如何在对话框上显示一张图片

如何在对话框上显示一张图片

在对话框上显示一张图片，可能是一个比较常用的功能，在MFC中提供了OnPaint()绘图函数，下面结合这个函数，提供 几种在对话框上显示一张图片的代码。首先假设你有一张24位的图片，放在e：\下，然后建立一个dialog based的MFC程序。

利用picture control显示

拖动一个picture control到dialog上，ID为IDC_PICTURE，然后在OnPaint()函数下的else条件下加入如下代码：

HBITMAP   hBitmap;
//get the picture control which is on the dialog
CStatic   *pStatic   =   (CStatic*)GetDlgItem(IDC_PICTURE);
//load the file
hBitmap   =   (HBITMAP)LoadImage(NULL, "E:\\2.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
pStatic->ModifyStyle(0xF,   SS_BITMAP);
//show the file on the picture control
pStatic->SetBitmap(hBitmap);

利用CImage类显示

加上头文件：#include <atlimage.h>

在OnPaint()函数下的else条件下加入如下代码：

CImage img;
img.Load("E:\\2.BMP");
img.Draw(this->GetDC()->GetSafeHdc(), 0, 0, img.GetWidth(), img.GetHeight(), 0, 0, img.GetWidth(), img.GetHeight());

利用BitBlt()函数显示

在OnPaint()函数下的else条件下加入如下代码：

CDC memdc;
CClientDC dc(this);

void* flag = LoadImage(NULL, "E:\\2.BMP", IMAGE_BITMAP, 0,0,LR_LOADFROMFILE);

//CBitmap defindes a series of operation on image files
CBitmap   *bitmap   =   CBitmap::FromHandle((HBITMAP)flag);

//BITMAP is bmp file
BITMAP     temp;
bitmap->GetBitmap(&temp);

//temp.bmBits = (unsigned char*)malloc(temp.bmHeight*temp.bmWidth*3);
//bitmap->GetBitmapBits(temp.bmHeight*temp.bmWidth, temp.bmBits);

//get the height and the width
int heigth =temp.bmHeight;
int width =temp.bmWidth;

memdc.CreateCompatibleDC(&dc);
memdc.SelectObject(bitmap);

//dc.FillSolidRect((GetSystemMetrics(SM_CXSCREEN)-m_Length)/2,  (GetSystemMetrics(SM_CYSCREEN)-m_Width)/2, m_Length,m_Width,RGB(0,0,255));
//dc.BitBlt(     0,0, width, heigth, &memdc, 0, 0,      SRCCOPY);
//dc.StretchBlt(50, 50, 300, 300, &memdc, 0, 0, heigth,  width,  SRCCOPY);

//BitBlt() is faster than StretchBlt()
dc.BitBlt(     0,0, width, heigth, &memdc, 0, 0,      SRCCOPY);
DeleteObject(bitmap);

利用SetDIBitsToDevice函数显示

在OnPaint()函数下的else条件下加入如下代码：

CClientDC dc(this);<br/>
void* flag = LoadImage(NULL, "E:\\2.BMP", IMAGE_BITMAP, 0,0,LR_LOADFROMFILE);
//CBitmap defindes a series of operation on image files
CBitmap   *bitmap   =   CBitmap::FromHandle((HBITMAP)flag);
//BITMAP is bmp file
BITMAP     temp;
bitmap->GetBitmap(&temp);
int height = temp.bmHeight;
int widht = temp.bmWidth;

temp.bmBits = (unsigned char*)malloc(temp.bmHeight*temp.bmWidth*4);
bitmap->GetBitmapBits(height*widht*4, temp.bmBits);

BITMAPINFO * info = new BITMAPINFO;
info->bmiHeader.biBitCount = temp.bmBitsPixel;
info->bmiHeader.biClrImportant = 0;
info->bmiHeader.biHeight = temp.bmHeight;
info->bmiHeader.biWidth = temp.bmWidth;
info->bmiHeader.biPlanes = temp.bmPlanes;
info->bmiHeader.biClrUsed = 0;
info->bmiHeader.biCompression = 0;
info->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
info->bmiHeader.biSizeImage = height*widht*3;
info->bmiHeader.biXPelsPerMeter = 0;
info->bmiHeader.biYPelsPerMeter = 0;

SetDIBitsToDevice(dc, 0, 0,
widht, height,
0,0,
0, height,
temp.bmBits,
info,
DIB_RGB_COLORS);

经过测试，在显示速度上，第四种方法是最快的，其次是第三种，前两种速度好像差不多。 若建立的是MFC single document, 找到view类下的onDraw()函数，图片显示是类似的。

http://iiec.cqu.edu.cn/wiki/index.php/%E5%A6%82%E4%BD%95%E5%9C%A8%E5%AF%B9%E8%AF%9D%E6%A1%86%E4%B8%8A%E6%98%BE%E7%A4%BA%E4%B8%80%E5%BC%A0%E5%9B%BE%E7%89%87