C++中最全的图像显示及处理类CxImage

remex 著于 发表 2007-8-13

MFC/C++

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CxImage 是一个C++类，可以加载、保存、显示，转换BMP, JPEG, GIF, PNG, TIFF, MNG, ICO, PCX, TGA, WMF, WBMP, JBG, J2K 等格式图像。

[翻译]
Davide Pizzolato.著CxImage



[简介]

CxImage 是一个C++类，可以加载、保存、显示，转换BMP, JPEG, GIF, PNG, TIFF, MNG, ICO, PCX, TGA, WMF, WBMP, JBG, J2K 等格式图像。


[程序结构]



Cximage以位图为基础，并附加一些信息保存信息。

Code:

class CxImage
  {
  ...
  protected:
  void* pDib;            //contains the header, the palette, the pixels
  BITMAPINFOHEADER head; //standard header
  CXIMAGEINFO info;      //extended information
  BYTE* pSelection;      //selected region
  BYTE* pAlpha;          //alpha channel
  CxImage** pLayers;     //generic layers
  }

CxImage::head 是一个位图头，CxImage::pDib 是通常的位图。CxImage::info 是一个存储在不同格式之间的许多共享信息。

Code:

typedef struct tagCxImageInfo {
    DWORD   dwEffWidth;       //DWORD aligned scan line width
    BYTE*   pImage;           //THE IMAGE BITS
    void*   pGhost;           //if this is a ghost, pGhost point to the body
    DWORD   dwType;           //original image format
    char    szLastError[256]; //debugging
    long    nProgress;        //monitor
    long    nEscape;          //escape
    long    nBkgndIndex;      //used for GIF, PNG, MNG
    RGBQUAD nBkgndColor;      //used for RGB transparency
    BYTE    nQuality;         //used for JPEG
    long    nFrame;           //used for TIF, GIF, MNG : actual frame
    long    nNumFrames;       //used for TIF, GIF, MNG : total number of
                              //frames
    DWORD   dwFrameDelay;     //used for GIF, MNG
    long    xDPI;             //horizontal resolution
    long    yDPI;             //vertical resolution
    RECT    rSelectionBox;    //bounding rectangle
    BYTE    nAlphaMax;        //max opacity (fade)
    bool    bAlphaPaletteEnabled;  //true if alpha values in the palette are
                              // enabled.
    bool    bEnabled;         //enables the painting functions
    long    xOffset;
    long    yOffset;
    DWORD   dwEncodeOption;   //for GIF, TIF : 0=def.1=unc,2=fax3,3=fax4,
                              // 4=pack,5=jpg
    RGBQUAD last_c;           //for GetNearestIndex optimization
    BYTE    last_c_index;
    bool    last_c_isvalid;
    long    nNumLayers;
    DWORD   dwFlags;
} CXIMAGEINFO;

CxImage对象还是多层的集合。每层的缓冲只在必要的时候才被分配。



CxImage::pDib是背景图，CxImage::pAlpha 是透明层，CxImage::pSelection 是选择层，用于创建图像处理的区域。在这三层外，你还可以定义，然后存储在CxImage::pLayers中。

CxImage类成员和操作

支持的格式和操作

[使用CxImage]

要想使用CxImage，你必须编辑以下设置
Project Settings
|- C/C++
| |- Code Generation
| | |- Use run-time library : Multithreaded DLL (must be the same for
| | | all the linked libraries)
| | |- Struct member alignment : must be the same for all the linked
| | | libraries
| |- Precompiled headers : not using precompiled headers
| |- Preprocessor
| |- Additional Include Directories: ../cximage
|- Link
|- General
|- Object/library modules: ../png/Debug/png.lib
../jpeg/Debug/jpeg.lib
../zlib/Debug/zlib.lib
../tiff/Debug/tiff.lib
../cximage/Debug/cximage.lib ...

