update README

fix landscape display when each side can be cut differently.
A doublepage is 1 big image, and should be cut as one.

README.md

@@ -148,7 +148,7 @@ Options:
     Grayscale                       : true
     Grayscale mode                  : normal
     Crop                            : true
-    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 10% - Skip true
+    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 0% - Skip false
     Auto contrast                   : true
     Auto rotate                     : true
     Auto split double page          : true
@@ -196,7 +196,7 @@ Options:
     Grayscale                       : true
     Grayscale mode                  : normal
     Crop                            : true
-    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 10% - Skip true
+    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 0% - Skip false
     Auto contrast                   : true
     Auto rotate                     : true
     Auto split double page          : true
@@ -254,7 +254,7 @@ Options:
     Grayscale                       : true
     Grayscale mode                  : normal
     Crop                            : true
-    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 10% - Skip true
+    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 0% - Skip false
     Auto contrast                   : false
     Auto rotate                     : false
     Auto split double page          : false
@@ -285,11 +285,12 @@ Options:
     Grayscale                       : true
     Grayscale mode                  : normal
     Crop                            : true
-    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 10% - Skip true
+    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 0% - Skip false
     Auto contrast                   : true
     Auto rotate                     : true
     Auto split double page          : true
     Keep double page if split       : true
+    Keep split double page aspect   : true
     No blank image                  : true
     Manga                           : true
     Has cover                       : true
@@ -318,15 +319,13 @@ Options:
     Grayscale                       : true
     Grayscale mode                  : normal
     Crop                            : true
-    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 10% - Skip true
+    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 0% - Skip false
-    Auto contrast                   : true
+    Auto contrast                   : false
-    Auto rotate                     : true
+    Auto rotate                     : false
-    Auto split double page          : true
+    Auto split double page          : false
-    Keep double page if split       : true
     No blank image                  : true
     Manga                           : false
     Has cover                       : true
-    Limit                           : 200 Mb
     Strip first directory from toc  : false
     Sort path mode                  : path=alphanumeric, file=alpha
     Foreground color                : #000
@@ -354,7 +353,7 @@ Options:
     Grayscale                       : true
     Grayscale mode                  : normal
     Crop                            : true
-    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 10% - Skip true
+    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 0% - Skip false
     Auto contrast                   : false
     Auto rotate                     : false
     Auto split double page          : false
@@ -389,13 +388,14 @@ Options:
     Grayscale                       : true
     Grayscale mode                  : normal
     Crop                            : true
-    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 10% - Skip true
+    Crop ratio                      : 1 Left - 1 Up - 1 Right - 3 Bottom - Limit 0% - Skip false
     Auto contrast                   : false
     Auto rotate                     : false
     Auto split double page          : false
     No blank image                  : true
     Manga                           : true
     Has cover                       : true
+    Limit                           : 200 Mb
     Strip first directory from toc  : false
     Sort path mode                  : path=alphanumeric, file=alpha
     Foreground color                : #000
@@ -482,9 +482,9 @@ Config:
     	Crop ratio right: ratio of pixels allow to be non blank while cutting on the right.
   -crop-ratio-bottom int (default 3)
     	Crop ratio bottom: ratio of pixels allow to be non blank while cutting on the bottom.
-  -crop-limit int (default 10)
+  -crop-limit int
     	Crop limit: maximum number of cropping in percentage allowed. 0 mean unlimited.
-  -crop-skip-if-limit-reached (default true)
+  -crop-skip-if-limit-reached
     	Crop skip if limit reached.
   -brightness int
     	Brightness readjustment: between -100 and 100, > 0 lighter, < 0 darker
@@ -498,6 +498,8 @@ Config:
     	Auto Split double page when width > height
   -keepdoublepageifsplit (default true)
     	Keep the double page if split
+  -keepsplitdoublepageaspect (default true)
+    	Keep aspect of split part of a double page (best for landscape rendering)
   -noblankimage (default true)
     	Remove blank image
   -manga

