/// <inheritdoc/>
public void Encode(Stream output, ImageDetails image, CancellationToken cancellationToken)
{
using (var stream = new BeBinaryWriter(output, Encoding.Default, true))
{
var h = image.Height;
int size = 0;
this.WriteHeader(stream, image);
for (int y = 0; y < h; y++)
{
if (cancellationToken.IsCancellationRequested)
{
stream.Flush();
break;
}
var row = image.GetScanline(y);
size += this.WritePixelScanLine(stream, image, row);
}
this.WriteTrailer(stream, size);
}
}
internal void WriteHeader(BeBinaryWriter imageOutput, ImageDetails imageDetails)
{
// If the image is indexed, it'll always be a single channel, otherwise PICT is always 3 Channels + Alpha
var pictComponents = (imageDetails.IsIndexed ? 1 : 4);
// If a source image is 24 bit, return 32 bit
// Otherwise 1, 4, 8, 16 and 32 bit images supported.
var pictBps = imageDetails.BitsPerPixel == 24 ? 32 : imageDetails.BitsPerPixel;
// I've seen all sorts of weird things
PackType packType = PackType.PackBits;
if (imageDetails.BitsPerPixel == 1)
{
packedBytes = (imageDetails.Width / 8 + ((imageDetails.Width % 8) != 0 ? 1 : 0));
rowBytes = packedBytes;
sourceRowBytes = rowBytes;
packType = PackType.PackBits;
}
if (imageDetails.BitsPerPixel == 2)
{
packedBytes = (imageDetails.Width / 4 + ((imageDetails.Width % 4) != 0 ? 1 : 0));
rowBytes = packedBytes;
sourceRowBytes = rowBytes;
packType = PackType.PackBits;
}
if (imageDetails.BitsPerPixel == 4)
{
packedBytes = (imageDetails.Width / 2 + ((imageDetails.Width % 2) != 0 ? 1 : 0));
rowBytes = packedBytes;
sourceRowBytes = rowBytes;
packType = PackType.PackBits;
}
else if (imageDetails.BitsPerPixel == 8)
{
packedBytes = (int)(((imageDetails.Width * 8) / imageDetails.BitsPerPixel) +
(((imageDetails.Width * 8) % imageDetails.Width) != 0 ? 1 : 0));
rowBytes = imageDetails.Width * 1;
sourceRowBytes = rowBytes;
packType = PackType.PackBits;
}
else if (imageDetails.BitsPerPixel == 16)
{
packedBytes = imageDetails.Width * 2;
rowBytes = imageDetails.Width * 2;
sourceRowBytes = imageDetails.Width * 2;
packType = PackType.PackBits;
}
else if (imageDetails.BitsPerPixel == 24)
{
packedBytes = imageDetails.Width * 4;
rowBytes = imageDetails.Width * 4;
sourceRowBytes = imageDetails.Width * 3;
packType = PackType.PackBitsRgb;
}
else if (imageDetails.BitsPerPixel == 32)
{
packedBytes = imageDetails.Width * pictComponents;
rowBytes = imageDetails.Width * pictComponents;
sourceRowBytes = imageDetails.Width * 4;
packType = PackType.PackBitsRgb;
}
if (rowBytes < 8)
{
packType = PackType.NotPacked;
}
// TODO: Make 512 byte header optional
// Write empty 512-byte header
byte[] buf = new byte[Pict.PICT_NULL_HEADER_SIZE];
imageOutput.Write(buf);
// Write out the size, leave as 0, this is ok
imageOutput.WriteShort(0);
// Write image frame (same as image bounds)
imageOutput.WriteShort(imageDetails.Top);
imageOutput.WriteShort(imageDetails.Left);
imageOutput.WriteShort(imageDetails.Bottom);
imageOutput.WriteShort(imageDetails.Right);
// Write version, version 2
imageOutput.WriteShort(Pict.OP_VERSION);
imageOutput.WriteShort(Pict.OP_VERSION_2);
// Version 2 HEADER_OP, extended version.
