//Except where stated all code and programs in this project are the copyright of Jim Blackler, 2008.
//jimblackler@gmail.com
//
//This is free software. Libraries and programs are distributed under the terms of the GNU Lesser
//General Public License. Please see the files COPYING and COPYING.LESSER.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;
using System.Windows.Forms;

namespace MiscControls
{
    /// <summary>
    /// A control that sizes all sub-controls on a parent form proportionally
    /// </summary>
    public partial class FormScaler : Component
    {
        /// <summary>
        /// Record of the parent form
        /// </summary>
        [Browsable(false)]
        [DefaultValue("")]
        public Control ParentControl
        {
            get
            {
                // Designer code ... set the form 
                if ((parentControl == null) && DesignMode)
                {
                    IDesignerHost host = (IDesignerHost)GetService(typeof(IDesignerHost));
                    if (host != null)
                    {
                        parentControl = host.RootComponent as Control;
                    }

                }
                return parentControl;
            }
            set
            {
                if (parentControl != value)
                {
                    // Quite a bit of setup is done as soon as we know the parent form

                    parentControl = value;

                    parentControl.FindForm().Load += new EventHandler(FormScaler_Load);

                    parentControl.Resize += new EventHandler(parentControl_Resize);
                }
            }
        }

        /// <summary>
        /// Called to record the positions of the controls after the client window is initialised
        /// </summary>
        void FormScaler_Load(object sender, EventArgs e)
        {
            originalWidth = parentControl.ClientRectangle.Width;
            originalHeight = parentControl.ClientRectangle.Height;

            // record the original positions of the controls
            originalSizesAndPositions = new List<OriginalSizeAndPosition>();

            Control.ControlCollection collection = parentControl.Controls;

            RecordControlCollection(collection);
        }

        private void RecordControlCollection(Control.ControlCollection collection)
        {
            foreach (Control control in collection)
            {
                if (control as MenuStrip == null)
                {
                    OriginalSizeAndPosition originalSizeAndPosition = new OriginalSizeAndPosition();
                    originalSizeAndPosition.originalWidth = control.Size.Width;
                    originalSizeAndPosition.originalHeight = control.Size.Height;
                    originalSizeAndPosition.originalX = control.Location.X;
                    originalSizeAndPosition.originalY = control.Location.Y;
                    originalSizeAndPosition.originalFontSize = control.Font.Size;
                    originalSizeAndPosition.control = control;
                    originalSizesAndPositions.Add(originalSizeAndPosition);
                    
                    RecordControlCollection(control.Controls);
                }
            }
        }

        /// <summary>
        /// Size the parent control proportionally
        /// </summary>
        void parentControl_Resize(object sender, EventArgs e)
        {
            if (originalSizesAndPositions == null)
            {
                return;
            }
            else
            {
                if (previousWidth != parentControl.ClientRectangle.Width || previousHeight != parentControl.ClientRectangle.Height)
                {
                    int currentWidth = parentControl.ClientRectangle.Width;
                    int currentHeight = parentControl.ClientRectangle.Height;

                    if (currentWidth > 0 && currentHeight > 0)
                    {
                        int topOffset;

                        Form clientForm = parentControl as Form;

                        if (clientForm == null)
                        {
                            topOffset = 0;
                        }
                        else
                        {
                            topOffset = clientForm.MainMenuStrip.Height;
                        }

                        float propX = (float)currentWidth / originalWidth;
                        float propY = (float)(currentHeight - topOffset) / (originalHeight - topOffset);
                        
                        parentControl.SuspendLayout();

                        foreach (OriginalSizeAndPosition originalSizeAndPosition in originalSizesAndPositions)
                        {
                            originalSizeAndPosition.control.SetBounds((int)(propX * originalSizeAndPosition.originalX),
                                (int)(topOffset + propY * (originalSizeAndPosition.originalY - topOffset)),
                                (int)(propX * originalSizeAndPosition.originalWidth),
                                (int)(propY * originalSizeAndPosition.originalHeight));
                            originalSizeAndPosition.control.Font =
                                new Font(originalSizeAndPosition.control.Font.FontFamily, 
                                Math.Min(propX, propY) * originalSizeAndPosition.originalFontSize,
                                originalSizeAndPosition.control.Font.Unit);
                        }

                        parentControl.ResumeLayout();

                    }

                    previousWidth = currentWidth;
                    previousHeight = currentHeight;
                }

                return;
            }
        }        


        // Fields follow 

        private Control parentControl;

        private List<OriginalSizeAndPosition> originalSizesAndPositions;

        private int originalWidth;

        private int originalHeight;

        private int previousWidth;

        private int previousHeight;
                
        /// <summary>
        /// A record of the original bounds stored for each child control
        /// </summary>
        class OriginalSizeAndPosition
        {
            public int originalWidth;
            public int originalHeight;
            public int originalX;
            public int originalY;
            public float originalFontSize;
            public Control control;
        }


    }
}