How can I make the effect to be shown only when moving the mouse?

Question

I have downloaded the source code files from here of a magnifier glass effect:

http://www.codeproject.com/Articles/18235/Simple-Magnifier

And this is the main Form code:

///----------------------------------------------------------------------------
/// Class     : MagnifierMainForm
/// Purpose   : Provide simple magnifier. 
/// Written by: Ogun TIGLI
/// History   : 31 May 2006/Wed starting date.
///             22 Dec 2006/Fri minor code fixes and hotsot support addition.
///             01 Apr 2007/Sun XML serialization support added.
///             
/// Notes: 
/// This software is provided 'as-is', without any express or implied 
/// warranty. In no event will the author be held liable for any damages 
/// arising from the use of this software.
/// 
/// Permission is granted to anyone to use this software for any purpose, 
/// including commercial applications, and to alter it and redistribute it 
/// freely, subject to the following restrictions:
///     1. The origin of this software must not be misrepresented; 
///        you must not claim that you wrote the original software. 
///        If you use this software in a product, an acknowledgment 
///        in the product documentation would be appreciated. 
///     2. Altered source versions must be plainly marked as such, and 
///        must not be misrepresented as being the original software.
///     3. This notice cannot be removed, changed or altered from any source 
///        code distribution.
/// 
///        (c) 2006-2007 Ogun TIGLI. All rights reserved. 
///----------------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace Magnifier20070401
{
    public partial class MagnifierMainForm : Form
    {
        public MagnifierMainForm()
        {
            InitializeComponent();

            GetConfiguration();

            //--- My Init ---
            FormBorderStyle = FormBorderStyle.None;
            TopMost = true;
            StartPosition = FormStartPosition.CenterScreen;

            mImageMagnifierMainControlPanel = Properties.Resources.magControlPanel;

            if (mImageMagnifierMainControlPanel == null)
                throw new Exception("Resource cannot be found!");

            Width = mImageMagnifierMainControlPanel.Width;
            Height = mImageMagnifierMainControlPanel.Height;

            HotSpot hsConfiguration = new HotSpot(new Rectangle(50, 15, 35, 30));
            hsConfiguration.OnMouseDown += new HotSpot.MouseEventDelegate(hsConfiguration_OnMouseDown);
            hsConfiguration.OnMouseUp += new HotSpot.MouseEventDelegate(hsConfiguration_OnMouseUp);
            hsConfiguration.OnMouseMove += new HotSpot.MouseEventDelegate(hsConfiguration_OnMouseMove);

            HotSpot hsMagnfier = new HotSpot(new Rectangle(10, 15, 30, 30));
            hsMagnfier.OnMouseMove += new HotSpot.MouseEventDelegate(hsMagnfier_OnMouseMove);
            hsMagnfier.OnMouseDown += new HotSpot.MouseEventDelegate(hsMagnfier_OnMouseDown);
            hsMagnfier.OnMouseUp += new HotSpot.MouseEventDelegate(hsMagnfier_OnMouseUp);

            HotSpot hsExit = new HotSpot(new Rectangle(95, 20, 15, 15));
            hsExit.OnMouseUp += new HotSpot.MouseEventDelegate(hsExit_OnMouseUp);

            mHotSpots.Add(hsConfiguration);
            mHotSpots.Add(hsMagnfier);
            mHotSpots.Add(hsExit);

            ShowInTaskbar = false;
        }

        protected override void OnShown(EventArgs e)
        {
            base.OnShown(e);

            if (mConfiguration.LocationX != -1 && mConfiguration.LocationY != -1)
            {
                Location = new Point(mConfiguration.LocationX, mConfiguration.LocationY);
            }            
        }

        private string mConfigFileName = "configData.xml";

        private void GetConfiguration() 
        {
            try
            {                
                mConfiguration = (Configuration)XmlUtility.Deserialize(mConfiguration.GetType(), mConfigFileName);                
            }
            catch 
            {
                mConfiguration = new Configuration();
            }
        }

