子窗口控件(3)之属性罗列和自绘按钮
Windows有29种系统颜色，每种颜色都在0-255之间，它使用GetSysColor和SetSysColors来调用颜色参数：
也就是Windows下的画板的颜色：
罗列一下具体的29种颜色的参数：
如下调用：
SetBkColor(hdc,GetSysColor(COLOR_BTNFACE));SetTextColor(hdc,GetSysColor(Color_WINDOWTEXT));//更改了系统颜色，要用下面的语句传递消息case WM_SYSCOLORCHANGE: InvalidateRect(hwnd,NULL,TRUE); break;
一般使用获取WM_CTLCOLORSTATIC:消息去改变颜色：
下面看一段自绘按钮的代码：
#include<windows.h>#include<windowsx.h>#define ID_SMALLER 1#define ID_LARGER 2#define BTN_WIDTH (8*cxChar)#define BTN_HEIGHT (4*cyChar)LRESULT CALLBACK WindowProc( HWND hwnd, // handle to window UINT uMsg, // message identifier WPARAM wParam, // first message parameter LPARAM lParam // second message parameter);HINSTANCE hInst;int WINAPI WinMain( HINSTANCE hInstance, // handle to current instance HINSTANCE hPrevInstance, // handle to previous instance LPSTR lpCmdLine, // command line int nCmdShow // show state){static TCHAR szAppName[]=TEXT("leidemingzi");HWND hwnd;MSG msg;WNDCLASS wndclass;hInst=hInstance;wndclass.cbClsExtra=0;wndclass.cbWndExtra=0;wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);wndclass.hCursor=LoadCursor(NULL,IDC_ARROW);wndclass.hIcon=LoadIcon(NULL,IDI_ERROR);wndclass.hInstance=hInstance;wndclass.lpfnWndProc=WindowProc;wndclass.lpszClassName=szAppName;wndclass.lpszMenuName=NULL;wndclass.style=CS_HREDRAW|CS_VREDRAW;if(!RegisterClass(&wndclass)){MessageBox(NULL,TEXT("the program requrie the window nt"),TEXT("tips"),MB_ICONERROR);return 0;}hwnd=CreateWindow( szAppName, // registered class name TEXT("this is title"), // window name WS_OVERLAPPEDWINDOW, // window style CW_USEDEFAULT, // horizontal position of window CW_USEDEFAULT, // vertical position of window CW_USEDEFAULT, // window width CW_USEDEFAULT, // window height NULL, // handle to parent or owner window NULL, // menu handle or child identifier hInstance, // handle to application instance NULL // window-creation data);ShowWindow(hwnd,nCmdShow);UpdateWindow(hwnd);while(GetMessage(&msg,NULL,0,0)){TranslateMessage(&msg);DispatchMessage(&msg);}return msg.wParam;}void Triangle(HDC hdc,POINT pt[]){SelectObject(hdc,GetStockObject(BLACK_BRUSH));Polygon(hdc,pt,3);SelectObject(hdc,GetStockObject(WHITE_BRUSH));}LRESULT CALLBACK WindowProc( HWND hwnd, // handle to window UINT uMsg, // message identifier WPARAM wParam, // first message parameter LPARAM lParam // second message parameter){static HWND hwndSmaller,hwndLarger;static int cxClient,cyClient,cxChar,cyChar;LPDRAWITEMSTRUCT pdis;POINT pt[3];int cx,cy;RECT rect;switch(uMsg){case WM_CREATE:cxChar=LOWORD(GetDialogBaseUnits());cyChar=HIWORD(GetDialogBaseUnits());hwndSmaller=CreateWindow(TEXT("button"),TEXT(""),WS_CHILD|WS_VISIBLE|BS_OWNERDRAW,0,0,BTN_WIDTH,BTN_HEIGHT,hwnd,(HMENU)ID_SMALLER,hInst,NULL);hwndLarger=CreateWindow(TEXT("button"),TEXT(""),WS_CHILD|WS_VISIBLE|BS_OWNERDRAW,0,0,BTN_WIDTH,BTN_HEIGHT,hwnd,(HMENU)ID_LARGER,hInst,NULL);return 0;case