Add a function to send media key events

Media keys (rewind, play/pause, fast forward on Mac function keys) are
different from normal keys. These use a different API, and sending
events to simulate those keys is different.

Here's a first stab at getting something working for posting simulated
media key events. This will be used for new special keys in mapping
actions. Haven't tested this at all yet, just happy that it finally
compiles.

Follow the two Stack Overflow answers referenced in the comments (from
Albert https://stackoverflow.com/users/133374/albert and Nick Sweeting
https://stackoverflow.com/users/2156113/nick-sweeting).

Add the `core-graphics` crate to give us access to `CGEvent`,
`CGKeyCode`, and related types.

Also include some commented `CGKeyCode` definitions for future use.

1 files changed, 153 insertions, 0 deletions

diff --git a/src/key_code.rs b/src/key_code.rs
new file mode 100644
index 0000000..e148555
--- /dev/null
+++ b/src/key_code.rs
@@ -0,0 +1,153 @@
+use cocoa::appkit::{
+    NSEvent,
+    NSEventModifierFlags,
+    NSEventSubtype::NSScreenChangedEventType,
+    NSEventType::NSSystemDefined,
+};
+use cocoa::base::nil;
+use cocoa::foundation::NSPoint;
+use core_graphics::event::{CGEvent, CGEventTapLocation, CGKeyCode, KeyCode};
+
+// impl KeyCode {
+//     pub const RETURN: CGKeyCode = 0x24;
+//     pub const TAB: CGKeyCode = 0x30;
+//     pub const SPACE: CGKeyCode = 0x31;
+//     pub const DELETE: CGKeyCode = 0x33;
+//     pub const ESCAPE: CGKeyCode = 0x35;
+//     pub const COMMAND: CGKeyCode = 0x37;
+//     pub const SHIFT: CGKeyCode = 0x38;
+//     pub const CAPS_LOCK: CGKeyCode = 0x39;
+//     pub const OPTION: CGKeyCode = 0x3A;
+//     pub const CONTROL: CGKeyCode = 0x3B;
+//     pub const RIGHT_COMMAND: CGKeyCode = 0x36;
+//     pub const RIGHT_SHIFT: CGKeyCode = 0x3C;
+//     pub const RIGHT_OPTION: CGKeyCode = 0x3D;
+//     pub const RIGHT_CONTROL: CGKeyCode = 0x3E;
+//     pub const FUNCTION: CGKeyCode = 0x3F;
+//     pub const VOLUME_UP: CGKeyCode = 0x48;
+//     pub const VOLUME_DOWN: CGKeyCode = 0x49;
+//     pub const MUTE: CGKeyCode = 0x4A;
+// }
+
+//   kVK_F13                       = 0x69,
+//   kVK_F14                       = 0x6B,
+//   kVK_F15                       = 0x71,
+//   kVK_F16                       = 0x6A,
+//   kVK_F17                       = 0x40,
+//   kVK_F18                       = 0x4F,
+//   kVK_F19                       = 0x50,
+//   kVK_F20                       = 0x5A,
+//
+// enum {
+//   kVK_Return                    = 0x24,
+//   kVK_Tab                       = 0x30,
+//   kVK_Space                     = 0x31,
+//   kVK_Delete                    = 0x33,
+//   kVK_Escape                    = 0x35,
+//   kVK_Command                   = 0x37,
+//   kVK_Shift                     = 0x38,
+//   kVK_CapsLock                  = 0x39,
+//   kVK_Option                    = 0x3A,
+//   kVK_Control                   = 0x3B,
+//   kVK_RightCommand              = 0x36,
+//   kVK_RightShift                = 0x3C,
+//   kVK_RightOption               = 0x3D,
+//   kVK_RightControl              = 0x3E,
+//   kVK_Function                  = 0x3F,
+//   kVK_F17                       = 0x40,
+//   kVK_VolumeUp                  = 0x48,
+//   kVK_VolumeDown                = 0x49,
+//   kVK_Mute                      = 0x4A,
+//   kVK_F18                       = 0x4F,
+//   kVK_F19                       = 0x50,
+//   kVK_F20                       = 0x5A,
+//   kVK_F5                        = 0x60,
+//   kVK_F6                        = 0x61,
+//   kVK_F7                        = 0x62,
+//   kVK_F3                        = 0x63,
+//   kVK_F8                        = 0x64,
+//   kVK_F9                        = 0x65,
+//   kVK_F11                       = 0x67,
+//   kVK_F13                       = 0x69,
+//   kVK_F16                       = 0x6A,
+//   kVK_F14                       = 0x6B,
+//   kVK_F10                       = 0x6D,
+//   kVK_F12                       = 0x6F,
+//   kVK_F15                       = 0x71,
+//   kVK_Help                      = 0x72,
+//   kVK_Home                      = 0x73,
+//   kVK_PageUp                    = 0x74,
+//   kVK_ForwardDelete             = 0x75,
+//   kVK_F4                        = 0x76,
+//   kVK_End                       = 0x77,
+//   kVK_F2                        = 0x78,
+//   kVK_PageDown                  = 0x79,
+//   kVK_F1                        = 0x7A,
+//   kVK_LeftArrow                 = 0x7B,
+//   kVK_RightArrow                = 0x7C,
+//   kVK_DownArrow                 = 0x7D,
+//   kVK_UpArrow                   = 0x7E
+// };
+
+
+
+    // unsafe fn otherEventWithType_location_modifierFlags_timestamp_windowNumber_context_subtype_data1_data2_(
+    //     _: Self,
+    //     eventType: NSEventType,
+    //     location: NSPoint,
+    //     modifierFlags: NSEventModifierFlags,
+    //     timestamp: NSTimeInterval,
+    //     windowNumber: NSInteger,
+    //     context: id /* (NSGraphicsContext *) */,
+    //     subtype: NSEventSubtype,
+    //     data1: NSInteger,
+    //     data2: NSInteger) -> id /* (NSEvent *) */
+
+
+// https://stackoverflow.com/questions/11045814/emulate-media-key-press-on-mac/11048135#11048135
+// https://stackoverflow.com/questions/10459085/cocoa-simulate-macbook-upper-keys-multimedia-keys/50574159#50574159
+unsafe fn press_play() {
+    let NX_KEYTYPE_PLAY = 16;
+    let code = NX_KEYTYPE_PLAY;
+
+    let key_down = NSEvent::otherEventWithType_location_modifierFlags_timestamp_windowNumber_context_subtype_data1_data2_(
+        nil,
+        NSSystemDefined,
+        NSPoint::new(0.0, 0.0),
+        NSEventModifierFlags::NSDeviceIndependentModifierFlagsMask,
+        0.0,
+        0,
+        nil,
+        NSScreenChangedEventType,
+        (code << 16 as i32) | (0xa << 8 as i32),
+        -1
+    );
+    let event = key_down.CGEvent() as *mut CGEvent;
+    let event = &*event;
+    event.post(CGEventTapLocation::HID);
+
+    let key_up = NSEvent::otherEventWithType_location_modifierFlags_timestamp_windowNumber_context_subtype_data1_data2_(
+        nil,
+        NSSystemDefined,
+        NSPoint::new(0.0, 0.0),
+        NSEventModifierFlags::NSDeviceIndependentModifierFlagsMask,
+        0.0,
+        0,
+        nil,
+        NSScreenChangedEventType,
+        (code << 16 as i32) | (0xb << 8 as i32),
+        -1
+    );
+    let event = key_down.CGEvent() as *mut CGEvent;
+    let event = &*event;
+    event.post(CGEventTapLocation::HID);
+}
+
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn send_media_key_event() {
+        press_play();
+    }
+}