        private void SaveConfiguration()
        {
            try
            {
                XmlUtility.Serialize(mConfiguration, mConfigFileName);
            }
            catch (Exception e)
            {
                Console.WriteLine("Serialization problem: " + e.Message);
            }
        }       


        private void hsConfiguration_OnMouseMove(Object sender)
        {

        }

        private void hsConfiguration_OnMouseUp(Object sender)
        {
            ConfigurationForm configForm = new ConfigurationForm(mConfiguration);
            configForm.ShowDialog(this);
        }

        private void hsConfiguration_OnMouseDown(Object sender)
        {

        }

        private void hsMagnfier_OnMouseUp(object sender)
        {

        }

        private void hsMagnfier_OnMouseDown(object sender)
        {
            int x = mLastCursorPosition.X;
            int y = mLastCursorPosition.Y;
            MagnifierForm magnifier = new MagnifierForm(mConfiguration, mLastCursorPosition);
            magnifier.Show();
        }


        private void hsMagnfier_OnMouseMove(object sender)
        {

        }        

        private void hsExit_OnMouseUp(Object sender)
        {
            SaveConfiguration();
            Application.Exit();
        }


        protected override void OnPaint(PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            if (mImageMagnifierMainControlPanel != null)
            {
                g.DrawImage(mImageMagnifierMainControlPanel, 0, 0, Width, Height);
            }
        }

        protected override void OnMouseDown(MouseEventArgs e)
        {
            int x = e.X;
            int y = e.Y;

            mPointMouseDown = new Point(e.X, e.Y);
            mLastCursorPosition = Cursor.Position;

            foreach (HotSpot hotSpot in mHotSpots)
            {
                // If mouse event handled by this hot-stop then return!
                if (hotSpot.ProcessMouseDown(e)) return;                
            }            
        }

        protected override void OnMouseUp(MouseEventArgs e)
        {
            foreach (HotSpot hotSpot in mHotSpots)
            {
                // If mouse event handled by this hot-stop then return!
                if (hotSpot.ProcessMouseUp(e)) return;
            } 
        }

        protected override void OnMouseMove(MouseEventArgs e)
        {                        
            foreach (HotSpot hotSpot in mHotSpots)
            {
                // If mouse event handled by this hot-stop then return!
                if (hotSpot.ProcessMouseMove(e))
                {
                    Cursor = Cursors.Hand;
                    return;
                }
            }
            Cursor = Cursors.SizeAll;

            if (e.Button == MouseButtons.Left)
            {
                int dx = e.X - mPointMouseDown.X;
                int dy = e.Y - mPointMouseDown.Y;

                Left += dx;
                Top += dy;

                mConfiguration.LocationX = Left;
                mConfiguration.LocationY = Top;
            }
        }

        private Image mImageMagnifierMainControlPanel = null;
        private List<HotSpot> mHotSpots = new List<HotSpot>();
        private Point mPointMouseDown;
        private Point mLastCursorPosition;
        private Configuration mConfiguration = new Configuration();
    }
}

Now it will work on two cases:

1. The mouse should be on the Form area on the magnifier glass icon.
2. The mouse button left button should be pressed down nonstop and then dragging the mouse will move the magnifier glass.

I want to change it to:

1. Click on a button.
2. After clicked the button you can move the magnifier glass effect anywhere around without pressing down the mouse left button all the time.

I tried many different things, but couldn't figure out how to do it.

How can I do it?

Answer 1

Ok, so this is a complete hack and should probably be done a bit cleaner, but this should get you what you want:

In MagnifierMainForm.cs move the hsMagnfier_OnMouseDown code to hsMagnfier_OnMouseUp function.

In MagnifierForm.cs remove mTimer completely. Everywhere you see mTimer.Enabled = true (except for in the constructor MagnifierForm), add the line HandleTimer(null, new EventArgs());

I see that in OnMouseDown and OnMouseMove

In OnMouseMove, remove the check for e.Button == MouseButtons.Left

Answer 2

I am the author for the code that I published in the codeproject many years ago (https://www.codeproject.com/Articles/18235/Simple-Magnifier), now making it publicly available in the GitHub.

Please feel free to contribute and/or request features.

Ogun (omt66)