CxImage Library

출처) http://www.codeproject.com/bitmap/cximage.asp

범용적 이미지 라이브러리
윈도우 종속적이지만 굉장히 간단한 이미지 라이브러리.
.jpg .tif .bmp .png .zlib jasper 등의 이미지를 지원한다.

Preface

CxImage grew together with the CodeProject site, since 2001, andreached this level thanks to the CodeProject community. Thanks a lotfor the suggestions, the contributions and for the critiques. However,if I look at the other image processing libraries, it is clear thatnowadays, the CxImage project is quite inadequate from many points ofview. For this reason, this one will be last release in this form. Ofcourse the development will not stop: it is just going to follow newdirections.

Introduction

CxImage is a C++ class that can load, save, display, transform images in a very simple and fast way.

Why another image library? Around there are many goodlibraries (OpenIL, FreeImage, PaintLib ...), these are powerful,complete, and constantly updated. However if you ever try to use them,you may find some difficulties; because these libraries are mainlyplatform independent, written in C, sometimes with a basic C++ wrapperand with tons of compiler switch declarations. Now with the new GDI+classes on the scene, maybe CxImage isn't so useful, but at least hereyou have the source code. It is not a MFC library, altogether it's awindows library, because of some particular constructors and thepainting functions, but the backbone is platform independent.

License

The class CxImage is free; as for the TIFF, JPEG, PNG and ZLIB libraries : "If you use this source code in a product, acknowledgment is not required but would be appreciated."

CxImage is open source and licensed under the zlib license . In a nutshell, this means that you can use the code however you wish, as long as you don't claim it as your own.

What's new in version 5.99c

Bugfixes

• CxImageTIF::Encode: default compression for 4 bpp image was NONE, now it's LZW.
• fixed SetXDPI and SetYDPI to accept only positive dpi values
• fixed EXIF decoder against invalid TAG_EXIF_OFFSET / TAG_INTEROP_OFFSET
• fixed missing definitions in ximawnd.cpp when CXIMAGE_SUPPORT_BMP is 0
• fixed CxFileJas constructor to avoid crashes, when Jasper deals with its temporary files, decoding large images
• removed default imagetype value from CxImage::Save
• fixed Mean() for images with an active selection
• fixed GIF decoder for animated images with corrupted frames.
• fixed GIF decoder for images with screen descriptor larger than the first frame.
• fixed GIF decoder to handle the disposal methods correctly.
• CxImageWMF reads images mapped in MM_TEXT, when MM_ANISOTROPIC fails.
• fixed Clear for 1 and 4 bpp images.
• fixed typo in ximajpg.cpp: ENTRPY_OPT_SUPPORTED -> ENTROPY_OPT_SUPPORTED
• fixed potential memory overflow in RLE decoder reading corrupted bitmaps.
• Better UNICODE support and fixed TCHAR mappings for Linux.
• fixed bug in IsTransparent , for images with a valid alpha layer.
• fixed bug in Create : a vaild image was created even if width or height were zero.
• CxMemFile: fixed problem for compilers where malloc(0) returns 0, improvements in Alloc.

Changes and major additions

• new functions: Rotate2() <BD>, Resample2() QIShrink(), RedEyeRemove(), Edge(), SelectionSplit() , IsSamePalette, BlendPixelColor, GetVersionNumber, Encode2RGBA
• new dithering algorithms: Bayer, Burkes, Stucki, Jarvis-Judice-Ninke, Sierra, Stevenson-Arce
• renamed AlphaGetBits with AlphaGetPointer
• new compiler switch: CXIMAGE_SUPPORT_INTERPOLATION to enable pixel color interpolations,
  implemented in the ximaint.cpp module
• New bEnableInterpolation parameter for Skew()
• New blend parameter for Colorize()
• color conversion routines now are declared as static
• FFT2 now works also with Borland compilers
• more interpolation kernels
• Smooth stretching parameter for Draw
• Added FreeMemory function, to avoid heap problems using Encode with memory buffers
• new bMixAlpha parameter and new OpScreen blending mode for Mix()
• LZW compression is the default algorithm for GIF compression.
• CxImagePNG now can encode interlaced images
• Get/SetCodecOption now has an "ImageType" parameter, so that each format keeps its specific options
• Faster RotateLeft and RotateRight
• CxImageJPG now can write back the EXIF information (verbatim copy).

