Merge pull request #13 from celogeek/compute-aspect-ratio

Compute aspect ratio

internal/converter/converter.go

@@ -84,6 +84,12 @@ func (c *Converter) AddIntParam(p *int, name string, value int, usage string) {
 	c.order = append(c.order, converterOrderName{value: name})
 }
 
+// Add an float parameter
+func (c *Converter) AddFloatParam(p *float64, name string, value float64, usage string) {
+	c.Cmd.Float64Var(p, name, value, usage)
+	c.order = append(c.order, converterOrderName{value: name})
+}
+
 // Add a boolean parameter
 func (c *Converter) AddBoolParam(p *bool, name string, value bool, usage string) {
 	c.Cmd.BoolVar(p, name, value, usage)
@@ -121,6 +127,7 @@ func (c *Converter) InitParse() {
 	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.AddFloatParam(&c.Options.AspectRatio, "aspect-ratio", c.Options.AspectRatio, "Aspect ratio (height/width) of the output\n -1 = same as device\n  0 = same as source\n1.6 = amazon advice for kindle")
 
 	c.AddSection("Default config")
 	c.AddBoolParam(&c.Options.Show, "show", false, "Show your default parameters")
@@ -351,6 +358,11 @@ func (c *Converter) Validate() error {
 		return errors.New("format should be jpeg or png")
 	}
 
+	// Aspect Ratio
+	if c.Options.AspectRatio < 0 && c.Options.AspectRatio != -1 {
+		return errors.New("aspect ratio should be: -1, 0, > 0")
+	}
+
 	return nil
 }
 

internal/converter/options/converter_options.go

@@ -43,6 +43,7 @@ type Options struct {
 	BackgroundColor            string  `yaml:"background_color"`
 	NoResize                   bool    `yaml:"noresize"`
 	Format                     string  `yaml:"format"`
+	AspectRatio                float64 `yaml:"aspect_ratio"`
 
 	// Default Config
 	Show  bool `yaml:"-"`
@@ -94,6 +95,7 @@ func New() *Options {
 		BackgroundColor:            "FFF",
 		NoResize:                   false,
 		Format:                     "jpeg",
+		AspectRatio:                0,
 		profiles:                   profiles.New(),
 	}
 }
@@ -145,7 +147,7 @@ func (o *Options) LoadConfig() error {
 
 // Get current settings for fields that can be saved
 func (o *Options) ShowConfig() string {
-	var profileDesc, viewDesc string
+	var profileDesc string
 	profile := o.GetProfile()
 	if profile != nil {
 		profileDesc = fmt.Sprintf(
@@ -155,13 +157,6 @@ func (o *Options) ShowConfig() string {
 			profile.Width,
 			profile.Height,
 		)
-
-		perfectWidth, perfectHeight := profile.PerfectDim()
-		viewDesc = fmt.Sprintf(
-			"%dx%d",
-			perfectWidth,
-			perfectHeight,
-		)
 	}
 
 	sortpathmode := ""
@@ -174,6 +169,13 @@ func (o *Options) ShowConfig() string {
 		sortpathmode = "path=alphanum, file=alphanum"
 	}
 
+	aspectRatio := "auto"
+	if o.AspectRatio > 0 {
+		aspectRatio = fmt.Sprintf("1:%.02f", o.AspectRatio)
+	} else if o.AspectRatio < 0 {
+		aspectRatio = fmt.Sprintf("1:%0.2f (device)", float64(profile.Height)/float64(profile.Width))
+	}
+
 	var b strings.Builder
 	for _, v := range []struct {
 		Key       string
@@ -181,8 +183,6 @@ func (o *Options) ShowConfig() string {
 		Condition bool
 	}{
 		{"Profile", profileDesc, true},
-		{"ViewRatio", fmt.Sprintf("1:%s", strings.TrimRight(fmt.Sprintf("%f", profiles.PerfectRatio), "0")), true},
-		{"View", viewDesc, true},
 		{"Format", o.Format, true},
 		{"Quality", o.Quality, o.Format == "jpeg"},
 		{"Grayscale", o.Grayscale, true},
@@ -201,6 +201,7 @@ func (o *Options) ShowConfig() string {
 		{"Foreground Color", fmt.Sprintf("#%s", o.ForegroundColor), true},
 		{"Background Color", fmt.Sprintf("#%s", o.BackgroundColor), true},
 		{"Resize", !o.NoResize, true},
+		{"Aspect Ratio", aspectRatio, true},
 	} {
 		if v.Condition {
 			b.WriteString(fmt.Sprintf("\n    %-26s: %v", v.Key, v.Value))

internal/converter/profiles/converter_profiles.go

@@ -15,21 +15,6 @@ type Profile struct {
 	Height      int
 }
 
-// Recommended ratio of image for perfect rendering Portrait or Landscape.
-const PerfectRatio = 1.6
-
-// Compute best dimension based on device size
-func (p Profile) PerfectDim() (int, int) {
-	width, height := float64(p.Width), float64(p.Height)
-	perfectWidth, perfectHeight := height/PerfectRatio, width*PerfectRatio
-	if perfectWidth > width {
-		perfectWidth = width
-	} else {
-		perfectHeight = height
-	}
-	return int(perfectWidth), int(perfectHeight)
-}
-
 type Profiles []Profile
 
