Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace imgMessCons
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        String pathTxtWrite = string.Empty,
               pathImgWrite = string.Empty,
               pathTxtRead = string.Empty,
               pathImgRead = string.Empty;

        ImgProc bmpWrite,
                bmpRead;

        int step;

        private void Form1_Load(object sender, EventArgs e)
        {
            labelSeparation1.AutoSize = false;
            labelSeparation1.Height = 4;
            labelSeparation1.BorderStyle = BorderStyle.Fixed3D;

            labelSepatation2.AutoSize = false;
            labelSepatation2.Height = 4;
            labelSepatation2.BorderStyle = BorderStyle.Fixed3D;

            numericUpDownWriteStep.Minimum = 1;
            numericUpDownWriteStep.Maximum = 255;

            labelWriteTxtPathState.Text = "Empty";
            labelWriteImgPathState.Text = "Empty";
            labelWriteState.Text = "Lock";
            labelWriteBusyReady.Text = "Ready";
            buttonWriteMess.Enabled = false;

            labelReadTxtPathState.Text = "Empty";
            labelReadImgPathState.Text = "Empty";
            labelReadState.Text = "Lock";
            labelReadBuseReady.Text = "Ready";
            buttonReadMess.Enabled = false;
        }

        private void buttonTextPath_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.Filter = "Message original (TXT)|*.txt";
            if(ofd.ShowDialog() == DialogResult.OK)
            {
                pathTxtWrite = ofd.FileName;
                textBoxWriteTxtPath.Text = pathTxtWrite;
            }

            CheckWriteMessageState();
        }

        private void CheckWriteMessageState()
        {
            labelWriteState.Text = "Lock";
            buttonWriteMess.Enabled = false;
            if((textBoxWriteTxtPath.Text.Length > 0) && (textBoxWriteImgPath.Text.Length > 0))
            {
                labelWriteState.Text = "Unlock";
                buttonWriteMess.Enabled = true;
            }
        }

        private void buttonClose_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void buttonWriteImgPath_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.Filter = "Image for message (PNG)|*png";

            if(ofd.ShowDialog() == DialogResult.OK)
            {
                pathImgWrite = ofd.FileName;
                textBoxWriteImgPath.Text = pathImgWrite;
            }
            CheckWriteMessageState();
        }

        private void buttonReadTxtPath_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.Filter = "Message from image (TXT)|*txt";
            if(ofd.ShowDialog() == DialogResult.OK)
            {
                pathTxtRead = ofd.FileName;
                textBoxReadTxtPath.Text = pathTxtRead;
            }

            CheckReadMessageState();
        }

        private void CheckReadMessageState()
        {
            labelReadState.Text = "Lock";
            buttonReadMess.Enabled = false;

            if((textBoxReadTxtPath.Text.Length > 0) && (textBoxReadImgPath.Text.Length > 0))
            {
                labelReadState.Text = "Unlock";
                buttonReadMess.Enabled = true;
            }
        }

        private void buttonReadImgPath_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.Filter = "Image with message (PNG)|*png";
            if(ofd.ShowDialog() == DialogResult.OK)
            {
                pathImgRead = ofd.FileName;
                textBoxReadImgPath.Text = pathImgRead;
            }

            CheckReadMessageState();

        }

        private void buttonWriteMess_Click(object sender, EventArgs e)
        {
            labelWriteBusyReady.Text = "Busy";

            step = (int)numericUpDownWriteStep.Value;
            bmpWrite = new ImgProc(pathImgWrite);
            bmpWrite.WriteMessage(pathTxtWrite, step);
            bmpWrite.SaveImg(pathImgWrite);

            bmpWrite = null;

            pathTxtWrite = string.Empty;
            pathImgWrite = string.Empty;

            textBoxWriteTxtPath.Text = string.Empty;
            textBoxWriteImgPath.Text = string.Empty;

            CheckWriteMessageState();

            labelWriteBusyReady.Text = "Ready";


        }

        private void buttonReadMess_Click(object sender, EventArgs e)
        {
            labelReadBuseReady.Text = "Busy";

            bmpRead = new ImgProc(pathImgRead);

            bmpRead.ReadMessage(pathTxtRead);

            bmpRead = null;

            pathTxtRead = string.Empty;
            pathImgRead = string.Empty;

            textBoxReadTxtPath.Text = string.Empty;
            textBoxReadImgPath.Text = string.Empty;

            CheckReadMessageState();

            labelReadBuseReady.Text = "Ready";

        }


    }
}