Png builder method

QrCodeGenerator/PngBuilder.cs

@@ -0,0 +1,144 @@
+using System;
+using System.IO;
+using System.IO.Compression;
+
+namespace Net.Codecrete.QrCodeGenerator;
+
+internal sealed class PngBuilder : IDisposable
+{
+    private static readonly byte[] Signature = { 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
+        };
+
+    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 MemoryStream stream = new();
+
+    public void Dispose()
+    {
+        stream.Dispose();
+    }
+
+    public byte[] GetBytes()
+    {
+        var bytes = stream.ToArray();
+        var chunkOffset = Signature.Length;
+
+        while (chunkOffset < bytes.Length)
+        {
+            var dataLength = (bytes[chunkOffset] << 24) | (bytes[chunkOffset + 1] << 16) | (bytes[chunkOffset + 2] << 8) | bytes[chunkOffset + 3];
+            var crc = Crc32(bytes, chunkOffset + 4, dataLength + 4);
+            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;
+
+            chunkOffset = crcOffset + 4;
+        }
+
+        return bytes;
+    }
+
+    public void WriteHeader(int width, int height, byte bitDepth, byte colorType)
+    {
+        stream.Write(Signature, 0, Signature.Length);
+
+        WriteChunkStart(IHDR, 13);
+        WriteIntBigEndian((uint)width);
+        WriteIntBigEndian((uint)height);
+
+        stream.WriteByte(bitDepth);
+        stream.WriteByte(colorType);
+        stream.WriteByte(0);
+        stream.WriteByte(0);
+        stream.WriteByte(0);
+
+        WriteChunkEnd();
+    }
+
+    public void WriteData(byte[] data)
+    {
+        using (var idatStream = new MemoryStream())
+        {
+            Deflate(idatStream, data);
+            WriteChunkStart(IDAT, (int)(idatStream.Length + 6));
+
+            stream.WriteByte(0x78);
+            stream.WriteByte(0x9C);
+
+            idatStream.Position = 0;
+            idatStream.CopyTo(stream);
+
+            var adler = Adler32(data, 0, data.Length);
+            WriteIntBigEndian(adler);
+            WriteChunkEnd();
+        }
+    }
+
+    public void WriteEnd()
+    {
+        WriteChunkStart(IEND, 0);
+        WriteChunkEnd();
+    }
+
+    private void WriteChunkStart(byte[] type, int length)
+    {
+        WriteIntBigEndian((uint)length);
+        stream.Write(type, 0, 4);
+    }
+
+    private void WriteChunkEnd()
+    {
+        stream.SetLength(stream.Length + 4);
+        stream.Position += 4;
+    }
+
+    private void WriteIntBigEndian(uint value)
+    {
+        stream.WriteByte((byte)(value >> 24));
+        stream.WriteByte((byte)(value >> 16));
+        stream.WriteByte((byte)(value >> 8));
+        stream.WriteByte((byte)value);
+    }
+
+    private static void Deflate(Stream output, byte[] bytes)
+    {
+        using (var stream = new DeflateStream(output, CompressionMode.Compress, true))
+            stream.Write(bytes, 0, bytes.Length);
+    }
+
+    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;
+    }
+
+    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;
+    }
+}

QrCodeGenerator/QrCode.cs

@@ -482,6 +482,17 @@ public byte[] ToBmpBitmap(int border = 0, int scale = 1)
             return ToBmpBitmap(border, scale, 0x000000, 0xffffff);
         }
 
+        /// <summary>
+        /// Creates bitmap in the PNG format data using black for dark modules and white for light modules.
+        /// </summary>
+        /// <param name="border">The border width, as a factor of the module (QR code pixel) size.</param>
+        /// <param name="scale">The width and height, in pixels, of each module.</param>
+        /// <returns>Bitmap data</returns>
+        public byte[] ToPngBitmap(int border = 0, int scale = 1)
+        {
+            return new QrCodePng(this, scale, border).GetBytes();
+        }
+
         /// <summary>
         /// Creates an RGB color value in little endian format.
         /// </summary>

QrCodeGenerator/QrCodePng.cs

@@ -0,0 +1,65 @@
+using System;
+
+namespace Net.Codecrete.QrCodeGenerator;
+
+internal sealed class QrCodePng
+{
+    private readonly QrCode _qr;
+    private readonly int _scale;
+    private readonly int _border;
+    private readonly int _realSize;
+    private readonly int _scaledSize;
+
+    public QrCodePng(QrCode qr, int scale, int border)
+    {
+        _qr = qr;
+        _scale = scale;
+        _border = border;
+        _realSize = qr.Size + border * 2;
+        _scaledSize = _realSize * scale;
+    }
+
+    public byte[] GetBytes()
+    {
+        using var png = new PngBuilder();
+
+        var data = Draw();
+
+        png.WriteHeader(_scaledSize, _scaledSize, 1, 0);
+        png.WriteData(data);
+        png.WriteEnd();
+
+        return png.GetBytes();
+    }
+
+    private byte[] Draw()
+    {
+        int bytesPerLine = (_scaledSize + 7) / 8 + 1;
+        var data = new byte[bytesPerLine * _scaledSize];
+
+        for (int y = 0; y < _realSize; y++)
+        {
+            int offset = y * bytesPerLine * _scale;
+
+            for (int x = 0; x < _realSize; x++)
+            {
+                if (_qr.GetModule(x - _border, y - _border))
+                    continue;
+
+                int pos = x * _scale;
+                int end = pos + _scale;
+
+                for (; pos < end; pos++)
+                {
+                    int index = offset + pos / 8 + 1;
+                    data[index] |= (byte)(0x80 >> pos % 8);
+                }
+            }
+
+            for (var i = 1; i < _scale; i++)
+                Array.Copy(data, offset, data, offset + i * bytesPerLine, bytesPerLine);
+        }
+
+        return data;
+    }
+}