 // Initialize list of all supported profiles.

internal/epub/epub.go

@@ -6,6 +6,7 @@ package epub
 import (
 	"archive/zip"
 	"fmt"
+	"math"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -193,6 +194,52 @@ func (e *ePub) getTree(images []*epubimage.Image, skip_files bool) string {
 	return c.WriteString("")
 }
 
+func (e *ePub) computeAspectRatio(epubParts []*epubPart) float64 {
+	var (
+		bestAspectRatio      float64
+		bestAspectRatioCount int
+		aspectRatio          = map[float64]int{}
+	)
+
+	trunc := func(v float64) float64 {
+		return float64(math.Round(v*10000)) / 10000
+	}
+
+	for _, p := range epubParts {
+		aspectRatio[trunc(p.Cover.OriginalAspectRatio)]++
+		for _, i := range p.Images {
+			aspectRatio[trunc(i.OriginalAspectRatio)]++
+		}
+	}
+
+	for k, v := range aspectRatio {
+		if v > bestAspectRatioCount {
+			bestAspectRatio, bestAspectRatioCount = k, v
+		}
+	}
+
+	return bestAspectRatio
+}
+
+func (e *ePub) computeViewPort(epubParts []*epubPart) {
+	if e.Image.View.AspectRatio == -1 {
+		return //keep device size
+	}
+
+	// readjusting view port
+	bestAspectRatio := e.Image.View.AspectRatio
+	if bestAspectRatio == 0 {
+		bestAspectRatio = e.computeAspectRatio(epubParts)
+	}
+
+	viewWidth, viewHeight := int(float64(e.Image.View.Height)/bestAspectRatio), int(float64(e.Image.View.Width)*bestAspectRatio)
+	if viewWidth > e.Image.View.Width {
+		e.Image.View.Height = viewHeight
+	} else {
+		e.Image.View.Width = viewWidth
+	}
+}
+
 // create the zip
 func (e *ePub) Write() error {
 	type zipContent struct {
@@ -231,6 +278,7 @@ func (e *ePub) Write() error {
 		Quiet:       e.Quiet,
 	})
 
+	e.computeViewPort(epubParts)
 	for i, part := range epubParts {
 		ext := filepath.Ext(e.Output)
 		suffix := ""

internal/epub/image/epub_image.go

@@ -22,6 +22,7 @@ type Image struct {
 	Name                string
 	Position            string
 	Format              string
+	OriginalAspectRatio float64
 }
 
 // key name of the blank plage after the image

internal/epub/imageprocessor/epub_image_processor.go

@@ -96,6 +96,7 @@ func (e *EPUBImageProcessor) Load() (images []*epubimage.Image, err error) {
 						Path:                input.Path,
 						Name:                input.Name,
 						Format:              e.Image.Format,
+						OriginalAspectRatio: float64(src.Bounds().Dy()) / float64(src.Bounds().Dx()),
 					}
 
 					if err = imgStorage.Add(img.EPUBImgPath(), dst, e.Image.Quality); err != nil {

internal/epub/options/epub_options.go

@@ -16,6 +16,7 @@ type Color struct {
 
 type View struct {
 	Width, Height int
+	AspectRatio   float64
 	Color         Color
 }
 

main.go

@@ -99,7 +99,6 @@ $ go install github.com/celogeek/go-comic-converter/v%d@%s
 	fmt.Fprintln(os.Stderr, cmd.Options)
 
 	profile := cmd.Options.GetProfile()
-	perfectWidth, perfectHeight := profile.PerfectDim()
 
 	if err := epub.New(&epuboptions.Options{
 		Input:                      cmd.Options.Input,
@@ -131,8 +130,9 @@ $ go install github.com/celogeek/go-comic-converter/v%d@%s
 			Manga:               cmd.Options.Manga,
 			HasCover:            cmd.Options.HasCover,
 			View: &epuboptions.View{
-				Width:  perfectWidth,
-				Height: perfectHeight,
+				Width:       profile.Width,
+				Height:      profile.Height,
+				AspectRatio: cmd.Options.AspectRatio,
 				Color: epuboptions.Color{
 					Foreground: cmd.Options.ForegroundColor,
 					Background: cmd.Options.BackgroundColor,