Output color categories

color.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 
+	colorful "github.com/lucasb-eyer/go-colorful"
 	"github.com/mgmeyers/unipdf/v3/core"
 	"github.com/mgmeyers/unipdf/v3/model"
 )
@@ -55,3 +56,83 @@ func getColor(annotation *model.PdfAnnotation) string {
 
 	return ""
 }
+
+func getColorCategory(annotation *model.PdfAnnotation) string {
+	if annotation == nil {
+		return ""
+	}
+
+	ctx := annotation.GetContext()
+	annotType := getType(ctx)
+
+	switch annotType {
+	case Highlight:
+		return pdfObjToColorCategory(ctx.(*model.PdfAnnotationHighlight).C)
+	case Strike:
+		return pdfObjToColorCategory(ctx.(*model.PdfAnnotationStrikeOut).C)
+	case Underline:
+		return pdfObjToColorCategory(ctx.(*model.PdfAnnotationUnderline).C)
+	case Rectangle:
+		return pdfObjToColorCategory(ctx.(*model.PdfAnnotationSquare).C)
+	case Text:
+		return pdfObjToColorCategory(ctx.(*model.PdfAnnotationText).C)
+	}
+
+	return ""
+}
+
+func pdfObjToColorCategory(c core.PdfObject) string {
+	if c == nil {
+		return ""
+	}
+
+	clr, err := c.(*core.PdfObjectArray).ToFloat64Array()
+	endIfErr(err)
+
+	if len(clr) < 3 {
+		return ""
+	}
+
+	color := colorful.Color{
+		R: clr[0],
+		G: clr[1],
+		B: clr[2],
+	}
+	h, s, l := color.Hsl()
+
+	// define color category based on HSL
+	if l < 0.12 {
+		return "Black"
+	}
+	if l > 0.98 {
+		return "White"
+	}
+	if s < 0.2 {
+		return "Gray"
+	}
+	if h < 15 {
+		return "Red"
+	}
+	if h < 45 {
+		return "Orange"
+	}
+	if h < 65 {
+		return "Yellow"
+	}
+	if h < 170 {
+		return "Green"
+	}
+	if h < 190 {
+		return "Cyan"
+	}
+	if h < 263 {
+		return "Blue"
+	}
+	if h < 280 {
+		return "Purple"
+	}
+	if h < 335 {
+		return "Magenta"
+	}
+	return "Red"
+}

go.mod

@@ -7,15 +7,16 @@ require (
 	github.com/gen2brain/go-fitz v1.18.0
 	github.com/golang/geo v0.0.0-20210211234256-740aa86cb551
 	github.com/mgmeyers/unipdf/v3 v3.9.0
+	github.com/lucasb-eyer/go-colorful v1.2.0
 )
 
 require (
-	github.com/softlandia/cpd v1.0.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/konsorten/go-windows-terminal-sequences v1.0.3 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/sirupsen/logrus v1.6.0 // indirect
+	github.com/softlandia/cpd v1.0.0 // indirect
 	github.com/stretchr/testify v1.7.0 // indirect
 	github.com/unidoc/unitype v0.2.0 // indirect
 	golang.org/x/image v0.0.0-20181116024801-cd38e8056d9b // indirect

go.sum

@@ -23,6 +23,8 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
+github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
 github.com/mgmeyers/unipdf/v3 v3.9.0 h1:sMeEIjjYNe+0bf5aITf+3P3rXbnHkWu79LUGVLbIO9g=
 github.com/mgmeyers/unipdf/v3 v3.9.0/go.mod h1:ZIbI0M9u3SfhUnF0wR2YGVWlebIqwCikx/sbPlVZSG0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
@@ -32,6 +34,7 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
 github.com/sirupsen/logrus v1.5.0/go.mod h1:+F7Ogzej0PZc/94MaYx/nvG9jOFMD2osvC3s+Squfpo=
 github.com/sirupsen/logrus v1.6.0 h1:UBcNElsrwanuuMsnGSlYmtmgbb23qDR5dG+6X6Oo89I=
 github.com/sirupsen/logrus v1.6.0/go.mod h1:7uNnSEd1DgxDLC74fIahvMZmmYsHGZGEOFrfsX/uA88=
+github.com/softlandia/cpd v1.0.0/go.mod h1:LcHy4FZYolw1FpyNAiwI1dblei1AGBBF2FpD1+L9Iqg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=

image.go

@@ -66,11 +66,12 @@ func handleImageAnnot(
 	}
 
 	builtAnnot := &Annotation{
-		Color:     getColor(annotation),
-		Comment:   comment,
-		ImagePath: imagePath,
-		Type:      Image,
-		Page:      pageIndex + 1,
+		Color:         getColor(annotation),
+		ColorCategory: getColorCategory(annotation),
+		Comment:       comment,
+		ImagePath:     imagePath,
+		Type:          Image,
+		Page:          pageIndex + 1,
 	}
 
 	date := getDate(annotation)

main.go

@@ -46,6 +46,7 @@ const (
 type Annotation struct {
 	AnnotatedText string `json:"annotatedText,omitempty"`
 	Color         string `json:"color,omitempty"`
+	ColorCategory string `json:"colorCategory,omitempty"`
 	Comment       string `json:"comment,omitempty"`
 	Date          string `json:"date,omitempty"`
 	ImagePath     string `json:"imagePath,omitempty"`
@@ -228,6 +229,7 @@ func processAnnotations(
 		builtAnnot := &Annotation{
 			AnnotatedText: str,
 			Color:         getColor(annotation),
+			ColorCategory: getColorCategory(annotation),
 			Comment:       comment,
 			Type:          annotType,
 			Page:          pageIndex + 1,