Add possibility to check, which keys are pressed togehter

New procs:
- isDown(key: Key): bool
- downKeys(): seq[Key]

3 files changed, 76 insertions, 19 deletions

diff --git a/src/nigui.nim b/src/nigui.nim
index f7b0f36..6667719 100755
--- a/src/nigui.nim
+++ b/src/nigui.nim
@@ -335,8 +335,9 @@ when useGtk():     include "nigui/private/gtk3/platform_types3"
 #                                    Global Variables
 # ----------------------------------------------------------------------------------------
 
-var quitOnLastWindowClose* = true
-var clickMaxXYMove* = 20
+var
+  quitOnLastWindowClose* = true
+  clickMaxXYMove* = 20
 
 # dummy type and object, needed to use get/set properties
 type App = object
@@ -377,6 +378,10 @@ proc `clipboardText=`*(app: App, text: string)
 
 proc rgb*(red, green, blue: byte, alpha: byte = 255): Color
 
+proc isDown*(key: Key): bool
+
+proc downKeys*(): seq[Key]
+
 
 # ----------------------------------------------------------------------------------------
 #                                       Dialogs
@@ -907,15 +912,17 @@ import unicode
 #                                   Global Variables
 # ----------------------------------------------------------------------------------------
 
-var fErrorHandler: ErrorHandlerProc = nil
-var windowList: seq[Window] = @[]
-var fScrollbarSize = -1
+var
+  fErrorHandler: ErrorHandlerProc = nil
+  windowList: seq[Window] = @[]
+  fScrollbarSize = -1
+  fDownKeys: seq[Key] = @[]
 
-# Default style:
-var fDefaultBackgroundColor: Color # initialized by platform-specific init()
-var fDefaultTextColor: Color # initialized by platform-specific init()
-var fDefaultFontFamily = ""
-var fDefaultFontSize = 15.float
+  # Default style:
+  fDefaultBackgroundColor: Color # initialized by platform-specific init()
+  fDefaultTextColor: Color # initialized by platform-specific init()
+  fDefaultFontFamily = ""
+  fDefaultFontSize = 15.float
 
 
 # ----------------------------------------------------------------------------------------
@@ -1042,6 +1049,19 @@ proc newSaveFileDialog(): SaveFileDialog =
   result.defaultName = ""
   result.file = ""
 
+proc isDown(key: Key): bool = fDownKeys.contains(key)
+
+proc downKeys(): seq[Key] = fDownKeys
+
+proc internalKeyDown(key: Key) =
+  if not fDownKeys.contains(key):
+    fDownKeys.add(key)
+
+proc internalKeyUp(key: Key) =
+  let i = fDownKeys.find(key)
+  if i != -1:
+    fDownKeys.delete(i)
+
 
 # ----------------------------------------------------------------------------------------
 #                                       Canvas
diff --git a/src/nigui/private/gtk3/platform_impl.nim b/src/nigui/private/gtk3/platform_impl.nim
index ba4f51a..52315f1 100755
--- a/src/nigui/private/gtk3/platform_impl.nim
+++ b/src/nigui/private/gtk3/platform_impl.nim
@@ -88,6 +88,7 @@ proc pKeyvalToKey(keyval: cint): Key =
 proc pWindowKeyPressSignal(widget: pointer, event: var GdkEventKey, data: pointer): bool {.cdecl.} =
   let window = cast[WindowImpl](data)
   window.fKeyPressed = pKeyvalToKey(event.keyval)
+  internalKeyDown(window.fKeyPressed)
   if gtk_im_context_filter_keypress(window.fIMContext, event) and window.fKeyPressed == Key_None:
     return
   var evt = new KeyboardEvent
@@ -104,6 +105,9 @@ proc pWindowKeyPressSignal(widget: pointer, event: var GdkEventKey, data: pointe
     handleException()
   result = evt.handled
 
+proc pWindowKeyReleaseSignal(widget: pointer, event: var GdkEventKey): bool {.cdecl.} =
+  internalKeyUp(pKeyvalToKey(event.keyval))
+
 proc pControlKeyPressSignal(widget: pointer, event: var GdkEventKey, data: pointer): bool {.cdecl.} =
   let control = cast[ControlImpl](data)
   control.fKeyPressed = pKeyvalToKey(event.keyval)
@@ -624,6 +628,7 @@ proc init(window: WindowImpl) =
   discard g_signal_connect_data(window.fHandle, "delete-event", pWindowDeleteSignal, cast[pointer](window))
   discard g_signal_connect_data(window.fHandle, "configure-event", pWindowConfigureSignal, cast[pointer](window))
   discard g_signal_connect_data(window.fHandle, "key-press-event", pWindowKeyPressSignal, cast[pointer](window))
+  discard g_signal_connect_data(window.fHandle, "key-release-event", pWindowKeyReleaseSignal, cast[pointer](window))
   discard g_signal_connect_data(window.fHandle, "window-state-event", pWindowStateEventSignal, cast[pointer](window))
 
