104 lines
3.6 KiB
C#
104 lines
3.6 KiB
C#
using System;
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using System.Windows;
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using System.Windows.Media;
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using HandyControl.Expression.Drawing;
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using HandyControl.Tools.Interop;
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namespace HandyControl.Tools
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{
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internal static class DpiHelper
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{
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private const double LogicalDpi = 96.0;
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[ThreadStatic]
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private static Matrix _transformToDip;
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static DpiHelper()
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{
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var dC = InteropMethods.GetDC(IntPtr.Zero);
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if (dC != IntPtr.Zero)
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{
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// 沿着屏幕宽度每逻辑英寸的像素数。在具有多个显示器的系统中，这个值对所有显示器都是相同的
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const int logicPixelsX = 88;
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// 沿着屏幕高度每逻辑英寸的像素数
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const int logicPixelsY = 90;
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DeviceDpiX = InteropMethods.GetDeviceCaps(dC, logicPixelsX);
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DeviceDpiY = InteropMethods.GetDeviceCaps(dC, logicPixelsY);
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InteropMethods.ReleaseDC(IntPtr.Zero, dC);
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}
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else
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{
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DeviceDpiX = LogicalDpi;
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DeviceDpiY = LogicalDpi;
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}
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var identity = Matrix.Identity;
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var identity2 = Matrix.Identity;
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identity.Scale(DeviceDpiX / LogicalDpi, DeviceDpiY / LogicalDpi);
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identity2.Scale(LogicalDpi / DeviceDpiX, LogicalDpi / DeviceDpiY);
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TransformFromDevice = new MatrixTransform(identity2);
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TransformFromDevice.Freeze();
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TransformToDevice = new MatrixTransform(identity);
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TransformToDevice.Freeze();
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}
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public static MatrixTransform TransformFromDevice { get; }
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public static MatrixTransform TransformToDevice { get; }
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public static double DeviceDpiX { get; }
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public static double DeviceDpiY { get; }
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public static double LogicalToDeviceUnitsScalingFactorX => TransformToDevice.Matrix.M11;
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public static double LogicalToDeviceUnitsScalingFactorY => TransformToDevice.Matrix.M22;
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public static Point DevicePixelsToLogical(Point devicePoint, double dpiScaleX, double dpiScaleY)
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{
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_transformToDip = Matrix.Identity;
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_transformToDip.Scale(1d / dpiScaleX, 1d / dpiScaleY);
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return _transformToDip.Transform(devicePoint);
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}
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public static Size DeviceSizeToLogical(Size deviceSize, double dpiScaleX, double dpiScaleY)
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{
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var pt = DevicePixelsToLogical(new Point(deviceSize.Width, deviceSize.Height), dpiScaleX, dpiScaleY);
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return new Size(pt.X, pt.Y);
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}
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public static Rect LogicalToDeviceUnits(this Rect logicalRect)
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{
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var result = logicalRect;
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result.Transform(TransformToDevice.Matrix);
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return result;
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}
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public static Rect DeviceToLogicalUnits(this Rect deviceRect)
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{
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var result = deviceRect;
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result.Transform(TransformFromDevice.Matrix);
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return result;
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}
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public static double RoundLayoutValue(double value, double dpiScale)
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{
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double newValue;
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if (!MathHelper.AreClose(dpiScale, 1.0))
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{
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newValue = Math.Round(value * dpiScale) / dpiScale;
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if (double.IsNaN(newValue) || double.IsInfinity(newValue) || MathHelper.AreClose(newValue, double.MaxValue))
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{
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newValue = value;
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}
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}
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else
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{
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newValue = Math.Round(value);
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}
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return newValue;
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}
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}
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} |