ShareX/Greenshot.ImageEditor/Forms/MovableShowColorForm.cs

/*
 * Greenshot - a free and open source screenshot tool
 * Copyright (C) 2007-2015 Thomas Braun, Jens Klingen, Robin Krom
 *
 * For more information see: http://getgreenshot.org/
 * The Greenshot project is hosted on Sourceforge: http://sourceforge.net/projects/greenshot/
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 1 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

using GreenshotPlugin.UnmanagedHelpers;
using System;
using System.Drawing;
using System.Windows.Forms;

namespace Greenshot.Forms
{
    /// <summary>
    /// This code was supplied by Hi-Coder as a patch for Greenshot
    /// Needed some modifications to be stable.
    /// </summary>
    public partial class MovableShowColorForm : Form
    {
        public Color color
        {
            get
            {
                return preview.BackColor;
            }
        }

        public MovableShowColorForm()
        {
            InitializeComponent();
        }

        /// <summary>
        /// Move the MovableShowColorForm to the specified location and display the color under the (current mouse) coordinates
        /// </summary>
        /// <param name="screenCoordinates">Coordinates</param>
        public void MoveTo(Point screenCoordinates)
        {
            Color c = GetPixelColor(screenCoordinates);
            preview.BackColor = c;
            html.Text = "#" + c.Name.Substring(2).ToUpper();
            red.Text = "" + c.R;
            blue.Text = "" + c.B;
            green.Text = "" + c.G;
            alpha.Text = "" + c.A;

            Size cursorSize = Cursor.Current.Size;
            Point hotspot = Cursor.Current.HotSpot;

            Point zoomerLocation = new Point(screenCoordinates.X, screenCoordinates.Y);
            zoomerLocation.X += cursorSize.Width + 5 - hotspot.X;
            zoomerLocation.Y += cursorSize.Height + 5 - hotspot.Y;

            foreach (Screen screen in Screen.AllScreens)
            {
                Rectangle screenRectangle = screen.Bounds;
                if (screen.Bounds.Contains(screenCoordinates))
                {
                    if (zoomerLocation.X < screenRectangle.X)
                    {
                        zoomerLocation.X = screenRectangle.X;
                    }
                    else if (zoomerLocation.X + Width > screenRectangle.X + screenRectangle.Width)
                    {
                        zoomerLocation.X = screenCoordinates.X - Width - 5 - hotspot.X;
                    }

                    if (zoomerLocation.Y < screenRectangle.Y)
                    {
                        zoomerLocation.Y = screenRectangle.Y;
                    }
                    else if (zoomerLocation.Y + Height > screenRectangle.Y + screenRectangle.Height)
                    {
                        zoomerLocation.Y = screenCoordinates.Y - Height - 5 - hotspot.Y;
                    }
                    break;
                }
            }
            Location = zoomerLocation;
            Update();
        }

        /// <summary>
        /// Get the color from the pixel on the screen at "x,y"
        /// </summary>
        /// <param name="screenCoordinates">Point with the coordinates</param>
        /// <returns>Color at the specified screenCoordinates</returns>
        private static Color GetPixelColor(Point screenCoordinates)
        {
            using (SafeWindowDCHandle screenDC = SafeWindowDCHandle.FromDesktop())
            {
                try
                {
                    uint pixel = GDI32.GetPixel(screenDC, screenCoordinates.X, screenCoordinates.Y);
                    Color color = Color.FromArgb(255, (int)(pixel & 0xFF), (int)(pixel & 0xFF00) >> 8, (int)(pixel & 0xFF0000) >> 16);
                    return color;
                }
                catch (Exception)
                {
                    return Color.Empty;
                }
            }
        }
    }
}