Project - Libraries - Demo application

• Demo: new dialogs for Resample, Rotate, Skew with more options, JPEG compression
• New license based on zlib/libpng philosophy, see ximage.h and license.txt
• Demo: new tool: tracker
• Demo: new View/Smooth menu to test smooth drawing in zoom and stretch modes
• Demo: more CodecOptions on the Options dialog, enabled LZW compression for GIF and TIF formats.
• PNG: updated to libpng 1.2.7
• JBIG: updated to version 1.6
• Better documentation : now using Doxygen.

CxImage structure

In the vertical hierarchy of the library, CxImage stayson the top of the other modules, it's not a clean OOP approach, but theresult was good since the first release and now it's too late to changeagain. Anyway you can always use the derived classes to perform theformat specific operations, like for CxImageTIF to save multipage TIFFs.

The glue to connect all the modules and the C libraries is CxFile, a virtual class that provides the standard methods to access the data from a file on the disk or in memory.

A Cximage object is basically a bitmap, with the addition of some member variables to store useful information:

 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 is the bitmap header and CxImage::pDib is a normal bitmap (as you can see in the implementation of CxImageBMP::Encode).

CxImage::info is a handy container of many information shared between different formats, and for all the member functions.

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;

A CxImage object is also a set of layers. The buffers in each layer are allocated only when necessary.

CxImage::pDib is the background image. CxImage::pAlpha is the transparency layer. CxImage::pSelection isthe selection layer, used to create regions of interest for imageprocessing. Over these 3 specific planes, you can add other genericlayers, stored in CxImage::pLayers. The generic layers are full CxImage objects, so you can build complex structures of nested layers.

CxImage Class Members & Operations

CxImage 5.99c is documented using Doxygen ,however for historical reasons, many uncommon features are stillundocumented. The class members reference, together with releasehistory, and license, can be found here

Supported formats and options

The whole library is quite big, in the main header file ximcfg.hyou'll find the switches to enable or disable a specific graphic formator feature. Each JPG, PNG and TIFF library adds about 100KB to thefinal application, while the CxImage impact is about 50KB. So you should support and link only the formats that your application really needs.

formats	#define	required libraries	size [Kbyte]
BMP GIF ICO TGA PCX WBMP WMF	CXIMAGE_SUPPORT_BMP CXIMAGE_SUPPORT_GIF CXIMAGE_SUPPORT_ICO CXIMAGE_SUPPORT_TGA CXIMAGE_SUPPORT_PCX CXIMAGE_SUPPORT_WBMP CXIMAGE_SUPPORT_WMF	built in	24
JPEG	CXIMAGE_SUPPORT_JPG	jpeg	88
PNG	CXIMAGE_SUPPORT_PNG	png, zlib	104
MNG	CXIMAGE_SUPPORT_MNG	mng, zlib, jpeg	148
TIFF	CXIMAGE_SUPPORT_TIF	tiff, zlib, jpeg	124
JBIG	CXIMAGE_SUPPORT_JBG	jbig	28
PNM,PPM,PGM RAS	CXIMAGE_SUPPORT_PNM CXIMAGE_SUPPORT_RAS	jasper	176
JPEG-2000	CXIMAGE_SUPPORT_JP2 CXIMAGE_SUPPORT_JPC CXIMAGE_SUPPORT_PGX	jasper	176

Option	#define	Size [Kbyte]
CxImage core	all switches off	20
geometric transformations	CXIMAGE_SUPPORT_TRANSFORMATION	16
image processing	CXIMAGE_SUPPORT_DSP	24
drawing and windows specific functions	CXIMAGE_SUPPORT_WINDOWS	12
transparency	CXIMAGE_SUPPORT_ALPHA	4
selections	CXIMAGE_SUPPORT_SELECTION	4
multiple layers	CXIMAGE_SUPPORT_LAYERS	< 4
graphic formats conversion	CXIMAGE_SUPPORT_DECODE CXIMAGE_SUPPORT_ENCODE	< 4

Using CxImage in your projects

The CxImgLib.dsw workspace shows the libraries required tobuild an application (demo.exe) including almost all the features andthe formats available in CxImage. You must compile all the librariesbefore you can link the final application. In the same workspace you'll find the projects to build different libraries and applications: CxImage : cximage.lib - static library CxImageCrtDll : cximagecrt.dll - DLL not using mfc CxImageMfcDll : cximage.dll - DLL using mfc Demo : demo.exe - program linked with cximage.lib and the C libraries DemoDll : demodll.exe - program linked with cximagecrt.dll j2k,jasper,jbig,jpeg,png,tiff,zlib : static C libraries Building the projects will need some minutes to complete (theintermediate files occupy 60MB!). When everything is done, select thedemo project and launch the application.

