CDC(HDC)绘图类:
五大GDI对象类:CPen,CBrush,CFont,CBitmap,CRgn
23.1 LoadImage API
HANDLE LoadImage(HINSTANCE hinst,LPCTSTR lpszName, UINT uType, int cxDesired,int cyDesired,UINT fuLoad
);
uType参数填写以下三种:
IMAGE_BITMAP Loads a bitmap.IMAGE_CURSOR Loads a cursor.IMAGE_ICON Loads an icon
从HINSTANCE内部加载
void CTestImageDlg::OnBnClickedButton1()
{static HICON hIcon = (HICON)::LoadImage(theApp.m_hInstance, (LPCTSTR)IDI_TEST, IMAGE_ICON, 0, 0, LR_DEFAULTCOLOR);SetIcon(hIcon, TRUE);SetIcon(hIcon, FALSE);//*.cur
}m_hBitmap = (HBITMAP)::LoadImage(AfxGetInstanceHandle(), MAKEINTRESOURCE(IDB_BITMAP1),IMAGE_BITMAP, 0, 0, LR_DEFAULTCOLOR);m_hBitmap = ::LoadBitmap(theApp.m_hInstance, MAKEINTRESOURCE(IDB_BITMAP1));
从文件中直接加载
m_hBitmap = (HBITMAP)::LoadImage(NULL, _T("./ban.bmp"),IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE | LR_DEFAULTSIZE);HICON hIcon = (HICON)::LoadImage(NULL, _T("DfIcon.ico"),IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE| LR_DEFAULTSIZE);SetIcon(hIcon, TRUE);SetIcon(hIcon, FALSE);
显示
//CDC mdc;
//BITMAP bm;
//::GetObject(m_hBitmap, sizeof(bm), &bm);
//mdc.CreateCompatibleDC(&dc);
//mdc.SelectObject(m_hBitmap);
dc.BitBlt(10, 40, m_mdc.GetWidth(), mdc.GetHeight(), &m_mdc, 0, 0, SRCCOPY);
23.2 解决闪烁问题:
1、禁用非客户区输出,让非客户区WM_NCPAINT
产生空输出。
2、禁用客户区背景输出:WM_ERASEBKGRAND
消息是Invalidate(TRUE)
要调用的背景输出。
3、调用Invalidate函数时,尽量使用FALSE
。
4、当有多层次输出时,使用双缓冲技术,在内存中做好多次输出的草稿。
23.3 CMemoryDC类
#ifndef __MEMDC_H__
#define __MEMDC_H__
//Author:www.baojy.comclass CMemoryDC :public CDC
{CSize m_size;
public:void BitTrans(int nXDest, // 目标起点Xint nYDest, // 目标起点Yint nWidthDest, // 目标宽度int nHeightDest,// 目标高度CDC* pDC, // 目标DCint nXSrc, // 来源起点Xint nYSrc, // 来源起点YCOLORREF crTrans// 透明色){CMemoryDC dcImage(nWidthDest, nHeightDest,pDC);//临时DCCBitmap bmpMask;bmpMask.CreateBitmap(nWidthDest, nHeightDest, 1, 1, NULL); // 创建单色掩码位图CDC dcMask;//掩码DC dcMask.CreateCompatibleDC(pDC);dcMask.SelectObject(bmpMask);//将载入位图的内存DC中的位图,拷贝到临时DC中dcImage.BitBlt( 0, 0, nWidthDest, nHeightDest, this, nXSrc, nYSrc, SRCCOPY);// 设置临时DC的透明色dcImage.SetBkColor(crTrans);//掩码DC的透明区域为白色其它区域为黑色dcMask.BitBlt(0, 0, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCCOPY);//临时DC透明区域为黑色,其它区域保持不变dcImage.SetBkColor(RGB(0,0,0));dcImage.SetTextColor(RGB(255,255,255));dcImage.BitBlt( 0, 0, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);// 目标DC透明部分保持屏幕不变,其它部分变成黑色pDC ->SetBkColor(RGB(255,255,255));pDC ->SetTextColor(RGB(0,0,0));pDC ->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);pDC ->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCPAINT);} void StretchTrans(int nXDest, // 目标起点Xint nYDest, // 目标起点Yint nWidthDest, // 目标宽度int nHeightDest, // 目标高度CDC* pDC, // 目标DCint