golang font settings

Golang is a powerful programming language that is very feature-rich and suitable for various software development projects. In Golang, setting fonts is a very important task because it directly affects the display effect of the program in the user interface. This article will introduce you how to set fonts in Golang.

In Golang, there is a package called "golang.org/x/image/font", which provides a simple way to set the font. The specific steps are as follows:

一, Install font files

First, you need to download and install the font files you want to use. This can be done in various ways, such as downloading from free font libraries or purchasing from commercial font suppliers.

2. Introduction of font package

After installing the font file, you need to introduce the "golang.org/x/image/font" package into your Golang project. You can use the following command to download it in the command line:

go get golang.org/x/image/font

3. Use the font file

After introducing the font package , you need to load the font files into your Golang project. You can use the following code to load the font file into the program:

fontBytes, err := ioutil.ReadFile("path/to/your/font/file.ttf")
if err != nil {
    log.Fatalf("read font file: %v", err)
}
font, err := truetype.Parse(fontBytes)
if err != nil {
    log.Fatalf("parse font: %v", err)
}

You can replace the path to the font file with the path to the font file you are actually using.

4. Set the font

After loading the font, you need to use the font to set the font and size for the text. Here is an example:

const dpi = 72
fontFace := truetype.NewFace(font, &truetype.Options{
    Size:    12,
    DPI:     dpi,
    Hinting: font.HintingFull,
})

In the above code, we specify the font and font size by creating a truetype.NewFace object. "DPI" refers to "PPI" or "pixels per inch," which is the number of dots you see on your monitor. In this case, we set it to 72, which is the default PPI value.

In addition to the font size, you can also set the font type, such as bold, italic, etc. You can use the following code:

fontFaceBold := truetype.NewFace(font, &truetype.Options{
    Size:    12,
    DPI:     dpi,
    Hinting: font.HintingFull,
    Weight:  truetype.Bold,
})

In the above code, we specify that the font is bold by setting "Weight" to truetype.Bold.

5. Using Fonts

After setting and loading the font, you can use it to set the font for your output. Here is an example:

import (
    "image"
    "image/color"
    "image/png"
    "os"

    "golang.org/x/image/font"
    "golang.org/x/image/font/basicfont"
    "golang.org/x/image/font/gofont/gomonobold"
    "golang.org/x/image/math/fixed"
)

func main() {
    img := image.NewRGBA(image.Rect(0, 0, 400, 200))
    col := color.RGBA{0xff, 0xff, 0xff, 0xff}
    drawString(img, "Hello, Golang!", 100, 100, fontFace, col)
    drawString(img, "Hello, Golang Bold!", 100, 150, fontFaceBold, col)

    f, err := os.Create("output.png")
    if err != nil {
        log.Fatalf("create output file: %v", err)
    }
    png.Encode(f, img)
    if err := f.Close(); err != nil {
        log.Fatalf("close file: %v", err)
    }
}

func drawString(img *image.RGBA, str string, x, y int, face font.Face, col color.Color) {
    d := &font.Drawer{
        Dst:  img,
        Src:  image.NewUniform(col),
        Face: face,
    }
    d.Dot = fixed.Point26_6{
        X: fixed.Int26_6(x * 64),
        Y: fixed.Int26_6(y * 64),
    }
    d.DrawString(str)
}

In the above code snippet, we created a custom function called "drawString" to write a string to the image. In this function, we take as function parameters the image itself, the string to be written, the string position, and the font type and color to use. We then use "font.Drawer" to write the string to the image.

The final output image will contain the output of Hello, Golang! and Hello, Golang Bold! in the set font.

Summary

In this article, we introduced a simple way to set fonts in Golang. Using the "golang.org/x/image/font" package provided by Golang, you can easily set the font as well as the font size and type. Hope this article helps you better understand how to set fonts in Golang.

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