#region PDFsharp - A .NET library for processing PDF
//
// Authors:
//   Stefan Lange (mailto:Stefan.Lange@pdfsharp.com)
//
// Copyright (c) 2005-2007 empira Software GmbH, Cologne (Germany)
//
// http://www.pdfsharp.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Runtime.InteropServices;
using System.Text;

namespace PdfSharp.Forms
{
  /// <summary>
  /// Contains information about a physical device like a display or a printer.
  /// </summary>
  public struct DeviceInfos
  {
    /// <summary>
    /// Width, in millimeters, of the physical screen or device.
    /// </summary>
    public int HorizontalSize;

    /// <summary>
    /// Height, in millimeters, of the physical screen or device.
    /// </summary>
    public int VerticalSize;

    /// <summary>
    /// Width, in pixels, of the screen or device.
    /// </summary>
    public int HorizontalResolution;

    /// <summary>
    /// Height, in pixels, of the screen or device.
    /// </summary>
    public int VerticalResolution;

    /// <summary>
    /// Number of pixels per logical inch along the screen or device width.
    /// </summary>
    public int LogicalDpiX;

    /// <summary>
    /// Number of pixels per logical inch along the screen or device height.
    /// </summary>
    public int LogicalDpiY;

    /// <summary>
    /// Number of pixels per physical inch along the screen or device width.
    /// </summary>
    public float PhysicalDpiX;

    /// <summary>
    /// Number of pixels per physical inch along the screen or device height.
    /// </summary>
    public float PhysicalDpiY;

    /// <summary>
    /// The ratio of LogicalDpiX and PhysicalDpiX.
    /// </summary>
    public float ScaleX;

    /// <summary>
    /// The ratio of LogicalDpiY and PhysicalDpiY.
    /// </summary>
    public float ScaleY;

    /// <summary>
    /// Gets a DeviceInfo for the specifed device context.
    /// </summary>
    public static DeviceInfos GetInfos(IntPtr hdc)
    {
      DeviceInfos devInfo;

      devInfo.HorizontalSize = GetDeviceCaps(hdc, HORZSIZE);
      devInfo.VerticalSize = GetDeviceCaps(hdc, VERTSIZE);
      devInfo.HorizontalResolution = GetDeviceCaps(hdc, HORZRES);
      devInfo.VerticalResolution = GetDeviceCaps(hdc, VERTRES);
      devInfo.LogicalDpiX = GetDeviceCaps(hdc, LOGPIXELSX);
      devInfo.LogicalDpiY = GetDeviceCaps(hdc, LOGPIXELSY);
      devInfo.PhysicalDpiX = devInfo.HorizontalResolution * 25.2f / devInfo.HorizontalSize;
      devInfo.PhysicalDpiY = devInfo.VerticalResolution * 25.4f / devInfo.VerticalSize;
      devInfo.ScaleX = devInfo.LogicalDpiX / devInfo.PhysicalDpiX;
      devInfo.ScaleY = devInfo.LogicalDpiY / devInfo.PhysicalDpiY;

      return devInfo;
    }

    [DllImport("gdi32.dll")]
    static extern int GetDeviceCaps(IntPtr hdc, int capability);
    const int HORZSIZE = 4;
    const int VERTSIZE = 6;
    const int HORZRES = 8;
    const int VERTRES = 10;
    const int LOGPIXELSX = 88;
    const int LOGPIXELSY = 90;
  }
}
