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#if NET40 || NET461
using System;using System.IO;using System.IO.Compression;
namespace Apewer.Internals.QrCode{ internal sealed class PngByteQRCode : AbstractQRCode, IDisposable { /// <summary>
/// Constructor without params to be used in COM Objects connections
/// </summary>
public PngByteQRCode() { }
public PngByteQRCode(QRCodeData data) : base(data) { }
/// <summary>
/// Creates a black & white PNG of the QR code, using 1-bit grayscale.
/// </summary>
public byte[] GetGraphic(int pixelsPerModule) { using (var png = new PngBuilder()) { var size = this.QrCodeData.ModuleMatrix.Count * pixelsPerModule; png.WriteHeader(size, size, 1, PngBuilder.ColorType.Greyscale); png.WriteScanlines(this.DrawScanlines(pixelsPerModule)); png.WriteEnd(); return png.GetBytes(); } }
/// <summary>
/// Creates 2-color PNG of the QR code, using 1-bit indexed color. Accepts 3-byte RGB colors for normal images and 4-byte RGBA-colors for transparent images.
/// </summary>
public byte[] GetGraphic(int pixelsPerModule, byte[] darkColorRgba, byte[] lightColorRgba) { using (var png = new PngBuilder()) { var size = this.QrCodeData.ModuleMatrix.Count * pixelsPerModule; png.WriteHeader(size, size, 1, PngBuilder.ColorType.Indexed); png.WritePalette(darkColorRgba, lightColorRgba); png.WriteScanlines(this.DrawScanlines(pixelsPerModule)); png.WriteEnd(); return png.GetBytes(); } }
/// <summary>
/// Creates a bitmap where each pixel is represented by a single bit, dark = 0 and light = 1.
/// </summary>
private byte[] DrawScanlines(int pixelsPerModule) { var moduleMatrix = this.QrCodeData.ModuleMatrix; var matrixSize = moduleMatrix.Count; var bytesPerScanline = (matrixSize * pixelsPerModule + 7) / 8 + 1; // A monochrome scanline is one byte for filter type then one bit per pixel.
var scanlines = new byte[bytesPerScanline * matrixSize * pixelsPerModule];
for (var y = 0; y < matrixSize; y++) { var modules = moduleMatrix[y]; var scanlineOffset = y * pixelsPerModule * bytesPerScanline;
// Draw a scanline with the modules from the QR code.
for (var x = 0; x < matrixSize; x++) { if (modules[x]) { continue; }
var pixelIndex = x * pixelsPerModule; var endIndex = pixelIndex + pixelsPerModule; for (; pixelIndex < endIndex; pixelIndex++) { scanlines[scanlineOffset + 1 + pixelIndex / 8] |= (byte)(0x80 >> (pixelIndex % 8)); } }
// Copy the scanline required number of times.
for (var copyCount = 1; copyCount < pixelsPerModule; copyCount++) { Array.Copy(scanlines, scanlineOffset, scanlines, scanlineOffset + copyCount * bytesPerScanline, bytesPerScanline); } }
return scanlines; }
/// <summary>
/// Writes the chunks that make up a PNG file.
/// </summary>
/// <remarks>
/// See https://www.w3.org/TR/2003/REC-PNG-20031110 and https://www.ietf.org/rfc/rfc1950.txt.
/// </remarks>
private sealed class PngBuilder : IDisposable { private static readonly byte[] PngSignature = { 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A };
private static readonly uint[] CrcTable = { 0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01, 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65, 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F, 0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B, 0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713, 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9, 0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D };
// ReSharper disable InconsistentNaming
// Chunk types
private static readonly byte[] IHDR = { 73, 72, 68, 82 };
private static readonly byte[] IDAT = { 73, 68, 65, 84 };
private static readonly byte[] IEND = { 73, 69, 78, 68 };
private static readonly byte[] PLTE = { 80, 76, 84, 69 };
private static readonly byte[] tRNS = { 116, 82, 78, 83 }; // ReSharper enable InconsistentNaming
public enum ColorType : byte { Greyscale = 0, Indexed = 3 }
private MemoryStream stream = new MemoryStream();
public void Dispose() { this.stream?.Dispose(); this.stream = null; }
public byte[] GetBytes() { var bytes = this.stream.ToArray();
// Enumerate chunks in file and insert their CRC32 checksums.
var chunkOffset = PngSignature.Length; while (chunkOffset < bytes.Length) { // Read length field.
var dataLength = (bytes[chunkOffset] << 24) | (bytes[chunkOffset + 1] << 16) | (bytes[chunkOffset + 2] << 8) | bytes[chunkOffset + 3];
// CRC is computed from type and data fields.
var crc = Crc32(bytes, chunkOffset + 4, dataLength + 4);
// Write CRC to end of chunk.
var crcOffset = chunkOffset + 8 + dataLength; bytes[crcOffset + 0] = (byte)(crc >> 24); bytes[crcOffset + 1] = (byte)(crc >> 16); bytes[crcOffset + 2] = (byte)(crc >> 8); bytes[crcOffset + 3] = (byte)crc;
// Seek to next chunk.
chunkOffset = crcOffset + 4; }
return bytes; }
/// <summary>
/// Writes the IHDR chunk. This must be the first chunk in the file.