CxImgLib.dsw

To use CxImage in your project, you must edit these settings:

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  ...

Adding your custom functions in CxImage

Writing a new function for image processing is not so hard with CxImage. Here I'm going to describe CxImage::Jitter,it's very simple but it shows many aspects to take care when you workinside CxImage. The first thing, of course, is the declaration : bool Jitter(long radius=2); in the CXIMAGE_SUPPORT_DSP section of ximage.h, you can declare the function everywhere in the public scope of the class. And now the definition:

bool CxImage::Jitter(long radius)

{

    // check if the image is valid, this should be always the first line in 

    // the function 

    if (!pDib) return false;

    

    // local variables

    long nx,ny;

    

    // temporary image to store the partial results of the algorithm

    CxImage tmp(*this,pSelection!=0,true,true);

    

    // limit the effects of the functions only in the smallest rectangle that

    // holds the selected region (defined with the Selection...() functions ),

    // this will speed up the loops.

    long xmin,xmax,ymin,ymax;

    if (pSelection){

        xmin = info.rSelectionBox.left; xmax = info.rSelectionBox.right;

        ymin = info.rSelectionBox.bottom; ymax = info.rSelectionBox.top;

    } else {

        xmin = ymin = 0;

        xmax = head.biWidth; ymax=head.biHeight;

    }

    

    // main loop : scan the image in vertical direction

    for(long y=ymin; y <ymax; y++){

    

        // monitor the progress of the loops

        info.nProgress = (long)(100*y/head.biHeight);

    

        // let the application a way to exit quickly

        if (info.nEscape) break;

    

        // main loop : scan the image in horizontal direction

        for(long x=xmin; x<xmax; x++){

    

        // if the feature is enabled, process only the pixels inside the 

        // selected region

#if CXIMAGE_SUPPORT_SELECTION

            if (SelectionIsInside(x,y))

#endif //CXIMAGE_SUPPORT_SELECTION

            {

                // main algorithm

                nx=x+(long)((rand()/(float)RAND_MAX - 0.5)*(radius*2));

                ny=y+(long)((rand()/(float)RAND_MAX - 0.5)*(radius*2));

                if (!IsInside(nx,ny)) {

                    nx=x;

                    ny=y;

                }



                // save the result in the temporary image.

                // if you can, use PixelColor only for 24 bpp images,

                // and PixelIndex for 8, 4 and 1 bpp images : it's faster

                if (head.biClrUsed==0){

                    tmp.SetPixelColor(x,y,GetPixelColor(nx,ny));

                } else {

                    tmp.SetPixelIndex(x,y,GetPixelIndex(nx,ny));

                }



                // if the feature is enabled, process also the pixels 

                // in the alpha layer

#if CXIMAGE_SUPPORT_ALPHA

                tmp.AlphaSet(x,y,AlphaGet(nx,ny));

#endif //CXIMAGE_SUPPORT_ALPHA

            }

        }

    }



    // save the result and exit

    Transfer(tmp);

    return true;

}

Examples: how to ...

... convert from a format to another

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);

}

... load an image resource

//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

//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

//Load a bitmap resource;

HBITMAP bitmap = ::LoadBitmap(AfxGetInstanceHandle(),

                              MAKEINTRESOURCE(IDB_BITMAP1)));

CxImage *newImage = new CxImage();

newImage->CreateFromHBITMAP(bitmap);

... decode an image from memory

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

or

CxMemFile memfile((BYTE*)buffer,size);

CxImage image(&memfile,image_type);

or

CxMemFile memfile((BYTE*)buffer,size);

CxImage* image = new CxImage();

image->Decode(&memfile,type);

... encode an image in memory

long size=0;

BYTE* buffer=0;

image.Encode(buffer,size,image_type);

...

free(buffer);

or

CxMemFile memfile;

memfile.Open();

image.Encode(&memfile,image_type);

BYTE* buffer = memfile.GetBuffer();

long size = memfile.Size();

...

free(buffer);

... create a multipage TIFF

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

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);

... copy/paste an image

//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();

... display a file in a picture box

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);

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