kmpdfkit_demo/ComPDFKit.Demo/Helper/DpiHelpers.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace ComPDFKitDemo.Helper
{
    internal class Helpers
    {
		/// <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 Helpers()
        {
            try
            {
				var flags = BindingFlags.NonPublic | BindingFlags.Static;
				var dpiProperty = typeof(SystemParameters).GetProperty("Dpi", flags);
				Dpi = (int)dpiProperty.GetValue(null, null);
				
			}
			catch (Exception ex)
            {
			}
        }
	
		/// <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>
		/// 当前DPI转换到PDF矩形
		/// </summary>
		/// <param name="oldValue"></param>
		/// <returns></returns>
		public static Rect GetRawRect(Rect oldValue,bool isStandDpi=false)
        {
			Rect standRect = oldValue;
			if(!isStandDpi)
            {
				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>
		/// 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));
		}
	}
}