学习windows编程 day3 之滚动条完善
1.不再使用setscrollrange,setscrollpos,getscrollrange,getscrollpos这些函数，这只是有助于理解其中运行原理
2.改用setscrollinfo,getscrollinfo函数和结构体scrollinfo去改变和获取滚动条信息，相对于上面会更加灵活，方便扩展
3.scrollwindow:滚动窗口客户区的内容，只滚动当前显示的内容，要显示其他内容，需要重绘失效的窗口，但是相对于重绘整个窗口是一个很节省内存的方法
#include <windows.h> #include "Sysmet.h" #include <strsafe.h> LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam); int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) { //声明全局数据：类名 static TCHAR szClassName[] = TEXT("MyWindows"); HWND hwnd; MSG msg; //注册窗口类 WNDCLASS wndclass; wndclass.hInstance = hInstance; wndclass.lpszClassName = szClassName; wndclass.cbClsExtra = 0; wndclass.cbWndExtra = 0; wndclass.lpfnWndProc = WndProc; wndclass.lpszMenuName = NULL; wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION); wndclass.hCursor = LoadCursor(NULL, IDC_ARROW); wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH); wndclass.style = CS_HREDRAW; if (!RegisterClass(&wndclass)) { MessageBox(NULL, TEXT("this program must run in Windows NT!"), szClassName, MB_ICONERROR); return 0; } hwnd = CreateWindow( szClassName, TEXT("MyFirstPractice"), WS_OVERLAPPEDWINDOW|WS_VSCROLL, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL ); ShowWindow(hwnd, nShowCmd); UpdateWindow(hwnd); while (GetMessage(&msg, NULL, 0, 0)) { TranslateMessage(&msg); DispatchMessage(&msg); } return msg.wParam; } LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { HDC hdc; PAINTSTRUCT ps; RECT rect; //获取字体大小，初始化数据 static int cxChar, cyChar, cxCaps; //获取每次重绘窗口后的大小尺寸 static int cxClient, cyClient; //获取总行数和当前行数 static numCount, curCount; static int y; int FirstLine, LastLine; TEXTMETRIC tm; TCHAR szBuffer[100]; size_t st; SCROLLINFO si; switch (message) { case WM_CREATE: hdc = GetDC(hwnd); //获取字体大小，初始化数据 GetTextMetrics(hdc, &tm); cxChar = tm.tmAveCharWidth; cyChar = tm.tmHeight + tm.tmExternalLeading; cxCaps = (tm.tmPitchAndFamily & 1 ? 3 : 2)*cxChar / 2; //初始化总行数和当前行数 numCount = NUMLINES; curCount = 0; //初始化滚动条位置 SetScrollRange(hwnd, SB_VERT, 0, numCount, FALSE); SetScrollPos(hwnd, SB_VERT, 0, TRUE); ReleaseDC(hwnd, &hdc); break; case WM_SIZE: //获取每次重绘后的屏幕大小 cxClient = LOWORD(lParam); //这是获取当前窗口的大小 cyClient = HIWORD(lParam); //设置垂直滚动条的范围和页面大小 si.cbSize = sizeof(si); //为了更好的兼容版本 si.fMask = SIF_RANGE | SIF_PAGE; si.nMin = 0; si.nMax = numCount - 1; si.nPage = cyClient / cyChar; //页面的大小设置 SetScrollInfo(hwnd, SB_VERT, &si, TRUE); break; case WM_VSCROLL: //获得垂直滚动条的信息 si.cbSize = sizeof(si); si.fMask = SIF_ALL; GetScrollInfo(hwnd, SB_VERT, &si); //保存当前滑块的位置 curCount = si.nPos; switch (LOWORD(wParam)) { case SB_LINEUP: si.nPos -= 1; break; case SB_LINEDOWN: si.nPos += 1; break; case SB_PAGEUP: //先获取当前页面有几行 si.nPos -= si.nPage; break; case SB_PAGEDOWN: //先获取当前页面的行数 si.nPos += si.nPage; break; case SB_THUMBTRACK: si.nPos = si.nTrackPos; break; //在si.nTrackPos中存放着SB_THUMBTRACK和SB_THUMBPOSITION的位置信息 case SB_THUMBPOSITION: si.nPos = si.nTrackPos; break; default: break; } //设置滚动滑块的新位置 si.fMask = SIF_POS; SetScrollInfo(hwnd, SB_VERT, &si, TRUE); //再次获得滚动滑块的位置，由于窗口调整，他可能不是同一个值 GetScrollInfo(hwnd, SB_VERT, &si); //curCount是前面未滚动的数据，si.nPos是刚刚滚动后的数据（除非是在顶部或者底部，不然由于窗口调整，两种一定不是同一个值） if (si.nPos != curCount) { ScrollWindow(hwnd, 0, cyChar*(curCount-si.nPos), NULL, NULL); /* hwnd :窗口句柄 0 :水平滚动的数量 cyChar*(curCount-si.nPos):垂直滚动的距离 NULL（lpRect） :为NULL时，当前整个客户区将被滚动 NULL（lpClipRect） :与上一个参数有关，当上一个设置区域后，该参数在其区域中裁剪区域进行滚动 */ UpdateWindow(hwnd); //不进入消息队列，直接发送WM_PAINT消息进行处理 } break; case WM_PAINT: hdc = BeginPaint(hwnd, &ps); //获取垂直滚动条的位置 si.cbSize = sizeof(si); si.fMask = SIF_POS; GetScrollInfo(hwnd,SB_VERT, &si); curCount = si.nPos; //计算需要重绘的区域 FirstLine = max(0, curCount + ps.rcPaint.top / cyChar); LastLine = min(numCount - 1, curCount + ps.rcPaint.bottom / cyChar); /* ps是结构体，ps.rcPaint是指需要重绘的部分窗口矩形，ps.rcPaint.top是该矩形的上部 */ for (int i = FirstLine; i < LastLine;i++) { y = cyChar*(i - curCount); //相当于将这个重绘区域看着新窗口，重这个区域的顶部开始重新绘制 StringCchLength(sysmetrics[i].szLabel, 100, &st); TextOut(hdc, 0, y, sysmetrics[i].szLabel, st); StringCchLength(sysmetrics[i].szDesc, 100, &st); TextOut(hdc, 40 * cxChar, y, sysmetrics[i].szDesc, st); SetTextAlign(hdc, TA_RIGHT | TA_TOP); StringCchPrintf(szBuffer, 100, L"%5d", GetSystemMetrics(sysmetrics[i].iIndex)); StringCchLength(szBuffer, 100, &st); TextOut(hdc, 40 * cxChar + 40 * cxCaps, y, szBuffer, st); SetTextAlign(hdc, TA_LEFT); } EndPaint(hwnd, &ps); break; case WM_DESTROY: PostQuitMessage(0); return 0; } return DefWindowProc(hwnd, message, wParam, lParam); }