nXSrc, // 来源起点Xint nYSrc, // 来源起点Yint nWidthSrc, // 来源宽度int nHeightSrc, // 来源高度COLORREF crTrans // 透明色){CMemoryDC dcImage(nWidthDest, nHeightDest,pDC);//临时DCCBitmap bmpMask;// 创建单色掩码位图bmpMask.CreateBitmap(nWidthDest, nHeightDest, 1, 1, NULL);CDC dcMask;dcMask.CreateCompatibleDC(pDC);dcMask.SelectObject(bmpMask);// 将载入位图的内存DC中的位图,拷贝到临时DC中if (nWidthDest == nWidthSrc && nHeightDest == nHeightSrc)dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, this, nXSrc, nYSrc, SRCCOPY);elsedcImage.StretchBlt(0, 0, nWidthDest, nHeightDest, this, nXSrc, nYSrc, nWidthSrc, nHeightSrc, SRCCOPY);// 设置临时DC的透明色dcImage.SetBkColor( crTrans);//掩码DC的透明区域为白色其它区域为黑色dcMask.BitBlt(0,0,nWidthDest, nHeightDest,&dcImage,0,0,SRCCOPY);//临时DC透明区域为黑色,其它区域保持不变dcImage.SetBkColor(RGB(0,0,0));dcImage.SetTextColor(RGB(255,255,255));dcImage.BitBlt(0, 0, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);// 目标DC透明部分保持屏幕不变,其它部分变成黑色pDC ->SetBkColor(RGB(255,255,255));pDC ->SetTextColor(RGB(0,0,0));pDC ->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcMask, 0, 0, SRCAND);pDC ->BitBlt(nXDest, nYDest, nWidthDest, nHeightDest, &dcImage, 0, 0, SRCPAINT);} CMemoryDC(){m_size.cx = m_size.cy = 0;}//从资源中加载位图BOOL LoadBitmap(UINT nBitmapID,CDC* pDC=NULL){CBitmap bitmap;bitmap.LoadBitmap(nBitmapID);BITMAP bm;bitmap.GetBitmap(&bm);m_size.cx = bm.bmWidth;m_size.cy = bm.bmHeight;CreateCompatibleDC(pDC);SelectObject(bitmap);return TRUE;}CMemoryDC(UINT nBitmapID,CDC* pDC=NULL){LoadBitmap(nBitmapID,pDC);}//从.bmp文件中加载位图BOOL LoadBitmap(LPCTSTR szBitmapFile,CDC* pDC=NULL){HBITMAP hBitmap = (HBITMAP)LoadImage(AfxGetInstanceHandle(),szBitmapFile,IMAGE_BITMAP,0,0,LR_LOADFROMFILE);BITMAP bm;GetObject(hBitmap,sizeof(bm),&bm);m_size.cx = bm.bmWidth;m_size.cy = bm.bmHeight;CreateCompatibleDC(pDC);SelectObject(hBitmap); return TRUE;}CMemoryDC(LPCTSTR szBitmapFile,CDC* pDC=NULL){LoadBitmap(szBitmapFile,pDC);}//创建一张空白内存画布BOOL Create(int cx,int cy,CDC* pDC = NULL){CreateCompatibleDC(pDC);CBitmap bitmap;if(pDC)bitmap.CreateCompatibleBitmap(pDC,cx,cy);elsebitmap.CreateCompatibleBitmap(&CClientDC(NULL),cx,cy);m_size.cx = cx;m_size.cy = cy;SelectObject(bitmap);return TRUE;}CMemoryDC(int cx,int cy,CDC* pDC = NULL){Create(cx,cy,pDC);}//摧毁BOOL DeleteDC(){if(!GetSafeHdc())return TRUE;CBitmap * pBitmap = GetCurrentBitmap();pBitmap ->DeleteObject();return CDC::DeleteDC();}~CMemoryDC(){DeleteDC();}inline int Width(){return m_size.cx;}inline int Height(){return m_size.cy;}
};
#endif //__MEMDC_H__
23.4 采用CMemoryDC类实现图片旋转
//1、加载资源位图
//2、加载外部位图
//3、创建空白位图(黑色:指定高宽)
//4、显示透明和伸缩透明图片
CMemoryDC m_dcBack; // 定义全局变量
m_dcBack.LoadBitmap(IDB_BITMAP1); // 初始化void CPageDlg::OnPaint()
