ximapal.cpp

信息隐藏中用于数字隐写的常用算法:LSB替换LSB匹配,包括随机的和排序的,以及对文件和文件夹进行操作,用CxImage类能快速读取各种格式的图象

// xImaPal.cpp : Palette and Pixel functions
/* 07/08/2001 v1.00 - Davide Pizzolato - www.xdp.it
 * CxImage version 5.99a 08/Feb/2004
 */

#include "ximage.h"

////////////////////////////////////////////////////////////////////////////////
// returns the palette dimension in byte
DWORD CxImage::GetPaletteSize()
{
	return (head.biClrUsed * sizeof(RGBQUAD));
}
////////////////////////////////////////////////////////////////////////////////
void CxImage::SetPaletteColor(BYTE idx, BYTE r, BYTE g, BYTE b, BYTE alpha)
{
	if ((pDib)&&(head.biClrUsed)){
		BYTE* iDst = (BYTE*)(pDib) + sizeof(BITMAPINFOHEADER);
		if (idx<head.biClrUsed){
			long ldx=idx*sizeof(RGBQUAD);
			iDst[ldx++] = (BYTE) b;
			iDst[ldx++] = (BYTE) g;
			iDst[ldx++] = (BYTE) r;
			iDst[ldx] = (BYTE) alpha;
			info.last_c_isvalid = false;
		}
	}
}
////////////////////////////////////////////////////////////////////////////////
void CxImage::SetPaletteColor(BYTE idx, RGBQUAD c)
{
	if ((pDib)&&(head.biClrUsed)){
		BYTE* iDst = (BYTE*)(pDib) + sizeof(BITMAPINFOHEADER);
		if (idx<head.biClrUsed){
			long ldx=idx*sizeof(RGBQUAD);
			iDst[ldx++] = (BYTE) c.rgbBlue;
			iDst[ldx++] = (BYTE) c.rgbGreen;
			iDst[ldx++] = (BYTE) c.rgbRed;
			iDst[ldx] = (BYTE) c.rgbReserved;
			info.last_c_isvalid = false;
		}
	}
}
////////////////////////////////////////////////////////////////////////////////
void CxImage::SetPaletteColor(BYTE idx, COLORREF cr)
{
	if ((pDib)&&(head.biClrUsed)){
		BYTE* iDst = (BYTE*)(pDib) + sizeof(BITMAPINFOHEADER);
		if (idx<head.biClrUsed){
			long ldx=idx*sizeof(RGBQUAD);
			iDst[ldx++] = (BYTE) GetBValue(cr);
			iDst[ldx++] = (BYTE) GetGValue(cr);
			iDst[ldx++] = (BYTE) GetRValue(cr);
			iDst[ldx] = (BYTE) 0;
			info.last_c_isvalid = false;
		}
	}
}
////////////////////////////////////////////////////////////////////////////////
// returns the pointer to the first palette index 
RGBQUAD* CxImage::GetPalette() const
{
	if ((pDib)&&(head.biClrUsed))
		return (RGBQUAD*)((BYTE*)pDib + sizeof(BITMAPINFOHEADER));
	return NULL;
}
////////////////////////////////////////////////////////////////////////////////
RGBQUAD CxImage::GetPaletteColor(BYTE idx)
{
	RGBQUAD rgb = {0,0,0,0};
	if ((pDib)&&(head.biClrUsed)){
		BYTE* iDst = (BYTE*)(pDib) + sizeof(BITMAPINFOHEADER);
		if (idx<head.biClrUsed){
			long ldx=idx*sizeof(RGBQUAD);
			rgb.rgbBlue = iDst[ldx++];
			rgb.rgbGreen=iDst[ldx++];
			rgb.rgbRed =iDst[ldx++];
			rgb.rgbReserved = iDst[ldx];
		}
	}
	return rgb;
}
////////////////////////////////////////////////////////////////////////////////
BYTE CxImage::GetPixelIndex(long x,long y)
{
	if ((pDib==NULL)||(head.biClrUsed==0)) return 0;

