add png output images format

internal/converter/converter.go

@@ -121,6 +121,7 @@ func (c *Converter) InitParse() {
 	c.AddStringParam(&c.Options.ForegroundColor, "foreground-color", c.Options.ForegroundColor, "Foreground color in hexa format RGB. Black=000, White=FFF")
 	c.AddStringParam(&c.Options.BackgroundColor, "background-color", c.Options.BackgroundColor, "Background color in hexa format RGB. Black=000, White=FFF, Light Gray=DDD, Dark Gray=777")
 	c.AddBoolParam(&c.Options.NoResize, "noresize", c.Options.NoResize, "Do not reduce image size if exceed device size")
+	c.AddStringParam(&c.Options.Format, "format", c.Options.Format, "Format of output images: jpeg (lossy), png (lossless)")
 
 	c.AddSection("Default config")
 	c.AddBoolParam(&c.Options.Show, "show", false, "Show your default parameters")
@@ -318,6 +319,11 @@ func (c *Converter) Validate() error {
 		return errors.New("background color must have color format in hexa: [0-9A-F]{3}")
 	}
 
+	// Format
+	if !(c.Options.Format == "jpeg" || c.Options.Format == "png") {
+		return errors.New("format should be jpeg or png")
+	}
+
 	return nil
 }
 

internal/converter/options/converter_options.go

@@ -43,6 +43,7 @@ type Options struct {
 	ForegroundColor            string `yaml:"foreground_color"`
 	BackgroundColor            string `yaml:"background_color"`
 	NoResize                   bool   `yaml:"noresize"`
+	Format                     string `yaml:"format"`
 
 	// Default Config
 	Show  bool `yaml:"-"`
@@ -86,6 +87,7 @@ func New() *Options {
 		ForegroundColor:            "000",
 		BackgroundColor:            "FFF",
 		NoResize:                   false,
+		Format:                     "jpeg",
 		profiles:                   profiles.New(),
 	}
 }
@@ -195,6 +197,7 @@ func (o *Options) ShowConfig() string {
 		{"Foreground Color", fmt.Sprintf("#%s", o.ForegroundColor)},
 		{"Background Color", fmt.Sprintf("#%s", o.BackgroundColor)},
 		{"Resize", !o.NoResize},
+		{"Format", o.Format},
 	} {
 		b.WriteString(fmt.Sprintf("\n    %-26s: %v", v.K, v.V))
 	}

internal/epub/epub.go

@@ -282,7 +282,7 @@ func (e *ePub) Write() error {
 			{"OEBPS/Text/title.xhtml", e.render(epubtemplates.Text, map[string]any{
 				"Title":      title,
 				"ViewPort":   fmt.Sprintf("width=%d,height=%d", e.Image.View.Width, e.Image.View.Height),
-				"ImagePath":  "Images/title.jpg",
+				"ImagePath":  fmt.Sprintf("Images/title.%s", e.Image.Format),
 				"ImageStyle": part.Cover.ImgStyle(e.Image.View.Width, e.Image.View.Height, titleAlign),
 			})},
 		}

internal/epub/image/epub_image.go

@@ -21,6 +21,7 @@ type Image struct {
 	Path       string
 	Name       string
 	Position   string
+	Format     string
 }
 
 // key name of the blank plage after the image
@@ -60,7 +61,7 @@ func (i *Image) ImgKey() string {
 
 // image path
 func (i *Image) ImgPath() string {
-	return fmt.Sprintf("Images/%s.jpg", i.ImgKey())
+	return fmt.Sprintf("Images/%s.%s", i.ImgKey(), i.Format)
 }
 
 // image path into the EPUB

internal/epub/imageprocessor/epub_image_processor.go

@@ -38,9 +38,10 @@ func (e *EPUBImageProcessor) Load() (images []*epubimage.Image, err error) {
 	if e.Dry {
 		for img := range imageInput {
 			images = append(images, &epubimage.Image{
-				Id:   img.Id,
+				Id:     img.Id,
-				Path: img.Path,
+				Path:   img.Path,
-				Name: img.Name,
+				Name:   img.Name,
+				Format: e.Image.Format,
 			})
 		}
 
@@ -59,13 +60,17 @@ func (e *EPUBImageProcessor) Load() (images []*epubimage.Image, err error) {
 	})
 	wg := &sync.WaitGroup{}
 
-	imgStorage, err := epubzip.NewEPUBZipStorageImageWriter(e.ImgStorage())
+	imgStorage, err := epubzip.NewEPUBZipStorageImageWriter(e.ImgStorage(), e.Image.Format)
 	if err != nil {
 		bar.Close()
 		return nil, err
 	}
 
-	for i := 0; i < e.WorkersRatio(50); i++ {
+	wr := 50
+	if e.Image.Format == "png" {
+		wr = 100
+	}
+	for i := 0; i < e.WorkersRatio(wr); i++ {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
@@ -90,6 +95,7 @@ func (e *EPUBImageProcessor) Load() (images []*epubimage.Image, err error) {
 						DoublePage: part == 0 && src.Bounds().Dx() > src.Bounds().Dy(),
 						Path:       input.Path,
 						Name:       input.Name,
+						Format:     e.Image.Format,
 					}
 
 					if err = imgStorage.Add(img.EPUBImgPath(), dst, e.Image.Quality); err != nil {
@@ -253,5 +259,10 @@ func (e *EPUBImageProcessor) CoverTitleData(src image.Image, title string) (*epu
 	dst := e.createImage(src, g.Bounds(src.Bounds()))
 	g.Draw(dst, src)
 