imageOutput.WriteShort(Pict.OP_HEADER_OP);
imageOutput.WriteInt(Pict.HEADER_V2_EXT); // incl 2 bytes reseverd
//imageOutput.WriteShort(FFEE); // FFEF or FFEE
//imageOutput.WriteShort(0x0); // Reservered
// Original Horizontal Resolution in Pixels / Inch
// Image resolution, 72 dpi (long)
imageOutput.WriteShort(72);
imageOutput.WriteShort(0);
// Original Verticale Resolution in Pixels / Inch
imageOutput.WriteShort(72);
imageOutput.WriteShort(0);
// Optimal source rectangle (same as image bounds)
// Frame at original resolution
imageOutput.WriteShort(imageDetails.Top);
imageOutput.WriteShort(imageDetails.Left);
imageOutput.WriteShort(imageDetails.Bottom);
imageOutput.WriteShort(imageDetails.Right);
// Reserved (4 bytes)
imageOutput.WriteInt(0);
// ------------------ END OF HEADER -------------------- //
// This is where things get weird...depending on bpp
// Set the clip rectangle
imageOutput.WriteShort(Pict.OP_CLIP_RGN);
imageOutput.WriteShort(10);
imageOutput.WriteShort(imageDetails.Top); // top
imageOutput.WriteShort(imageDetails.Left); // left
imageOutput.WriteShort(imageDetails.Bottom);
imageOutput.WriteShort(imageDetails.Right);
if (imageDetails.IsIndexed)
{
if (imageDetails.BitsPerPixel == 1)
{
imageOutput.WriteShort(Pict.OP_BITS_RECT);
imageOutput.WriteShort(rowBytes);
// Write bounds rectangle (same as image bounds)
imageOutput.WriteShort(imageDetails.Top); // top
imageOutput.WriteShort(imageDetails.Left); // left
imageOutput.WriteShort(imageDetails.Bottom); // TODO: Handle overflow? // bottom
imageOutput.WriteShort(imageDetails.Right); // right
// Source and dest rect (both are same as image bounds)
imageOutput.WriteShort(imageDetails.Top);
imageOutput.WriteShort(imageDetails.Left);
imageOutput.WriteShort(imageDetails.Bottom);
imageOutput.WriteShort(imageDetails.Right);
// Dest Rect
imageOutput.WriteShort(imageDetails.Top);
imageOutput.WriteShort(imageDetails.Left);
imageOutput.WriteShort(imageDetails.Bottom);
imageOutput.WriteShort(imageDetails.Right);
// Transfer mode
imageOutput.WriteShort(0);
imageOutput.Flush();
return;
}
else
{
imageOutput.WriteShort(Pict.OP_PACK_BITS_RECT); // Packbits
// The offset in bytes from one row of the image to the next. The value must be even, less than $4000, and for best performance it should be a multiple of 4.
// The high 2 bits of rowBytes are used as flags. If bit 15 = 1, the data structure pointed to is a PixMap record; otherwise it is a BitMap record.
imageOutput.WriteUShort((ushort)(rowBytes | 0x8000));
}
}
else // RGB Image
{
// Pixmap operation
imageOutput.WriteShort(Pict.OP_DIRECT_BITS_RECT); // 0x9A - sometimes called pict9a
// PixMap pointer (always 0x000000FF);
imageOutput.WriteInt(0xff);
// I see conflicting things about writing out row bytes at this point...
imageOutput.WriteUShort((ushort)(rowBytes | 0x8000));
}
// Write bounds rectangle (same as image bounds)
imageOutput.WriteShort(imageDetails.Top); // top
imageOutput.WriteShort(imageDetails.Left); // left
imageOutput.WriteShort(imageDetails.Bottom); // TODO: Handle overflow? // bottom
imageOutput.WriteShort(imageDetails.Right); // right
// PixMap record version
// The version number of Color QuickDraw that created this PixMap record.
// The value of pmVersion is normally 0. If pmVersion is 4, Color QuickDraw treats the PixMap record's baseAddr field as 32-bit clean.
// (All other flags are private.) Most applications never need to set this field.
imageOutput.WriteShort(0);
// Packing format (always 4: PackBits)
// * 0 is default indexed packing.
// * 1 is no packing (rowBytes < 8)
// * 2
// * 3
// * 4 is default direct packing - run length encoded scan lines by component, red first.
imageOutput.WriteShort(packType);
// Size of packed data (leave as 0)
// The size of the packed image in bytes. When the packType field contains the value 0, this field is always set to 0
imageOutput.WriteInt(0);
// Pixmap resolution, 72 dpi
//imageOutput.WriteShort(Pict.MAC_DEFAULT_DPI+0.5);
imageOutput.WriteShort(72);
imageOutput.WriteShort(0);
//imageOutput.WriteShort(Pict.MAC_DEFAULT_DPI+0.5);
imageOutput.WriteShort(72);
imageOutput.WriteShort(0);
// Pixel type
// The storage format for a pixel image. Indexed pixels are indicated by a value of 0.
