Shift+Arrow key events not detected in osx backend

Consider the following example code:

import matplotlib.pyplot as plt
fig = plt.figure()

def on_key(event):
    print('you pressed', event.key, event.xdata, event.ydata)

fig.canvas.mpl_connect('key_press_event', on_key)

Now when I run this code and press Shift+Left Arrow, the qt5 backend correctly detects this event as shift+left. However, the osx backend (which AFAIK is the default backend on macOS) doesn't register the shift key at all, I only get left. Is it possible to fix this somehow?

I delved into the key handling recently, I'll have a look at see if I can do anything

Awesome! Let me know if I can be of any help!

I've tracked it back to the OSX c code, which converts whatever the key press event is to a char here:

matplotlib/src/_macosx.m

Line 2622 in 813d842

const char* s = [self convertKeyEvent: event];

Unfortunately I don't really do C, so someone else is going to have to figure it out from here

And I'm guessing this is the function that needs to be modified somehow:

matplotlib/src/_macosx.m

Lines 2558 to 2617 in 813d842

    
           - (const char*)convertKeyEvent:(NSEvent*)event 
        
           { 
        
               NSDictionary* specialkeymappings = [NSDictionary dictionaryWithObjectsAndKeys: 
        
                                                   @"left", [NSNumber numberWithUnsignedLong:NSLeftArrowFunctionKey], 
        
                                                   @"right", [NSNumber numberWithUnsignedLong:NSRightArrowFunctionKey], 
        
                                                   @"up", [NSNumber numberWithUnsignedLong:NSUpArrowFunctionKey], 
        
                                                   @"down", [NSNumber numberWithUnsignedLong:NSDownArrowFunctionKey], 
        
                                                   @"f1", [NSNumber numberWithUnsignedLong:NSF1FunctionKey], 
        
                                                   @"f2", [NSNumber numberWithUnsignedLong:NSF2FunctionKey], 
        
                                                   @"f3", [NSNumber numberWithUnsignedLong:NSF3FunctionKey], 
        
                                                   @"f4", [NSNumber numberWithUnsignedLong:NSF4FunctionKey], 
        
                                                   @"f5", [NSNumber numberWithUnsignedLong:NSF5FunctionKey], 
        
                                                   @"f6", [NSNumber numberWithUnsignedLong:NSF6FunctionKey], 
        
                                                   @"f7", [NSNumber numberWithUnsignedLong:NSF7FunctionKey], 
        
                                                   @"f8", [NSNumber numberWithUnsignedLong:NSF8FunctionKey], 
        
                                                   @"f9", [NSNumber numberWithUnsignedLong:NSF9FunctionKey], 
        
                                                   @"f10", [NSNumber numberWithUnsignedLong:NSF10FunctionKey], 
        
                                                   @"f11", [NSNumber numberWithUnsignedLong:NSF11FunctionKey], 
        
                                                   @"f12", [NSNumber numberWithUnsignedLong:NSF12FunctionKey], 
        
                                                   @"f13", [NSNumber numberWithUnsignedLong:NSF13FunctionKey], 
        
                                                   @"f14", [NSNumber numberWithUnsignedLong:NSF14FunctionKey], 
        
                                                   @"f15", [NSNumber numberWithUnsignedLong:NSF15FunctionKey], 
        
                                                   @"f16", [NSNumber numberWithUnsignedLong:NSF16FunctionKey], 
        
                                                   @"f17", [NSNumber numberWithUnsignedLong:NSF17FunctionKey], 
        
                                                   @"f18", [NSNumber numberWithUnsignedLong:NSF18FunctionKey], 
        
                                                   @"f19", [NSNumber numberWithUnsignedLong:NSF19FunctionKey], 
        
                                                   @"scroll_lock", [NSNumber numberWithUnsignedLong:NSScrollLockFunctionKey], 
        
                                                   @"break", [NSNumber numberWithUnsignedLong:NSBreakFunctionKey], 
        
                                                   @"insert", [NSNumber numberWithUnsignedLong:NSInsertFunctionKey], 
        
                                                   @"delete", [NSNumber numberWithUnsignedLong:NSDeleteFunctionKey], 
        
                                                   @"home", [NSNumber numberWithUnsignedLong:NSHomeFunctionKey], 
        
                                                   @"end", [NSNumber numberWithUnsignedLong:NSEndFunctionKey], 
        
                                                   @"pagedown", [NSNumber numberWithUnsignedLong:NSPageDownFunctionKey], 
        
                                                   @"pageup", [NSNumber numberWithUnsignedLong:NSPageUpFunctionKey], 
        
                                                   @"backspace", [NSNumber numberWithUnsignedLong:NSDeleteCharacter], 
        
                                                   @"enter", [NSNumber numberWithUnsignedLong:NSEnterCharacter], 
        
                                                   @"tab", [NSNumber numberWithUnsignedLong:NSTabCharacter], 
        
                                                   @"enter", [NSNumber numberWithUnsignedLong:NSCarriageReturnCharacter], 
        
                                                   @"backtab", [NSNumber numberWithUnsignedLong:NSBackTabCharacter], 
        
                                                   @"escape", [NSNumber numberWithUnsignedLong:27], 
        
                                                   nil 
        
                                                   ]; 
        
               NSMutableString* returnkey = [NSMutableString string]; 
        
               if ([event modifierFlags] & NSControlKeyMask) 
        
                   [returnkey appendString:@"ctrl+" ]; 
        
               if ([event modifierFlags] & NSAlternateKeyMask) 
        
                   [returnkey appendString:@"alt+" ]; 
        
               if ([event modifierFlags] & NSCommandKeyMask) 
        
                   [returnkey appendString:@"cmd+" ]; 
        
               unichar uc = [[event charactersIgnoringModifiers] characterAtIndex:0]; 
        
               NSString* specialchar = [specialkeymappings objectForKey:[NSNumber numberWithUnsignedLong:uc]]; 
        
               if (specialchar) 
        
                   [returnkey appendString:specialchar]; 
        
               else 
        
                   [returnkey appendString:[event charactersIgnoringModifiers]]; 
        
               return [returnkey UTF8String]; 
        
           }

This looks promising. I wonder if it as easy as adding

if ([event modifierFlags] & NSShiftKeyMask)
        [returnkey appendString:@"shift+" ];

in line 2608... but I guess this needs to be restricted to only a subset of keys such as the arrow keys.

