PDFOffice_Windows_exe/PDF Office/Helper/DpiHelpers.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Windows;

namespace PDF_Office.Helper
{
    internal class DpiHelpers
    {
        /// <summary>
        /// 当前系统DPI
        /// </summary>
        public static int Dpi { get; private set; }
        /// <summary>
        /// 当前DPI相对系统标准DPI(96)缩小比例
        /// </summary>
        public static float ScaleDpi { get { return (96F / Dpi); } }
        /// <summary>
        /// 系统DPI相对PDF文档DPI放大倍数
        /// </summary>
        public static double ScaleFactor { get { return (Dpi / 72D); } }
        /// <summary>
        /// PDF文档DPI相对系统标准DPI(96)缩小倍数
        /// </summary>
        public static double InvertScaleFactor { get { return (72D / Dpi); } }
        static DpiHelpers()
        {
            try
            {
                var flags = BindingFlags.NonPublic | BindingFlags.Static;
                var dpiProperty = typeof(SystemParameters).GetProperty("Dpi", flags);
                Dpi = (int)dpiProperty.GetValue(null, null);

            }
            catch { }
        }

        /// <summary>
        /// 从WPF获取的数值转换成标准DPI时的大小
        /// 缩小
        /// </summary>
        /// <param name="oldValue">当前数值</param>
        /// <returns></returns>
        public static int GetDpiUnrelatedNum(int oldValue)
        {
            return (int)(oldValue * ScaleDpi);
        }
        /// <summary>
        /// 从WPF获取的数值转换成标准DPI时的大小
        /// 缩小
        /// </summary>
        /// <param name="oldValue">当前数值</param>
        /// <returns></returns>
        public static double GetDpiUnrelatedNum(double oldValue)
        {
            return (double)(oldValue * ScaleDpi);
        }
        /// <summary>
        /// 标准DPI时的大小转换成当前DPI对应大小
        /// 放大
        /// </summary>
        /// <param name="oldValue">当前数值</param>
        /// <returns></returns>
        public static double GetDpiRelatedNum(double oldValue)
        {
            return (oldValue / ScaleDpi);
        }
        /// <summary>
        /// 当前矩形换成标准DPI时的大小
        /// </summary>
        /// <param name="oldValue"></param>
        /// <returns></returns>
        public static Rect GetDpiUnrelatedRect(Rect oldValue)
        {
            return new Rect(GetDpiUnrelatedNum(oldValue.Left), GetDpiUnrelatedNum(oldValue.Top),
                GetDpiUnrelatedNum(oldValue.Width), GetDpiUnrelatedNum(oldValue.Height));
        }


        /// <summary>
        /// 转换到PDF矩形
        /// </summary>
        /// <param name="oldValue"></param>
        /// <returns></returns>
        public static Rect GetRawRect(Rect oldValue)
        {
            Rect standRect = new Rect(GetDpiUnrelatedNum(oldValue.Left), GetDpiUnrelatedNum(oldValue.Top),
                GetDpiUnrelatedNum(oldValue.Width), GetDpiUnrelatedNum(oldValue.Height));
            return new Rect((int)(standRect.Left * 72D / 96D), (int)(standRect.Top * 72D / 96D), (int)(standRect.Width * 72D / 96D), (int)(standRect.Height * 72D / 96D));
        }

        /// <summary>
        /// 当前矩形换成当前DPI时的矩形大小
        /// </summary>
        /// <param name="oldValue"></param>
        /// <returns></returns>
        public static Rect GetDpiRelatedRect(Rect oldValue)
        {
            return new Rect(GetDpiRelatedNum(oldValue.Left), GetDpiRelatedNum(oldValue.Top),
                GetDpiRelatedNum(oldValue.Width), GetDpiRelatedNum(oldValue.Height));
        }

        /// <summary>
        /// 将PDF矩形，转换为当前DPI时的矩形大小
        /// </summary>
        /// <param name="standRect"></param>
        /// <returns></returns>
        public static Rect GetRawRelatedRect(Rect standRect)
        {
            Rect newRect = new Rect(standRect.Left / 72D *96D, standRect.Top / 72D * 96D, standRect.Width / 72D * 96D, standRect.Height / 72D * 96D);
            return GetDpiRelatedRect(newRect);
        }


        /// <summary>
        /// 当前点转换成标准DPI时的大小
        /// </summary>
        /// <param name="oldValue"></param>
        /// <returns></returns>
        public static Point GetDpiUnrelatedPoint(Point oldValue)
        {
            return new Point(GetDpiUnrelatedNum(oldValue.X), GetDpiUnrelatedNum(oldValue.Y));
        }
        /// <summary>
        /// 点换成当前DPI时的大小
        /// </summary>
        /// <param name="oldValue"></param>
        /// <returns></returns>
        public static Point GetDpiRelatedPoint(Point oldValue)
        {
            return new Point(GetDpiRelatedNum(oldValue.X), GetDpiRelatedNum(oldValue.Y));
        }
        /// <summary>
        /// 当前Size转换成标准DPI时的大小
        /// </summary>
        /// <param name="oldValue"></param>
        /// <returns></returns>
        public static Size GetDpiUnrelatedSize(Size oldValue)
        {
            return new Size(GetDpiUnrelatedNum(oldValue.Width), GetDpiUnrelatedNum(oldValue.Height));
        }
        /// <summary>
        /// Size换成当前DPI时的大小
        /// </summary>
        /// <param name="oldValue"></param>
        /// <returns></returns>
        public static Size GetDpiRelatedSize(Size oldValue)
        {
            return new Size(GetDpiRelatedNum(oldValue.Width), GetDpiRelatedNum(oldValue.Height));
        }
    }
}