ximaint.cpp

用Cximage 库显示各种格式图片小程序

            kernelx[i]=KernelBlackman((float)(xi+i-1-x));
            kernely[i]=KernelBlackman((float)(yi+i-1-y));
          }//for i
          break;
        case IM_BESSEL:
          for (i=0; i<4; i++) {
            kernelx[i]=KernelBessel((float)(xi+i-1-x));
            kernely[i]=KernelBessel((float)(yi+i-1-y));
          }//for i
          break;
        case IM_GAUSSIAN:
          for (i=0; i<4; i++) {
            kernelx[i]=KernelGaussian((float)(xi+i-1-x));
            kernely[i]=KernelGaussian((float)(yi+i-1-y));
          }//for i
          break;
        case IM_QUADRATIC:
          for (i=0; i<4; i++) {
            kernelx[i]=KernelQuadratic((float)(xi+i-1-x));
            kernely[i]=KernelQuadratic((float)(yi+i-1-y));
          }//for i
          break;
        case IM_MITCHELL:
          for (i=0; i<4; i++) {
            kernelx[i]=KernelMitchell((float)(xi+i-1-x));
            kernely[i]=KernelMitchell((float)(yi+i-1-y));
          }//for i
          break;
        case IM_CATROM:
          for (i=0; i<4; i++) {
            kernelx[i]=KernelCatrom((float)(xi+i-1-x));
            kernely[i]=KernelCatrom((float)(yi+i-1-y));
          }//for i
          break;
        case IM_HANNING:
          for (i=0; i<4; i++) {
            kernelx[i]=KernelHanning((float)(xi+i-1-x));
            kernely[i]=KernelHanning((float)(yi+i-1-y));
          }//for i
          break;
        case IM_POWER:
          for (i=0; i<4; i++) {
            kernelx[i]=KernelPower((float)(xi+i-1-x));
            kernely[i]=KernelPower((float)(yi+i-1-y));
          }//for i
          break;
      }//switch
      rr=gg=bb=aa=0;
      if (((xi+2)<head.biWidth) && xi>=1 && ((yi+2)<head.biHeight) && (yi>=1) && !IsIndexed()) {
        //optimized interpolation (faster pixel reads) for RGB24 images with all pixels inside bounds
        BYTE *pxptr, *pxptra;
        for (yii=yi-1; yii<yi+3; yii++) {
          pxptr=(BYTE *)BlindGetPixelPointer(xi-1, yii);    //calculate pointer to first byte in row
          kernelyc=kernely[yii-(yi-1)];
#if CXIMAGE_SUPPORT_ALPHA
          if (AlphaIsValid()) {
            //alpha is supported and valid (optimized bicubic int. for image with alpha)
            pxptra=AlphaGetPointer(xi-1, yii);
            kernel=kernelyc*kernelx[0];
            bb+=kernel*(*pxptr++); gg+=kernel*(*pxptr++); rr+=kernel*(*pxptr++); aa+=kernel*(*pxptra++);
            kernel=kernelyc*kernelx[1];
            bb+=kernel*(*pxptr++); gg+=kernel*(*pxptr++); rr+=kernel*(*pxptr++); aa+=kernel*(*pxptra++);
            kernel=kernelyc*kernelx[2];
            bb+=kernel*(*pxptr++); gg+=kernel*(*pxptr++); rr+=kernel*(*pxptr++); aa+=kernel*(*pxptra++);
            kernel=kernelyc*kernelx[3];
            bb+=kernel*(*pxptr++); gg+=kernel*(*pxptr++); rr+=kernel*(*pxptr); aa+=kernel*(*pxptra);
          } else
#endif
          //alpha not supported or valid (optimized bicubic int. for no alpha channel)
          {
            kernel=kernelyc*kernelx[0];
            bb+=kernel*(*pxptr++); gg+=kernel*(*pxptr++); rr+=kernel*(*pxptr++);
            kernel=kernelyc*kernelx[1];
            bb+=kernel*(*pxptr++); gg+=kernel*(*pxptr++); rr+=kernel*(*pxptr++);
            kernel=kernelyc*kernelx[2];
            bb+=kernel*(*pxptr++); gg+=kernel*(*pxptr++); rr+=kernel*(*pxptr++);
            kernel=kernelyc*kernelx[3];
            bb+=kernel*(*pxptr++); gg+=kernel*(*pxptr++); rr+=kernel*(*pxptr);
          }
        }//yii
      } else {
        //slower more flexible interpolation for border pixels and paletted images
        RGBQUAD rgbs;
        for (yii=yi-1; yii<yi+3; yii++) {
          kernelyc=kernely[yii-(yi-1)];
          for (xii=xi-1; xii<xi+3; xii++) {
            kernel=kernelyc*kernelx[xii-(xi-1)];
            rgbs=GetPixelColorWithOverflow(xii, yii, ofMethod, rplColor);
            rr+=kernel*rgbs.rgbRed;
            gg+=kernel*rgbs.rgbGreen;
            bb+=kernel*rgbs.rgbBlue;
#if CXIMAGE_SUPPORT_ALPHA
            aa+=kernel*rgbs.rgbReserved;
#endif
          }//xii
        }//yii
      }//if
      //for all colors, clip to 0..255 and assign to RGBQUAD
      if (rr>255) rr=255; if (rr<0) rr=0; color.rgbRed=(BYTE) rr;
      if (gg>255) gg=255; if (gg<0) gg=0; color.rgbGreen=(BYTE) gg;
      if (bb>255) bb=255; if (bb<0) bb=0; color.rgbBlue=(BYTE) bb;
#if CXIMAGE_SUPPORT_ALPHA
      if (AlphaIsValid()) {
        if (aa>255) aa=255; if (aa<0) aa=0; color.rgbReserved=(BYTE) aa;
      } else
#endif
		{ //Alpha not supported or no alpha at all
			color.rgbReserved = 0;
		}
      return color;
    case IM_LANCZOS:
      //lanczos window (16*16) sinc interpolation
      if (((xi+6)<0) || ((xi-5)>=head.biWidth) || ((yi+6)<0) || ((yi-5)>=head.biHeight)) {
        //all points are outside bounds
        switch (ofMethod) {
          case OM_COLOR: case OM_TRANSPARENT: case OM_BACKGROUND:
            //we don't need to interpolate anything with all points outside in this case
            return GetPixelColorWithOverflow(-999, -999, ofMethod, rplColor);
            break;
          default:
            //recalculate coordinates and use faster method later on
            OverflowCoordinates(x,y,ofMethod);
            xi=(int)(x); if (x<0) xi--;   //x and/or y have changed ... recalculate xi and yi
            yi=(int)(y); if (y<0) yi--;
        }//switch
      }//if

