pixclient/pixclient.go

package pixclient

import (
	"bufio"
	"errors"
	"net"
	"strconv"
	"strings"
)

type Client struct {
	connection net.Conn
	width      int
	height     int
}

func Init(addr net.IP, port int) *Client {
	var client Client
	connection, err := net.Dial("tcp", addr.String()+":"+strconv.Itoa(port))
	check(err)
	client.connection = connection
	client.Size()
	return &client
}

func (Client *Client) WritePixel(x, y int, r, g, b, a byte) error {
	var bytes []byte
	if x <= 0 || y <= 0 || x >= Client.width || y >= Client.height {
		return errors.New("Pixel out of range.")
	}
	bytes = append(appendTwoDigitHex(appendTwoDigitHex(appendTwoDigitHex(appendTwoDigitHex(append(append(append(append(append(
		bytes, []byte("PX ")...),
		[]byte(strconv.FormatInt(int64(x), 10))...),
		[]byte(" ")...),
		[]byte(strconv.FormatInt(int64(y), 10))...),
		[]byte(" ")...),
		r),
		g),
		b),
		a),
		[]byte("\n")...)
	Client.connection.Write(bytes)

	//
	//Client.connection.Write([]byte(
	//	fmt.Sprintf("PX %d %d %X\n", x, y, []byte{r, g, b, a})))
	return nil
}

func (Client *Client) Size() (int, int) {
	Client.connection.Write([]byte("SIZE\n"))
	reader := bufio.NewReader(Client.connection)
	size, err := reader.ReadBytes('\n')
	check(err)
	sizeString := string(size)
	sizeArray := strings.Split(sizeString, " ")
	Client.width, _ = strconv.Atoi(sizeArray[1])
	Client.height, _ = strconv.Atoi(sizeArray[2])
	return Client.width, Client.height
}

func appendTwoDigitHex(bytes []byte, val byte) []byte {
	if val < 0x10 {
		bytes = append(bytes, []byte("0")...)
	}
	return strconv.AppendInt(bytes, int64(val), 16)
}

func check(e error) {
	if e != nil {
		panic(e)
	}
}