support thumbnails in file managers

README.md

@@ -8,6 +8,8 @@ CBconvert is a [Comic Book](http://en.wikipedia.org/wiki/Comic_Book_Archive_file
 
 It can convert one comic at a time or bulk convert comics to different formats to fit your various devices.
 
+![screenshot](http://cbconvert.com/screenshot.png)
+
 Features
 --------
 
@@ -28,6 +30,21 @@ Download
  - [Linux 64bit GUI](https://github.com/gen2brain/cbconvert/releases/download/0.5.0/cbconvert-0.5.tar.gz)
  - [Linux 64bit CMD](https://github.com/gen2brain/cbconvert/releases/download/0.5.0/cbconvert-cmd-0.5.tar.gz)
 
+Using cbconvert in file managers to generate freedesktop thumbnails
+-------------------------------------------------------------------
+
+Just copy cbconvert cmd binary to your PATH and create file ~/.local/share/thumbnailers/cbconvert.thumbnailer :
+    
+    [Thumbnailer Entry]
+    TryExec=cbconvert
+    Exec=cbconvert thumbnail --quiet --width %s --outfile %o %i
+    MimeType=application/pdf;application/x-pdf;image/pdf;application/x-cbz;application/x-cbr;application/x-cb7;application/x-cbt;application/oxps;application/vnd.ms-xpsdocument;application/epub+zip;
+
+This is how it looks like in PCManFM file manager:
+
+![thumbnails](http://cbconvert.com/thumbnails.png)
+
+
 Using command line app
 ----------------------
 

cbconvert.go

@@ -91,6 +91,7 @@ type Options struct {
 	Suffix       string  // add suffix to file basename
 	Cover        bool    // extract cover
 	Thumbnail    bool    // extract cover thumbnail (freedesktop spec.)
+	Outfile      string  // output file
 	Outdir       string  // output directory
 	Grayscale    bool    // convert images to grayscale (monochromatic)
 	Rotate       int     // Rotate images, valid values are 0, 90, 180, 270
@@ -998,8 +999,17 @@ func (c *Convertor) ExtractThumbnail(file string, info os.FileInfo) {
 		fmt.Fprintf(os.Stderr, "Error ReadImageBlob: %v\n", err.Error())
 	}
 
-	fileuri := "file://" + file
-	filename := filepath.Join(c.Opts.Outdir, fmt.Sprintf("%x.png", md5.Sum([]byte(fileuri))))
+	var fileuri string
+	var filename string
+
+	if c.Opts.Outfile == "" {
+		fileuri = "file://" + file
+		filename = filepath.Join(c.Opts.Outdir, fmt.Sprintf("%x.png", md5.Sum([]byte(fileuri))))
+	} else {
+		abs, _ := filepath.Abs(c.Opts.Outfile)
+		fileuri = "file://" + abs
+		filename = abs
+	}
 
 	mw.SetImageFormat("PNG")
 	mw.SetImageProperty("Software", "CBconvert")

cmd/main.go

@@ -77,6 +77,7 @@ func parseFlags() (cbconvert.Options, []string) {
 
 	thumbnail := kingpin.Command("thumbnail", "Extract cover thumbnail (freedesktop spec.)")
 	thumbnail.Arg("args", "filename or directory").Required().ExistingFilesOrDirsVar(&args)
+	thumbnail.Flag("outfile", "Output file").Default("").StringVar(&opts.Outfile)
 	thumbnail.Flag("width", "Image width").Default(strconv.Itoa(0)).IntVar(&opts.Width)
 	thumbnail.Flag("height", "Image height").Default(strconv.Itoa(0)).IntVar(&opts.Height)
 	thumbnail.Flag("fit", "Best fit for required width and height").BoolVar(&opts.Fit)

cmd/versioninfo.json

@@ -3,13 +3,13 @@
 	{
 		"FileVersion": {
 			"Major": 0,
-			"Minor": 5,
+			"Minor": 6,
 			"Patch": 0,
 			"Build": 0
 		},
 		"ProductVersion": {
 			"Major": 0,
-			"Minor": 5,
+			"Minor": 6,
 			"Patch": 0,
 			"Build": 0
 		},
@@ -24,14 +24,14 @@
 		"Comments": "Comic Book converter",
 		"CompanyName": "",
 		"FileDescription": "CBconvert CLI",
-		"FileVersion": "0.5.0",
+		"FileVersion": "0.6.0",
 		"InternalName": "",
 		"LegalCopyright": "",
 		"LegalTrademarks": "",
 		"OriginalFilename": "cbconvert.exe",
 		"PrivateBuild": "",
 		"ProductName": "CBconvert",
-		"ProductVersion": "0.5.0",
+		"ProductVersion": "0.6.0",
 		"SpecialBuild": ""
 	},
 	"VarFileInfo":

gui/main.go

@@ -257,6 +257,7 @@ func (c *Comics) SetEnabled(b bool) {
 	c.Root.ObjectByName("checkBoxNoRGB").Set("enabled", b)
 	c.Root.ObjectByName("checkBoxConvertCover").Set("enabled", b)
 	c.Root.ObjectByName("spinboxSize").Set("enabled", b)
+	c.Root.ObjectByName("buttonLevels").Set("enabled", b)
 	c.Root.ObjectByName("sliderBrightness").Set("enabled", b)
 	c.Root.ObjectByName("sliderContrast").Set("enabled", b)
 	c.Root.ObjectByName("checkBoxGrayscale").Set("enabled", b)

gui/versioninfo.json

@@ -3,13 +3,13 @@
 	{
 		"FileVersion": {
 			"Major": 0,
-			"Minor": 5,
+			"Minor": 6,
 			"Patch": 0,
 			"Build": 0
 		},
 		"ProductVersion": {
 			"Major": 0,
-			"Minor": 5,
+			"Minor": 6,
 			"Patch": 0,
 			"Build": 0
 		},
@@ -24,14 +24,14 @@
 		"Comments": "Comic Book converter",
 		"CompanyName": "",
 		"FileDescription": "CBconvert GUI",
-		"FileVersion": "0.5.0",
+		"FileVersion": "0.6.0",
 		"InternalName": "",
 		"LegalCopyright": "",
 		"LegalTrademarks": "",
 		"OriginalFilename": "cbconvert.exe",
 		"PrivateBuild": "",
 		"ProductName": "CBconvert",
-		"ProductVersion": "0.5.0",
+		"ProductVersion": "0.6.0",
 		"SpecialBuild": ""
 	},
 	"VarFileInfo":