internal/converter/converter.go

@@ -122,6 +122,7 @@ func (c *Converter) InitParse() {
 	c.AddBoolParam(&c.Options.AutoRotate, "autorotate", c.Options.AutoRotate, "Auto Rotate page when width > height")
 	c.AddBoolParam(&c.Options.AutoSplitDoublePage, "autosplitdoublepage", c.Options.AutoSplitDoublePage, "Auto Split double page when width > height")
 	c.AddBoolParam(&c.Options.KeepDoublePageIfSplit, "keepdoublepageifsplit", c.Options.KeepDoublePageIfSplit, "Keep the double page if split")
+	c.AddBoolParam(&c.Options.KeepSplitDoublePageAspect, "keepsplitdoublepageaspect", c.Options.KeepSplitDoublePageAspect, "Keep aspect of split part of a double page (best for landscape rendering)")
 	c.AddBoolParam(&c.Options.NoBlankImage, "noblankimage", c.Options.NoBlankImage, "Remove blank image")
 	c.AddBoolParam(&c.Options.Manga, "manga", c.Options.Manga, "Manga mode (right to left)")
 	c.AddBoolParam(&c.Options.HasCover, "hascover", c.Options.HasCover, "Has cover. Indicate if your comic have a cover. The first page will be used as a cover and include after the title.")
@@ -274,6 +275,11 @@ func (c *Converter) Parse() {
 	if c.Options.AppleBookCompatibility {
 		c.Options.AutoSplitDoublePage = true
 		c.Options.KeepDoublePageIfSplit = false
+		c.Options.KeepSplitDoublePageAspect = true
+	}
+
+	if c.Options.PortraitOnly {
+		c.Options.KeepSplitDoublePageAspect = false
 	}
 }
 

internal/converter/options/converter_options.go

@@ -38,6 +38,7 @@ type Options struct {
 	AutoRotate                 bool    `yaml:"auto_rotate"`
 	AutoSplitDoublePage        bool    `yaml:"auto_split_double_page"`
 	KeepDoublePageIfSplit      bool    `yaml:"keep_double_page_if_split"`
+	KeepSplitDoublePageAspect  bool    `yaml:"keep_split_double_page_aspect"`
 	NoBlankImage               bool    `yaml:"no_blank_image"`
 	Manga                      bool    `yaml:"manga"`
 	HasCover                   bool    `yaml:"has_cover"`
@@ -90,11 +91,10 @@ func New() *Options {
 		CropRatioUp:               1,
 		CropRatioRight:            1,
 		CropRatioBottom:           3,
-		CropLimit:              10,
-		CropSkipIfLimitReached: true,
 		NoBlankImage:              true,
 		HasCover:                  true,
 		KeepDoublePageIfSplit:     true,
+		KeepSplitDoublePageAspect: true,
 		SortPathMode:              1,
 		ForegroundColor:           "000",
 		BackgroundColor:           "FFF",
@@ -179,6 +179,7 @@ func (o *Options) MarshalJSON() ([]byte, error) {
 		out["autosplitdoublepage"] = o.AutoSplitDoublePage
 		if o.AutoSplitDoublePage {
 			out["keepdoublepageifsplit"] = o.KeepDoublePageIfSplit
+			out["keepsplitdoublepageaspect"] = o.KeepSplitDoublePageAspect
 		}
 	}
 	if o.LimitMb != 0 {
@@ -285,6 +286,7 @@ func (o *Options) ShowConfig() string {
 		{"Auto rotate", o.AutoRotate, true},
 		{"Auto split double page", o.AutoSplitDoublePage, o.PortraitOnly || !o.AppleBookCompatibility},
 		{"Keep double page if split", o.KeepDoublePageIfSplit, (o.PortraitOnly || !o.AppleBookCompatibility) && o.AutoSplitDoublePage},
+		{"Keep split double page aspect", o.KeepSplitDoublePageAspect, (o.PortraitOnly || !o.AppleBookCompatibility) && o.AutoSplitDoublePage},
 		{"No blank image", o.NoBlankImage, true},
 		{"Manga", o.Manga, true},
 		{"Has cover", o.HasCover, true},