/// </summary>
public void WriteHeader(int width, int height, byte bitDepth, ColorType colorType) { this.stream.Write(PngSignature, 0, PngSignature.Length); this.WriteChunkStart(IHDR, 13);
// Size.
this.WriteIntBigEndian((uint)width); this.WriteIntBigEndian((uint)height);
// Color.
this.stream.WriteByte(bitDepth); this.stream.WriteByte((byte)colorType);
// Constants.
this.stream.WriteByte(0); this.stream.WriteByte(0); this.stream.WriteByte(0);
this.WriteChunkEnd(); }
/// <summary>
/// Writes the PLTE chunk, and also the tRNS chunk if necessary. Must come before the IDAT chunk.
/// </summary>
public void WritePalette(params byte[][] rgbaColors) { const int Red = 0, Green = 1, Blue = 2, Alpha = 3; const byte Opaque = 255; var hasAlpha = false;
this.WriteChunkStart(PLTE, 3 * rgbaColors.Length); foreach (var color in rgbaColors) { hasAlpha |= color.Length > Alpha && color[Alpha] < Opaque; this.stream.WriteByte(color[Red]); this.stream.WriteByte(color[Green]); this.stream.WriteByte(color[Blue]); } this.WriteChunkEnd();
if (!hasAlpha) { return; }
this.WriteChunkStart(tRNS, rgbaColors.Length); foreach (var color in rgbaColors) { this.stream.WriteByte(color.Length > Alpha ? color[Alpha] : Opaque); } this.WriteChunkEnd(); }
/// <summary>
/// Writes the IDAT chunk with the actual picture.
/// </summary>
public void WriteScanlines(byte[] scanlines) { using (var idatStream = new MemoryStream()) { Deflate(idatStream, scanlines);
this.WriteChunkStart(IDAT, (int)(idatStream.Length + 6));
// Deflate header.
this.stream.WriteByte(0x78); // 8 Deflate algorithm, 7 max window size
this.stream.WriteByte(0x9C); // Check bits.
// Compressed data.
idatStream.Position = 0;#if NET35
idatStream.WriteTo(this.stream);#else
idatStream.CopyTo(this.stream);#endif
// Deflate checksum.
var adler = Adler32(scanlines, 0, scanlines.Length); this.WriteIntBigEndian(adler);
this.WriteChunkEnd(); } }
/// <summary>
/// Writes the IEND chunk. This must be the last chunk in the file.
/// </summary>
public void WriteEnd() { this.WriteChunkStart(IEND, 0); this.WriteChunkEnd(); }
private void WriteChunkStart(byte[] type, int length) { this.WriteIntBigEndian((uint)length); this.stream.Write(type, 0, 4); }
private void WriteChunkEnd() { // Reserves 4 bytes space for crc32 so GetBytes can add it later.
this.stream.SetLength(this.stream.Length + 4); this.stream.Position += 4; }
private void WriteIntBigEndian(uint value) { this.stream.WriteByte((byte)(value >> 24)); this.stream.WriteByte((byte)(value >> 16)); this.stream.WriteByte((byte)(value >> 8)); this.stream.WriteByte((byte)value); }
private static void Deflate(Stream output, byte[] bytes) { using (var deflateStream = new DeflateStream(output, CompressionMode.Compress, leaveOpen: true)) { deflateStream.Write(bytes, 0, bytes.Length); } }
// Reference implementation from RFC 1950. Not optimized.
private static uint Adler32(byte[] data, int index, int length) { const uint Base = 65521; uint s1 = 1, s2 = 0;
var end = index + length; for (var n = index; n < end; n++) { s1 = (s1 + data[n]) % Base; s2 = (s2 + s1) % Base; }
return (s2 << 16) + s1; }
// Reference implementation from REC-PNG-20031110. Not optimized.
private static uint Crc32(byte[] data, int index, int length) { var c = 0xffffffff;
var end = index + length; for (var n = index; n < end; n++) { c = CrcTable[(c ^ data[n]) & 0xff] ^ (c >> 8); }
return c ^ 0xffffffff; } } }}
#endif
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