bool reactionKnown = true;

            isCaptured = false;

            recordButton.Sensitive = false;

            clearReactionButton.Sensitive = false;

            clearReactionButton.Visible = false;

            recipe.Clear();

            if ((reagentName = GetSelectedReagentName(1)) == null)

            {

                // Nothing selected as reagent 1

                ingredient2ComboBox.Sensitive = false;

                ingredient3ComboBox.Sensitive = false;

                unmodifiedSwatch.Clear();

                reactionSwatch.Clear();

                captureButton.Sensitive = false;

                return;

            }

            recipe.AddReagent(reagentName);

            reagents[0] = ReagentManager.GetReagent(reagentName);

            ingredient2ComboBox.Sensitive = true;

            if ((reagentName = GetSelectedReagentName(2)) == null)

            {

                ingredient3ComboBox.Sensitive = false;

                recordButton.Sensitive = false;

                reactionKnown = false;

                reactionSwatch.Clear();

                return;

            }

            recipe.AddReagent(reagentName);

            reagents[1] = ReagentManager.GetReagent(reagentName);

            ingredient3ComboBox.Sensitive = true;

            captureButton.Sensitive = true;

            reaction1 = profile.FindReaction(reagents[0], reagents[1]);

            // TODO: really should handle reagent0==reagent1 better

            if ((reaction1 != null) || (reagents[0] == reagents[1]))

            {

                clearReactionButton.Sensitive = recordEnabled;

                clearReactionButton.Visible = true;

                ingredient3ComboBox.Sensitive = true;

                if ((reagentName = GetSelectedReagentName(3)) != null)

                {

                    clearReactionButton.Sensitive = false;

                    clearReactionButton.Visible = false;

                    recipe.AddReagent(reagentName);

                    reagents[2] = ReagentManager.GetReagent(reagentName);

                    if (!reactionKnown)

                    {

                        Gtk.MessageDialog md = new Gtk.MessageDialog((Gtk.Window)Toplevel, 

                            Gtk.DialogFlags.DestroyWithParent,

                            Gtk.MessageType.Error, Gtk.ButtonsType.Ok, 

                            "To do a three-ingredient reaction test, " +

                            "you must first recored the reaction of " +

                            "the first two ingredients.");

                        md.Run();

                        md.Destroy();

                        captureButton.Sensitive = false;

                    }

                    reaction1 = profile.FindReaction(reagents[0], reagents[2]);

                    reaction2 = profile.FindReaction(reagents[1], reagents[2]);

                    if (reactionKnown && (reaction1 == null) && (reaction2 == null))

                    {

                        Gtk.MessageDialog md = new Gtk.MessageDialog((Gtk.Window)Toplevel, 

                            Gtk.DialogFlags.DestroyWithParent,

                            Gtk.MessageType.Error, Gtk.ButtonsType.Ok, 

                            "To do a three-ingredient reaction test, " +

                            "you must first record the reaction of " +

                            "either the first or second ingredient " +

                            "with the third ingredient.");

                        md.Run();

                        md.Destroy();   

                        captureButton.Sensitive = false;

                    }

                    if ((reaction1 == null) && (reagents[0] != reagents[2]))

                    {

                        reactionKnown = false;  

                    }

                    if ((reaction2 == null) && (reagents[1] != reagents[2]))

                    {

                        reactionKnown = false;  

                    }

                }

            }

            else

            {

                reactionKnown = false;

                ingredient3ComboBox.Sensitive = false;

            }

            expectedColor.Set(recipe.BaseColor);

            unmodifiedSwatch.Color = expectedColor;

            //SetExpectedColor(recipeColor.Red, recipeColor.Green, recipeColor.Blue);

            if (reactionKnown)

            {

                reactedColor.Set(recipe.ReactedColor);

                reactionSwatch.Color = reactedColor;

            }

            else

            {

                reactionSwatch.Clear(); 

            }

        }

        unsafe void BeginCapture()

        {

            captureButton.Sensitive = false;

            ingredient1ComboBox.Sensitive = false;

            ingredient2ComboBox.Sensitive = false;

            ingredient3ComboBox.Sensitive = false;

            clearReactionButton.Sensitive = false;

            progressBar.Show();

            recordButton.Hide();

            bool enableDebugMenu = false;

            DesertPaintLab.AppSettings.Get("EnableDebugMenu", out enableDebugMenu);

            StreamWriter log = null;

            if (enableDebugMenu)

            {

                string logfile = FileUtils.FindNumberedFile("DesertPaintLab_Capture", "log", Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments));

                log = new StreamWriter(logfile);

                ReactionRecorder.Instance.Log = log;

            }

            if (notifyCaptureProgress == null)

