Merge branch 'main' into main

Author: LuisAlfredo92

src/ImageSharp/Formats/Bmp/BmpEncoderCore.cs

@@ -668,7 +668,7 @@ private void Write1BitPixelData<TPixel>(Configuration configuration, Stream stre
 
             if (quantizedPixelRow.Length % 8 != 0)
             {
-                int startIdx = quantizedPixelRow.Length - 7;
+                int startIdx = quantizedPixelRow.Length - (quantizedPixelRow.Length % 8);
                 endIdx = quantizedPixelRow.Length;
                 Write1BitPalette(stream, startIdx, endIdx, quantizedPixelRow);
             }

src/ImageSharp/Formats/Pbm/BinaryDecoder.cs

@@ -152,7 +152,6 @@ private static void ProcessBlackAndWhite<TPixel>(Configuration configuration, Bu
     {
         int width = pixels.Width;
         int height = pixels.Height;
-        int startBit = 0;
         MemoryAllocator allocator = configuration.MemoryAllocator;
         using IMemoryOwner<L8> row = allocator.Allocate<L8>(width);
         Span<L8> rowSpan = row.GetSpan();
@@ -162,23 +161,12 @@ private static void ProcessBlackAndWhite<TPixel>(Configuration configuration, Bu
             for (int x = 0; x < width;)
             {
                 int raw = stream.ReadByte();
-                int bit = startBit;
-                startBit = 0;
-                for (; bit < 8; bit++)
+                int stopBit = Math.Min(8, width - x);
+                for (int bit = 0; bit < stopBit; bit++)
                 {
                     bool bitValue = (raw & (0x80 >> bit)) != 0;
                     rowSpan[x] = bitValue ? black : white;
                     x++;
-                    if (x == width)
-                    {
-                        startBit = (bit + 1) & 7; // Round off to below 8.
-                        if (startBit != 0)
-                        {
-                            stream.Seek(-1, System.IO.SeekOrigin.Current);
-                        }
-
-                        break;
-                    }
                 }
             }
 

src/ImageSharp/Formats/Pbm/BinaryEncoder.cs

@@ -33,25 +33,40 @@ public static void WritePixels<TPixel>(Configuration configuration, Stream strea
             {
                 WriteGrayscale(configuration, stream, image);
             }
-            else
+            else if (componentType == PbmComponentType.Short)
             {
                 WriteWideGrayscale(configuration, stream, image);
             }
+            else
+            {
+                throw new ImageFormatException("Component type not supported for Grayscale PBM.");
+            }
         }
         else if (colorType == PbmColorType.Rgb)
         {
             if (componentType == PbmComponentType.Byte)
             {
                 WriteRgb(configuration, stream, image);
             }
-            else
+            else if (componentType == PbmComponentType.Short)
             {
                 WriteWideRgb(configuration, stream, image);
             }
+            else
+            {
+                throw new ImageFormatException("Component type not supported for Color PBM.");
+            }
         }
         else
         {
-            WriteBlackAndWhite(configuration, stream, image);
+            if (componentType == PbmComponentType.Bit)
+            {
+                WriteBlackAndWhite(configuration, stream, image);
+            }
+            else
+            {
+                throw new ImageFormatException("Component type not supported for Black & White PBM.");
+            }
         }
     }
 
@@ -164,8 +179,6 @@ private static void WriteBlackAndWhite<TPixel>(Configuration configuration, Stre
         using IMemoryOwner<L8> row = allocator.Allocate<L8>(width);
         Span<L8> rowSpan = row.GetSpan();
 
-        int previousValue = 0;
-        int startBit = 0;
         for (int y = 0; y < height; y++)
         {
             Span<TPixel> pixelSpan = pixelBuffer.DangerousGetRowSpan(y);
@@ -177,28 +190,19 @@ private static void WriteBlackAndWhite<TPixel>(Configuration configuration, Stre
 
             for (int x = 0; x < width;)
             {
-                int value = previousValue;
-                for (int i = startBit; i < 8; i++)
+                int value = 0;
+                int stopBit = Math.Min(8, width - x);
+                for (int i = 0; i < stopBit; i++)
                 {
                     if (rowSpan[x].PackedValue < 128)
                     {
                         value |= 0x80 >> i;
                     }
 
                     x++;
-                    if (x == width)
-                    {
-                        previousValue = value;
-                        startBit = (i + 1) & 7; // Round off to below 8.
-                        break;
-                    }
                 }
 
-                if (startBit == 0)
-                {
-                    stream.WriteByte((byte)value);
-                    previousValue = 0;
-                }
+                stream.WriteByte((byte)value);
             }
         }
     }

src/ImageSharp/Formats/Tiff/Compression/Decompressors/T6BitReader.cs

@@ -125,13 +125,29 @@ public bool ReadNextCodeWord()
                     if (value == Len7Code0000000.Code)
                     {
                         this.Code = Len7Code0000000;
-                        return false;
+
+                        // We do not support Extensions1D codes, but some encoders (scanner from epson) write a premature EOL code,
+                        // which at this point cannot be distinguished from the marker, because we read the data bit by bit.
+                        // Read the next 5 bit, if its a EOL code return true, indicating its the end of the image.
+                        if (this.ReadValue(5) == 1)
+                        {
+                            return true;
+                        }
+
+                        throw new NotSupportedException("ccitt extensions 1D codes are not supported.");
                     }
 
                     if (value == Len7Code0000001.Code)
                     {
                         this.Code = Len7Code0000001;
-                        return false;
+
+                        // Same as above, we do not support Extensions2D codes, but it could be a EOL instead.
+                        if (this.ReadValue(5) == 1)
+                        {
+                            return true;
+                        }
+
+                        throw new NotSupportedException("ccitt extensions 2D codes are not supported.");
                     }
 
                     if (value == Len7Code0000011.Code)

src/ImageSharp/Formats/Tiff/Compression/HorizontalPredictor.cs

@@ -44,6 +44,7 @@ public static void Undo(Span<byte> pixelBytes, int width, TiffColorType colorTyp
                 UndoRgb24Bit(pixelBytes, width);
                 break;
             case TiffColorType.Rgba8888:
+            case TiffColorType.Cmyk:
                 UndoRgba32Bit(pixelBytes, width);
                 break;
             case TiffColorType.Rgb161616:

src/ImageSharp/PixelFormats/PixelImplementations/Rgb48.cs

@@ -8,7 +8,7 @@
 namespace SixLabors.ImageSharp.PixelFormats;
 
 /// <summary>
-/// Packed pixel type containing three 16-bit unsigned normalized values ranging from 0 to 635535.
+/// Packed pixel type containing three 16-bit unsigned normalized values ranging from 0 to 65535.
 /// <para>
 /// Ranges from [0, 0, 0, 1] to [1, 1, 1, 1] in vector form.
 /// </para>

src/ImageSharp/Primitives/LongRational.cs

@@ -131,6 +131,11 @@ public string ToString(IFormatProvider provider)
     /// <param name="bestPrecision">Whether to use the best possible precision when parsing the value.</param>
     public static LongRational FromDouble(double value, bool bestPrecision)
     {
+        if (value == 0.0)
+        {
+            return new LongRational(0, 1);
+        }
+
         if (double.IsNaN(value))
         {
             return new LongRational(0, 0);
@@ -201,11 +206,6 @@ public LongRational Simplify()
             return this;
         }
 
-        if (this.Numerator == 0)
-        {
-            return new LongRational(0, 0);
-        }
-
         if (this.Numerator == this.Denominator)
         {
             return new LongRational(1, 1);