test-example-projects/c++_projects/84wsoui3/components/imgdecoder-stb/imgdecoder-stb.cpp


#define WIN32_LEAN_AND_MEAN             // Exclude rarely-used stuff from Windows headers
#include <windows.h>
#include "imgdecoder-stb.h"

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"

namespace SOUI
{
    //////////////////////////////////////////////////////////////////////////
    //  SImgFrame_STB
    SImgFrame_STB::SImgFrame_STB(BYTE *data,int w,int h):m_data(data),m_nWid(w),m_nHei(h)
    {

    }

    SImgFrame_STB::~SImgFrame_STB()
    {
        if(m_data) free(m_data);
    }

    BOOL SImgFrame_STB::GetSize( UINT *pWid,UINT *pHei )
    {
        *pWid = m_nWid;
        *pHei = m_nHei;
        return TRUE;
    }

    BOOL SImgFrame_STB::CopyPixels( /* [unique][in] */ const RECT *prc, /* [in] */ UINT cbStride, /* [in] */ UINT cbBufferSize, /* [size_is][out] */ BYTE *pbBuffer )
    {
        if(cbBufferSize != m_nHei * m_nWid *4) return FALSE;
        memcpy(pbBuffer,m_data,cbBufferSize);
        return TRUE;
    }

    
    //////////////////////////////////////////////////////////////////////////
    // SImgX_STB
    int SImgX_STB::LoadFromMemory( void *pBuf,size_t bufLen )
    {
        if(m_pImg) delete m_pImg;
        m_pImg = NULL;

        if(!pBuf) return 0;

        int w=0,h=0;
        unsigned char *data = stbi_load_from_memory((stbi_uc const *)pBuf,bufLen,&w,&h,NULL,4);
        if(!data)
        {
            return 0;
        }
        _DoPromultiply(data,w,h);
        m_pImg = new SImgFrame_STB(data,w,h);
        return 1;
    }

    int SImgX_STB::LoadFromFile( LPCWSTR pszFileName )
    {
        if(m_pImg) delete m_pImg;
        m_pImg = NULL;

        FILE *f=_wfopen(pszFileName,L"rb");
        if(!f) return 0;
        int w=0,h=0;
        unsigned char *data = stbi_load_from_file(f,&w,&h,NULL,4);
        fclose(f);
        if(!data)
        {
            return 0;
        }
        _DoPromultiply(data,w,h);
        m_pImg = new SImgFrame_STB(data,w,h);
        return 1;
    }

    int SImgX_STB::LoadFromFile( LPCSTR pszFileName )
    {
        wchar_t wszFileName[MAX_PATH+1];
        MultiByteToWideChar(CP_ACP,0,pszFileName,-1,wszFileName,MAX_PATH);
        if(GetLastError()==ERROR_INSUFFICIENT_BUFFER) return 0;
        return LoadFromFile(wszFileName);
    }

    SImgX_STB::SImgX_STB(BOOL bPremultiple)
        :m_pImg(NULL)
        ,m_bPremultiple(bPremultiple)
    {

    }

    SImgX_STB::~SImgX_STB( void )
    {
        if(m_pImg) delete m_pImg;
    }

    void SImgX_STB::_DoPromultiply( BYTE *pdata,int nWid,int nHei )
    {
        //swap rgba to bgra and do premultiply
        BYTE *p=pdata;
        int pixel_count = nWid * nHei;
        for (int i=0; i < pixel_count; ++i) {
            stbi_uc a = p[3];
            stbi_uc t = p[0];
            if (a) 
            {
                p[0] = (p[2] *a)/255;
                p[1] = (p[1] * a)/255;
                p[2] =  (t   * a)/255;
            }else
            {
                memset(p,0,4);
            }
            p += 4;
        }    
    }

    //////////////////////////////////////////////////////////////////////////
    //  SImgDecoderFactory_STB

    SImgDecoderFactory_STB::SImgDecoderFactory_STB( )
    {
    }

    SImgDecoderFactory_STB::~SImgDecoderFactory_STB()
    {

    }

    BOOL SImgDecoderFactory_STB::CreateImgX( IImgX **ppImgDecoder )
    {
        *ppImgDecoder = new SImgX_STB(TRUE);
        return TRUE;
    }
    
    LPCWSTR SImgDecoderFactory_STB::GetDescription() const
    {
        return DESC_IMGDECODER;
    }

    //////////////////////////////////////////////////////////////////////////
    BOOL IMGDECODOR_STB::SCreateInstance( IObjRef **pImgDecoderFactory )
    {
        *pImgDecoderFactory = new SImgDecoderFactory_STB();
        return TRUE;
    }

}//end of namespace SOUI