Add ZipLevel, issue #48

cbconvert.go

@@ -23,6 +23,8 @@ type Options struct {
 	Format string
 	// Archive format, valid values are zip, tar
 	Archive string
+	// ZIP compression level: -1 default, 0 store (no compression), 1-9 deflate (1 fastest, 9 smallest)
+	ZipLevel int
 	// JPEG image quality
 	Quality int
 	// Encoder speed/effort, format-specific: webp method 0-6, avif speed 0-10, jxl effort 1-10; -1 uses the format default
@@ -137,6 +139,7 @@ func NewOptions() Options {
 	o.Archive = "zip"
 	o.Quality = 75
 	o.Effort = -1
+	o.ZipLevel = -1
 	o.Filter = 2
 
 	return o

cbconvert_archive.go

@@ -3,6 +3,7 @@ package cbconvert
 import (
 	"archive/tar"
 	"archive/zip"
+	"compress/flate"
 	"context"
 	"fmt"
 	"io"
@@ -50,6 +51,13 @@ func (c *Converter) archiveSaveZip(fileName string) error {
 
 	z := zip.NewWriter(zipFile)
 
+	if c.Opts.ZipLevel >= 1 {
+		level := c.Opts.ZipLevel
+		z.RegisterCompressor(zip.Deflate, func(out io.Writer) (io.WriteCloser, error) {
+			return flate.NewWriter(out, level)
+		})
+	}
+
 	files, err := os.ReadDir(c.Workdir)
 	if err != nil {
 		return fmt.Errorf("archiveSaveZip: %w", err)
@@ -72,6 +80,9 @@ func (c *Converter) archiveSaveZip(fileName string) error {
 		}
 
 		zipInfo.Method = zip.Deflate
+		if c.Opts.ZipLevel == 0 {
+			zipInfo.Method = zip.Store
+		}
 		w, err := z.CreateHeader(zipInfo)
 		if err != nil {
 			return fmt.Errorf("archiveSaveZip: %w", err)

cbconvert_test.go

@@ -203,6 +203,58 @@ func TestConvertTar(t *testing.T) {
 	}
 }
 
+func TestZipLevel(t *testing.T) {
+	convertWith := func(level int) *zip.ReadCloser {
+		tmpDir, err := os.MkdirTemp(os.TempDir(), "cbc")
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(func() { os.RemoveAll(tmpDir) })
+
+		opts := NewOptions()
+		opts.OutDir = tmpDir
+		opts.ZipLevel = level
+		opts.NoConvert = true
+
+		conv := New(opts)
+
+		files, err := conv.Files([]string{"testdata/test.cbz"})
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, file := range files {
+			if err := conv.Convert(file); err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		zr, err := zip.OpenReader(filepath.Join(tmpDir, "test.cbz"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(func() { zr.Close() })
+
+		return zr
+	}
+
+	store := convertWith(0)
+	for _, f := range store.File {
+		if f.Method != zip.Store {
+			t.Errorf("level 0: %s stored with method %d, want Store", f.Name, f.Method)
+		}
+		if f.CompressedSize64 != f.UncompressedSize64 {
+			t.Errorf("level 0: %s is compressed (%d < %d)", f.Name, f.CompressedSize64, f.UncompressedSize64)
+		}
+	}
+
+	deflate := convertWith(9)
+	for _, f := range deflate.File {
+		if f.Method != zip.Deflate {
+			t.Errorf("level 9: %s method %d, want Deflate", f.Name, f.Method)
+		}
+	}
+}
+
 func TestImageTransforms(t *testing.T) {
 	conv := New(NewOptions())
 