WM_SIZE:cxClient=GET_X_LPARAM(lParam);cyClient=GET_Y_LPARAM(lParam);MoveWindow(hwndSmaller,cxClient/2-3*BTN_WIDTH/2,cyClient/2-BTN_HEIGHT/2,BTN_WIDTH,BTN_HEIGHT,TRUE);MoveWindow(hwndLarger,cxClient/2+BTN_WIDTH/2,cyClient/2-BTN_HEIGHT/2,BTN_WIDTH,BTN_HEIGHT,TRUE);return 0;case WM_COMMAND:GetWindowRect(hwnd,&rect);switch(wParam){case ID_SMALLER:rect.left+=cxClient/20;rect.right-=cxClient/20;rect.top+=cyClient/20;rect.right-=cyClient/20;break;case ID_LARGER:rect.left-=cxClient/20;rect.right+=cxClient/20;rect.top-=cyClient/20;rect.right+=cyClient/20;break;}MoveWindow(hwnd,rect.left,rect.top,rect.right-rect.left,rect.bottom-rect.top,TRUE);return 0;case WM_DRAWITEM:pdis=(LPDRAWITEMSTRUCT)lParam;FillRect(pdis->hDC,&pdis->rcItem,(HBRUSH)GetStockObject(WHITE_BRUSH));FrameRect(pdis->hDC,&pdis->rcItem,(HBRUSH)GetStockObject(BLACK_BRUSH));cx=pdis->rcItem.right-pdis->rcItem.left;cy=pdis->rcItem.bottom-pdis->rcItem.top;switch (pdis->CtlID) { case ID_SMALLER : pt[0].x = 3 * cx / 8 ; pt[0].y = 1 * cy / 8 ; pt[1].x = 5 * cx / 8 ; pt[1].y = 1 * cy / 8 ; pt[2].x = 4 * cx / 8 ; pt[2].y = 3 * cy / 8 ; Triangle (pdis->hDC, pt) ; pt[0].x = 7 * cx / 8 ; pt[0].y = 3 * cy / 8 ; pt[1].x = 7 * cx / 8 ; pt[1].y = 5 * cy / 8 ; pt[2].x = 5 * cx / 8 ; pt[2].y = 4 * cy / 8 ; Triangle (pdis->hDC, pt) ; pt[0].x = 5 * cx / 8 ; pt[0].y = 7 * cy / 8 ; pt[1].x = 3 * cx / 8 ; pt[1].y = 7 * cy / 8 ; pt[2].x = 4 * cx / 8 ; pt[2].y = 5 * cy / 8 ; Triangle (pdis->hDC, pt) ; pt[0].x = 1 * cx / 8 ; pt[0].y = 5 * cy / 8 ; pt[1].x = 1 * cx / 8 ; pt[1].y = 3 * cy / 8 ; pt[2].x = 3 * cx / 8 ; pt[2].y = 4 * cy / 8 ; Triangle (pdis->hDC, pt) ; break ; case ID_LARGER : pt[0].x = 5 * cx / 8 ; pt[0].y = 3 * cy / 8 ; pt[1].x = 3 * cx / 8 ; pt[1].y = 3 * cy / 8 ; pt[2].x = 4 * cx / 8 ; pt[2].y = 1 * cy / 8 ; Triangle (pdis->hDC, pt) ; pt[0].x = 5 * cx / 8 ; pt[0].y = 5 * cy / 8 ; pt[1].x = 5 * cx / 8 ; pt[1].y = 3 * cy / 8 ; pt[2].x = 7 * cx / 8 ; pt[2].y = 4 * cy / 8 ; Triangle (pdis->hDC, pt) ; pt[0].x = 3 * cx / 8 ; pt[0].y = 5 * cy / 8 ; pt[1].x = 5 * cx / 8 ; pt[1].y = 5 * cy / 8 ; pt[2].x = 4 * cx / 8 ; pt[2].y = 7 * cy / 8 ; Triangle (pdis->hDC, pt) ; pt[0].x = 3 * cx / 8 ; pt[0].y = 3 * cy / 8 ; pt[1].x = 3 * cx / 8 ; pt[1].y = 5 * cy / 8 ; pt[2].x = 1 * cx / 8 ; pt[2].y = 4 * cy / 8 ; Triangle (pdis->hDC, pt) ; break ; }if(pdis->itemState*ODS_SELECTED)InvertRect(pdis->hDC,&pdis->rcItem);if(pdis->itemState&ODS_FOCUS){pdis->rcItem.left+=cx/16;pdis->rcItem.top+=cy/16;pdis->rcItem.right-=cx/16;pdis->rcItem.bottom-=cy/16;DrawFocusRect(pdis->hDC,&pdis->rcItem);}return 0;case WM_DESTROY:PostQuitMessage(0);return 0;}return DefWindowProc(hwnd,uMsg,wParam,lParam);}
其中，GetDialogBaseUnits()方法类似于TEXTMETRIC的tmAveCharWidth属性
case WM_DRAWITEM在绘制OWNERDRAW控件生效
再看一下DRAWITEMSTRUCT的定义，详细请看MSDN
typedef struct tagDRAWITEMSTRUCT { UINT CtlType; UINT CtlID; UINT itemID; UINT itemAction; UINT itemState; HWND hwndItem; HDC hDC; RECT rcItem; ULONG_PTR itemData; } DRAWITEMSTRUCT
效果图如下：
选中的时候，按钮颜色取反，左边按钮使窗体变小，右边按钮使窗体变大
忠告：
对于使用自绘按钮的人，Windows会为你获得设备环境，并把它放在DRAWITEMSTRUCT结构的一个字段中，必须原样不动保持这个设备的状态，任何一个被选入该设备环境的GDI对象必须设置回原有的不被选中的状态，此外不能在按钮的区域以外绘制任何图形。