程式語言 - Flat Assembler (FASM) - Win32 API - Create Pen

參考資訊：
https://board.flatassembler.net/

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 "head.asm"

    section ".text" code readable executable
proc WndProc hWnd, uMsg, wParam, lParam
    local hdc:DWORD
    local pen:DWORD
    local ps:PAINTSTRUCT
   
    mov eax, [uMsg]
    cmp eax, WM_PAINT
    je .handle_paint
    cmp eax, WM_CLOSE
    je .handle_close
    cmp eax, WM_DESTROY
    je .handle_destroy
    invoke CallWindowProc, [pDefWndProc], [hWnd], [uMsg], [wParam], [lParam]
    jmp .finish
    
.handle_paint:
    lea eax, [ps]
    invoke BeginPaint, [hWnd], eax
    mov [hdc], eax
   
    invoke CreatePen, PS_SOLID, 10, 0ffh
    mov [pen], eax
    invoke SelectObject, [hdc], [pen]
    invoke MoveToEx, [hdc], 0, 0, NULL
    invoke LineTo, [hdc], 100, 100
  
    lea eax, [ps]
    invoke EndPaint, [hWnd], eax
    invoke DeleteObject, [pen]
    xor eax, eax
    jmp .finish
    
.handle_close:
    invoke DestroyWindow, [hWnd]
    xor eax, eax
    jmp .finish
        
.handle_destroy:
    invoke PostQuitMessage, 0
    xor eax, eax
    jmp .finish
         
.finish:
    ret
endp
        
proc WinMain hInst, hPrevInst, CmdLine, CmdShow
    local msg:MSG
        
    invoke CreateWindowEx, WS_EX_LEFT, WC_DIALOG, szName, \
        WS_OVERLAPPEDWINDOW or WS_VISIBLE, 0, 0, 300, 300, NULL, NULL, NULL, NULL
    mov [hWin], eax
        
    invoke SetWindowLong, [hWin], GWL_WNDPROC, WndProc
    mov [pDefWndProc], eax
     
@@:
    lea eax, [msg]
    invoke GetMessage, eax, NULL, 0, 0
    cmp eax, 0
    je @f
    lea eax, [msg]
    invoke DispatchMessage, eax
    jmp @b
@@:
    mov eax, [msg.wParam]
    ret
endp
        
start:
    invoke GetModuleHandle, NULL
    mov [hInstance], eax
         
    invoke GetCommandLine
    mov [pCommand], eax
         
    stdcall WinMain, [hInstance], NULL, [pCommand], SW_SHOWNORMAL
    invoke ExitProcess, eax

Line 24：創造一支Pen，粗細是10，顏色則是紅色
Line 26：選擇要使用的Pen
Line 27~28：畫一條線
Line 32：刪除資源

完成