/// <summary>
/// Transforms the pixels of a FreeImageBitmap using a standard color profile
/// for the bitmap's color space and the current color profile.
/// </summary>
/// <param name="freeImageBitmap">FreeImageBitmap whose pixels to convert.</param>
/// <remarks>
/// Since Excel does not support color management at all, conversions are done
/// using standard color profiles that LittleCMS provides.
/// </remarks>
public void TransformFromStandardProfile(FreeImageAPI.FreeImageBitmap freeImageBitmap)
{
cmsHProfile standardProfile = CreateStandardProfile(freeImageBitmap);
if (standardProfile == cmsHProfile.Zero)
{
throw new InvalidOperationException(
"Unable to create standard profile for " + freeImageBitmap.ColorType.ToString());
}
cmsHProfile targetProfile = cmsOpenProfileFromFile(GetPathFromName(), "r");
if (targetProfile == cmsHProfile.Zero)
{
throw new InvalidOperationException(
"Unable to open desired color profile: " + Name);
}
// Create transform with perceptual intent (0) and no special options (0)
cmsHTransform t = cmsCreateTransform(
standardProfile, Lcms.Formatters.TYPE_BGRA_8,
targetProfile, GetLcmsPixelFormat(ColorSpace),
0, 0);
if (t == cmsHTransform.Zero)
{
throw new InvalidOperationException("Unable to create CMS transform.");
}
UInt32 numPixels = (UInt32)freeImageBitmap.Size.Width * (UInt32)freeImageBitmap.Size.Height;
cmsDoTransform(t, freeImageBitmap.Bits, freeImageBitmap.Bits, numPixels);
freeImageBitmap.CreateICCProfile(GetIccBytes());
cmsDeleteTransform(t);
cmsCloseProfile(standardProfile);
cmsCloseProfile(targetProfile);
}
private static extern void cmsDoTransform(
cmsHTransform hTransform,
IntPtr InputBuffer,
IntPtr OutputBuffer,
cmsUInt32Number Size);
private static extern void cmsDeleteTransform(cmsHTransform hTransform);