internal/epub/imagefilters/epub_image_filters_autocrop.go

@@ -28,10 +28,8 @@ type cutRatioOptions struct {
 func findMargin(img image.Image, bounds image.Rectangle, cutRatio cutRatioOptions, limit int, skipIfLimitReached bool) image.Rectangle {
 	imgArea := bounds
 
-	maxCropX, maxCropY := imgArea.Dx()*limit/100, imgArea.Dy()*limit/100
-
 LEFT:
-	for x, maxCrop := imgArea.Min.X, maxCropX; x < imgArea.Max.X && (limit == 0 || maxCrop > 0); x, maxCrop = x+1, maxCrop-1 {
+	for x := imgArea.Min.X; x < imgArea.Max.X; x++ {
 		allowNonBlank := imgArea.Dy() * cutRatio.Left / 100
 		for y := imgArea.Min.Y; y < imgArea.Max.Y; y++ {
 			if !colorIsBlank(img.At(x, y)) {
@@ -42,13 +40,10 @@ LEFT:
 			}
 		}
 		imgArea.Min.X++
-		if limit > 0 && maxCrop == 1 && skipIfLimitReached {
-			return bounds
-		}
 	}
 
 UP:
-	for y, maxCrop := imgArea.Min.Y, maxCropY; y < imgArea.Max.Y && (limit == 0 || maxCrop > 0); y, maxCrop = y+1, maxCrop-1 {
+	for y := imgArea.Min.Y; y < imgArea.Max.Y; y++ {
 		allowNonBlank := imgArea.Dx() * cutRatio.Up / 100
 		for x := imgArea.Min.X; x < imgArea.Max.X; x++ {
 			if !colorIsBlank(img.At(x, y)) {
@@ -59,13 +54,10 @@ UP:
 			}
 		}
 		imgArea.Min.Y++
-		if limit > 0 && maxCrop == 1 && skipIfLimitReached {
-			return bounds
-		}
 	}
 
 RIGHT:
-	for x, maxCrop := imgArea.Max.X-1, maxCropX; x >= imgArea.Min.X && (limit == 0 || maxCrop > 0); x, maxCrop = x-1, maxCrop-1 {
+	for x := imgArea.Max.X - 1; x >= imgArea.Min.X; x-- {
 		allowNonBlank := imgArea.Dy() * cutRatio.Right / 100
 		for y := imgArea.Min.Y; y < imgArea.Max.Y; y++ {
 			if !colorIsBlank(img.At(x, y)) {
@@ -76,13 +68,10 @@ RIGHT:
 			}
 		}
 		imgArea.Max.X--
-		if limit > 0 && maxCrop == 1 && skipIfLimitReached {
-			return bounds
-		}
 	}
 
 BOTTOM:
-	for y, maxCrop := imgArea.Max.Y-1, maxCropY; y >= imgArea.Min.Y && (limit == 0 || maxCrop > 0); y, maxCrop = y-1, maxCrop-1 {
+	for y := imgArea.Max.Y - 1; y >= imgArea.Min.Y; y-- {
 		allowNonBlank := imgArea.Dx() * cutRatio.Bottom / 100
 		for x := imgArea.Min.X; x < imgArea.Max.X; x++ {
 			if !colorIsBlank(img.At(x, y)) {
@@ -93,10 +82,42 @@ BOTTOM:
 			}
 		}
 		imgArea.Max.Y--
-		if limit > 0 && maxCrop == 1 && skipIfLimitReached {
+	}
+
+	// no limit or blankImage
+	if limit == 0 || imgArea.Dx() == 0 || imgArea.Dy() == 0 {
+		return imgArea
+	}
+
+	exceedX, exceedY := limitExceed(bounds, imgArea, limit)
+	if skipIfLimitReached && (exceedX > 0 || exceedY > 0) {
 		return bounds
 	}
-	}
+
+	imgArea.Min.X, imgArea.Max.X = correctLine(imgArea.Min.X, imgArea.Max.X, bounds.Min.X, bounds.Max.X, exceedX)
+	imgArea.Min.Y, imgArea.Max.Y = correctLine(imgArea.Min.Y, imgArea.Max.Y, bounds.Min.Y, bounds.Max.Y, exceedY)
 