Adding that for me and rebuilding does get me shift events, but as you expected, shift + g produces "shift+G". It looks like the Qt backend has a list of special keys it looks for first, then it assumes characters and removes the shift modifier.

@cbrnr

@cbrnr Have a look at #9836 if you are able to download development versions....

Closing since #9836 was merged.

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Shift+Arrow key events not detected in osx backend #9835

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	- (const char)convertKeyEvent:(NSEvent)event
	{
	NSDictionary* specialkeymappings = [NSDictionary dictionaryWithObjectsAndKeys:
	@"left", [NSNumber numberWithUnsignedLong:NSLeftArrowFunctionKey],
	@"right", [NSNumber numberWithUnsignedLong:NSRightArrowFunctionKey],
	@"up", [NSNumber numberWithUnsignedLong:NSUpArrowFunctionKey],
	@"down", [NSNumber numberWithUnsignedLong:NSDownArrowFunctionKey],
	@"f1", [NSNumber numberWithUnsignedLong:NSF1FunctionKey],
	@"f2", [NSNumber numberWithUnsignedLong:NSF2FunctionKey],
	@"f3", [NSNumber numberWithUnsignedLong:NSF3FunctionKey],
	@"f4", [NSNumber numberWithUnsignedLong:NSF4FunctionKey],
	@"f5", [NSNumber numberWithUnsignedLong:NSF5FunctionKey],
	@"f6", [NSNumber numberWithUnsignedLong:NSF6FunctionKey],
	@"f7", [NSNumber numberWithUnsignedLong:NSF7FunctionKey],
	@"f8", [NSNumber numberWithUnsignedLong:NSF8FunctionKey],
	@"f9", [NSNumber numberWithUnsignedLong:NSF9FunctionKey],
	@"f10", [NSNumber numberWithUnsignedLong:NSF10FunctionKey],
	@"f11", [NSNumber numberWithUnsignedLong:NSF11FunctionKey],
	@"f12", [NSNumber numberWithUnsignedLong:NSF12FunctionKey],
	@"f13", [NSNumber numberWithUnsignedLong:NSF13FunctionKey],
	@"f14", [NSNumber numberWithUnsignedLong:NSF14FunctionKey],
	@"f15", [NSNumber numberWithUnsignedLong:NSF15FunctionKey],
	@"f16", [NSNumber numberWithUnsignedLong:NSF16FunctionKey],
	@"f17", [NSNumber numberWithUnsignedLong:NSF17FunctionKey],
	@"f18", [NSNumber numberWithUnsignedLong:NSF18FunctionKey],
	@"f19", [NSNumber numberWithUnsignedLong:NSF19FunctionKey],
	@"scroll_lock", [NSNumber numberWithUnsignedLong:NSScrollLockFunctionKey],
	@"break", [NSNumber numberWithUnsignedLong:NSBreakFunctionKey],
	@"insert", [NSNumber numberWithUnsignedLong:NSInsertFunctionKey],
	@"delete", [NSNumber numberWithUnsignedLong:NSDeleteFunctionKey],
	@"home", [NSNumber numberWithUnsignedLong:NSHomeFunctionKey],
	@"end", [NSNumber numberWithUnsignedLong:NSEndFunctionKey],
	@"pagedown", [NSNumber numberWithUnsignedLong:NSPageDownFunctionKey],
	@"pageup", [NSNumber numberWithUnsignedLong:NSPageUpFunctionKey],
	@"backspace", [NSNumber numberWithUnsignedLong:NSDeleteCharacter],
	@"enter", [NSNumber numberWithUnsignedLong:NSEnterCharacter],
	@"tab", [NSNumber numberWithUnsignedLong:NSTabCharacter],
	@"enter", [NSNumber numberWithUnsignedLong:NSCarriageReturnCharacter],
	@"backtab", [NSNumber numberWithUnsignedLong:NSBackTabCharacter],
	@"escape", [NSNumber numberWithUnsignedLong:27],
	nil
	];

	NSMutableString* returnkey = [NSMutableString string];
	if ([event modifierFlags] & NSControlKeyMask)
	[returnkey appendString:@"ctrl+" ];
	if ([event modifierFlags] & NSAlternateKeyMask)
	[returnkey appendString:@"alt+" ];
	if ([event modifierFlags] & NSCommandKeyMask)
	[returnkey appendString:@"cmd+" ];

	unichar uc = [[event charactersIgnoringModifiers] characterAtIndex:0];
	NSString* specialchar = [specialkeymappings objectForKey:[NSNumber numberWithUnsignedLong:uc]];
	if (specialchar)
	[returnkey appendString:specialchar];
	else
	[returnkey appendString:[event charactersIgnoringModifiers]];

	return [returnkey UTF8String];
	}

Shift+Arrow key events not detected in osx backend #9835

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dstansby commented on Nov 22, 2017

cbrnr commented on Nov 22, 2017

dstansby commented on Nov 22, 2017

dstansby commented on Nov 22, 2017

cbrnr commented on Nov 22, 2017

dopplershift commented on Nov 22, 2017

jklymak commented on Nov 23, 2017

cbrnr commented on Nov 29, 2017

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