dsdeeaquu38538545 2015-03-11 16:40 采纳率: 100%
浏览 544


I want to draw a mailing label with some rectangles, barcodes, and then finally generate a PNG/PDF file.

Is there is a better way to draw a shape in Go other than to do it with primitives - pixel by pixel?

  • 写回答

4条回答 默认 最新

  • doudai3012 2015-03-12 07:37

    The standard Go library does not provide primitive drawing or painting capabilities.

    What it provides is models for colors (image/color package) and an Image interface with several implementations (image package). The blog post The Go Image package is a good introduction to this.

    It also provides a capability to combine images (e.g. draw them on each other) with different operations in the image/draw package. This can be used to a lot more than it sounds at first. There is a nice blog article about the image/draw package which showcases some of its potential: The Go image/draw package

    Another example is the open-source game Gopher's Labyrinth (disclosure: I'm the author) which has a graphical interface and it uses nothing else just the standard Go library to assemble its view.

    Gopher's Labyrinth Screenshot

    It's open source, check out its sources how it is done. It has a scrollable game view with moving images/animations in it.

    The standard library also supports reading and writing common image formats like GIF, JPEG, PNG, and support for other formats are available out of the box: BMP, RIFF, TIFF and even WEBP (only a reader/decoder).

    Although support is not given by the standard library, it is fairly easy to draw lines and rectangles on an image. Given an img image which supports changing a pixel with a method: Set(x, y int, c color.Color) (for example image.RGBA is perfect for us) and a col of type color.Color:

    // HLine draws a horizontal line
    func HLine(x1, y, x2 int) {
        for ; x1 <= x2; x1++ {
            img.Set(x1, y, col)
    // VLine draws a veritcal line
    func VLine(x, y1, y2 int) {
        for ; y1 <= y2; y1++ {
            img.Set(x, y1, col)
    // Rect draws a rectangle utilizing HLine() and VLine()
    func Rect(x1, y1, x2, y2 int) {
        HLine(x1, y1, x2)
        HLine(x1, y2, x2)
        VLine(x1, y1, y2)
        VLine(x2, y1, y2)

    Using these simple functions here is a runnable example program which draws a line and a rectangle and saves the image into a .png file:

    import (
    var img = image.NewRGBA(image.Rect(0, 0, 100, 100))
    var col color.Color
    func main() {
        col = color.RGBA{255, 0, 0, 255} // Red
        HLine(10, 20, 80)
        col = color.RGBA{0, 255, 0, 255} // Green
        Rect(10, 10, 80, 50)
        f, err := os.Create("draw.png")
        if err != nil {
        defer f.Close()
        png.Encode(f, img)

    If you want to draw texts, you can use the Go implementation of FreeType. Also check out this question for a simple introduction to drawing strings on images: How to add a simple text label to an image in Go?

    If you want advanced and more complex drawing capabilities, there are also many external libraries available, for example:



    本回答被题主选为最佳回答 , 对您是否有帮助呢?



  • ¥15 咨询一下有关于王者荣耀赢藏战绩
  • ¥100 求购一套带接口实现实习自动签到打卡
  • ¥50 MacOS 使用虚拟机安装k8s
  • ¥500 亚马逊 COOKIE我如何才能实现 登录一个亚马逊账户 下发新 COOKIE ..我使用下发新COOKIE 导入ADS 指纹浏览器登录,我把账户密码 修改过后,原来下发新COOKIE 不会失效的方式
  • ¥20 玩游戏gpu和cpu利用率特别低,玩游戏卡顿
  • ¥25 oracle中的正则匹配
  • ¥15 关于#vscode#的问题:把软件卸载不会再出现蓝屏
  • ¥15 vimplus出现的错误
  • ¥15 usb无线网卡转typec口
  • ¥30 怎么使用AVL fire ESE软件自带的优化模式来优化设计Soot和NOx?