程式語言 - Flat Assembler (FASM) - Win32 API - Draw Text



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

使用TextOut()顯示文字時,只有X、Y參數可以用來設定顯示的位置,當文字長度超過顯示區域時,就需要拆解文字,包含置中顯示也是需要花費額外的計算,如果遇到這些問題,建議使用DrawText()顯示文字,DrawText()提供更多選項使用,包含多行顯示、置中顯示,使用者只需要傳入顯示範圍即可

main.asm

    include "head.asm"

    section ".text" code readable executable
proc WndProc hWnd, uMsg, wParam, lParam
    local hdc:DWORD
    local font: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 CreateFont, 48, 0, 0, 0, FW_BOLD, 0, 0, 0, 0, \
        OUT_OUTLINE_PRECIS, CLIP_DEFAULT_PRECIS, \
        CLEARTYPE_QUALITY, DEFAULT_PITCH or FF_DONTCARE, szFont
    mov [font], eax
  
    invoke SetTextColor, [hdc], 0ff0000h
    invoke SetBkMode, [hdc], TRANSPARENT
    invoke SelectObject, [hdc], [font]
 
    lea eax, [ps.rcPaint]
    invoke DrawText, [hdc], szMsg, MsgLen, eax, DT_SINGLELINE or DT_CENTER or DT_VCENTER
  
    lea eax, [ps]
    invoke EndPaint, [hWnd], eax
    invoke DeleteObject, [font]
    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 33~34:使用DrawText()顯示文字

完成