更新时间:2015-12-06 13:11:56浏览次数:1+次
我们可以看到,第一次绘制的就是一串文字,在擦除背景后再绘制文字(一串下划线字符),则看不到原先的字符串了,只有下划线字符了。而不擦除背景绘制文字时,背景的文字(本次以前绘制的内容)都保留,然后这次就在背景文字上继续绘制。所以此时就将下划线字符画在了字符串的底部,因为下划线字符只占底部一点点空间,所以并没有与字符串重叠,看到的就是给字符串添加下划线的效果。而如果话字符“-”,就可以实现删除线效果,而如果是其他字符,就在中间位置,与原先文字叠加后变得混乱不堪。效果图如下:
#include "windows.h"
#include <tchar.h>
// - 项目是Unicode字符集
LRESULT CALLBACK WinProc(HWND hwnd,UINT message,WPARAM wParam,LPARAM lParam)
{
HDC hdc;
PAINTSTRUCT ps;
RECT rect;
static TCHAR str[]=_T("C++技术网http://www.cjjjs.com");
static int i=0;
static TCHAR ch;
switch (message)
{
case WM_PAINT:
hdc = BeginPaint(hwnd,&ps);
GetClientRect(hwnd,&rect);
SetBkMode(hdc,TRANSPARENT);
DrawText(hdc,str,-1,&rect,DT_SINGLELINE | DT_VCENTER |DT_CENTER);
break;
case WM_LBUTTONDOWN:
hdc = GetWindowDC(hwnd);
GetClientRect(hwnd,&rect);
InvalidateRect(hwnd,&rect,FALSE);
lstrcpy(str,_T("________________________"));
break;
case WM_DESTROY:
PostQuitMessage(0);
default:
return DefWindowProc(hwnd, message, wParam, lParam);
}
}
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrev,LPSTR lpCmd,int iShow)
{
TCHAR ClassName[] = _T("MyClass");
TCHAR title1[] = _T("C++技术网www.cjjjs.com");
WNDCLASS wndClass;
wndClass.cbClsExtra=0;
wndClass.cbWndExtra=0;
wndClass.hbrBackground= (HBRUSH)GetStockObject(WHITE_BRUSH);
wndClass.hCursor=LoadCursor(NULL,IDC_ARROW);
wndClass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
wndClass.hInstance = hInstance;
wndClass.lpfnWndProc = WinProc;
wndClass.lpszClassName = ClassName;
wndClass.lpszMenuName=NULL;
wndClass.style=CS_HREDRAW|CS_VREDRAW;
if(!RegisterClass(&wndClass))
{
return 0;
}
HWND hwnd = CreateWindow(ClassName,title1,WS_OVERLAPPEDWINDOW,0,0,440,400,NULL,NULL,hInstance,NULL);
ShowWindow(hwnd,SW_SHOWNORMAL);
MSG msg;
while (GetMessage(&msg,NULL,0,0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
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