A simple, lightweight Pixel Font (aka bitmap fonts) package for Go that works with the standard image/draw package. If you want scaling, anti-aliasing, TrueType fonts, or other "fancy" features then I suggest you check out https://github.com/golang/freetype

However, if you just want to put a little bit of text in your generated image and don't care about aliasing, or if you can't afford run-time font dependencies or additional overhead, or you need something that "just works"... Well then pixfont has exactly what you want.

pixfont comes ready-to-go with a public domain 8x8 pixel fixed-width font from the bygone era of PCs (created by Marcel Sondaar / IBM).

Basic, just-put-some-text-in-my-image usage is straightforward:

package main

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

        "github.com/pbnjay/pixfont"
)

func main() {
        img := image.NewRGBA(image.Rect(0, 0, 150, 30))

        pixfont.DrawString(img, 10, 10, "Hello, World!", color.Black)

        f, _ := os.OpenFile("hello.png", os.O_CREATE|os.O_RDWR, 0644)
        png.Encode(f, img)
}

Resulting Image:

The default font isn't what you're looking for? Here's how to create your own pixel font for use with this package.

Step one: Create a .png image of all the characters you want to include in a single row. For example, say we want to use the great font Minecraftia by Andrew Tyler. Here's a copy of the preview image provided with the download.

Step two: Find the start offset and list of characters in order. In the image above, we have a start offset of 1,20 and characters A-Z a-z 0-9. Many more are available in the real font, which could be extracted as well with a more complete image.

Step three: If you're lucky, just run fontgen on the image to create your font:

$ ./fontgen -x=1 -y=20 -h=8 -a="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" -img minecraftia.png -o minecraftia

In the minecraftia example however, we need to do a minor edit before we can generate the pixfont code, so we follow the alternate path:

Step three: Run fontgen on the image and create an intermedia text representation:

$ ./fontgen -x=1 -y=20 -h=8 -a="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" -img minecraftia.png > minecraftia.txt

Step four: Review the text version to be sure that all characters matched up correctly. The first character on each line is the letter being mapped, and either a space or an 'X' occurs between the square brackets to denote the pixels.

In Minecraftia, the tail of the lowercase L touches the lowercase M, causing the automatic extracter to merge the characters:

		l  [X      ]
		l  [X      ]
		l  [X XX X ]
		l  [X X X X]
		l  [X X X X]
		l  [X X   X]
		l  [ XX   X]
		l  [       ]
		m  [       ]
		m  [       ]
		m  [ XXXX  ]
		m  [ X   X ]
		m  [ X   X ]
		m  [ X   X ]
		m  [ X   X ]
		m  [       ]

The easiest way to handle this without making a new image is to remove an l or m from the -a alphabet parameter, and edit the intermediate text file to separate the letters:

$ ./fontgen -x=1 -y=20 -h=8 -a="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklnopqrstuvwxyz0123456789" -img minecraftia.png > minecraftia.txt
$ vim minecraftia.txt

Step five: Generate the output file using the intermediate text file:

$ ./fontgen -txt minecraftia.txt -o minecraftia

Now just import the font into your code. For example, to use Minecraftia in the Hello World example above:

// file main.go

package main

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

        "main/minecraftia"
)

func main() {
        img := image.NewRGBA(image.Rect(0, 0, 150, 30))

        minecraftia.Font.DrawString(img, 10, 10, "Hello, World!", color.Black)

        f, _ := os.OpenFile("hello.png", os.O_CREATE|os.O_RDWR, 0644)
        png.Encode(f, img)
}

Resulting Image: -- Note the missing , and ! since they were not included in the extracted character set. I'll leave inclusion of those as an excercise for the reader.

To create a variable width font (i.e. an i is skinnier than a w), just add -v to all invocations of fontgen. When you need to make edits to the font, just ensure that characters are flush with the left edge for best display.

Here's the minecraftia result image with a variable width:

Code for this package is release under the MIT License. The bundled 8x8 font was released into the public domain by Marcel Sondaar / IBM.