      for (xii=xi-5; xii<xi+7; xii++) kernelx[xii-(xi-5)]=KernelLanczosSinc((float)(xii-x), 6.0f);
      rr=gg=bb=aa=0;

      if (((xi+6)<head.biWidth) && ((xi-5)>=0) && ((yi+6)<head.biHeight) && ((yi-5)>=0) && !IsIndexed()) {
        //optimized interpolation (faster pixel reads) for RGB24 images with all pixels inside bounds
        BYTE *pxptr, *pxptra;
        for (yii=yi-5; yii<yi+7; yii++) {
          pxptr=(BYTE *)BlindGetPixelPointer(xi-5, yii);    //calculate pointer to first byte in row
          kernelyc=KernelLanczosSinc((float)(yii-y),6.0f);
#if CXIMAGE_SUPPORT_ALPHA
          if (AlphaIsValid()) {
            //alpha is supported and valid
            pxptra=AlphaGetPointer(xi-1, yii);
            for (xii=0; xii<12; xii++) {
              kernel=kernelyc*kernelx[xii];
              bb+=kernel*(*pxptr++); gg+=kernel*(*pxptr++); rr+=kernel*(*pxptr++); aa+=kernel*(*pxptra++);
            }//for xii
          } else
#endif
          //alpha not supported or valid
          {
            for (xii=0; xii<12; xii++) {
              kernel=kernelyc*kernelx[xii];
              bb+=kernel*(*pxptr++); gg+=kernel*(*pxptr++); rr+=kernel*(*pxptr++);
            }//for xii
          }
        }//yii
      } else {
        //slower more flexible interpolation for border pixels and paletted images
        RGBQUAD rgbs;
        for (yii=yi-5; yii<yi+7; yii++) {
          kernelyc=KernelLanczosSinc((float)(yii-y),6.0f);
          for (xii=xi-5; xii<xi+7; xii++) {
            kernel=kernelyc*kernelx[xii-(xi-5)];
            rgbs=GetPixelColorWithOverflow(xii, yii, ofMethod, rplColor);
            rr+=kernel*rgbs.rgbRed;
            gg+=kernel*rgbs.rgbGreen;
            bb+=kernel*rgbs.rgbBlue;
#if CXIMAGE_SUPPORT_ALPHA
            aa+=kernel*rgbs.rgbReserved;
#endif
          }//xii
        }//yii
      }//if
      //for all colors, clip to 0..255 and assign to RGBQUAD
      if (rr>255) rr=255; if (rr<0) rr=0; color.rgbRed=(BYTE) rr;
      if (gg>255) gg=255; if (gg<0) gg=0; color.rgbGreen=(BYTE) gg;
      if (bb>255) bb=255; if (bb<0) bb=0; color.rgbBlue=(BYTE) bb;
#if CXIMAGE_SUPPORT_ALPHA
      if (AlphaIsValid()) {
        if (aa>255) aa=255; if (aa<0) aa=0; color.rgbReserved=(BYTE) aa;   
      } else
#endif
		{ //Alpha not supported or no alpha at all
			color.rgbReserved = 0;
		}
      return color;
  }//switch
}
////////////////////////////////////////////////////////////////////////////////
/**
 * Helper function for GetAreaColorInterpolated.
 * Adds 'surf' portion of image pixel with color 'color' to (rr,gg,bb,aa).
 */
void CxImage::AddAveragingCont(RGBQUAD const &color, float const surf, float &rr, float &gg, float &bb, float &aa)
{
  rr+=color.rgbRed*surf;
  gg+=color.rgbGreen*surf;
  bb+=color.rgbBlue*surf;
#if CXIMAGE_SUPPORT_ALPHA
  aa+=color.rgbReserved*surf;
#endif
}
////////////////////////////////////////////////////////////////////////////////
/**
 * This method is similar to GetPixelColorInterpolated, but this method also properly handles 
 * subsampling.
 * If you need to sample original image with interval of more than 1 pixel (as when shrinking an image), 
 * you should use this method instead of GetPixelColorInterpolated or aliasing will occur.
