improve crop

internal/converter/converter.go

@@ -98,6 +98,7 @@ func (c *Converter) InitParse() {
 	c.AddStringParam(&c.Options.Profile, "profile", c.Options.Profile, fmt.Sprintf("Profile to use: \n%s", c.Options.AvailableProfiles()))
 	c.AddIntParam(&c.Options.Quality, "quality", c.Options.Quality, "Quality of the image")
 	c.AddBoolParam(&c.Options.Crop, "crop", c.Options.Crop, "Crop images")
+	c.AddIntParam(&c.Options.CropRatio, "crop-ratio", c.Options.CropRatio, "Crop ratio: ratio of pixels allow to be non blank while cutting. 0 mean first non blank stop cutting. 5 may help to remove number.")
 	c.AddIntParam(&c.Options.Brightness, "brightness", c.Options.Brightness, "Brightness readjustement: between -100 and 100, > 0 lighter, < 0 darker")
 	c.AddIntParam(&c.Options.Contrast, "contrast", c.Options.Contrast, "Contrast readjustement: between -100 and 100, > 0 more contrast, < 0 less contrast")
 	c.AddBoolParam(&c.Options.AutoRotate, "autorotate", c.Options.AutoRotate, "Auto Rotate page when width > height")

internal/converter/options/converter_options.go

@@ -24,6 +24,7 @@ type Options struct {
 	Profile                    string `yaml:"profile"`
 	Quality                    int    `yaml:"quality"`
 	Crop                       bool   `yaml:"crop"`
+	CropRatio                  int    `yaml:"crop_ratio"`
 	Brightness                 int    `yaml:"brightness"`
 	Contrast                   int    `yaml:"contrast"`
 	Auto                       bool   `yaml:"-"`
@@ -59,6 +60,7 @@ func New() *Options {
 		Profile:                    "",
 		Quality:                    85,
 		Crop:                       true,
+		CropRatio:                  5,
 		Brightness:                 0,
 		Contrast:                   0,
 		AutoRotate:                 false,
@@ -159,6 +161,7 @@ func (o *Options) ShowConfig() string {
     View                      : %s
     Quality                   : %d
     Crop                      : %v
+    CropRatio                 : %d
     Brightness                : %d
     Contrast                  : %d
     AutoRotate                : %v
@@ -174,6 +177,7 @@ func (o *Options) ShowConfig() string {
 		viewDesc,
 		o.Quality,
 		o.Crop,
+		o.CropRatio,
 		o.Brightness,
 		o.Contrast,
 		o.AutoRotate,

internal/epub/image/epub_image_options.go

@@ -3,6 +3,7 @@ package epubimage
 // options for image transformation
 type Options struct {
 	Crop                bool
+	CropRatio           int
 	ViewWidth           int
 	ViewHeight          int
 	Quality             int

internal/epub/imageprocessing/epub_image_processing.go

@@ -102,7 +102,7 @@ func LoadImages(o *Options) ([]*epubimage.Image, error) {
 				}
 
 				if o.Image.Crop {
-					g := gift.New(gift.Crop(findMarging(src)))
+					g := gift.New(gift.Crop(findMarging(src, o.Image.CropRatio)))
 					newSrc := image.NewNRGBA(g.Bounds(src.Bounds()))
 					g.Draw(newSrc, src)
 					src = newSrc

internal/epub/imageprocessing/epub_image_processing_helpers.go

@@ -21,18 +21,22 @@ func isSupportedImage(path string) bool {
 // check if the color is blank enough
 func colorIsBlank(c color.Color) bool {
 	g := color.GrayModel.Convert(c).(color.Gray)
-	return g.Y >= 0xf0
+	return g.Y >= 0xe0
 }
 
 // lookup for margin (blank) around the image
-func findMarging(img image.Image) image.Rectangle {
+func findMarging(img image.Image, cutRatio int) image.Rectangle {
 	imgArea := img.Bounds()
 
 LEFT:
 	for x := imgArea.Min.X; x < imgArea.Max.X; x++ {
+		allowNonBlank := imgArea.Dy() * cutRatio / 100
 		for y := imgArea.Min.Y; y < imgArea.Max.Y; y++ {
 			if !colorIsBlank(img.At(x, y)) {
-				break LEFT
+				allowNonBlank--
+				if allowNonBlank <= 0 {
+					break LEFT
+				}
 			}
 		}
 		imgArea.Min.X++
@@ -40,9 +44,13 @@ LEFT:
 
 UP:
 	for y := imgArea.Min.Y; y < imgArea.Max.Y; y++ {
+		allowNonBlank := imgArea.Dx() * cutRatio / 100
 		for x := imgArea.Min.X; x < imgArea.Max.X; x++ {
 			if !colorIsBlank(img.At(x, y)) {
-				break UP
+				allowNonBlank--
+				if allowNonBlank <= 0 {
+					break UP
+				}
 			}
 		}
 		imgArea.Min.Y++
@@ -50,9 +58,13 @@ UP:
 
 RIGHT:
 	for x := imgArea.Max.X - 1; x >= imgArea.Min.X; x-- {
+		allowNonBlank := imgArea.Dy() * cutRatio / 100
 		for y := imgArea.Min.Y; y < imgArea.Max.Y; y++ {
 			if !colorIsBlank(img.At(x, y)) {
-				break RIGHT
+				allowNonBlank--
+				if allowNonBlank <= 0 {
+					break RIGHT
+				}
 			}
 		}
 		imgArea.Max.X--
@@ -60,9 +72,13 @@ RIGHT:
 
 BOTTOM:
 	for y := imgArea.Max.Y - 1; y >= imgArea.Min.Y; y-- {
+		allowNonBlank := imgArea.Dx() * cutRatio / 100
 		for x := imgArea.Min.X; x < imgArea.Max.X; x++ {
 			if !colorIsBlank(img.At(x, y)) {
-				break BOTTOM
+				allowNonBlank--
+				if allowNonBlank <= 0 {
+					break BOTTOM
+				}
 			}
 		}
 		imgArea.Max.Y--

main.go

@@ -114,6 +114,7 @@ $ go install github.com/celogeek/go-comic-converter/v%d@%s
 			ViewHeight:          perfectHeight,
 			Quality:             cmd.Options.Quality,
 			Crop:                cmd.Options.Crop,
+			CropRatio:           cmd.Options.CropRatio,
 			Brightness:          cmd.Options.Brightness,
 			Contrast:            cmd.Options.Contrast,
 			AutoRotate:          cmd.Options.AutoRotate,