-	return epubzip.CompressImage("OEBPS/Images/title.jpg", dst, e.Image.Quality)
+	return epubzip.CompressImage(
+		fmt.Sprintf("OEBPS/Images/title.%s", e.Image.Format),
+		e.Image.Format,
+		dst,
+		e.Image.Quality,
+	)
 }

internal/epub/options/epub_options.go

@@ -32,6 +32,7 @@ type Image struct {
 	View                *View
 	GrayScale           bool
 	Resize              bool
+	Format              string
 }
 
 type Options struct {

internal/epub/templates/epub_templates_content.go

@@ -127,7 +127,7 @@ func getManifest(o *ContentOptions) []tag {
 	var imageTags, pageTags, spaceTags []tag
 	addTag := func(img *epubimage.Image, withSpace bool) {
 		imageTags = append(imageTags,
-			tag{"item", tagAttrs{"id": img.ImgKey(), "href": img.ImgPath(), "media-type": "image/jpeg"}, ""},
+			tag{"item", tagAttrs{"id": img.ImgKey(), "href": img.ImgPath(), "media-type": fmt.Sprintf("image/%s", o.ImageOptions.Format)}, ""},
 		)
 		pageTags = append(pageTags,
 			tag{"item", tagAttrs{"id": img.PageKey(), "href": img.PagePath(), "media-type": "application/xhtml+xml"}, ""},
@@ -144,7 +144,7 @@ func getManifest(o *ContentOptions) []tag {
 		{"item", tagAttrs{"id": "css", "href": "Text/style.css", "media-type": "text/css"}, ""},
 		{"item", tagAttrs{"id": "space_title", "href": "Text/space_title.xhtml", "media-type": "application/xhtml+xml"}, ""},
 		{"item", tagAttrs{"id": "page_title", "href": "Text/title.xhtml", "media-type": "application/xhtml+xml"}, ""},
-		{"item", tagAttrs{"id": "img_title", "href": "Images/title.jpg", "media-type": "image/jpeg"}, ""},
+		{"item", tagAttrs{"id": "img_title", "href": fmt.Sprintf("Images/title.%s", o.ImageOptions.Format), "media-type": fmt.Sprintf("image/%s", o.ImageOptions.Format)}, ""},
 	}
 
 	if o.ImageOptions.HasCover || o.Current > 1 {

internal/epub/zip/epub_zip_image.go

@@ -4,9 +4,11 @@ import (
 	"archive/zip"
 	"bytes"
 	"compress/flate"
+	"fmt"
 	"hash/crc32"
 	"image"
 	"image/jpeg"
+	"image/png"
 	"time"
 )
 
@@ -16,13 +18,20 @@ type ZipImage struct {
 }
 
 // create gzip encoded jpeg
-func CompressImage(filename string, img image.Image, quality int) (*ZipImage, error) {
+func CompressImage(filename string, format string, img image.Image, quality int) (*ZipImage, error) {
 	var (
 		data, cdata bytes.Buffer
 		err         error
 	)
 
-	err = jpeg.Encode(&data, img, &jpeg.Options{Quality: quality})
+	switch format {
+	case "png":
+		err = png.Encode(&data, img)
+	case "jpeg":
+		err = jpeg.Encode(&data, img, &jpeg.Options{Quality: quality})
+	default:
+		err = fmt.Errorf("unknown format %q", format)
+	}
 	if err != nil {
 		return nil, err
 	}

internal/epub/zip/epub_zip_storage_image.go

@@ -8,19 +8,19 @@ import (
 )
 
 type EPUBZipStorageImageWriter struct {
-	fh *os.File
+	fh     *os.File
-	fz *zip.Writer
+	fz     *zip.Writer
-
+	format string
-	mut *sync.Mutex
+	mut    *sync.Mutex
 }
 
-func NewEPUBZipStorageImageWriter(filename string) (*EPUBZipStorageImageWriter, error) {
+func NewEPUBZipStorageImageWriter(filename string, format string) (*EPUBZipStorageImageWriter, error) {
 	fh, err := os.Create(filename)
 	if err != nil {
 		return nil, err
 	}
 	fz := zip.NewWriter(fh)
-	return &EPUBZipStorageImageWriter{fh, fz, &sync.Mutex{}}, nil
+	return &EPUBZipStorageImageWriter{fh, fz, format, &sync.Mutex{}}, nil
 }
 
 func (e *EPUBZipStorageImageWriter) Close() error {
@@ -32,7 +32,7 @@ func (e *EPUBZipStorageImageWriter) Close() error {
 }
 
 func (e *EPUBZipStorageImageWriter) Add(filename string, img image.Image, quality int) error {
-	zipImage, err := CompressImage(filename, img, quality)
+	zipImage, err := CompressImage(filename, e.format, img, quality)
 	if err != nil {
 		return err
 	}

main.go

@@ -139,6 +139,7 @@ $ go install github.com/celogeek/go-comic-converter/v%d@%s
 				},
 			},
 			Resize: !cmd.Options.NoResize,
+			Format: cmd.Options.Format,
 		},
 	}).Write(); err != nil {
 		fmt.Fprintf(os.Stderr, "Error: %v\n", err)