OnDoc/zz_winsign/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 zz_winsign
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void cmbPenWidth_SelectedIndexChanged(object sender, EventArgs e)
        {
            //sign1.PenWidth = Convert.ToInt32(cmbPenWidth.Text);
        }

        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            sign1.PenWidth = Convert.ToInt32(listBox1.Text);
        }

        private void colorUIControl1_ColorSelected(object sender, EventArgs e)
        {
            sign1.PenColor = colorUIControl1.SelectedColor;
        }

        private void listBox2_SelectedIndexChanged(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            saveFileDialog1.Filter = "JPG-Dateien | *.jpg";
            saveFileDialog1.DefaultExt = "jpg";
            if (saveFileDialog1.ShowDialog() == DialogResult.OK)
            {
                if (System.IO.File.Exists(saveFileDialog1.FileName)) { System.IO.File.Delete(saveFileDialog1.FileName); }
                Bitmap newSign = AdjustBrightness(sign1.SignatureBitmap, Convert.ToInt32(listBox2.Text));

                newSign.Save(saveFileDialog1.FileName, System.Drawing.Imaging.ImageFormat.Jpeg);

                //sign1.ClearSignature();

            }
        }

        public Bitmap AdjustBrightness(Bitmap inputB, int brightnessvalue)
        {
            Bitmap bmap = inputB;
            Color c;


            for (int i = 0; i < bmap.Width; i++)
            {
                for (int j = 0; j < bmap.Height; j++)
                {

                    c = bmap.GetPixel(i, j);

                    int cR = c.R + brightnessvalue;
                    int cG = c.G + brightnessvalue;
                    int cB = c.B + brightnessvalue;


                    if (cR < 0) cR = 1;
                    if (cR > 255) cR = 255;


                    if (cG < 0) cG = 1;
                    if (cG > 255) cG = 255;
                    if (cB < 0) cB = 1;
                    if (cB > 255) cB = 255;


                    bmap.SetPixel(i, j, Color.FromArgb(cR, cG, cB));
                }
            }

            return bmap;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            colorUIControl1.SelectedColor = Color.Black;
            listBox1.Text = "6";
            listBox2.Text = "100";
            sign1.PenColor=Color.Black;
            sign1.PenWidth = 4;
        }

        private void btnDeleteImage_Click(object sender, EventArgs e)
        {
            sign1.ClearSignature();
        }
    }
}