程式語言 - Flat Assembler (FASM) - Win32 API - Set Scrollbar

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

當視窗的可視區域(如：300x300像素)小於顯示圖片大小(如：640x480像素)時，這時可以使用Windows視窗元件Scrollbar，用來做顯示位置調整的動作，Scrollbar元件有垂直和水平兩種方向並且提供視窗事件回報機制(WM_VSCROLL、WM_HSCROLL)，因此，這裡的Scrollbar元件並不能夠自動幫忙做顯示位置調整的動作，取而代之的是，在收到WM_VSCROLL、WM_HSCROLL事件時，使用者必須自己決定哪些東西要顯示在視窗的可視區域上

main.asm

    include "head.asm"
 
    section ".text" code readable executable
proc WndProc hWnd, uMsg, wParam, lParam
    mov eax, [uMsg]
    cmp eax, WM_VSCROLL
    je .handle_vscroll
    cmp eax, WM_CLOSE
    je .handle_close
    cmp eax, WM_DESTROY
    je .handle_destroy
    invoke CallWindowProc, [pDefWndProc], [hWnd], [uMsg], [wParam], [lParam]
    jmp .finish
 
.handle_vscroll:
    cmp word [wParam], SB_LINEUP
    je .handle_sb_line_up
    cmp word [wParam], SB_LINEDOWN
    je .handle_sb_line_down
    cmp word [wParam], SB_PAGEUP
    je .handle_sb_page_up
    cmp word [wParam], SB_PAGEDOWN
    je .handle_sb_page_down
    jmp .finish
 
.handle_sb_line_up:
    invoke SetWindowText, [hWnd], SLUP
    jmp .finish
 
.handle_sb_line_down:
    invoke SetWindowText, [hWnd], SLDN
    jmp .finish
 
.handle_sb_page_up:
    invoke SetWindowText, [hWnd], SPUP
    jmp .finish
 
.handle_sb_page_down:
    invoke SetWindowText, [hWnd], SPDN
    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 or WS_VSCROLL, 0, 0, 300, 300, NULL, NULL, NULL, NULL
    mov [hWin], eax
     
    invoke SetWindowLong, [hWin], GWL_WNDPROC, WndProc
    mov [pDefWndProc], eax
  
    invoke SetScrollRange, [hWin], SB_VERT, 0, 100, FALSE
    invoke SetScrollPos, [hWin], SB_VERT, 50, TRUE
@@:
    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 26~40：處理Scrollbar訊息並且顯示在視窗標題
Line 60：WS_VSCROLL是垂直的Scrollbar，WS_HSCROLL則是水平的Scrollbar
Line 66：設定Scrollbar最大的範圍
Line 67：設定Scrollbar目前的位置

完成