{CPaintDC dc(this); // 用于绘制的设备上下文CRect rect;GetClientRect(rect);CMemoryDC mdc(rect.Width(), rect.Height(),&dc);//缓冲DC:黑色mdc.FillSolidRect(rect, GetSysColor(COLOR_3DFACE)); // 缓冲DC:灰色mdc.StretchBlt(m_nLeft, 0, rect.Width() - m_nLeft * 2, rect.Height(),&m_dcBack, 0, 0, rect.Width(), rect.Height(), SRCCOPY); // 绘图输出到缓冲DC中dc.BitBlt(0, 0, rect.Width(),rect.Height(), &mdc, 0, 0, SRCCOPY);//一次性对界面(dc)输出
}
23.5 采用CMemoryDC类实现蝴蝶动画
#include "MemoryDC.h"
#pragma once// CfsDlg 对话框
class CfsDlg : public CDialogEx
{CMemoryDC m_dc;//缓冲enum { PAGE_COUNT =7};CMemoryDC m_dcBack;CMemoryDC m_dcFly[PAGE_COUNT];struct SData{CPoint pos;CPoint dir;//5,5 -5,5 5,-5 -5,-5int nIndex;};CArray<SData> m_arr;//动态数组
public:CfsDlg(CWnd* pParent = NULL); // 标准构造函数
protected:HICON m_hIcon;virtual BOOL OnInitDialog();afx_msg void OnPaint();afx_msg HCURSOR OnQueryDragIcon();DECLARE_MESSAGE_MAP()
public:afx_msg BOOL OnEraseBkgnd(CDC* pDC);afx_msg void OnNcPaint();afx_msg void OnLButtonDown(UINT nFlags, CPoint point);afx_msg void OnTimer(UINT_PTR nIDEvent);
};BOOL CfsDlg::OnInitDialog()
{CDialogEx::OnInitDialog();srand(time(NULL));m_dcBack.LoadBitmap(_T("./images/back.bmp"));int cx = GetSystemMetrics(SM_CXSCREEN);int cy = GetSystemMetrics(SM_CYSCREEN);SetWindowPos(NULL, 0, 0, cx, cy, 0);m_dc.Create(cx, cy);int i = -1;CString str;while (++i<_countof(m_dcFly)){str.Format(_T("./images/%03d.bmp"), i + 1);m_dcFly[i].LoadBitmap(str);}SetTimer(1, 20, NULL);SetIcon(m_hIcon, TRUE); // 设置大图标SetIcon(m_hIcon, FALSE); // 设置小图标return TRUE; // 除非将焦点设置到控件,否则返回 TRUE
}void CfsDlg::OnPaint()
{CPaintDC dc(this); //界面dcCRect rect;GetClientRect(rect);//dc.BitBlt(0, 0, m_dcBack.GetWidth(), m_dcBack.GetHeight(), &m_dcBack, 0, 0, SRCCOPY);m_dc.StretchBlt(0, 0, rect.Width(), rect.Height(), &m_dcBack, 0, 0, m_dcBack.GetWidth(), m_dcBack.GetHeight(), SRCCOPY);int i = 0,nSize = m_arr.GetSize();while (i < nSize){SData& d = m_arr[i];m_dcFly[d.nIndex].BitTrans(d.pos.x,d.pos.y ,m_dcFly->GetWidth(),m_dcFly->GetHeight(),&m_dc,0,0,0);if (++d.nIndex > 6)d.nIndex = 0;d.pos.Offset(d.dir);GetClientRect(rect);if (d.pos.x >= rect.right - m_dcFly->GetWidth() || d.pos.x <= 0)d.dir.x *= -1;if (d.pos.y >= rect.bottom - m_dcFly->GetHeight() || d.pos.y <= 0)d.dir.y *= -1; ++i;}dc.BitBlt(0, 0, rect.Width(), rect.Height(), &m_dc, 0, 0, SRCCOPY);
}BOOL CfsDlg::OnEraseBkgnd(CDC* pDC)
{return TRUE;
}void CfsDlg::OnNcPaint()
{}void CfsDlg::OnLButtonDown(UINT nFlags, CPoint point)
{//无限增长的蝴蝶个数SData data = { point,{5,5},0 };if(rand()%2) //893253%2 data.dir.x *= -1;if (rand() % 2) //547547%2 data.dir.y *= -1;m_arr.Add(data);CDialogEx::OnLButtonDown(nFlags, point);
}void CfsDlg::OnTimer(UINT_PTR nIDEvent)
{Invalidate(FALSE);CDialogEx::OnTimer(nIDEvent);
}