Issue drawing graphics to Bitmap in c#

Question

I am trying to make a paint program. I have got the basic's working as well as a way to record all mouse clicks so that I can draw them to a bitmap and then save it except it doesn't work, using this method I can redraw the graphics except when I try to save the file the bitmap image is blank?

Heres my code:

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;
using System.Drawing.Imaging;
namespace Paint_Program
{
    public partial class PaintImg : Form
    {

    public Boolean veryimportantbool = false;
    int drawcount = 0;
    int brushsize = 16;

    List<Point> pts = new List<Point>();
    Point recordpoint { get; set; }

    public PaintImg()
    {
        InitializeComponent();
        //Cursor drawCursor = new Cursor("Pencil.cur");
        //this.Cursor = drawCursor;


    }


    private void Form1_Load(object sender, EventArgs e)
    {


        //Cursor.Position = new Point(this.Location.X - this.Width / 2, this.Location.Y - this.Height / 2)
        UserControl1 userc1 = new UserControl1();
        userc1.Show();
        brushsize = Convert.ToInt16(label1.Text);


    }

    private void rectangleShape1_Click(object sender, EventArgs e)
    {

    }

    private void Test_Click(object sender, EventArgs e)
    {
        //testing 
        //Console.WriteLine("X:" + mousex);
        //onsole.WriteLine("Y: " + mousey);
    }

    private void Form1_SizeChanged(object sender, EventArgs e)
    {

    }


    public void Form1_MouseClick(object sender, MouseEventArgs i)
    {

            drawcount = drawcount + 1;
            System.Drawing.SolidBrush myBrush = new System.Drawing.SolidBrush(System.Drawing.Color.Red);
            System.Drawing.Graphics formGraphics;
            formGraphics = this.CreateGraphics();
            formGraphics.FillRectangle(myBrush, new Rectangle(i.X, i.Y, brushsize, brushsize));
            myBrush.Dispose();
            formGraphics.Dispose();
            count.Text = Convert.ToString(drawcount);


    }

    private void Paint_Paint(object sender, PaintEventArgs e)
    {
        //this method will be used later when page resizing is added to the program.

        //Graphics g = e.Graphics;
        //Control control = (Control)sender;
        //drawPoint = control.PointToScreen(new Point(MousePosition.X, MousePosition.Y));
        //g.DrawRectangle(System.Drawing.Pens.Red, drawPoint.X, drawPoint.Y, 1, 1);

    }

    private void newToolStripButton_Click(object sender, EventArgs e)
    {
        //SetupDoc newsetup = new SetupDoc();
        //newsetup.ShowDialog();
    }

    private void PaintImg_MouseMove(object sender, MouseEventArgs e)
    {

    }

    private void panel1_Paint(object sender, PaintEventArgs e)
    {

    }

    private void panel1_Click(object sender, MouseEventArgs i)
    {
        drawcount = drawcount + 1;
        recordpoint = new Point(i.X, i.Y);
        pts.Add(recordpoint);
        System.Drawing.SolidBrush myBrush = new System.Drawing.SolidBrush(System.Drawing.Color.Red);
        System.Drawing.Graphics formGraphics;
        formGraphics = this.CreateGraphics();
        formGraphics.FillRectangle(myBrush, new Rectangle(i.X, i.Y, brushsize, brushsize));
        myBrush.Dispose();
        formGraphics.Dispose();
        count.Text = Convert.ToString(drawcount);
    }

    private void label1_Click(object sender, EventArgs e)
    {

    }

    private void button1_Click(object sender, EventArgs e)
    {
        brushsize = brushsize + 1;
        label1.Text = Convert.ToString(brushsize);
    }

    private void button2_Click(object sender, EventArgs e)
    {
        brushsize = brushsize - 1;
        label1.Text = Convert.ToString(brushsize);
    }

    private void button3_Click(object sender, EventArgs e)
    {
        Image bmp = new Bitmap(this.Width - panel1.Width, this.Height - panel1.Height);
        using (Graphics g = Graphics.FromImage(bmp))
        {
            foreach (var recordpoint in pts)
            {

                g.FillRectangle(new SolidBrush(Color.Red), new Rectangle(Convert.ToInt16(recordpoint.X), Convert.ToInt16(recordpoint.Y), brushsize, brushsize));
            }
        }
        bmp.Save("testing.bmp");
    }

}
}

If anyone knows what I am doing wrong please tell mee!!!

Answer 1

panel1_Click records the coordinates in your pts collection, but the Form1_MouseClick event does not do this. Both methods do draw the points, though.

Are you sure you are adding to the pts collection where you are expecting?

Answer 2

检查位图大小

this.Width - panel1.Width,this.Height - panel1.Height