程式語言 - Netwide Assembler (NASM) - Win32 API (NASMX) - Painting - Create Pen

參考資訊：
https://masm32.com/board/index.php
https://www.nasm.us/xdoc/2.13rc9/html/nasmdoc0.html

Pen可以想像成是一支畫筆，粗細、顏色都可以設定，DC(Device Context)可以透過SelectObject()選擇畫筆

main.asm

    %include "c:\\nasmx\\inc\\nasmx.inc"
    %include "c:\\nasmx\\inc\\win32\\msvcrt.inc"
    %include "c:\\nasmx\\inc\\win32\\windows.inc"
    %include "c:\\nasmx\\inc\\win32\\gdi32.inc"
    %include "c:\\nasmx\\inc\\win32\\user32.inc"
    %include "c:\\nasmx\\inc\\win32\\kernel32.inc"
      
    entry start
      
    section .data
hWin         dd 0
hInstance    dd 0
defWndProc   dd 0
CommandLine  dd 0
szCaption    declare(NASMX_TCHAR) NASMX_TEXT("main"),0
       
NASMX_ISTRUC msg, MSG
NASMX_IENDSTRUC
  
NASMX_ISTRUC ps, PAINTSTRUCT
NASMX_IENDSTRUC
       
    section .text
proc WndProc, dword hWnd, uint_t uMsg, dword wParam, dword lParam
    locals
        local hdc, DWORD
        local pen, DWORD
    endlocals
    
    switch dword [argv(.uMsg)]
    case dword WM_PAINT
        invoke BeginPaint, [argv(.hWnd)], ps
        mov [var(.hdc)], eax
  
        invoke CreatePen, PS_SOLID, 10, 0ffh
        mov [var(.pen)], eax

        invoke SelectObject, [var(.hdc)], [var(.pen)]

        invoke MoveToEx, [var(.hdc)], 0, 0, NULL
        invoke LineTo, [var(.hdc)], 100, 100
 
        invoke EndPaint, [argv(.hWnd)], ps
        invoke DeleteObject, [var(.pen)]
        break
    case dword WM_CLOSE
        invoke DestroyWindow, [argv(.hWnd)]
        break
    case dword WM_DESTROY
        invoke PostQuitMessage, 0
        break
    default
        invoke CallWindowProc, [defWndProc], [argv(.hWnd)], [argv(.uMsg)], [argv(.wParam)], [argv(.lParam)]
    endswitch
endproc
       
proc WinMain, dword hInst, dword hPrevInst, dword CmdLine, dword CmdShow
    locals none
        
    invoke CreateWindowEx, WS_EX_LEFT, WC_DIALOG, szCaption, \
        WS_OVERLAPPEDWINDOW | WS_VISIBLE, 0, 0, 300, 300, NULL, NULL, NULL, NULL
    mov [hWin], eax
       
    invoke SetWindowLong, [hWin], GWL_WNDPROC, WndProc
    mov [defWndProc], eax
   
    do
        invoke DispatchMessage, msg
        invoke GetMessage, msg, NULL, NULL, NULL
    while eax, !=, 0
        
    mov eax, dword [msg + MSG.wParam]
endproc
        
proc start, dword argc, dword argv
    locals none
        
    invoke GetModuleHandle, NULL
    mov [hInstance], eax
        
    invoke GetCommandLine, NULL
    mov [CommandLine], eax
        
    invoke WinMain, [hInstance], NULL, [CommandLine], SW_SHOWNORMAL
    invoke ExitProcess, NULL
endproc

Line 35~36：創造一支Pen，粗細是10，顏色則是紅色
Line 38：選擇要使用的Pen
Line 40~41：畫一條線
Line 44：刪除資源

完成