// Direct pixels are specified by a value of RGBDirect, or 16.
// In the PixMap record of the GDevice record (described in the chapter "Graphics Devices")
// for a direct device, this field is set to the constant RGBDirect when the screen depth is set.
if (imageDetails.IsIndexed)
{
imageOutput.WriteShort(0);
}
else
{
imageOutput.WriteShort(16);
}
// Pixel size
// Pixel depth; that is, the number of bits used to represent a pixel.
// Indexed pixels can have sizes of 1, 2, 4, and 8 bits; direct pixel sizes are 16 and 32 bits.
imageOutput.WriteShort(pictBps);
// Pixel component count (planes) - ie 1 for indexed, 3 or 4 for RGB
imageOutput.WriteShort(pictComponents);
// Pixel component size
/*
* The size in bits of each component for a pixel. Color QuickDraw expects that the sizes of all components
* are the same, and that the value of the cmpCount field multiplied by the value of the cmpSize field
* is less than or equal to the value in the pixelSize field.
* For an indexed pixel value, which has only one component, the value of the cmpSize field is the same
* as the value of the pixelSize field--that is, 1, 2, 4, or 8.
* For direct pixels there are two additional possibilities:
* A 16-bit pixel, which has three components, has a cmpSize value
* of 5. This leaves an unused high-order bit, which Color QuickDraw sets to 0.
* A 32-bit pixel, which has three components (red, green, and blue), has a cmpSize value of 8.
* This leaves an unused high-order byte, which Color QuickDraw sets to 0.
*/
if (imageDetails.IsIndexed)
{
imageOutput.WriteShort(pictBps);
}
else if (imageDetails.BitsPerPixel == 16)
{
imageOutput.WriteShort(5);
}
else
{
imageOutput.WriteShort(8);
}
// PlaneBytes, ignored for now
imageOutput.WriteInt(0);
// TODO: Allow IndexColorModel?
// ColorTable record (for RGB direct pixels, just write 0)
// Pixmap Colour Table (seems to always be 0?)
imageOutput.WriteInt(0);
//imageOutput.WriteInt(0x101F);
// Reserved (4 bytes)
imageOutput.WriteInt(0);
// Write out ColorTable
if (imageDetails.IsIndexed)
{
imageOutput.WriteInt(0); // color seed - Resource ID
// Colour Flags Flags. A value of $0000 identifies this as a color table for a pixel map. A value of $8000 identifies this as a color table for an indexed device.
imageOutput.WriteShort(0);
// Entry count / Size. One less than the number of color specification entries in the rest of this resource.
imageOutput.WriteShort((ushort)(imageDetails.Palette.Length - 1));
for (ushort i = 0; i < imageDetails.Palette.Length; i++)
{
imageOutput.WriteShort(i); // pixel value
// Each colour is a 16bit value...scale to short
imageOutput.WriteUShort(ScaleQuantumToShort(imageDetails.Palette[i].R));
imageOutput.WriteUShort(ScaleQuantumToShort(imageDetails.Palette[i].G));
imageOutput.WriteUShort(ScaleQuantumToShort(imageDetails.Palette[i].B));
}
}
// Source and dest rect (both are same as image bounds)
imageOutput.WriteShort(imageDetails.Top);
imageOutput.WriteShort(imageDetails.Left);
imageOutput.WriteShort(imageDetails.Bottom);
imageOutput.WriteShort(imageDetails.Right);
// Dest Rect
imageOutput.WriteShort(imageDetails.Top);
imageOutput.WriteShort(imageDetails.Left);
imageOutput.WriteShort(imageDetails.Bottom);
imageOutput.WriteShort(imageDetails.Right);
// Transfer mode
if (imageDetails.IsIndexed)
{
imageOutput.WriteShort(0);
}
else
{
imageOutput.WriteShort(/*QuickDraw.SRC_COPY*/ 0x40);
}
imageOutput.Flush();
// Now write image data
}
/// <inheritdoc/> public void Encode(Stream output, ImageDetails image) => this.Encode(output, image, CancellationToken.None);
/// <summary>
/// Writes and compresses (if needed) each scan line
/// </summary>
/// <param name="imageOutput"></param>
/// <param name="imageDetails"></param>
/// <param name="scanLine"></param>
/// <returns></returns>
internal int WritePixelScanLine(BeBinaryWriter imageOutput, ImageDetails imageDetails, byte[] scanLine)
{
int xOffset = 0;
var pixels = scanLine;
int w = imageDetails.IsIndexed ? packedBytes : imageDetails.Width;
uint bytesPerPixel = imageDetails.IsIndexed ? 1 : imageDetails.BitsPerPixel / 8;
uint pixelsPerByte = 8 / imageDetails.BitsPerPixel;
byte[] scanlineBytes = new byte[rowBytes];
bool invert = imageDetails.BitsPerPixel == 1;
// Mask for Pixel Packing based on bits per pixel
int packMask = (1 << (int)imageDetails.BitsPerPixel) - 1;
// Masks for RGB555 (16bit) encoding
int redMask = 0x7C00;
int greenMask = 0x3E0;
int blueMask = 0x1F;
int byteCount = 0;
// Treat the scanline.
