Expose `RAYGUI_WINDOWBOX_CLOSEBUTTON_HEIGHT` in `GuiWindowBox`. (#453)

src/raygui.h

@@ -1596,6 +1596,10 @@ int GuiWindowBox(Rectangle bounds, const char *title)
         #define RAYGUI_WINDOWBOX_STATUSBAR_HEIGHT        24
     #endif
 
+    #if !defined(RAYGUI_WINDOWBOX_CLOSEBUTTON_HEIGHT)
+        #define RAYGUI_WINDOWBOX_CLOSEBUTTON_HEIGHT      18
+    #endif
+
     int result = 0;
     //GuiState state = guiState;
 
@@ -1604,9 +1608,12 @@ int GuiWindowBox(Rectangle bounds, const char *title)
     Rectangle statusBar = { bounds.x, bounds.y, bounds.width, (float)statusBarHeight };
     if (bounds.height < statusBarHeight*2.0f) bounds.height = statusBarHeight*2.0f;
 
+    const float vPadding = statusBarHeight/2.0f - RAYGUI_WINDOWBOX_CLOSEBUTTON_HEIGHT/2.0f;
     Rectangle windowPanel = { bounds.x, bounds.y + (float)statusBarHeight - 1, bounds.width, bounds.height - (float)statusBarHeight + 1 };
-    Rectangle closeButtonRec = { statusBar.x + statusBar.width - GuiGetStyle(STATUSBAR, BORDER_WIDTH) - 20,
-                                 statusBar.y + statusBarHeight/2.0f - 18.0f/2.0f, 18, 18 };
+    Rectangle closeButtonRec = { statusBar.x + statusBar.width - GuiGetStyle(STATUSBAR, BORDER_WIDTH) - RAYGUI_WINDOWBOX_CLOSEBUTTON_HEIGHT - vPadding,
+                                 statusBar.y + vPadding,
+                                 RAYGUI_WINDOWBOX_CLOSEBUTTON_HEIGHT,
+                                 RAYGUI_WINDOWBOX_CLOSEBUTTON_HEIGHT };
 
     // Update control
     //--------------------------------------------------------------------