程式語言 - Netwide Assembler (NASM) - Win32 API - Painting - Draw Rectangle

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

繪畫圖形需要透過SelectObject()去選擇Pen、Brush

main.asm

    %include "head.asm" 

    segment .text
WndProc:
    push ebp
    mov ebp, esp
           
    cmp dword [ebp + ARG2], WM_PAINT
    je .handle_paint
    cmp dword [ebp + ARG2], WM_CLOSE
    je .handle_close
    cmp dword [ebp + ARG2], WM_DESTROY
    je .handle_destroy
    jmp .handle_default
      
.handle_paint:
    push ps
    push dword [ebp + ARG1]
    call BeginPaint
    mov [hDC], eax
 
    push 0ffh
    push 3
    push PS_SOLID
    call CreatePen
    mov [hPen], eax
 
    push 0ff00h
    call CreateSolidBrush
    mov [hBrush], eax
 
    push dword [hPen]
    push dword [hDC]
    call SelectObject
 
    push dword [hBrush]
    push dword [hDC]
    call SelectObject
 
    push 200
    push 200
    push 10
    push 10
    push dword [hDC]
    call Rectangle
    
    push ps
    push dword [ebp + ARG1]
    call EndPaint
    
    push dword [hPen]
    call DeleteObject
    push dword [hBrush]
    call DeleteObject
    xor eax, eax
    jmp .finish
      
.handle_close:
    push dword [ebp + ARG1]
    call DestroyWindow
    xor eax, eax
    jmp .finish
           
.handle_destroy:
    push 0
    call PostQuitMessage
    xor eax, eax
    jmp .finish
           
.handle_default:
    push dword [ebp + ARG4]
    push dword [ebp + ARG3]
    push dword [ebp + ARG2]
    push dword [ebp + ARG1]
    push dword [pDefWndProc]
    call CallWindowProc
           
.finish:
    leave
    ret 16
           
WinMain:
    push ebp
    mov ebp, esp
            
    push 0
    push 0
    push 0
    push 0
    push 300
    push 300
    push 0
    push 0
    push WS_OVERLAPPEDWINDOW | WS_VISIBLE
    push szAppName
    push WC_DIALOG
    push WS_EX_LEFT
    call CreateWindowEx
    mov [hWin], eax
           
    push WndProc
    push GWL_WNDPROC
    push dword [hWin]
    call SetWindowLong
    mov [pDefWndProc], eax
        
.loop:
    push 0
    push 0
    push 0
    push msg
    call GetMessage
    cmp eax, 0
    je .exit
            
    push msg
    call DispatchMessage
    jmp .loop
            
.exit:
    mov eax, [msg + MSG.wParam]
    leave
    ret 16
            
_start:
    push 0
    call GetModuleHandle
    mov [hInstance], eax
            
    call GetCommandLine
    mov [pCommand], eax
            
    push SW_SHOWNORMAL
    push dword [pCommand]
    push 0
    push dword [hInstance]
    call WinMain
            
    push eax
    call ExitProcess

Line 40~45：畫一個長方形，起始點位置是(x=10, y=10)，結束點位置是(x=200, y=200)

完成