Basic 2d drawing primitives for the terminal

I found myself writing subsets of this code over and over for quick experiments. So I figured I'd put it in a package.

package main

import (
	"fmt"
	"log"
	"os"

	"github.com/icholy/draw"
)

func main() {
	cv := draw.NewCanvas(80, 40)

	// draw a point
	p := draw.Point{
		X: 10,
		Y: 10,
	}
	cv.Draw(p, '$')

	// draw a line
	l := draw.Line{
		A: cv.Bounds().TopRight(),
		B: draw.Point{
			X: 40,
			Y: 5,
		},
	}
	cv.Draw(l, '*')

	// add a border
	cv.Draw(cv.Bounds().Box(), 0)

	// draw text
	t := draw.Text{
		Origin: cv.Bounds().TopLeft().AddXY(20, 10),
		Text:   "You can draw\nmulti-line text",
	}
	cv.Draw(t, 0)

	// add border to text
	cv.Draw(draw.BoxAround(t), 0)

	// draw circle
	c := draw.Circle{
		Center: cv.Bounds().Center().AddXY(5, 5),
		Radius: 10,
	}
	cv.Draw(c, '%')

	if err := cv.WriteTo(os.Stdout); err != nil {
		log.Fatal(err)
	}
	fmt.Println()
}

|------------------------------------------------------------------------------|
|                                                                   ********   |
|                                                           ********           |
|                                                   ********                   |
|                                           ********                           |
|                                       ****                                   |
|                                                                              |
|                                                                              |
|                                                                              |
|                  |---------------|                                           |
|         $        |You can draw   |                                           |
|                  |multi-line text|                                           |
|                  |---------------|                                           |
|                                                                              |
|                                                                              |
|                                   %%%%%%%%%%%%%%%%%%                         |
|                                %%%%                %%%%                      |
|                             %%%                        %%%                   |
|                            %%                            %%                  |
|                          %%                                %%                |
|                         %%                                  %%               |
|                        %%                                    %%              |
|                        %                                      %              |
|                        %                                      %              |
|                        %                                      %              |
|                        %                                      %              |
|                        %                                      %              |
|                        %                                      %              |
|                        %%                                    %               |
|                         %%                                  %%               |
|                          %%                                %%                |
|                            %%                            %%                  |
|                             %%%                        %%%                   |
|                                %%%%                %%%%                      |
|                                   %%%%%%%%%%%%%%%%%%                         |
|                                                                              |
|                                                                              |
|                                                                              |
|                                                                              |
|------------------------------------------------------------------------------|