Code

code.odin

Control :: struct
{
    kind : ControlKind,
    name : string,
    handle : HWND,
    controlID : UINT,
    parent : ^Form,
    text : string,
    width, height : int,
    xpos, ypos : int,
    font : ^Font,
    backColor : uint,
    foreColor : uint,
    enabled : bool,
    visible : bool,
    ....
  }
  
Font :: struct
{
    name : string,
    size : int,
    weight : FontWeight,
    underline : bool,
    italics : bool,
    handle : HFONT,
    _defFontChanged : bool,
}

new_font_1 :: proc() -> ^Font
{
    f := new(Font)
    f.name = _def_font_name
    f.size = _def_font_size
    f.weight = FontWeight.Normal
    f.underline = false
    f.italics = false
    f._defFontChanged = false
    return f
}


Form :: struct
{
      using control : Control, 
      start_pos : StartPosition,
      ....
 }
 
 @private
new_form_internal :: proc(t : string = "", w : int = 500, h : int = 400) -> Form
{
    app.formCount += 1
    f : Form
    f.kind = .Form
    f.text = t == "" ? concat_number("Form_", app.formCount) : t
    f.width = w
    f.height = h
    f.start_pos = .Center
    f.style = .Default
    f.maximizeBox = true
    f.minimizeBox = true
    f.font = new_font() // Creating new font
    f._drawMode = .Default
    f.backColor = def_window_color
    f.foreColor = app.clrBlack

    f.windowState = .Normal
    f._uDrawChilds = make(map[UINT]HWND)
    return  f
}

create_form_hwnd :: proc(frm : ^Form )
{
    frm.handle = CreateWindowEx(.....)
    if frm.handle == nil { fmt.println("Error in CreateWindoeEx,", GetLastError()) }
    else
    {       
        set_form_font_internal(frm) // Setting up the font handle and send it form's wndproc
        SetWindowLongPtr(frm.handle, GWLP_USERDATA, cast(LONG_PTR) cast(UINT_PTR) frm)
    }
}

@private
form_dtor :: proc(frm : ^Form)
{
    delete_gdi_object(frm.font.handle)
    delete(frm._uDrawChilds)
    delete(frm._cDrawChilds)
    free(frm.font)
    print("frm dtor called")
}


@private
window_proc :: proc "std" (hw : HWND, msg : u32, wp : WPARAM, lp : LPARAM ) -> LRESULT
{
    context = runtime.default_context()
    frm := direct_cast(GetWindowLongPtr(hw, GWLP_USERDATA), ^Form)
    switch msg {
      case WM_DESTROY:
            form_dtor(frm) // Caling form's destructor
    ......
}