v1.2 版本内容

README.md

@@ -3,22 +3,21 @@
 批量图片等比缩放、类型转换工具  
 1. 支持图片类型：bmp、tiff、jpg、jpeg、gif、png、webp  
 1. 支持类型转换为：bmp、tiff、jpg、jpeg、gif、png  
-1. 支持自定义宽度、高度  
+1. 支持自定义宽度、高度
 1. 五种等比缩放模式
 
 ## 使用方法
 
 ```
 ImgResizer -source {source} -dest {dest} -mode {mode}
-
   -dest string
-        Destination file or directory
+        Destination file or directory.
   -format string
-        Ouput format (png|jpg|jpeg|bmp|tiff|gif)
+        Ouput format. Supported values: png|jpg|jpeg|bmp|tiff|gif. Omit to keep original format.
   -height int
-        Destination height (default 128)
+        Destination height. Omit to keep original height (default -1)
   -help
-        Show help message
+        Show help message.
   -mode int
         0 - (Default) Nearest-neighbor interpolation
         1 - Bilinear interpolation
@@ -27,25 +26,34 @@ ImgResizer -source {source} -dest {dest} -mode {mode}
         4 - Lanczos resampling with a=2
         5 - Lanczos resampling with a=3
   -source string
-        Source file or directory
+        Source file or directory.
   -width int
-        Destination width (default 300)
+        Destination width. Omit to keep original width (default -1)
 ```
 
-## 批量等比缩放处理
+## 注意事项
+
+1. **如果不需要改变原图类型，请省略 `-format` 参数**
+1. **webp 格式图片，默认转换为 png 格式处理(目前没有 webp 图片的高效、简洁处理办法)**
+1. **如果不需要改变原图尺寸，请同时省略 `-width` 和 `-height` 参数** 
+
+## 使用示例
+
+### 1. 批量等比缩放
 
 ```
-ImgResizer -source ~/Desktop/pics -dest ~/Desktop/new_pics -mode 5
+ImgResizer -source ~/pics -dest ~/new_pics -mode 5 -height 128 -width 300
 ```
 
-## 单个文件指定宽度缩放
+### 2. 单文件指定宽度
 
 ```
 ImgResizer -source ~/pics/hello.gif -dest ~/newpics/wow.gif -width 900
 ```
 
-## 批量文件类型转换
+### 3. 批量类型转换
+
 ```
-ImgResizer -source ~/Desktop/pics -dest ~/Desktop/new_pics -format jpg
+ImgResizer -source ~/pics -dest ~/new_pics -format jpg
 ```
 

core/file.go

@@ -39,7 +39,7 @@ func DealWithFile(source string, option OutputOptions) error {
 	}
 	defer file.Close()
 
-	fileFormat, err := guessImageType(file)
+	fileFormat, width, height, err := retrieveImageInfo(file)
 	if err != nil {
 		fmt.Printf("Could not guess mime type of file %s, %v", source, err)
 		return err
@@ -72,6 +72,14 @@ func DealWithFile(source string, option OutputOptions) error {
 		return err
 	}
 
+	if option.Width == -1 {
+		option.Width = width
+	}
+
+	if option.Height == -1 {
+		option.Height = height
+	}
+
 	afterResize := resize.Resize(uint(option.Width), uint(option.Height), data, option.Interpolation)
 
 	if strings.EqualFold("", string(option.Format)) {
@@ -101,11 +109,11 @@ func DealWithFile(source string, option OutputOptions) error {
 
 //
 //Guess image type
-func guessImageType(r io.Reader) (string, error) {
-	_, format, err := image.DecodeConfig(r)
+func retrieveImageInfo(r io.Reader) (string, int, int, error) {
+	config, format, err := image.DecodeConfig(r)
 	if err != nil {
-		return "", err
+		return "", -1, -1, err
 	}
 
-	return format, nil
+	return format, config.Width, config.Height, nil
 }

main.go

@@ -12,7 +12,7 @@ import (
 	"github.com/nfnt/resize"
 )
 
-const Version string = "v1.1"
+const Version string = "v1.2"
 
 var (
 	cmdSource     string
@@ -25,12 +25,12 @@ var (
 )
 
 func init() {
-	flag.StringVar(&cmdFormat, "format", "", "Ouput format (png|jpg|jpeg|bmp|tiff|gif)")
-	flag.BoolVar(&cmdHelp, "help", false, "Show help message")
-	flag.IntVar(&cmdWidth, "width", 300, "Destination width")
-	flag.IntVar(&cmdHeight, "height", 128, "Destination height")
-	flag.StringVar(&cmdSource, "source", "", "Source file or directory")
-	flag.StringVar(&cmdDest, "dest", "", "Destination file or directory")
+	flag.StringVar(&cmdFormat, "format", "", "Ouput format. Supported values: png|jpg|jpeg|bmp|tiff|gif. Omit to keep original format.")
+	flag.BoolVar(&cmdHelp, "help", false, "Show help message.")
+	flag.IntVar(&cmdWidth, "width", -1, "Destination width. Omit to keep original width")
+	flag.IntVar(&cmdHeight, "height", -1, "Destination height. Omit to keep original height")
+	flag.StringVar(&cmdSource, "source", "", "Source file or directory.")
+	flag.StringVar(&cmdDest, "dest", "", "Destination file or directory.")
 	flag.IntVar(&cmdResizeMode, "mode", 0, `0 - (Default) Nearest-neighbor interpolation
 1 - Bilinear interpolation
 2 - Bicubic interpolation
@@ -39,7 +39,7 @@ func init() {
 5 - Lanczos resampling with a=3`)
 
 	flag.Usage = func() {
-		fmt.Printf("Usage of ImgResizer %s \nImgResizer -source {source} -dest {dest} -mode {mode}\n\n", Version)
+		fmt.Printf("Usage of ImgResizer %s \nFor more information, please visit: \nhttps://github.com/barats/ImgResizer \nhttps://gitee.com/barat/imgresizer \n\nImgResizer -source {source} -dest {dest} -mode {mode}\n", Version)
 		flag.PrintDefaults()
 	}
 }
@@ -53,6 +53,11 @@ func main() {
 		return
 	}
 
+	if strings.EqualFold("", strings.TrimSpace(cmdSource)) || strings.EqualFold("", strings.TrimSpace(cmdDest)) {
+		fmt.Println("Missing parameter <-source> or <-dest>. Please -h or -help to show help message.")
+		return
+	}
+
 	sourceInfo, err := os.Stat(cmdSource)
 	if err != nil {
 		fmt.Printf("Cant not open %s, error %v", cmdSource, err)