for (int x = 0; x < w; x++)
{
var colorIndex = x * bytesPerPixel;
if (imageDetails.IsIndexed)
{
// 8 Bit images
if (pixelsPerByte == 1)
{
scanlineBytes[x] = pixels[x];
}
else
{
// Pack 1, 2, 4 bit image palette entries into a single byte
int shift = 8 - (int)imageDetails.BitsPerPixel;
byte packedPixel = 0;
xOffset = x * (int)pixelsPerByte;
// Calculate the reamining pixels from the end of the buffer
int remaining = 0;
byte pixel;
if (xOffset >= pixels.Length - pixelsPerByte)
{
remaining = (int)pixelsPerByte - (pixels.Length % (int)pixelsPerByte);
}
;
for (int j = 0; j < pixelsPerByte - remaining; j++)
{
pixel = pixels[xOffset + j];
// 1bpp images are inverted, that is zero is white.
if (invert)
{
pixel = (byte)~pixel; // reverse the pixel value
}
packedPixel = (byte)(packedPixel | ((byte)(pixel & packMask) << shift));
shift -= (int)imageDetails.BitsPerPixel;
}
scanlineBytes[x] = packedPixel;
}
}
else if (imageDetails.BitsPerPixel == 16)
{
// not working yet, not sure if it's the header or what...
var pixelShort = (short)((pixels[colorIndex + 0] << 8) + pixels[colorIndex + 1]);
byte r = (byte)(((pixelShort & redMask) >> 10) << 3);
byte g = (byte)(((pixelShort & greenMask) >> 5) << 3);
byte b = (byte)((pixelShort & blueMask) << 3);
var color = new PaletteEntry(255, r, g, b);
// this is the colour at this location, but we can probably just copy it back out?
scanlineBytes[colorIndex] = pixels[colorIndex + 1];
scanlineBytes[colorIndex + 1] = pixels[colorIndex];
}
else // True color
{
PaletteEntry color;
if (imageDetails.BitsPerPixel == 32)
{
color = new PaletteEntry(pixels[colorIndex + 3], pixels[colorIndex + 2], pixels[colorIndex + 1], pixels[colorIndex + 0]);
}
else //(imageDetails.BitsPerPixel == 24)
{
color = new PaletteEntry(255, pixels[colorIndex + 2], pixels[colorIndex + 1], pixels[colorIndex + 0]);
}
// Write out as rows of pixels, 1 per channel
scanlineBytes[xOffset + x] = color.A;
scanlineBytes[xOffset + w + x] = color.R;
scanlineBytes[xOffset + 2 * w + x] = color.G;
scanlineBytes[xOffset + 3 * w + x] = color.B;
}
}
// Pack using PackBitsEncoder
// https://web.archive.org/web/20080705155158/http://developer.apple.com/technotes/tn/tn1023.html
// Small images aren't compressed
if (rowBytes < 8)
{
byteCount += scanlineBytes.Length;
imageOutput.BaseStream.Write(scanlineBytes, 0, scanlineBytes.Length);
}
// TODO Check the compression setting
else // Pack the bytes
{
var packedBytes = PackBitsCompressor.PackBits(scanlineBytes);
//var packedBytes = new PackBitsEncoder().compress(scanlineBytes);
if (rowBytes > 250) // apple says 250, ImageMagick has 200...hmm
{
imageOutput.WriteShort((short)packedBytes.Length);
byteCount += 2;
}
else
{
imageOutput.Write((byte)packedBytes.Length);
byteCount++;
}
byteCount += packedBytes.Length;
imageOutput.BaseStream.Write(packedBytes, 0, packedBytes.Length);
}
imageOutput.Flush();
return(byteCount);
}