            {

                notifyCaptureProgress = new Gtk.ThreadNotify(new Gtk.ReadyEvent(NotifyCaptureProgress));

                notifyCaptureComplete = new Gtk.ThreadNotify(new Gtk.ReadyEvent(NotifyCaptureComplete));

            }

            this.reactionSwatch.Clear();

            Thread thr = new Thread(new ThreadStart(this.CaptureReactionThread));

            thr.Priority = ThreadPriority.AboveNormal;

            thr.Start();

            //OnCaptureComplete(isCaptured, reactedColor, screenWidth, screenHeight, stride, redPixelStart);

        }

        unsafe private void CaptureReactionThread()

        {

            byte* pixBytes = (byte*)screenBuffer.Pixels;

            ReactionRecorder.Instance.OnCaptureProgress += OnCaptureProgress;

            ReactionRecorder.Instance.CaptureReaction(pixBytes, screenBuffer.Width, screenBuffer.Height, screenBuffer.Rowstride);

            ReactionRecorder.Instance.OnCaptureProgress -= OnCaptureProgress;

            notifyCaptureComplete.WakeupMain();

        }

        private void OnCaptureProgress(int x, int y)

        {

            notifyCaptureProgress.WakeupMain();

        }

        private void NotifyCaptureProgress()

        {

            // TODO: progress bar

            //ReactionRecorder.Instance.X;

            //ReactionRecorder.Instance.Y;

            progressBar.Fraction = ((double)(ReactionRecorder.Instance.X) / (double)(ReactionRecorder.Instance.ScreenWidth - ReactionRecorder.Instance.ColorBarWidth));

        }

        void OnCaptureComplete(bool isCaptured, PaintColor reactedColor, int swatchX, int swatchY)

        {

            int screenWidth = screenBuffer.Width;

            int screenHeight = screenBuffer.Height;

            int stride = screenBuffer.Rowstride;

            StreamWriter log = ReactionRecorder.Instance.Log;

            if (log != null)

            {

                log.Flush();

                log.Close();

                log = null;

                ReactionRecorder.Instance.Log = null;

            }

            bool enableDebugMenu = false;

            DesertPaintLab.AppSettings.Get("EnableDebugMenu", out enableDebugMenu);

            bool debugScreenshot = false;

            DesertPaintLab.AppSettings.Get("DebugScreenshot", out debugScreenshot);

            if (enableDebugMenu && debugScreenshot)

            {

                if (!isCaptured)

                {

                    // write out the whole screenshot on a failure to capture

                    string screenshotDir = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

                    string filename = FileUtils.FindNumberedFile("DesertPaintLab_Colormatch", "png", screenshotDir);

                    screenBuffer.Save(filename, "png");

                }

                else

                {

                    // record the swatch that was captured

                    // write out the screenshot

                    string screenshotDir = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

                    string filename = FileUtils.FindNumberedFile("DesertPaintLab_Colormatch", "png", screenshotDir);

                    int x = swatchX - 16;

                    int captureAreaWidth = ReactionRecorder.Instance.ColorBarWidth + 32;

                    captureAreaWidth = Math.Min(screenWidth - x, captureAreaWidth);

                    int y = swatchY - 16;

                    int captureAreaHeight = ReactionRecorder.Instance.BlueBarSpacing + 42;

                    captureAreaHeight = Math.Min(screenHeight - y, captureAreaHeight);

                    Gdk.Pixbuf outPixBuf = new Gdk.Pixbuf(screenBuffer, Math.Max(0, x), Math.Max(0, y), 

                        captureAreaWidth, captureAreaHeight);

                    //Gdk.Pixbuf outPixBuf = new Gdk.Pixbuf(screenBuffer, Math.Max(0, redPixelStartX), Math.Max(0, redPixelStartY),

                    //    ReactionRecorder.Instance.ColorBarWidth, ReactionRecorder.Instance.GreenBarSpacing - ReactionRecorder.Instance.RedBarSpacing);

                    //screenBuffer.Save(filename, "png");

                    outPixBuf.Save(filename, "png");

                }

            }

            //screenBuffer.Save("screenshot.png", "png");

            if (isCaptured)

            {

                string warning = "";

                if (reactedColor.Red == 0)

                {

                    warning = warning + "\nRed is too low.";

                }

                if (reactedColor.Green == 0)

                {

                    warning = warning + "\nGreen is too low.";

                }

                if (reactedColor.Blue == 0)

                {

                    warning = warning + "\nBlue is too low.";

                }

                if (reactedColor.Red == 255)

                {

                    warning = warning + "\nRed is too high.";

                }

                if (reactedColor.Green == 255)

                {

                    warning = warning + "\nGreen is too high.";

                }

                if (reactedColor.Blue == 255)

