vfp 调用api 在表单上画线

本文介绍了如何在Visual FoxPro(VFP)环境下利用API调用来实现在表单上绘制线条的功能。作者通过对比C/C++中的实现,探讨了在VFP 9.0 SP2环境下实现相同功能的方法,具体操作包括在表单上添加按钮,并在按钮点击事件中编写相关API调用代码。

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最近复习win32sdk,看到某些api在C/C++中的实现,突然想看看能不能在vfp下是不是也能实现同样的功能

虽然简单,权当实验

实现环境 xp sp3  中文版 + vfp 9.0 sp2 7423 汉化版


准备

新建一个表单,然后在表单上放置一个按钮(Command)

复制下面代码到按钮的Click 事件中

*!*	typedef struct tagPAINTSTRUCT { 
*!*	  HDC  hdc; 
*!*	  BOOL fErase; 
*!*	  RECT rcPaint; 
*!*	  BOOL fRestore; 
*!*	  BOOL fIncUpdate; 
*!*	  BYTE rgbReserved[32]; 
*!*	} PAINTSTRUCT, *PPAINTSTRUCT; 

*!*	typedef struct tagRECT { 
*!*	  LONG left; 
*!*	  LONG top; 
*!*	  LONG right; 
*!*	  LONG bottom; 
*!*	} RECT, *PRECT, NEAR *NPRECT, FAR *LPRECT;
                                                         

Declare GetClientRect In user32 Long hWnd, ;
	String @lpRect
Declare Long BeginPaint In user32 Long hwnd, ;
	String @lpPaint
Declare Long EndPaint In user32 Long hwnd, ;
	String @lpPaint
Declare Integer MoveToEx In gdi32 Long hdc,;
	Integer x, ;
	Integer y, ;
	String @lpPoint
Declare Integer LineTo In gdi32 Long hdc
vfp9.0调用API制作照相软件实例 PUBLIC WM_CAP_DRIVER_DISCONNECT PUBLIC hwndc,WM_CAP_SAVEDIB,WM_CAP_FILE_SET_CAPTURE_FILEA,WM_CAP_SEQUENCE,WM_CAP_STOP DECLARE INTEGER capCreateCaptureWindowA IN "AVICAP32.DLL" STRING lpszWindowName ,INTEGER dwStyle , INTEGER x, INTEGER Y, INTEGER nWidth ,INTEGER nHeight,INTEGER ParentWin,INTEGER nId DECLARE INTEGER SendMessage IN "user32" INTEGER HWND, INTEGER wmsg,INTEGER wpar1, INTEGER wpar2 DECLARE INTEGER SendMessage IN "user32" AS SendMessageA INTEGER HWND, INTEGER wmsg,INTEGER wpar1, STRING wpar2 *!* 显示: WM_USER = 1024 WM_CAP_START = WM_USER WM_CAP_STOP = WM_CAP_START + 68 WM_CAP_DRIVER_CONNECT = WM_CAP_START + 10 WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + 11 WM_CAP_SAVEDIB = WM_CAP_START + 25 WM_CAP_GRAB_FRAME = WM_CAP_START + 60 WM_CAP_SEQUENCE = WM_CAP_START + 62 WM_CAP_FILE_SET_CAPTURE_FILEA = WM_CAP_START + 20 WM_CAP_SEQUENCE_NOFILE =WM_CAP_START+ 63 WM_CAP_SET_OVERLAY =WM_CAP_START+ 51 WM_CAP_SET_PREVIEW =WM_CAP_START+ 50 WM_CAP_SET_CALLBACK_VIDEOSTREAM = WM_CAP_START +6 WM_CAP_SET_CALLBACK_ERROR=WM_CAP_START +2 WM_CAP_SET_CALLBACK_STATUSA= WM_CAP_START +3 WM_CAP_SET_CALLBACK_FRAME= WM_CAP_START +5 WM_CAP_SET_SCALE=WM_CAP_START+ 53 WM_CAP_SET_PREVIEWRATE=WM_CAP_START+ 52 hWndC = capCreateCaptureWindowA('My Own Capture Window',1342177280,0,0,200,150,THISFORM.HWND ,0) &&显示大小 IF hWndC 0 SendMessage(hWndC, WM_CAP_SET_CALLBACK_VIDEOSTREAM, 0, 0) SendMessage(hWndC, WM_CAP_SET_CALLBACK_ERROR, 0, 0) SendMessage(hWndC, WM_CAP_SET_CALLBACK_STATUSA, 0, 0) SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, 0, 0) SendMessage(hWndC, WM_CAP_SET_SCALE, 1, 0) SendMessage(hWndC, WM_CAP_SET_PREVIEWRATE, 66, 0) SendMessage(hWndC, WM_CAP_SET_OVERLAY, 1, 0) SendMessage(hWndC, WM_CAP_SET_PREVIEW, 1, 0) * THISFORM.ACTIVATE ENDIF
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