汇编教程：位图初步

核心提示：例子:.386.model flat,stdcalloption casemap:noneinclude \masm32\include\windows.incinclude \masm32\include\user32.incinclude \masm32\include\kernel32.incinclude \m

例子:

.386
.model flat,stdcall
option casemap:none
include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
include \masm32\include\gdi32.inc
includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\gdi32.lib
WinMain proto :DWORD,:DWORD,:DWORD,:DWORD
IDB_MAIN equ 1
.data
ClassName db "SimpleWin32ASMBitmapClass",0
AppName db "Win32ASM Simple Bitmap Example",0
.data?
hInstance HINSTANCE ?
CommandLine LPSTR ?
hBitmap dd ?
.code
start:
invoke GetModuleHandle, NULL
mov hInstance,eax
invoke GetCommandLine
mov CommandLine,eax
invoke WinMain, hInstance,NULL,CommandLine, SW_SHOWDEFAULT
invoke ExitProcess,eax
WinMain proc hInst:HINSTANCE,hPrevInst:HINSTANCE,CmdLine:LPSTR,CmdShow:DWORD
LOCAL wc:WNDCLASSEX
LOCAL msg:MSG
LOCAL hwnd:HWND
mov wc.cbSize,SIZEOF WNDCLASSEX
mov wc.style, CS_HREDRAW or CS_VREDRAW
mov wc.lpfnWndProc, OFFSET WndProc
mov wc.cbClsExtra,NULL
mov wc.cbWndExtra,NULL
push hInstance
pop wc.hInstance
mov wc.hbrBackground,COLOR_WINDOW+1
mov wc.lpszMenuName,NULL
mov wc.lpszClassName,OFFSET ClassName
invoke LoadIcon,NULL,IDI_APPLICATION
mov wc.hIcon,eax
mov wc.hIconSm,eax
invoke LoadCursor,NULL,IDC_ARROW
mov wc.hCursor,eax
invoke RegisterClassEx, addr wc
INVOKE CreateWindowEx,NULL,ADDR ClassName,ADDR AppName,\
WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,\
CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,\
hInst,NULL
mov hwnd,eax
invoke ShowWindow, hwnd,SW_SHOWNORMAL
invoke UpdateWindow, hwnd
.while TRUE
invoke GetMessage, ADDR msg,NULL,0,0
.break .if (!eax)
invoke TranslateMessage, ADDR msg
invoke DispatchMessage, ADDR msg
.endw
mov eax,msg.wParam
ret
WinMain endp
WndProc proc hWnd:HWND, uMsg:UINT, wParam:WPARAM, lParam:LPARAM
LOCAL ps:PAINTSTRUCT
LOCAL hdc:HDC
LOCAL hMemDC:HDC
LOCAL rect:RECT
.if uMsg==WM_CREATE
invoke LoadBitmap,hInstance,IDB_MAIN
mov hBitmap,eax
.elseif uMsg==WM_PAINT
invoke BeginPaint,hWnd,addr ps
mov hdc,eax
invoke CreateCompatibleDC,hdc
mov hMemDC,eax
invoke SelectObject,hMemDC,hBitmap
invoke GetClientRect,hWnd,addr rect
invoke BitBlt,hdc,0,0,rect.right,rect.bottom,hMemDC,0,0,SRCCOPY
invoke DeleteDC,hMemDC
invoke EndPaint,hWnd,addr ps
.elseif uMsg==WM_DESTROY
invoke DeleteObject,hBitmap
invoke PostQuitMessage,NULL
.ELSE
invoke DefWindowProc,hWnd,uMsg,wParam,lParam
ret
.ENDIF
xor eax,eax
ret
WndProc endp
end start
;---------------------------------------------------------------------
; 资源定义
;---------------------------------------------------------------------
#define IDB_MAIN 1
IDB_MAIN BITMAP "tweety78.bmp"

分析:

#define IDB_MAIN 1
IDB_MAIN BITMAP "tweety78.bmp"
定义整数宏IDB_MAIN的值为1，然后把它指向一个与资源文件处于相同目录文件名为“tweety.bmp"的位图。
.if uMsg==WM_CREATE
invoke LoadBitmap,hInstance,IDB_MAIN
mov hBitmap,eax

在处理 WM_CREATE 消息时, 我们通过API函数 LoadBitmap 载入位图资源，并通过函数返回值取得位图句柄。

然后，我们就可以把位图画在窗口客户区上。

.elseif uMsg==WM_PAINT
invoke BeginPaint,hWnd,addr ps
mov hdc,eax
invoke CreateCompatibleDC,hdc
mov hMemDC,eax
invoke SelectObject,hMemDC,hBitmap
invoke GetClientRect,hWnd,addr rect
invoke BitBlt,hdc,0,0,rect.right,rect.bottom,hMemDC,0,0,SRCCOPY
invoke DeleteDC,hMemDC
invoke EndPaint,hWnd,addr ps

在本例中，我们选用在响应WM_PAINT消息时画出位图。首先我们通过API函数l BeginPaint 获得窗口客户区的DC句柄。 接着我们通过API函数 CreateCompatibleDC 创建该DC 的内存映像，并通过API函数 SelectObject 把位图放进内存映像中。下一步，我们通过API函数 GetClientRect 取得窗口客户区的大小。最后，我们通过API函数 BitBlt 把位图从DC内存映像复制到真正的客户区DC中。 完成显示工作后，我们通过API函数 DeleteDC 释放DC内存映像，并用API函数 EndPaint 释放客户区DC， 结束画图工作。本文来自编程入门网

.elseif uMsg==WM_DESTROY
invoke DeleteObject,hBitmap
invoke PostQuitMessage,NULL

当我们不再需要位图时，通过API函数 DeleteObject 把它释放。