                {

                    warning = warning + "\nBlue is too high.";

                }

                // Always update the reacted swatch

                this.reactionSwatch.Color = reactedColor;

                if (warning.Length != 0)

                {

                    isCaptured = true;

                    Gtk.MessageDialog md = new Gtk.MessageDialog((Gtk.Window)Toplevel,

                    Gtk.DialogFlags.DestroyWithParent,

                    Gtk.MessageType.Error, Gtk.ButtonsType.Ok,

                    "Reaction clipped.  You will need to do a " +

                    "3-way reaction to test this pair.  Details: " +

                    warning);

                    md.Run();

                    md.Destroy();

                    // reaction clipped - don't let them record

                    recordButton.Sensitive = false;

                }

                else

                {

                    recordButton.Sensitive = recordEnabled;

                }

            }

            else

            {

                Gtk.MessageDialog md = new Gtk.MessageDialog((Gtk.Window)Toplevel,

                    Gtk.DialogFlags.DestroyWithParent,

                    Gtk.MessageType.Error, Gtk.ButtonsType.Ok,

                    "Pigment Lab dialog box NOT FOUND.  Please ensure " +

                    "that there is an unobstructed view of the dialog " +

                    "and that your interface size is set to 'small' " +

                    "when you press the Capture button.");

                md.Run();

                md.Destroy();

            }

            progressBar.Hide();

            recordButton.Show();

            ingredient1ComboBox.Sensitive = true;

            ingredient2ComboBox.Sensitive = true;

            ingredient3ComboBox.Sensitive = (GetSelectedReagentName(1) != null) && (GetSelectedReagentName(2) != null);

        }

        private void NotifyCaptureComplete()

        {

            OnCaptureComplete(

                ReactionRecorder.Instance.IsCaptured,

                ReactionRecorder.Instance.RecordedColor,

                ReactionRecorder.Instance.SwatchX,

                ReactionRecorder.Instance.SwatchY);

        }

        unsafe void CaptureReactionColor()

        {

            // Take a screenshot.

            int screenWidth, screenHeight;

            Gdk.Window rootWindow = Gdk.Global.DefaultRootWindow;

            DesertPaintLab.AppSettings.Get("ScreenWidth", out screenWidth);

            DesertPaintLab.AppSettings.Get("ScreenHeight", out screenHeight);

            Gdk.Image rootImage = rootWindow.GetImage(0, 0, screenWidth, screenHeight);

            screenBuffer.GetFromImage(rootImage, rootImage.Colormap, 0, 0, 0, 0, screenWidth, screenHeight);

            rootImage.Unref();

            System.GC.Collect(); // really, clean up now

            BeginCapture();

        }

        protected virtual void OnCapture(object sender, System.EventArgs e)

        {

            CaptureReactionColor();

        }

        protected virtual void OnRecord(object sender, System.EventArgs e)

        {

            if (ReactionRecorder.Instance.RecordReaction(profile, expectedColor, reactedColor, reagents))

            {

                recordButton.Sensitive = false;

            }

        }

        protected virtual void OnChangedIngredient1(object sender, System.EventArgs e)

        {

            UpdateIngredients();

        }

        protected virtual void OnChangedIngredient2(object sender, System.EventArgs e)

        {

            UpdateIngredients();

        }

        protected virtual void OnChangedIngredient3(object sender, System.EventArgs e)

        {

            UpdateIngredients();

        }

        protected void OnClearReaction(object sender, EventArgs e)

        {

            string reagentName1 = GetSelectedReagentName(1);

            string reagentName2 = GetSelectedReagentName(2);

            string reagentName3 = GetSelectedReagentName(3);

            if ((reagentName1 != null) && (reagentName2 != null) && (reagentName3 == null))

            {

                Reagent reagent1 = ReagentManager.GetReagent(reagentName1);

                Reagent reagent2 = ReagentManager.GetReagent(reagentName2);

                if (null != profile.FindReaction(reagent1, reagent2))

                {

                    Gtk.MessageDialog md = new Gtk.MessageDialog((Gtk.Window)Toplevel, 

                        Gtk.DialogFlags.DestroyWithParent,

                        Gtk.MessageType.Warning, Gtk.ButtonsType.OkCancel, 

                        "This will delete the reaction status between " +

                        // TODO: ingredient1Name + " and " + ingredient2Name + "\n\n" +

                        "ARE YOU SURE?"

                    );

                    Gtk.ResponseType response = (Gtk.ResponseType)md.Run();

                    if (response == Gtk.ResponseType.Ok)

                    {

                        // really delete it

                        profile.ClearReaction(reagent1, reagent2);

                    }

                    md.Destroy();

                }

            }

        }

    }

}