cmd/cbconvert-gui/main.go

@@ -141,6 +141,7 @@ func options() cbconvert.Options {
 	opts.NoConvert = iup.GetHandle("NoConvert").GetAttribute("VALUE") == "ON"
 	opts.NoNonImage = iup.GetHandle("NoNonImage").GetAttribute("VALUE") == "ON"
 	opts.Archive = strings.ToLower(iup.GetHandle("Archive").GetAttribute("VALUESTRING"))
+	opts.ZipLevel = zipLevel(iup.GetHandle("ZipLevel").GetAttribute("VALUESTRING"))
 	opts.Format = strings.ToLower(iup.GetHandle("Format").GetAttribute("VALUESTRING"))
 	opts.Width = iup.GetHandle("Width").GetInt("VALUE")
 	opts.Height = iup.GetHandle("Height").GetInt("VALUE")
@@ -246,6 +247,29 @@ func setActive() {
 	} else {
 		iup.GetHandle("VboxOutFile").SetAttribute("ACTIVE", "NO")
 	}
+
+	if opts.Archive == "zip" {
+		iup.GetHandle("VboxZipLevel").SetAttribute("ACTIVE", "YES")
+	} else {
+		iup.GetHandle("VboxZipLevel").SetAttribute("ACTIVE", "NO")
+	}
+}
+
+// zipLevel maps the compression dropdown selection to Options.ZipLevel.
+func zipLevel(value string) int {
+	switch value {
+	case "Default":
+		return -1
+	case "Store (none)":
+		return 0
+	default:
+		level, err := strconv.Atoi(value)
+		if err != nil {
+			return -1
+		}
+
+		return level
+	}
 }
 
 func setEffort(format string) {
@@ -521,8 +545,32 @@ func tabs() iup.Ihandle {
 					"VALUE":    "1",
 					"1":        "ZIP",
 					"2":        "TAR",
-				}).SetHandle("Archive"),
+				}).SetHandle("Archive").
+					SetCallback("VALUECHANGED_CB", iup.ValueChangedFunc(func(ih iup.Ihandle) int {
+						setActive()
+
+						return iup.DEFAULT
+					})),
 			),
+			iup.Vbox(
+				iup.Label("Compression:"),
+				iup.List().SetAttributes(map[string]string{
+					"DROPDOWN": "YES",
+					"VALUE":    "1",
+					"1":        "Default",
+					"2":        "Store (none)",
+					"3":        "1",
+					"4":        "2",
+					"5":        "3",
+					"6":        "4",
+					"7":        "5",
+					"8":        "6",
+					"9":        "7",
+					"10":       "8",
+					"11":       "9",
+				}).SetHandle("ZipLevel").
+					SetAttribute("TIP", "ZIP compression: Store disables it, 1 is fastest, 9 is smallest"),
+			).SetHandle("VboxZipLevel"),
 		).SetAttributes("NGAP=10"),
 		iup.Space().SetAttribute("SIZE", "15"),
 		iup.Vbox(

cmd/cbconvert/main.go

@@ -177,6 +177,7 @@ func parseFlags() (cbconvert.Options, []string) {
 	convert.BoolVar(&opts.Fit, "fit", false, "Best fit for required width and height")
 	convert.StringVar(&opts.Format, "format", "jpeg", "Image format, valid values are jpeg, png, tiff, bmp, webp, avif, jxl")
 	convert.StringVar(&opts.Archive, "archive", "zip", "Archive format, valid values are zip, tar")
+	convert.IntVar(&opts.ZipLevel, "zip-level", -1, "ZIP compression level, 0 disables compression, 1-9 sets deflate level (1 fastest, 9 smallest), -1 uses the default")
 	convert.IntVar(&opts.Quality, "quality", 75, "Image quality")
 	convert.IntVar(&opts.Effort, "effort", -1, "Encoder speed/effort, format-specific (webp method 0-6, avif speed 0-10, jxl effort 1-10), -1 uses the format default")
 	convert.BoolVar(&opts.Lossless, "lossless", false, "Lossless compression (webp, avif, jxl), ignores quality")
@@ -235,7 +236,7 @@ func parseFlags() (cbconvert.Options, []string) {
 		fmt.Fprintf(os.Stderr, "Usage: %s <command> [<flags>] [file1 dir1 ... fileOrDirN]\n\n", filepath.Base(os.Args[0]))
 		fmt.Fprintf(os.Stderr, "\nCommands:\n")
 		fmt.Fprintf(os.Stderr, "\n  convert\n    \tConvert archive or document\n\n")
-		order := []string{"width", "height", "fit", "format", "archive", "quality", "effort", "lossless", "combine", "outfile", "filter", "no-cover", "no-rgb",
+		order := []string{"width", "height", "fit", "format", "archive", "zip-level", "quality", "effort", "lossless", "combine", "outfile", "filter", "no-cover", "no-rgb",
 			"no-nonimage", "no-convert", "grayscale", "rotate", "brightness", "contrast", "suffix", "outdir", "size", "recursive", "quiet"}
 		for _, name := range order {
 			f := convert.Lookup(name)