	if ((x<0)||(y<0)||(x>=head.biWidth)||(y>=head.biHeight)) {
		if (info.nBkgndIndex != -1)	return (BYTE)info.nBkgndIndex;
		else return *info.pImage;
	}
	if (head.biBitCount==8){
		return info.pImage[y*info.dwEffWidth + x];
	} else {
		BYTE pos;
		BYTE iDst= info.pImage[y*info.dwEffWidth + (x*head.biBitCount >> 3)];
		if (head.biBitCount==4){
			pos = (BYTE)(4*(1-x%2));
			iDst &= (0x0F<<pos);
			return (BYTE)(iDst >> pos);
		} else if (head.biBitCount==1){
			pos = (BYTE)(7-x%8);
			iDst &= (0x01<<pos);
			return (BYTE)(iDst >> pos);
		}
	}
	return 0;
}
////////////////////////////////////////////////////////////////////////////////
RGBQUAD CxImage::GetPixelColor(long x,long y, bool bGetAlpha)
{
//	RGBQUAD rgb={0,0,0,0};
	RGBQUAD rgb=info.nBkgndColor; //<mpwolski>
	if ((pDib==NULL)||(x<0)||(y<0)||
		(x>=head.biWidth)||(y>=head.biHeight)){
		if (info.nBkgndIndex != -1){
			if (head.biBitCount<24) rgb = GetPaletteColor((BYTE)info.nBkgndIndex);
			else rgb = info.nBkgndColor;
		} else if (pDib) rgb = GetPixelColor(0,0);
		return rgb;
	}

	if (head.biClrUsed){
		rgb = GetPaletteColor(GetPixelIndex(x,y));
	} else {
		BYTE* iDst  = info.pImage + y*info.dwEffWidth + x*3;
		rgb.rgbBlue = *iDst++;
		rgb.rgbGreen= *iDst++;
		rgb.rgbRed  = *iDst;
	}
#if CXIMAGE_SUPPORT_ALPHA
	if (pAlpha && bGetAlpha) rgb.rgbReserved = AlphaGet(x,y);
#else
	rgb.rgbReserved = 0;
#endif //CXIMAGE_SUPPORT_ALPHA
	return rgb;
}
////////////////////////////////////////////////////////////////////////////////
BYTE CxImage::GetPixelGray(long x, long y)
{
	RGBQUAD color = GetPixelColor(x,y);
	return (BYTE)RGB2GRAY(color.rgbRed,color.rgbGreen,color.rgbBlue);
}
////////////////////////////////////////////////////////////////////////////////
void CxImage::SetPixelIndex(long x,long y,BYTE i)
{
	if ((pDib==NULL)||(head.biClrUsed==0)||
		(x<0)||(y<0)||(x>=head.biWidth)||(y>=head.biHeight)) return ;

	if (head.biBitCount==8){
		info.pImage[y*info.dwEffWidth + x]=i;
		return;
	} else {
		BYTE pos;
		BYTE* iDst= info.pImage + y*info.dwEffWidth + (x*head.biBitCount >> 3);
		if (head.biBitCount==4){
			pos = (BYTE)(4*(1-x%2));
			*iDst &= ~(0x0F<<pos);
			*iDst |= ((i & 0x0F)<<pos);
			return;
		} else if (head.biBitCount==1){
			pos = (BYTE)(7-x%8);
			*iDst &= ~(0x01<<pos);
			*iDst |= ((i & 0x01)<<pos);
			return;
		}
	}
}
////////////////////////////////////////////////////////////////////////////////
void CxImage::SetPixelColor(long x,long y,COLORREF cr)
{
	SetPixelColor(x,y,RGBtoRGBQUAD(cr));
}
////////////////////////////////////////////////////////////////////////////////
void CxImage::SetPixelColor(long x,long y,RGBQUAD c, bool bSetAlpha)
{
	if ((pDib==NULL)||(x<0)||(y<0)||
		(x>=head.biWidth)||(y>=head.biHeight)) return;
	if (head.biClrUsed)
		SetPixelIndex(x,y,GetNearestIndex(c));
	else {
		BYTE* iDst = info.pImage + y*info.dwEffWidth + x*3;
		*iDst++ = c.rgbBlue;
		*iDst++ = c.rgbGreen;
		*iDst   = c.rgbRed;
#if CXIMAGE_SUPPORT_ALPHA
		if (bSetAlpha) AlphaSet(x,y,c.rgbReserved);
#endif //CXIMAGE_SUPPORT_ALPHA
	}
}
////////////////////////////////////////////////////////////////////////////////
BYTE CxImage::GetNearestIndex(RGBQUAD c)
{
	if ((pDib==NULL)||(head.biClrUsed==0)) return 0;

