add:直线拉直与端点吸附

Ink Canvas/MainWindow_cs/MW_Settings.cs

@@ -722,6 +722,34 @@ namespace Ink_Canvas {
             SaveSettingsToFile();
         }
 
+        private void ToggleSwitchAutoStraightenLine_Toggled(object sender, RoutedEventArgs e) {
+            if (!isLoaded) return;
+            
+            Settings.Canvas.AutoStraightenLine = ToggleSwitchAutoStraightenLine.IsOn;
+            SaveSettingsToFile();
+        }
+        
+        private void AutoStraightenLineThresholdSlider_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e) {
+            if (!isLoaded) return;
+            
+            Settings.Canvas.AutoStraightenLineThreshold = (int)e.NewValue;
+            SaveSettingsToFile();
+        }
+        
+        private void ToggleSwitchLineEndpointSnapping_Toggled(object sender, RoutedEventArgs e) {
+            if (!isLoaded) return;
+            
+            Settings.Canvas.LineEndpointSnapping = ToggleSwitchLineEndpointSnapping.IsOn;
+            SaveSettingsToFile();
+        }
+        
+        private void LineEndpointSnappingThresholdSlider_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e) {
+            if (!isLoaded) return;
+            
+            Settings.Canvas.LineEndpointSnappingThreshold = (int)e.NewValue;
+            SaveSettingsToFile();
+        }
+
         #endregion
 
         #region Canvas
@@ -1477,6 +1505,10 @@ namespace Ink_Canvas {
             Settings.Canvas.FitToCurve = true;
             Settings.Canvas.EnablePressureTouchMode = false;
             Settings.Canvas.DisablePressure = false;
+            Settings.Canvas.AutoStraightenLine = true;
+            Settings.Canvas.AutoStraightenLineThreshold = 30;
+            Settings.Canvas.LineEndpointSnapping = true;
+            Settings.Canvas.LineEndpointSnappingThreshold = 15;
             Settings.Canvas.UsingWhiteboard = false;
             Settings.Canvas.HyperbolaAsymptoteOption = 0;