- Return default values, if compression, photometricInterpretation or rowsPerStrip is not present.

- Throw Exception, if width or height is not set

src/ImageSharp/Formats/README.md → src/ImageSharp/Formats/Tga/README.md

@@ -1,4 +1,4 @@
-# Encoder/Decoder for true vision targa files
+# Encoder/Decoder for true vision targa files
 
 Useful links for reference:
 

src/ImageSharp/Formats/Tiff/Constants/TiffConstants.cs

@@ -35,6 +35,11 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Tiff.Constants
         /// </summary>
         public const ushort HeaderMagicNumber = 42;
 
+        /// <summary>
+        /// RowsPerStrip default value, which is effectively infinity.
+        /// </summary>
+        public const int RowsPerStripInfinity = 2147483647;
+
         /// <summary>
         /// Size (in bytes) of the TIFF file header.
         /// </summary>

src/ImageSharp/Formats/Tiff/README.md

@@ -32,7 +32,6 @@
     - NB: Need to handle this for both planar and chunky data
   - If the SampleFormat field is present and not 1 - fail gracefully if you cannot handle this
   - Compression=None should treat 16/32-BitsPerSample for all samples as SHORT/LONG (for byte order and padding rows)
-  - RowsPerStrip should default to 2^32-1 (effectively infinity) to store the image as a single strip
   - Check Planar format data - is this encoded as strips in order RGBRGBRGB or RRRGGGBBB?
   - Make sure we ignore any strips that are not needed for the image (if too many are present)
 

src/ImageSharp/Formats/Tiff/TiffDecoderCore.cs

@@ -34,11 +34,6 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Tiff
         /// </summary>
         private BufferedReadStream inputStream;
 
-        /// <summary>
-        /// RowsPerStrip default value, which is effectively infinity.
-        /// </summary>
-        private const int RowsPerStripInfinity = 2147483647;
-
         /// <summary>
         /// Initializes a new instance of the <see cref="TiffDecoderCore" /> class.
         /// </summary>
@@ -287,7 +282,7 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Tiff
            where TPixel : unmanaged, IPixel<TPixel>
         {
             // If the rowsPerStrip has the default value, which is effectively infinity. That is, the entire image is one strip.
-            if (rowsPerStrip == RowsPerStripInfinity)
+            if (rowsPerStrip == TiffConstants.RowsPerStripInfinity)
             {
                 rowsPerStrip = frame.Height;
             }

src/ImageSharp/Formats/Tiff/TiffFrameMetadata.cs

@@ -54,12 +54,36 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Tiff
         /// <summary>
         /// Gets the number of columns in the image, i.e., the number of pixels per row.
         /// </summary>
-        public Number Width => this.ExifProfile.GetValue(ExifTag.ImageWidth).Value;
+        public Number Width
+        {
+            get
+            {
+                IExifValue<Number> width = this.ExifProfile.GetValue(ExifTag.ImageWidth);
+                if (width == null)
+                {
+                    TiffThrowHelper.ThrowImageFormatException("The TIFF image is missing the ImageWidth");
+                }
+
+                return width.Value;
+            }
+        }
 
         /// <summary>
         /// Gets the number of rows of pixels in the image.
         /// </summary>
-        public Number Height => this.ExifProfile.GetValue(ExifTag.ImageLength).Value;
+        public Number Height
+        {
+            get
+            {
+                IExifValue<Number> height = this.ExifProfile.GetValue(ExifTag.ImageLength);
+                if (height == null)
+                {
+                    TiffThrowHelper.ThrowImageFormatException("The TIFF image is missing the ImageLength");
+                }
+
+                return height.Value;
+            }
+        }
 
         /// <summary>
         /// Gets the number of bits per component.
@@ -104,12 +128,36 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Tiff
         /// Gets the compression scheme used on the image data.
         /// </summary>
         /// <value>The compression scheme used on the image data.</value>
-        public TiffCompression Compression => (TiffCompression)this.ExifProfile.GetValue(ExifTag.Compression).Value;
+        public TiffCompression Compression
+        {
+            get
+            {
+                IExifValue<ushort> compression = this.ExifProfile.GetValue(ExifTag.Compression);
+                if (compression == null)
+                {
+                    return TiffCompression.None;
+                }
+
+                return (TiffCompression)compression.Value;
+            }
+        }
 
         /// <summary>
         /// Gets the color space of the image data.
         /// </summary>
-        public TiffPhotometricInterpretation PhotometricInterpretation => (TiffPhotometricInterpretation)this.ExifProfile.GetValue(ExifTag.PhotometricInterpretation).Value;
+        public TiffPhotometricInterpretation PhotometricInterpretation
+        {
+            get
+            {
+                IExifValue<ushort> photometricInterpretation = this.ExifProfile.GetValue(ExifTag.PhotometricInterpretation);
+                if (photometricInterpretation == null)
+                {
+                    return TiffPhotometricInterpretation.WhiteIsZero;
+                }
+
+                return (TiffPhotometricInterpretation)photometricInterpretation.Value;
+            }
+        }
 
         /// <summary>
         /// Gets the logical order of bits within a byte.
@@ -156,7 +204,19 @@ namespace SixLabors.ImageSharp.Formats.Experimental.Tiff
         /// <summary>
         /// Gets the number of rows per strip.
         /// </summary>
-        public Number RowsPerStrip => this.ExifProfile.GetValue(ExifTag.RowsPerStrip).Value;
+        public Number RowsPerStrip
+        {
+            get
+            {
+                IExifValue<Number> rowsPerStrip = this.ExifProfile.GetValue(ExifTag.RowsPerStrip);
+                if (rowsPerStrip == null)
+                {
+                    return TiffConstants.RowsPerStripInfinity;
+                }
+
+                return rowsPerStrip.Value;
+            }
+        }
 
         /// <summary>
         /// Gets for each strip, the number of bytes in the strip after compression.