	// <RJ> check matching with the previous result
	if (info.last_c_isvalid && (*(long*)&info.last_c == *(long*)&c)) return info.last_c_index;
	info.last_c = c;
	info.last_c_isvalid = true;

	BYTE* iDst = (BYTE*)(pDib) + sizeof(BITMAPINFOHEADER);
	long distance=200000;
	int i,j = 0;
	long k,l;
	int m = (int)(head.biClrImportant==0 ? head.biClrUsed : head.biClrImportant);
	for(i=0,l=0;i<m;i++,l+=sizeof(RGBQUAD)){
		k = (iDst[l]-c.rgbBlue)*(iDst[l]-c.rgbBlue)+
			(iDst[l+1]-c.rgbGreen)*(iDst[l+1]-c.rgbGreen)+
			(iDst[l+2]-c.rgbRed)*(iDst[l+2]-c.rgbRed);
//		k = abs(iDst[l]-c.rgbBlue)+abs(iDst[l+1]-c.rgbGreen)+abs(iDst[l+2]-c.rgbRed);
		if (k==0){
			j=i;
			break;
		}
		if (k<distance){
			distance=k;
			j=i;
		}
	}
	info.last_c_index = j;
	return (BYTE)j;
}
////////////////////////////////////////////////////////////////////////////////
// swaps the blue and red components (for RGB images)
// > buffer: pointer to the pixels
// > lenght: number of bytes to swap. lenght may not exceed the scan line.
void CxImage::RGBtoBGR(BYTE *buffer, int length)
{
	if (buffer && (head.biClrUsed==0)){
		BYTE temp;
		length = min(length,(int)info.dwEffWidth);
		for (int i=0;i<length;i+=3){
			temp = buffer[i]; buffer[i] = buffer[i+2]; buffer[i+2] = temp;
		}
	}
}
////////////////////////////////////////////////////////////////////////////////
RGBQUAD CxImage::RGBtoRGBQUAD(COLORREF cr)
{
	RGBQUAD c;
	c.rgbRed = GetRValue(cr);	/* get R, G, and B out of DWORD */
	c.rgbGreen = GetGValue(cr);
	c.rgbBlue = GetBValue(cr);
	c.rgbReserved=0;
	return c;
}
////////////////////////////////////////////////////////////////////////////////
COLORREF CxImage::RGBQUADtoRGB (RGBQUAD c)
{
	return RGB(c.rgbRed,c.rgbGreen,c.rgbBlue);
}
////////////////////////////////////////////////////////////////////////////////
bool CxImage::GetPaletteColor(BYTE i, BYTE* r, BYTE* g, BYTE* b)
{
	RGBQUAD* ppal=GetPalette();
	if (ppal) {
		*r = ppal[i].rgbRed;
		*g = ppal[i].rgbGreen;
		*b = ppal[i].rgbBlue; 
		return true;
	}
	return false;
}
////////////////////////////////////////////////////////////////////////////////