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侃侃无极
下面的程序采用一个输入文件名和一个输出文件名。它将打开输入文件，对其进行解码，将其转换为灰度，然后将其编码为输出文件。该程序并非特定于PNG，但是要支持其他文件格式，您必须导入正确的图像包。例如，要添加JPEG支持，可以将其添加到导入列表_ "image/jpeg"。如果你只是想支持PNG，那么你可以使用图像/ png.Decode，而不是直接image.Decode。package mainimport ( "image" "image/png" // register the PNG format with the image package "os")func main() { infile, err := os.Open(os.Args[1]) if err != nil { // replace this with real error handling panic(err.String()) } defer infile.Close() // Decode will figure out what type of image is in the file on its own. // We just have to be sure all the image packages we want are imported. src, _, err := image.Decode(infile) if err != nil { // replace this with real error handling panic(err.String()) } // Create a new grayscale image bounds := src.Bounds() w, h := bounds.Max.X, bounds.Max.Y gray := image.NewGray(w, h) for x := 0; x < w; x++ { for y := 0; y < h; y++ { oldColor := src.At(x, y) grayColor := image.GrayColorModel.Convert(oldColor) gray.Set(x, y, grayColor) } } // Encode the grayscale image to the output file outfile, err := os.Create(os.Args[2]) if err != nil { // replace this with real error handling panic(err.String()) } defer outfile.Close() png.Encode(outfile, gray)}
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慕婉清6462132
我自己遇到了这个问题，并提出了一个略有不同的解决方案。我介绍了一种新类型Converted，它实现了image.Image。Converted由原始图片和组成color.Model。Converted 每次访问都会进行转换，这可能会导致性能稍差，但另一方面，它却很酷而且很容易组合。package mainimport ( "image" _ "image/jpeg" // Register JPEG format "image/png" // Register PNG format "image/color" "log" "os")// Converted implements image.Image, so you can// pretend that it is the converted image.type Converted struct { Img image.Image Mod color.Model}// We return the new color model...func (c *Converted) ColorModel() color.Model{ return c.Mod}// ... but the original boundsfunc (c *Converted) Bounds() image.Rectangle{ return c.Img.Bounds()}// At forwards the call to the original image and// then asks the color model to convert it.func (c *Converted) At(x, y int) color.Color{ return c.Mod.Convert(c.Img.At(x,y))}func main() { if len(os.Args) != 3 { log.Fatalln("Needs two arguments")} infile, err := os.Open(os.Args[1]) if err != nil { log.Fatalln(err) } defer infile.Close() img, _, err := image.Decode(infile) if err != nil { log.Fatalln(err) } // Since Converted implements image, this is now a grayscale image gr := &Converted{img, color.GrayModel} // Or do something like this to convert it into a black and // white image. // bw := []color.Color{color.Black,color.White} // gr := &Converted{img, color.Palette(bw)} outfile, err := os.Create(os.Args[2]) if err != nil { log.Fatalln(err) } defer outfile.Close() png.Encode(outfile,gr)}
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拉丁的传说
我如下进行调整。可悲的是，它确实输出了灰度图像，但是内容杂乱无章，目前我不知道为什么。我在这里提供它供您参考。 package main import ( "image" "image/color" "image/png" "math" "os" ) func main() { filename := "dir/to/myfile/somefile.png" infile, err := os.Open(filename) if err != nil { // replace this with real error handling panic(err.Error()) } defer infile.Close() // Decode will figure out what type of image is in the file on its own. // We just have to be sure all the image packages we want are imported. src, _, err := image.Decode(infile) if err != nil { // replace this with real error handling panic(err.Error()) } // Create a new grayscale image bounds := src.Bounds() w, h := bounds.Max.X, bounds.Max.Y gray := image.NewGray(image.Rectangle{image.Point{0, 0}, image.Point{w, h}}) for x := 0; x < w; x++ { for y := 0; y < h; y++ { oldColor := src.At(x, y) r, g, b, _ := oldColor.RGBA() avg := 0.2125*float64(r) + 0.7154*float64(g) + 0.0721*float64(b) grayColor := color.Gray{uint8(math.Ceil(avg))} gray.Set(x, y, grayColor) } } // Encode the grayscale image to the output file outfilename := "result.png" outfile, err := os.Create(outfilename) if err != nil { // replace this with real error handling panic(err.Error()) } defer outfile.Close() png.Encode(outfile, gray) }顺便说一句，golang无法自动解码图像文件，我们需要直接使用图像类型的Decode方法。