Photoshop-Like Gradient Editor

#region - Terms of Usage -
/*
 * Copyright 2006 Sameera Perera
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
#endregion   

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

namespace Inferno.Utilities
{
    public partial class GradientTypeEditorUI : UserControl
    {
        private Marker marker;

        public event EventHandler GradientChanged;

        [Browsable(false), DefaultValue(null)]
        public Gradient Gradient
        {
            get { return this.gradientBuilder.Gradient; }
            set { this.gradientBuilder.Gradient = value; }
        }

        // <summary>
        /// Gets or sets whether the GradientChanged event is fired when a marker
        /// is dragged.
        /// </summary>
        [DefaultValue(false)]
        public bool SilentMarkers
        {
            get { return this.gradientBuilder.SilentMarkers; }
            set { this.gradientBuilder.SilentMarkers = value; }
        }
        
        public GradientTypeEditorUI()
        {
            InitializeComponent();

            colorEditor.EditedType  = typeof( Color );
            colorEditor.Value       = Color.White;

            Font editorFont         = new Font( this.Font.FontFamily, 7.0f );
            colorEditor.Font        = editorFont;
        }

        private void gradientBuilder_MarkerSelected( object sender, EventArgs e )
        {
            Marker tempMarker   = sender as Marker;
            marker              = null; // Freeze all other event handlers
            if ( tempMarker != null )
            {
                colorEditor.Value   = tempMarker.Color;
                opacityBox.Value    = Convert.ToDecimal( tempMarker.Color.A * ( 100.0f/255 ) );
                positionBox.Enabled = tempMarker.IsMovable;
                positionBox.Value   = (int)(tempMarker.Position * 100.0f);
                grpEditor.Enabled   = true;
            }
            else
                grpEditor.Enabled = false;
            marker  = tempMarker;
        }

        private void colorMixerFieldValueChanged( object sender, EventArgs e )
        {
            if ( marker != null )
                UpdateMarkerColor();
        }

        private void UpdateMarkerColor()
        {
            Color color     = (Color)colorEditor.Value;
            int a           = Convert.ToInt32( (float)opacityBox.Value * ( 255.0f / 100 ) );
            marker.Color    = Color.FromArgb( a, color );
            if ( marker.IsMovable )
                marker.Position = (float)positionBox.Value / 100.0f;
        }

        private void gradientBuilder_GradientChanged( object sender, EventArgs e )
        {
            if ( this.GradientChanged != null )
                GradientChanged( this, EventArgs.Empty );
        }
    }
}