 * When area width and height are both less than pixel, this method gets pixel color by interpolating
 * color of frame center with selected (inMethod) interpolation by calling GetPixelColorInterpolated. 
 * If width and height are more than 1, method calculates color by averaging color of pixels within area.
 * Interpolation method is not used in this case. Pixel color is interpolated by averaging instead.
 * If only one of both is more than 1, method uses combination of interpolation and averaging.
 * Chosen interpolation method is used, but since it is averaged later on, there is little difference
 * between IM_BILINEAR (perhaps best for this case) and better methods. IM_NEAREST_NEIGHBOUR again
 * leads to aliasing artifacts.
 * This method is a bit slower than GetPixelColorInterpolated and when aliasing is not a problem, you should
 * simply use the later. 
 *
 * \param  xc, yc - center of (rectangular) area
 * \param  w, h - width and height of area
 * \param  inMethod - interpolation method that is used, when interpolation is used (see above)
 * \param  ofMethod - overflow method used when retrieving individual pixel colors
 * \param  rplColor - replacement colour to use, in OM_COLOR
 *
 * \author ***bd*** 2.2004
 */
RGBQUAD CxImage::GetAreaColorInterpolated(
  float const xc, float const yc, float const w, float const h, 
  InterpolationMethod const inMethod, 
  OverflowMethod const ofMethod, 
  RGBQUAD* const rplColor)
{
	RGBQUAD color;      //calculated colour
	
	if (h<=1 && w<=1) {
		//both width and height are less than one... we will use interpolation of center point
		return GetPixelColorInterpolated(xc, yc, inMethod, ofMethod, rplColor);
	} else {
		//area is wider and/or taller than one pixel:
		CxRect2 area(xc-w/2.0f, yc-h/2.0f, xc+w/2.0f, yc+h/2.0f);   //area
		int xi1=(int)(area.botLeft.x+0.49999999f);                //low x
		int yi1=(int)(area.botLeft.y+0.49999999f);                //low y
		
		
		int xi2=(int)(area.topRight.x+0.5f);                      //top x
		int yi2=(int)(area.topRight.y+0.5f);                      //top y (for loops)
		
		float rr,gg,bb,aa;                                        //red, green, blue and alpha components
		rr=gg=bb=aa=0;
		int x,y;                                                  //loop counters
		float s=0;                                                //surface of all pixels
		float cps;                                                //surface of current crosssection
		if (h>1 && w>1) {
			//width and height of area are greater than one pixel, so we can employ "ordinary" averaging
			CxRect2 intBL, intTR;     //bottom left and top right intersection
			intBL=area.CrossSection(CxRect2(((float)xi1)-0.5f, ((float)yi1)-0.5f, ((float)xi1)+0.5f, ((float)yi1)+0.5f));
			intTR=area.CrossSection(CxRect2(((float)xi2)-0.5f, ((float)yi2)-0.5f, ((float)xi2)+0.5f, ((float)yi2)+0.5f));
			float wBL, wTR, hBL, hTR;
			wBL=intBL.Width();            //width of bottom left pixel-area intersection
			hBL=intBL.Height();           //height of bottom left...
			wTR=intTR.Width();            //width of top right...
			hTR=intTR.Height();           //height of top right...
			
