IS3ColorReplaceImage

[lincoln]

Chris,
I'm trying to replace the colors on my image using IS3ColorReplaceImage, but not happen.
My image in memory is 8 bit grayscale, but the original file is 4 bit grayscale, so the palette is 256 colors but only 16 is used.
I would like to change 15% to black and 85% to white.

<pre>
BYTE *pImage = GetImagePointer();
if(pImage==NULL) return(IS_ERR_BADPARAM);

UINT32 arrayColor[256];
memset(&arrayColor,0,sizeof(UINT32)*256);
ISrc(IS3FindColorsUsedIn8BitImage)(pImage,m_czPix. cx,m_czPix.cy,m_czPix.cx,arrayColor);

UINT32 unPixels=m_czPix.cx*m_czPix.cy;
double pBlack=0.0;

for(UINT32 i=0;i<16;i++)
{
pBlack+=((double)((double)arrayColor[i]/unPixels)*100.0);
if(pBlack>=15.0)
ISrc(IS3ColorReplaceImage)(pImage,m_czPix.cx,m_czP ix.cy,m_czPix.cx,1,i,15,0,0); //15=white
else
ISrc(IS3ColorReplaceImage)(pImage,m_czPix.cx,m_czP ix.cy,m_czPix.cx,1,i, 0,0,0); //0=black
}
</pre>

[Chris]

>Chris,
>I'm trying to replace the colors on my image using
>IS3ColorReplaceImage, but not happen.

what happens?

>My image in memory is 8 bit grayscale, but the original file
>is 4 bit grayscale, so the palette is 256 colors but only 16
>is used.

are the pixel values 0..15 or 0..255 ?

>I would like to change 15% to black and 85% to white.

(put code inside <code> ... </code> tags - but use square brackets instead of < and >)

  BYTE *pImage = GetImagePointer();
  if(pImage==NULL) return(IS_ERR_BADPARAM);

  UINT32 arrayColor[256];
  memset(&arrayColor,0,sizeof(UINT32)*256);
  
  ISrc(IS3FindColorsUsedIn8BitImage)(pImage,m_czPix.cx,m_czPix.cy,m_czPix.cx,arrayColor);

  UINT32 unPixels=m_czPix.cx*m_czPix.cy;
  double pBlack=0.0;

  for(UINT32 i=0;i<16;i++)
  {
    pBlack+=((double)((double)arrayColor[i]/unPixels)*100.0);
    if(pBlack>=15.0) 
      ISrc(IS3ColorReplaceImage)(pImage,m_czPix.cx,m_czPix.cy,m_czPix.cx,1,i,15,0,0);//15=white
    else
      ISrc(IS3ColorReplaceImage)(pImage,m_czPix.cx,m_czPix.cy,m_czPix.cx,1,i,0,0,0); //0=black
  }

so, if the pixel is equal or brighter than 15% of the total pixels, you set it to white, else to black ?

a faster way might be:

  BYTE *pImage = GetImagePointer();
  if(pImage==NULL) return(IS_ERR_BADPARAM);

  UINT32 arrayColor[256];
  memset(&arrayColor,0,sizeof(UINT32)*256);
  
  ISrc(IS3FindColorsUsedIn8BitImage)(pImage,m_czPix.cx,m_czPix.cy,m_czPix.cx,arrayColor);

  UINT32 unPixels=m_czPix.cx*m_czPix.cy;
  double pBlack=0.0;

  BYTE lut[16];
  BYTE *luts[1];
  luts[0] = lut;
  for(UINT32 i=0;i<16;i++)
  {
    pBlack+=((double)((double)arrayColor[i]/unPixels)*100.0);
    if(pBlack>=15.0) 
       lut[i] = 15;
    else
       lut[i] = 0;
  }
  IS3ApplyLUTsToImage(pImage,m_czPix.cx,m_czPix.cy,1,m_czPix.cx,luts);

besides being probably 20 times faster, this way, you can look at the LUT in the debugger and see exactly how you are mapping the original colors to the new colors.

[lincoln]

-> what happens?
The image seems me unchanged.

-> are the pixel values 0..15 or 0..255 ?
0..15.

-> so, if the pixel is equal or brighter than 15% of the total pixels, you set it to white, else to black ?
because the palette is inverted.

The other way works very well.

If my image source is 256 colors how it works ?

[Chris]

>If my image source is 256 colors how it works ?

just change the 15's and 16s to 255s and 256s. it should work the same.