[使用实例]

转换图像格式

Code:

CxImage  image;
// bmp -> jpg
image.Load("image.bmp", CXIMAGE_FORMAT_BMP);
if (image.IsValid()){
    if(!image.IsGrayScale()) image.IncreaseBpp(24);
    image.SetJpegQuality(99);
    image.Save("image.jpg",CXIMAGE_FORMAT_JPG);
}
// png -> tif
image.Load("image.png", CXIMAGE_FORMAT_PNG);
if (image.IsValid()){
    image.Save("image.tif",CXIMAGE_FORMAT_TIF);
}

加载图像资源

Code:

//Load the resource IDR_PNG1 from the PNG resource type
CxImage* newImage = new CxImage();
newImage->LoadResource(FindResource(NULL,MAKEINTRESOURCE(IDR_PNG1),
                       "PNG"),CXIMAGE_FORMAT_PNG);

or

Code:

//Load the resource IDR_JPG1 from DLL
CxImage* newImage = new CxImage();
HINSTANCE hdll=LoadLibrary("imagelib.dll");
if (hdll){
    HRSRC hres=FindResource(hdll,MAKEINTRESOURCE(IDR_JPG1),"JPG");
    newImage->LoadResource(hres,CXIMAGE_FORMAT_JPG,hdll);
    FreeLibrary(hdll);
}

or

Code:

//Load a bitmap resource;
HBITMAP bitmap = ::LoadBitmap(AfxGetInstanceHandle(),
                              MAKEINTRESOURCE(IDB_BITMAP1)));
CxImage *newImage = new CxImage();
newImage->CreateFromHBITMAP(bitmap);

解码内存中的图像

Code:

CxImage image((BYTE*)buffer,size,image_type);

or

Code:

CxMemFile memfile((BYTE*)buffer,size);
CxImage image(&memfile,image_type);

or

Code:

CxMemFile memfile((BYTE*)buffer,size);
CxImage* image = new CxImage();
image->Decode(&memfile,type);

编码内存中的图像

Code:

long size=0;
BYTE* buffer=0;
image.Encode(buffer,size,image_type);
...
free(buffer);

or

Code:

CxMemFile memfile;
memfile.Open();
image.Encode(&memfile,image_type);
BYTE* buffer = memfile.GetBuffer();
long size = memfile.Size();
...
free(buffer);

创建一个多页的TIFF

Code:

CxImage *pimage[3];
pimage[0]=&image1;
pimage[1]=&image2;
pimage[2]=&image3;

FILE* hFile;
hFile = fopen("multipage.tif","w+b");

CxImageTIF multiimage;
multiimage.Encode(hFile,pimage,3);

fclose(hFile);

or

Code:

FILE* hFile;
hFile = fopen("c://multi.tif","w+b");

CxImageTIF image;
image.Load("c://1.tif",CXIMAGE_FORMAT_TIF);
image.Encode(hFile,true);
image.Load("c://2.bmp",CXIMAGE_FORMAT_BMP);
image.Encode(hFile,true);
image.Load("c://3.png",CXIMAGE_FORMAT_PNG);
image.Encode(hFile);

fclose(hFile);

拷贝粘贴图像

Code:

//copy
HANDLE hDIB = image->CopyToHandle();
if (::OpenClipboard(AfxGetApp()->m_pMainWnd->GetSafeHwnd())) {
    if(::EmptyClipboard()) {
        if (::SetClipboardData(CF_DIB,hDIB) == NULL ) {
            AfxMessageBox( "Unable to set Clipboard data" );
}    }    }
CloseClipboard();

//paste
HANDLE hBitmap=NULL;
CxImage *newima = new CxImage();
if (OpenClipboard()) hBitmap=GetClipboardData(CF_DIB);
if (hBitmap) newima->CreateFromHANDLE(hBitmap);
CloseClipboard();

在picture框中显示图像文件

Code:

HBITMAP m_bitmap = NULL;
CxImage image("myfile.png", CXIMAGE_FORMAT_PNG);
...
m_bitmap = image.MakeBitmap(m_picture.GetDC()->m_hDC);
m_picture.SetBitmap(m_bitmap);
...
if (m_bitmap) DeleteObject(m_bitmap);