fix(tiff): add missing tag names and value decoding (#40)

Add proper names and enum decoding for standard TIFF 6.0 tags:
- FillOrder (0x010A): Normal, Reversed
- PageNumber (0x0129)
- Predictor (0x013D): None, Horizontal differencing, Floating point
- ExtraSamples (0x0152): Unspecified, Associated/Unassociated Alpha
- SampleFormat (0x0153): Unsigned/Signed integer, IEEE float, Undefined

Fixes #39

Co-authored-by: Claude Opus 4.5 <[email protected]>

Author: rpuneet

internal/parser/tiff/lookup.go

@@ -44,6 +44,7 @@ var tiffTagNames = map[uint16]string{
 	0x0102: "BitsPerSample",
 	0x0103: "Compression",
 	0x0106: "PhotometricInterpretation",
+	0x010A: "FillOrder",
 	0x010E: "ImageDescription",
 	0x010F: "Make",
 	0x0110: "Model",
@@ -56,14 +57,18 @@ var tiffTagNames = map[uint16]string{
 	0x011B: "YResolution",
 	0x011C: "PlanarConfiguration",
 	0x0128: "ResolutionUnit",
+	0x0129: "PageNumber",
 	0x0131: "Software",
 	0x0132: "DateTime",
 	0x013B: "Artist",
 	0x013C: "HostComputer",
+	0x013D: "Predictor",
 	0x013E: "WhitePoint",
 	0x013F: "PrimaryChromaticities",
 	0x0142: "TileWidth",
 	0x0143: "TileLength",
+	0x0152: "ExtraSamples",
+	0x0153: "SampleFormat",
 	0x0201: "JPEGInterchangeFormat",
 	0x0202: "JPEGInterchangeFormatLength",
 	0x0211: "YCbCrCoefficients",

internal/parser/tiff/lookup_test.go

@@ -22,6 +22,11 @@ func TestGetTIFFTagName(t *testing.T) {
 		{"Software", 0x0131, "Software"},
 		{"DateTime", 0x0132, "DateTime"},
 		{"Artist", 0x013B, "Artist"},
+		{"FillOrder", 0x010A, "FillOrder"},
+		{"PageNumber", 0x0129, "PageNumber"},
+		{"Predictor", 0x013D, "Predictor"},
+		{"ExtraSamples", 0x0152, "ExtraSamples"},
+		{"SampleFormat", 0x0153, "SampleFormat"},
 		{"Copyright", 0x8298, "Copyright"},
 		{"ExifIFDPointer", 0x8769, "ExifIFDPointer"},
 		{"GPSInfoIFDPointer", 0x8825, "GPSInfoIFDPointer"},

internal/parser/tiff/values.go

@@ -134,13 +134,41 @@ var tiffEnumValues = map[uint16]map[uint16]string{
 		2: "Planar",
 	},
 
+	// FillOrder (0x010A)
+	0x010A: {
+		1: "Normal",
+		2: "Reversed",
+	},
+
 	// ResolutionUnit (0x0128)
 	0x0128: {
 		1: "None",
 		2: "inches",
 		3: "centimeters",
 	},
 
+	// Predictor (0x013D)
+	0x013D: {
+		1: "None",
+		2: "Horizontal differencing",
+		3: "Floating point predictor",
+	},
+
+	// ExtraSamples (0x0152)
+	0x0152: {
+		0: "Unspecified",
+		1: "Associated Alpha",
+		2: "Unassociated Alpha",
+	},
+
+	// SampleFormat (0x0153)
+	0x0153: {
+		1: "Unsigned integer",
+		2: "Signed integer",
+		3: "IEEE floating point",
+		4: "Undefined",
+	},
+
 	// YCbCrPositioning (0x0213)
 	0x0213: {
 		1: "Centered",

internal/parser/tiff/values_test.go

@@ -60,6 +60,62 @@ func TestDecodeEnumValue(t *testing.T) {
 			value:    uint16(1),
 			expected: "Centered",
 		},
+		{
+			name:     "FillOrder Normal",
+			tag:      0x010A,
+			dirName:  "IFD0",
+			value:    uint16(1),
+			expected: "Normal",
+		},
+		{
+			name:     "FillOrder Reversed",
+			tag:      0x010A,
+			dirName:  "IFD0",
+			value:    uint16(2),
+			expected: "Reversed",
+		},
+		{
+			name:     "Predictor None",
+			tag:      0x013D,
+			dirName:  "IFD0",
+			value:    uint16(1),
+			expected: "None",
+		},
+		{
+			name:     "Predictor Horizontal differencing",
+			tag:      0x013D,
+			dirName:  "IFD0",
+			value:    uint16(2),
+			expected: "Horizontal differencing",
+		},
+		{
+			name:     "ExtraSamples Unspecified",
+			tag:      0x0152,
+			dirName:  "IFD0",
+			value:    uint16(0),
+			expected: "Unspecified",
+		},
+		{
+			name:     "ExtraSamples Associated Alpha",
+			tag:      0x0152,
+			dirName:  "IFD0",
+			value:    uint16(1),
+			expected: "Associated Alpha",
+		},
+		{
+			name:     "SampleFormat Unsigned integer",
+			tag:      0x0153,
+			dirName:  "IFD0",
+			value:    uint16(1),
+			expected: "Unsigned integer",
+		},
+		{
+			name:     "SampleFormat IEEE floating point",
+			tag:      0x0153,
+			dirName:  "IFD0",
+			value:    uint16(3),
+			expected: "IEEE floating point",
+		},
 
 		// EXIF tags
 		{