   # Enable drag and drop of files:
diff --git a/src/nigui/private/windows/platform_impl.nim b/src/nigui/private/windows/platform_impl.nim
index 3251b61..24d5c8c 100755
--- a/src/nigui/private/windows/platform_impl.nim
+++ b/src/nigui/private/windows/platform_impl.nim
@@ -231,7 +231,34 @@ proc pVirtualKeyToKey(keyval, scancode: int32): Key =
   of VK_DELETE: result = Key_Delete
   else: result = cast[Key](keyval.unicodeToUpper)
 
+proc pWMParamsToKey(wParam, lParam: pointer): Key =
+  case cast[int32](wParam)
+  of VK_CONTROL, VK_SHIFT, VK_MENU:
+    let scancode = (cast[int32](lParam) and 0x00FF0000) shr 16
+    case MapVirtualKeyW(scancode, MAPVK_VSC_TO_VK_EX)
+    of VK_LCONTROL: result = Key_ControlL
+    of VK_RCONTROL: result = Key_ControlR
+    of VK_LSHIFT: result = Key_ShiftL
+    of VK_RSHIFT: result = Key_ShiftR
+    of VK_LMENU: result = Key_AltL
+    of VK_RMENU: result = Key_AltR
+    else: discard
+  of VK_PRIOR: result = Key_PageUp
+  of VK_NEXT: result = Key_PageDown
+  of VK_END: result = Key_End
+  of VK_HOME: result = Key_Home
+  of VK_LEFT: result = Key_Left
+  of VK_UP: result = Key_Up
+  of VK_RIGHT: result = Key_Right
+  of VK_DOWN: result = Key_Down
+  of VK_INSERT: result = Key_Insert
+  of VK_DELETE: result = Key_Delete
+  of VK_OEM_5: result = Key_Circumflex
+  else: result = cast[Key](cast[int32](wParam).unicodeToUpper)
+
 proc pHandleWMKEYDOWNOrWMCHAR(window: Window, control: Control, unicode: int): bool =
+  internalKeyDown(pKeyDownKey)
+
   var windowEvent = new KeyboardEvent
   windowEvent.window = window
   windowEvent.key = pKeyDownKey
@@ -262,17 +289,17 @@ proc pHandleWMKEYDOWNOrWMCHAR(window: Window, control: Control, unicode: int): b
 
 proc pHandleWMKEYDOWN(window: Window, control: Control, wParam, lParam: pointer): bool =
   if not GetKeyboardState(pKeyState): pRaiseLastOSError()
+
+  pKeyDownKey = pWMParamsToKey(wParam, lParam)
   # Save the key for WM_CHAR, because WM_CHAR only gets the key combined with the dead key state
-  var widestring = newString(2)
-  let scancode = (cast[int32](lParam) and 0x00FF0000) shr 16
-  pKeyDownKey = pVirtualKeyToKey(cast[int32](wParam), scancode)
-  if cast[int](wParam) == VK_OEM_5:
+
+  if pKeyDownKey != Key_Circumflex:
     # When the dead key "^" on German keyboard is pressed, don't call ToUnicode(), because this would destroy the dead key state
-    pKeyDownKey = Key_Circumflex
-    return pHandleWMKEYDOWNOrWMCHAR(window, control, 0)
-  let ret = ToUnicode(cast[int](wParam).int32, scancode, pKeyState, widestring, 1, 0)
-  if ret == 1:
-    return # Unicode characters are handled by WM_CHAR
+    let scancode = (cast[int32](lParam) and 0x00FF0000) shr 16
+    var widestring = newString(2)
+    let ret = ToUnicode(cast[int](wParam).int32, scancode, pKeyState, widestring, 1, 0)
+    if ret == 1:
+      return # Unicode characters are handled by WM_CHAR
   result = pHandleWMKEYDOWNOrWMCHAR(window, control, 0)
 
 proc pHandleWMCHAR(window: Window, control: Control, wParam, lParam: pointer): bool =
@@ -324,6 +351,8 @@ proc pWindowWndProc(hWnd: pointer, uMsg: int32, wParam, lParam: pointer): pointe
     let window = cast[Window](pGetWindowLongPtr(hWnd, GWLP_USERDATA))
     if window != nil and pHandleWMKEYDOWN(window, nil, wParam, lParam):
       return
+  of WM_KEYUP:
+    internalKeyUp(pWMParamsToKey(wParam, lParam))
   of WM_CHAR:
     let window = cast[Window](pGetWindowLongPtr(hWnd, GWLP_USERDATA))
     if window != nil and pHandleWMCHAR(window, nil, wParam, lParam):
@@ -1044,6 +1073,9 @@ proc pCommonControlWndProc(hWnd: pointer, uMsg: int32, wParam, lParam: pointer):
     if control != nil and pHandleWMKEYDOWN(control.parentWindow, control, wParam, lParam):
       return PWndProcResult_False
 
+  of WM_KEYUP:
+    internalKeyUp(pWMParamsToKey(wParam, lParam))
+
   of WM_CHAR:
     let control = cast[Control](pGetWindowLongPtr(hWnd, GWLP_USERDATA))
     if control != nil and pHandleWMCHAR(control.parentWindow, control, wParam, lParam):