 	return imgArea
 }
+
+func limitExceed(bounds, newBounds image.Rectangle, limit int) (int, int) {
+	return bounds.Dx() - newBounds.Dx() - bounds.Dx()*limit/100, bounds.Dy() - newBounds.Dy() - bounds.Dy()*limit/100
+}
+
+func correctLine(min, max, bMin, bMax, exceed int) (int, int) {
+	if exceed <= 0 {
+		return min, max
+	}
+
+	min -= exceed / 2
+	max += exceed / 2
+	if min < bMin {
+		max += bMin - min
+		min = bMin
+	}
+	if max > bMax {
+		min -= max - bMax
+		max = bMax
+	}
+	return min, max
+}

internal/epub/imageprocessor/epub_image_processor.go

@@ -178,7 +178,9 @@ func (e *EPUBImageProcessor) transformImage(input *task, part int, right bool) *
 	src := input.Image
 	srcBounds := src.Bounds()
 
-	if part > 0 {
+	// In portrait only, we don't need to keep aspect ratio between each split.
+	// We first cut, the crop.
+	if part > 0 && !e.Image.KeepSplitDoublePageAspect {
 		g.Add(epubimagefilters.CropSplitDoublePage(right))
 	}
 
@@ -205,11 +207,18 @@ func (e *EPUBImageProcessor) transformImage(input *task, part int, right bool) *
 		}
 	}
 
+	// With landscape support, we need to keep aspect ratio between each split
+	// We first crop, then cut
+	if part > 0 && e.Image.KeepSplitDoublePageAspect {
+		g.Add(epubimagefilters.CropSplitDoublePage(right))
+	}
+
 	dstBounds := g.Bounds(src.Bounds())
 	// Original && Cropped version need to landscape oriented
-	isDoublePage := srcBounds.Dx() > srcBounds.Dy() && dstBounds.Dx() > dstBounds.Dy()
+	// Only part 0 can be a double page
+	isDoublePage := part == 0 && srcBounds.Dx() > srcBounds.Dy() && dstBounds.Dx() > dstBounds.Dy()
 
-	if part == 0 && e.Image.AutoRotate && isDoublePage {
+	if e.Image.AutoRotate && isDoublePage {
 		g.Add(gift.Rotate90())
 	}
 

internal/epub/options/epub_options.go

@@ -30,6 +30,7 @@ type Image struct {
 	AutoRotate                bool
 	AutoSplitDoublePage       bool
 	KeepDoublePageIfSplit     bool
+	KeepSplitDoublePageAspect bool
 	NoBlankImage              bool
 	Manga                     bool
 	HasCover                  bool

main.go

@@ -141,6 +141,7 @@ $ go install github.com/celogeek/go-comic-converter/v%d@%s
 			AutoRotate:                cmd.Options.AutoRotate,
 			AutoSplitDoublePage:       cmd.Options.AutoSplitDoublePage,
 			KeepDoublePageIfSplit:     cmd.Options.KeepDoublePageIfSplit,
+			KeepSplitDoublePageAspect: cmd.Options.KeepSplitDoublePageAspect,
 			NoBlankImage:              cmd.Options.NoBlankImage,
 			Manga:                     cmd.Options.Manga,
 			HasCover:                  cmd.Options.HasCover,