DictElem GetColorspace()
{
if (ICCP != null || (Gamma == 1f && !HasCHRM))
{
return((ColorType & 2) == 0 ? DictName.DeviceGray : DictName.DeviceRGB);
}
else
{
DictArray array = new DictArray();
Dict dic = new Dict();
if ((ColorType & 2) == 0)
{
if (Gamma == 1f)
{
return(DictName.DeviceGray);
}
array.Add(DictName.CalGray);
dic.Put(DictName.Gamma, Gamma);
dic.Put(DictName.WhitePoint, "[ 1 1 1 ]");
array.Add(dic);
}
else
{
DictArray wp = new DictArray(new float[] { 1, 1, 1 });
array.Add(DictName.CalRGB);
if (Gamma != 1f)
{
DictArray gm = new DictArray(new float[] { Gamma, Gamma, Gamma });
dic.Put(DictName.Gamma, gm);
}
if (HasCHRM)
{
float z = yW * ((xG - xB) * yR - (xR - xB) * yG + (xR - xG) * yB);
float YA = yR * ((xG - xB) * yW - (xW - xB) * yG + (xW - xG) * yB) / z;
float XA = YA * xR / yR;
float ZA = YA * ((1 - xR) / yR - 1);
float YB = -yG * ((xR - xB) * yW - (xW - xB) * yR + (xW - xR) * yB) / z;
float XB = YB * xG / yG;
float ZB = YB * ((1 - xG) / yG - 1);
float YC = yB * ((xR - xG) * yW - (xW - xG) * yW + (xW - xR) * yG) / z;
float XC = YC * xB / yB;
float ZC = YC * ((1 - xB) / yB - 1);
float XW = XA + XB + XC;
float YW = 1;//YA+YB+YC;
float ZW = ZA + ZB + ZC;
wp = new DictArray(new float[] { XW, YW, ZW });
DictArray matrix = new DictArray(new float[] { XA, YA, ZA, XB, YB, ZB, XC, YC, ZC });
dic.Put(DictName.Matrix, matrix);
}
dic.Put(DictName.WhitePoint, wp);
array.Add(dic);
}
return(array);
}
}
void ReadPng()
{
for (int i = 0; i < PNGID.Length; i++)
{
Assert(PNGID[i] == Inp.ReadByte());
}
byte[] buffer = new byte[1024];
while (true)
{
int len = GetInt(Inp);
uint chunktype = GetUInt(Inp);
Assert(len >= 0);
if (chunktype == IHDR) // header
{
Width = GetInt(Inp);
Height = GetInt(Inp);
BitDepth = Inp.ReadByte();
ColorType = Inp.ReadByte();
CompressionMethod = Inp.ReadByte();
FilterMethod = Inp.ReadByte();
InterlaceMethod = Inp.ReadByte();
}
else if (chunktype == IDAT) // the image data
{
Util.Copy(Inp, Idat, len, buffer);
}
else if (chunktype == tRNS) // transparency information
{
switch (ColorType)
{
case 0:
if (len >= 2)
{
len -= 2;
int gray = GetWord(Inp);
if (BitDepth == 16)
{
TransRedGray = gray;
}
else
{
Additional.Put(DictName.Mask, "[ " + gray + " " + gray + " ]");
}
}
break;
case 2:
if (len >= 6)
{
len -= 6;
int red = GetWord(Inp);
int green = GetWord(Inp);
int blue = GetWord(Inp);
if (BitDepth == 16)
{
TransRedGray = red;
TransGreen = green;
TransBlue = blue;
}
else
{
Additional.Put(DictName.Mask, "[ " + red + " " + red + " " + green + " " + green + " " + blue + " " + blue + " ]");
}
}
break;
case 3:
if (len > 0)
{
Trans = new byte[len];
for (int k = 0; k < len; ++k)
{
Trans[k] = ( byte )Inp.ReadByte();
}
len = 0;
}
break;
}
Util.Skip(Inp, len);
}
else if (chunktype == PLTE) // contains the palette; list of colors.
{
if (ColorType == 3)
{
DictArray colorspace = new DictArray();
colorspace.Add(DictName.Indexed);
colorspace.Add(GetColorspace());
colorspace.Add(len / 3 - 1);
ColorTable = new byte[len];
int ix = 0; while ((len--) > 0)
{
ColorTable[ix++] = ( byte )Inp.ReadByte();
}
colorspace.Add(new PdfByteStr(ColorTable));
Additional.Put(DictName.ColorSpace, colorspace);
}
else
{
Util.Skip(Inp, len);
}
}
else if (chunktype == pHYs) // Currently nothing is done with this info.
{
int dx = GetInt(Inp);
int dy = GetInt(Inp);
int unit = Inp.ReadByte();
if (unit == 1)
{
DpiX = ( int )(( float )dx * 0.0254f + 0.5f);
DpiY = ( int )(( float )dy * 0.0254f + 0.5f);
}
else
{
if (dy != 0)
{
XYRatio = ( float )dx / ( float )dy;
}
}
}
else if (chunktype == cHRM) // gives the chromaticity coordinates of the display primaries and white point.
{
xW = ( float )GetInt(Inp) / 100000f;
yW = ( float )GetInt(Inp) / 100000f;
xR = ( float )GetInt(Inp) / 100000f;
yR = ( float )GetInt(Inp) / 100000f;
xG = ( float )GetInt(Inp) / 100000f;
yG = ( float )GetInt(Inp) / 100000f;
xB = ( float )GetInt(Inp) / 100000f;
yB = ( float )GetInt(Inp) / 100000f;
HasCHRM = !(Math.Abs(xW) < 0.0001f || Math.Abs(yW) < 0.0001f || Math.Abs(xR) < 0.0001f || Math.Abs(yR) < 0.0001f ||
Math.Abs(xG) < 0.0001f || Math.Abs(yG) < 0.0001f || Math.Abs(xB) < 0.0001f || Math.Abs(yB) < 0.0001f);
}
else if (chunktype == sRGB) // indicates that the standard sRGB color space is used.
{
int ri = Inp.ReadByte();
Intent = Intents[ri];
Gamma = 2.2f;
xW = 0.3127f; yW = 0.329f; xR = 0.64f; yR = 0.33f;
xG = 0.3f; yG = 0.6f; xB = 0.15f; yB = 0.06f;
HasCHRM = true;
}
else if (chunktype == gAMA)
{
int gm = GetInt(Inp);
if (gm != 0)
{
Gamma = 100000f / ( float )gm;
if (!HasCHRM)
{
xW = 0.3127f; yW = 0.329f; xR = 0.64f; yR = 0.33f;
xG = 0.3f; yG = 0.6f; xB = 0.15f; yB = 0.06f;
HasCHRM = true;
}
}
}
else if (chunktype == iCCP)
{
// Console.WriteLine( "iCCP chunk found" );
do
{
len -= 1;
} while (Inp.ReadByte() != 0);
Inp.ReadByte(); len -= 1;
byte[] icc = new byte[len];
Util.ReadN(Inp, icc, 0, len);
icc = Util.Inflate(icc);
ICCP = ICC_Profile.GetInstance(icc);
}
else if (chunktype == IEND)
{
break;
}
else
{
Util.Skip(Inp, len);
}
Util.Skip(Inp, 4);
}
}