragImageForSelectionWithEvent:origin:] + 843
9 MyApp 0x000000010022070a $s13MyApp10MyViewC12mouseDragged4withySo7NSEventC_tF + 842
10 MyApp 0x0000000100220b2c $s13MyApp10MyViewC12mouseDragged4withySo7NSEventC_tFTo + 60
11 AppKit 0x00007fff3caf2b9f -[NSWindow(NSEventRouting) _reallySendEvent:isDelayedEvent:] + 6840
12 AppKit 0x00007fff3caf0e9f -[NSWindow(NSEventRouting) sendEvent:] + 478
13 AppKit 0x00007fff3c9906c3 -[NSApplication(NSEvent) sendEvent:] + 331
14 AppKit 0x00007fff3c97eee8 -[NSApplication run] + 755
15 AppKit 0x00007fff3c96e3f0 NSApplicationMain + 777
16 MyApp 0x00000001001a94dd main + 13
17 libdyld.dylib 0x00007fff6b7783d5 start + 1
18 ??? 0x0000000000000003 0x0 + 3
)
The Objective-C version is practically identical, and does not crash:
NSDraggingItem *dragItem = [[NSDraggingItem alloc] initWithPasteboardWriter:self];
[self.textView setSelectedRange:NSMakeRange(0, [self.textView.textStorage length])];
NSImage *dragImage = [self.textView dragImageForSelectionWithEvent:theEvent origin:nil];
[dragItem setDraggingFrame:NSMakeRect(0.0, 0.0, theRect.size.width, theRect.size.height) contents:dragImage];
NSArray *dragItems = [NSArray arrayWithObject:dragItem];
[self beginDraggingSessionWithItems:dragItems event:theEvent source:self];I've checked the NSTextView and it is correct, the selection is being set correctly, but the crash happens in the Swift version.
Has anybody got a clue how to fix this?
Thanks,
John
