private static Size DecodeJfif(BinaryReader binaryReader)
{
while (binaryReader.ReadByte() == 0xff)
{
byte marker = binaryReader.ReadByte();
short chunkLength = ByteHelper.ReadInt16BE(binaryReader);
if (marker == 0xc0 || marker == 0xc2) // c2: progressive
{
binaryReader.ReadByte();
int height = ByteHelper.ReadInt16BE(binaryReader);
int width = ByteHelper.ReadInt16BE(binaryReader);
return(new Size(width, height));
}
if (chunkLength < 0)
{
ushort uchunkLength = (ushort)chunkLength;
binaryReader.ReadBytes(uchunkLength - 2);
}
else
{
binaryReader.ReadBytes(chunkLength - 2);
}
}
return(Size.Empty);
}
// https://www.cyotek.com/blog/reading-photoshop-color-swatch-aco-files-using-csharp
public static List <Color> ReadPhotoShopSwatchFile(string fileName)
{
List <Color> colorPalette;
using (Stream stream = File.OpenRead(fileName))
{
FileVersion version;
// read the version, which occupies two bytes
version = (FileVersion)ByteHelper.ReadInt16BE(stream);
if (version != FileVersion.Version1 && version != FileVersion.Version2)
{
throw new InvalidDataException("Invalid version information.");
}
// the specification states that a version2 palette follows a version1
// the only difference between version1 and version2 is the inclusion
// of a name property. Perhaps there's addtional color spaces as well
// but we can't support them all anyway
// I noticed some files no longer include a version 1 palette
colorPalette = ReadSwatches(stream, version);
if (version == FileVersion.Version1)
{
version = (FileVersion)ByteHelper.ReadInt16BE(stream);
if (version == FileVersion.Version2)
{
colorPalette = ReadSwatches(stream, version);
}
}
}
return(colorPalette);
}
private static Size DecodeTiffBE(BinaryReader binaryReader)
{
int idfStart = ByteHelper.ReadInt32BE(binaryReader);
binaryReader.BaseStream.Seek(idfStart, SeekOrigin.Begin);
int numberOfIDF = ByteHelper.ReadInt16BE(binaryReader);
int width = -1;
int height = -1;
for (int i = 0; i < numberOfIDF; i++)
{
short field = ByteHelper.ReadInt16BE(binaryReader);
switch (field)
{
// https://www.awaresystems.be/imaging/tiff/tifftags/baseline.html
default:
binaryReader.ReadBytes(10);
break;
case 256: // image width
binaryReader.ReadBytes(6);
width = ByteHelper.ReadInt32BE(binaryReader);
break;
case 257: // image length
binaryReader.ReadBytes(6);
height = ByteHelper.ReadInt32BE(binaryReader);
break;
}
if (width != -1 && height != -1)
{
return(new Size(width, height));
}
}
return(Size.Empty);
}
// https://www.cyotek.com/blog/reading-photoshop-color-swatch-aco-files-using-csharp
private static List <Color> ReadSwatches(Stream stream, FileVersion version)
{
int colorCount;
List <Color> results;
results = new List <Color>();
// read the number of colors, which also occupies two bytes
colorCount = ByteHelper.ReadInt16BE(stream);
for (int i = 0; i < colorCount; i++)
{
ColorSpace colorSpace;
int value1;
int value2;
int value3;
int value4;
// again, two bytes for the color space
colorSpace = (ColorSpace)(ByteHelper.ReadInt16BE(stream));
value1 = ByteHelper.ReadInt16BE(stream);
value2 = ByteHelper.ReadInt16BE(stream);
value3 = ByteHelper.ReadInt16BE(stream);
value4 = ByteHelper.ReadInt16BE(stream);
if (version == FileVersion.Version2)
{
int length;
// need to read the name even though currently our colour collection doesn't support names
length = ByteHelper.ReadInt32BE(stream);
Helper.ReadString(stream, length);
}
switch (colorSpace)
{
case ColorSpace.Rgb:
int red;
int green;
int blue;
// RGB.
// The first three values in the color data are red , green , and blue . They are full unsigned
// 16-bit values as in Apple's RGBColor data structure. Pure red = 65535, 0, 0.
red = value1 / 256; // 0-255
green = value2 / 256; // 0-255
blue = value3 / 256; // 0-255
results.Add(ARGB.FromARGB(red.ToByte(), green.ToByte(), blue.ToByte()));
break;
case ColorSpace.Hsb:
float hue;
float saturation;
float brightness;
// HSB.
// The first three values in the color data are hue , saturation , and brightness . They are full
// unsigned 16-bit values as in Apple's HSVColor data structure. Pure red = 0,65535, 65535.
hue = value1 / 182.04f; // 0-359
saturation = value2 / 655.35f; // 0-100
brightness = value3 / 655.35f; // 0-100
results.Add(new HSB(hue, saturation, brightness).ToColor());
break;
case ColorSpace.Grayscale:
int gray;
// Grayscale.
// The first value in the color data is the gray value, from 0...10000.
gray = (int)(value1 / 39.0625); // 0-255
results.Add(ARGB.FromARGB(gray.ToByte(), gray.ToByte(), gray.ToByte()));
break;
default:
throw new InvalidDataException(string.Format("Color space '{0}' not supported.", colorSpace));
}
}
return(results);
}
