public Png(Stream s)
{
if (!Verify(s))
{
throw new InvalidDataException("PNG Signature is bogus");
}
s.Position += 8;
var headerParsed = false;
var isPaletted = false;
var is24Bit = false;
var data = new List <byte>();
for (;;)
{
var length = IPAddress.NetworkToHostOrder(s.ReadInt32());
var type = Encoding.UTF8.GetString(s.ReadBytes(4));
var content = s.ReadBytes(length);
/*var crc = */ s.ReadInt32();
if (!headerParsed && type != "IHDR")
{
throw new InvalidDataException("Invalid PNG file - header does not appear first.");
}
using (var ms = new MemoryStream(content))
{
switch (type)
{
case "IHDR":
{
if (headerParsed)
{
throw new InvalidDataException("Invalid PNG file - duplicate header.");
}
Width = IPAddress.NetworkToHostOrder(ms.ReadInt32());
Height = IPAddress.NetworkToHostOrder(ms.ReadInt32());
var bitDepth = ms.ReadUInt8();
var colorType = (PngColorType)ms.ReadByte();
isPaletted = IsPaletted(bitDepth, colorType);
is24Bit = colorType == PngColorType.Color;
var dataLength = Width * Height;
if (!isPaletted)
{
dataLength *= 4;
}
Data = new byte[dataLength];
var compression = ms.ReadByte();
/*var filter = */ ms.ReadByte();
var interlace = ms.ReadByte();
if (compression != 0)
{
throw new InvalidDataException("Compression method not supported");
}
if (interlace != 0)
{
throw new InvalidDataException("Interlacing not supported");
}
headerParsed = true;
break;
}
case "PLTE":
{
Palette = new Color[256];
for (var i = 0; i < length / 3; i++)
{
var r = ms.ReadByte(); var g = ms.ReadByte(); var b = ms.ReadByte();
Palette[i] = Color.FromArgb(r, g, b);
}
break;
}
case "tRNS":
{
if (Palette == null)
{
throw new InvalidDataException("Non-Palette indexed PNG are not supported.");
}
for (var i = 0; i < length; i++)
{
Palette[i] = Color.FromArgb(ms.ReadByte(), Palette[i]);
}
break;
}
case "IDAT":
{
data.AddRange(content);
break;
}
case "tEXt":
{
var key = ms.ReadASCIIZ();
EmbeddedData.Add(key, ms.ReadASCII(length - key.Length - 1));
break;
}
case "IEND":
{
using (var ns = new MemoryStream(data.ToArray()))
{
using (var ds = new InflaterInputStream(ns))
{
var pxStride = isPaletted ? 1 : is24Bit ? 3 : 4;
var srcStride = Width * pxStride;
var destStride = Width * (isPaletted ? 1 : 4);
var prevLine = new byte[srcStride];
for (var y = 0; y < Height; y++)
{
var filter = (PngFilter)ds.ReadByte();
var line = ds.ReadBytes(srcStride);
for (var i = 0; i < srcStride; i++)
{
line[i] = i < pxStride
? UnapplyFilter(filter, line[i], 0, prevLine[i], 0)
: UnapplyFilter(filter, line[i], line[i - pxStride], prevLine[i], prevLine[i - pxStride]);
}
if (is24Bit)
{
// Fold alpha channel into RGB data
for (var i = 0; i < line.Length / 3; i++)
{
Array.Copy(line, 3 * i, Data, y * destStride + 4 * i, 3);
Data[y * destStride + 4 * i + 3] = 255;
}
}
else
{
Array.Copy(line, 0, Data, y * destStride, line.Length);
}
prevLine = line;
}
}
}
if (isPaletted && Palette == null)
{
throw new InvalidDataException("Non-Palette indexed PNG are not supported.");
}
return;
}
}
}
}
}
public Png(Stream s)
{
if (!Verify(s))
{
throw new InvalidDataException("PNG Signature is bogus");
}
s.Position += 8;
var headerParsed = false;
var data = new List <byte>();
Type = SpriteFrameType.Rgba32;
while (true)
{
var length = IPAddress.NetworkToHostOrder(s.ReadInt32());
var type = Encoding.UTF8.GetString(s.ReadBytes(4));
var content = s.ReadBytes(length);
/*var crc = */
s.ReadInt32();
if (!headerParsed && type != "IHDR")
{
throw new InvalidDataException("Invalid PNG file - header does not appear first.");
}
using (var ms = new MemoryStream(content))
{
switch (type)
{
case "IHDR":
{
if (headerParsed)
{
throw new InvalidDataException("Invalid PNG file - duplicate header.");
}
Width = IPAddress.NetworkToHostOrder(ms.ReadInt32());
Height = IPAddress.NetworkToHostOrder(ms.ReadInt32());
var bitDepth = ms.ReadUInt8();
var colorType = (PngColorType)ms.ReadByte();
if (IsPaletted(bitDepth, colorType))
{
Type = SpriteFrameType.Indexed8;
}
else if (colorType == PngColorType.Color)
{
Type = SpriteFrameType.Rgb24;
}
Data = new byte[Width * Height * PixelStride];
var compression = ms.ReadByte();
/*var filter = */
ms.ReadByte();
var interlace = ms.ReadByte();
if (compression != 0)
{
throw new InvalidDataException("Compression method not supported");
}
if (interlace != 0)
{
throw new InvalidDataException("Interlacing not supported");
}
headerParsed = true;
break;
}
case "PLTE":
{
Palette = new Color[256];
for (var i = 0; i < length / 3; i++)
{
var r = ms.ReadByte(); var g = ms.ReadByte(); var b = ms.ReadByte();
Palette[i] = Color.FromArgb(r, g, b);
}
break;
}
case "tRNS":
{
if (Palette == null)
{
throw new InvalidDataException("Non-Palette indexed PNG are not supported.");
}
for (var i = 0; i < length; i++)
{
Palette[i] = Color.FromArgb(ms.ReadByte(), Palette[i]);
}
break;
}
case "IDAT":
{
data.AddRange(content);
break;
}
case "tEXt":
{
var key = ms.ReadASCIIZ();
EmbeddedData.Add(key, ms.ReadASCII(length - key.Length - 1));
break;
}
case "IEND":
{
using (var ns = new MemoryStream(data.ToArray()))
{
using (var ds = new InflaterInputStream(ns))
{
var pxStride = PixelStride;
var rowStride = Width * pxStride;
var prevLine = new byte[rowStride];
for (var y = 0; y < Height; y++)
{
var filter = (PngFilter)ds.ReadByte();
var line = ds.ReadBytes(rowStride);
for (var i = 0; i < rowStride; i++)
{
line[i] = i < pxStride
? UnapplyFilter(filter, line[i], 0, prevLine[i], 0)
: UnapplyFilter(filter, line[i], line[i - pxStride], prevLine[i], prevLine[i - pxStride]);
}
Array.Copy(line, 0, Data, y * rowStride, rowStride);
prevLine = line;
}
}
}
if (Type == SpriteFrameType.Indexed8 && Palette == null)
{
throw new InvalidDataException("Non-Palette indexed PNG are not supported.");
}
return;
}
}
}
}
}