			AddAveragingCont(GetPixelColorWithOverflow(xi1,yi1,ofMethod,rplColor), wBL*hBL, rr, gg, bb, aa);    //bottom left pixel
			AddAveragingCont(GetPixelColorWithOverflow(xi2,yi1,ofMethod,rplColor), wTR*hBL, rr, gg, bb, aa);    //bottom right pixel
			AddAveragingCont(GetPixelColorWithOverflow(xi1,yi2,ofMethod,rplColor), wBL*hTR, rr, gg, bb, aa);    //top left pixel
			AddAveragingCont(GetPixelColorWithOverflow(xi2,yi2,ofMethod,rplColor), wTR*hTR, rr, gg, bb, aa);    //top right pixel
			//bottom and top row
			for (x=xi1+1; x<xi2; x++) {
				AddAveragingCont(GetPixelColorWithOverflow(x,yi1,ofMethod,rplColor), hBL, rr, gg, bb, aa);    //bottom row
				AddAveragingCont(GetPixelColorWithOverflow(x,yi2,ofMethod,rplColor), hTR, rr, gg, bb, aa);    //top row
			}
			//leftmost and rightmost column
			for (y=yi1+1; y<yi2; y++) {
				AddAveragingCont(GetPixelColorWithOverflow(xi1,y,ofMethod,rplColor), wBL, rr, gg, bb, aa);    //left column
				AddAveragingCont(GetPixelColorWithOverflow(xi2,y,ofMethod,rplColor), wTR, rr, gg, bb, aa);    //right column
			}
			for (y=yi1+1; y<yi2; y++) {
				for (x=xi1+1; x<xi2; x++) { 
					color=GetPixelColorWithOverflow(x,y,ofMethod,rplColor);
					rr+=color.rgbRed;
					gg+=color.rgbGreen;
					bb+=color.rgbBlue;
#if CXIMAGE_SUPPORT_ALPHA
					aa+=color.rgbReserved;
#endif
				}//for x
			}//for y
		} else {
			//width or height greater than one:
			CxRect2 intersect;                                          //intersection with current pixel
			CxPoint2 center;
			for (y=yi1; y<=yi2; y++) {
				for (x=xi1; x<=xi2; x++) {
					intersect=area.CrossSection(CxRect2(((float)x)-0.5f, ((float)y)-0.5f, ((float)x)+0.5f, ((float)y)+0.5f));
					center=intersect.Center();
					color=GetPixelColorInterpolated(center.x, center.y, inMethod, ofMethod, rplColor);
					cps=intersect.Surface();
					rr+=color.rgbRed*cps;
					gg+=color.rgbGreen*cps;
					bb+=color.rgbBlue*cps;
#if CXIMAGE_SUPPORT_ALPHA
					aa+=color.rgbReserved*cps;
#endif
				}//for x
			}//for y      
		}//if
		
		s=area.Surface();
		rr/=s; gg/=s; bb/=s; aa/=s;
		if (rr>255) rr=255; if (rr<0) rr=0; color.rgbRed=(BYTE) rr;
		if (gg>255) gg=255; if (gg<0) gg=0; color.rgbGreen=(BYTE) gg;
		if (bb>255) bb=255; if (bb<0) bb=0; color.rgbBlue=(BYTE) bb;
#if CXIMAGE_SUPPORT_ALPHA
		if (AlphaIsValid()) {
			if (aa>255) aa=255; if (aa<0) aa=0; color.rgbReserved=(BYTE) aa;
		}//if
#endif
	}//if
	return color;
}

////////////////////////////////////////////////////////////////////////////////
float CxImage::KernelBSpline(const float x)
{
	if (x>2.0f) return 0.0f;
	// thanks to Kristian Kratzenstein
	float a, b, c, d;
	float xm1 = x - 1.0f; // Was calculatet anyway cause the "if((x-1.0f) < 0)"
	float xp1 = x + 1.0f;
	float xp2 = x + 2.0f;

	if ((xp2) <= 0.0f) a = 0.0f; else a = xp2*xp2*xp2; // Only float, not float -> double -> float
	if ((xp1) <= 0.0f) b = 0.0f; else b = xp1*xp1*xp1;
	if (x <= 0) c = 0.0f; else c = x*x*x;  
	if ((xm1) <= 0.0f) d = 0.0f; else d = xm1*xm1*xm1;

	return (0.16666666666666666667f * (a - (4.0f * b) + (6.0f * c) - (4.0f * d)));

	/* equivalent <Vladim韗 Kloucek>
	if (x < -2.0)
		return(0.0f);
	if (x < -1.0)
		return((2.0f+x)*(2.0f+x)*(2.0f+x)*0.16666666666666666667f);
	if (x < 0.0)
		return((4.0f+x*x*(-6.0f-3.0f*x))*0.16666666666666666667f);
	if (x < 1.0)
		return((4.0f+x*x*(-6.0f+3.0f*x))*0.16666666666666666667f);
	if (x < 2.0)
		return((2.0f-x)*(2.0f-x)*(2.0f-x)*0.16666666666666666667f);
	return(0.0f);
	*/
}