[racket] Key events, shift, and, get-shift-key-code

Cool!

On Thu, Jan 1, 2015 at 6:51 PM, Jens Axel Søgaard <jensaxel at soegaard.net> wrote:
> 2014-12-24 16:57 GMT+01:00 Robby Findler <robby at eecs.northwestern.edu>:
>> I believe that "other-shift-key-code" is really just a field with
>> getters and setters; there's no smarts in the key-event class that can
>> do the translation you want.
>
>> It may be possible to do this via calls directly to the os, but I'm
>> not sure how to do that and I've never had much luck reading the cocoa
>> docs, I'm sorry to say. It might help to look at the code inside
>> racket/gui that constructs the key-event; it's in the collection
>> mred/private/wx/cocoa.
>
> I'll see what I can do with respect to an FFI. I had a bit of trouble
> getting simple example working directly in Swift, but I have finally
> figured it out.
>
> The output is:
>
>   Keyboard: <TSMInputSource 0x1005139a0> KB Layout: U.S. (id=0)
>   Layout: 0x0000000100812830
>   KbdType 44
>   Status: 0
>   Out:>
>   Done
>   Program ended with exit code: 0
>
>
>
> import Foundation
> import Cocoa
> import Carbon
> import AppKit
>
> // The current text input source (read keyboard) has a layout in which
> // we can lookup how key-codes are resolved.
>
> // Get keyboard using the current layout.
> let keyboard = TISCopyCurrentKeyboardInputSource().takeRetainedValue()
> let rawLayoutData = TISGetInputSourceProperty(keyboard,
> kTISPropertyUnicodeKeyLayoutData)
> print("Keyboard: ") ; println(keyboard)
>
> // Get the layout
> var layoutData      = unsafeBitCast(rawLayoutData, CFDataRef.self)
> var layout: UnsafePointer<UCKeyboardLayout> =
> unsafeBitCast(CFDataGetBytePtr(layoutData),
> UnsafePointer<UCKeyboardLayout>.self)
> print("Layout: "); println(layout)
> print("KbdType "); println(LMGetKbdType()) // Sanity check (prints 44)
>
> // As an example, let's figure out what <shift>+<period> is:
>
> var keycode             = UInt16(kVK_ANSI_Period)
>    // Keycode for a
> var keyaction           = UInt16(kUCKeyActionDisplay)
> var modifierKeyState    = UInt32(1 << 1)
>    // Shift
> var keyboardType        = UInt32(LMGetKbdType())
> var keyTranslateOptions = OptionBits(kUCKeyTranslateNoDeadKeysBit)
> var deadKeyState        = UInt32(0)
>    // Is 0 the correct value?
> var maxStringLength     = UniCharCount(4)
>    // uint32
> var chars: [UniChar]    = [0,0,0,0]
> var actualStringLength  = UniCharCount(1)
> var result = UCKeyTranslate(layout, keycode, keyaction,
> modifierKeyState, keyboardType, keyTranslateOptions,
>                             &deadKeyState, maxStringLength,
> &actualStringLength, &chars)
>
> // Print the results
> print("Status: "); println(result)
> print("Out:"); println(UnicodeScalar(chars[0]))
> println("Done")