// Indexed Image with Bit Depth == 8
private byte[] GetImageColorType3BitDepth8(byte[] buf)
{
byte[] image = new byte[3 * (this.w * this.h)];
byte[] filters = new byte[this.h];
byte[] alpha = null;
if (tRNS != null)
{
alpha = new byte[this.w * this.h];
for (int i = 0; i < alpha.Length; i++)
{
alpha[i] = (byte)0xff;
}
}
int bytesPerLine = this.w + 1;
int m = 0;
int n = 0;
int j = 0;
for (int i = 0; i < buf.Length; i++)
{
if (i % bytesPerLine == 0)
{
filters[m++] = buf[i];
}
else
{
int k = ((int)buf[i]) & 0xff;
if (tRNS != null && k < tRNS.Length)
{
alpha[n] = tRNS[k];
}
n++;
image[j++] = pLTE[3 * k];
image[j++] = pLTE[3 * k + 1];
image[j++] = pLTE[3 * k + 2];
}
}
ApplyFilters(filters, image, this.w, this.h, 3);
if (tRNS != null)
{
deflatedAlphaData = Compressor.deflate(alpha);
}
return(image);
}
// Truecolor Image with Alpha Transparency
private byte[] GetImageColorType6BitDepth8(byte[] buf)
{
byte[] idata = new byte[3 * this.w * this.h]; // Image data
byte[] alpha = new byte[this.w * this.h]; // Alpha values
byte[] image = new byte[4 * this.w * this.h];
byte[] filters = new byte[this.h];
int bytesPerLine = 4 * this.w + 1;
int k = 0;
int j = 0;
int i = 0;
for (; i < buf.Length; i++)
{
if (i % bytesPerLine == 0)
{
filters[j++] = buf[i];
}
else
{
image[k++] = buf[i];
}
}
ApplyFilters(filters, image, this.w, this.h, 4);
k = 0;
j = 0;
i = 0;
while (i < image.Length)
{
idata[j++] = image[i++];
idata[j++] = image[i++];
idata[j++] = image[i++];
alpha[k++] = image[i++];
}
deflatedAlphaData = Compressor.deflate(alpha);
return(idata);
}
/**
* Used to embed PNG images in the PDF document.
*
*/
public PNGImage(Stream inputStream)
{
ValidatePNG(inputStream);
List <Chunk> chunks = ProcessPNG(inputStream);
for (int i = 0; i < chunks.Count; i++)
{
Chunk chunk = chunks[i];
String chunkType = System.Text.Encoding.UTF8.GetString(chunk.type);
if (chunkType.Equals("IHDR"))
{
this.w = (int)ToUInt32(chunk.GetData(), 0); // Width
this.h = (int)ToUInt32(chunk.GetData(), 4); // Height
this.bitDepth = chunk.GetData()[8]; // Bit Depth
this.colorType = chunk.GetData()[9]; // Color Type
// Console.WriteLine(
// "Bit Depth == " + chunk.GetData()[8]);
// Console.WriteLine(
// "Color Type == " + chunk.GetData()[9]);
// Console.WriteLine(chunk.GetData()[10]);
// Console.WriteLine(chunk.GetData()[11]);
// Console.WriteLine(chunk.GetData()[12]);
if (chunk.GetData()[12] == 1)
{
Console.WriteLine("Interlaced PNG images are not supported.");
Console.WriteLine("Convert the image using OptiPNG:\noptipng -i0 -o7 myimage.png\n");
}
}
else if (chunkType.Equals("IDAT"))
{
iDAT = AppendIdatChunk(iDAT, chunk.GetData());
}
else if (chunkType.Equals("PLTE"))
{
pLTE = chunk.GetData();
if (pLTE.Length % 3 != 0)
{
throw new Exception("Incorrect palette length.");
}
}
else if (chunkType.Equals("gAMA"))
{
// TODO:
// Console.WriteLine("gAMA chunk found!");
}
else if (chunkType.Equals("tRNS"))
{
// Console.WriteLine("tRNS chunk found!");
if (colorType == 3)
{
tRNS = chunk.GetData();
}
}
else if (chunkType.Equals("cHRM"))
{
// TODO:
// Console.WriteLine("cHRM chunk found!");
}
else if (chunkType.Equals("sBIT"))
{
// TODO:
// Console.WriteLine("sBIT chunk found!");
}
else if (chunkType.Equals("bKGD"))
{
// TODO:
// Console.WriteLine("bKGD chunk found!");
}
}
byte[] inflatedImageData = Decompressor.inflate(iDAT);
byte[] imageData;
if (colorType == 0)
{
// Grayscale Image
if (bitDepth == 16)
{
imageData = GetImageColorType0BitDepth16(inflatedImageData);
}
else if (bitDepth == 8)
{
imageData = GetImageColorType0BitDepth8(inflatedImageData);
}
else if (bitDepth == 4)
{
imageData = GetImageColorType0BitDepth4(inflatedImageData);
}
else if (bitDepth == 2)
{
imageData = GetImageColorType0BitDepth2(inflatedImageData);
}
else if (bitDepth == 1)
{
imageData = GetImageColorType0BitDepth1(inflatedImageData);
}
else
{
throw new Exception("Image with unsupported bit depth == " + bitDepth);
}
}
else if (colorType == 6)
{
if (bitDepth == 8)
{
imageData = GetImageColorType6BitDepth8(inflatedImageData);
}
else
{
throw new Exception("Image with unsupported bit depth == " + bitDepth);
}
}
else
{
// Color Image
if (pLTE == null)
{
// Trucolor Image
if (bitDepth == 16)
{
imageData = GetImageColorType2BitDepth16(inflatedImageData);
}
else
{
imageData = GetImageColorType2BitDepth8(inflatedImageData);
}
}
else
{
// Indexed Image
if (bitDepth == 8)
{
imageData = GetImageColorType3BitDepth8(inflatedImageData);
}
else if (bitDepth == 4)
{
imageData = GetImageColorType3BitDepth4(inflatedImageData);
}
else if (bitDepth == 2)
{
imageData = GetImageColorType3BitDepth2(inflatedImageData);
}
else if (bitDepth == 1)
{
imageData = GetImageColorType3BitDepth1(inflatedImageData);
}
else
{
throw new Exception("Image with unsupported bit depth == " + bitDepth);
}
}
}
deflatedImageData = Compressor.deflate(imageData);
}
