WPF迁移.Net Core时XAML Islands调用UWP MapControl绘制折线出现锯齿如何解决

解决方案1：补全MapPolyline的线样式属性 #

你现有代码锯齿明显的核心原因是没有和旧版WPF MapControl一样配置拐角、线帽的平滑属性，UWP版本的MapPolyline原生支持这些配置，直接补充即可：

var myPolyLine = new MapPolyline
{
    Path = myPath,
    FillColor = MY_COLOR,
    StrokeColor = MY_STROKE_COLOR,
    StrokeThickness = 6d, // 用双精度类型避免整数像素对齐导致的锯齿
    ZIndex = 1,
    // 新增以下3个属性
    StrokeLineJoin = Windows.UI.Xaml.Media.PenLineJoin.Round,
    StrokeStartCap = Windows.UI.Xaml.Media.PenLineCap.Round,
    StrokeEndCap = Windows.UI.Xaml.Media.PenLineCap.Round,
    StrokeMiterLimit = 10
};

myMap.MapElements.Add(myPolyLine);

解决方案2：开启WPF宿主的高画质渲染 #

由于你用的是Microsoft.Toolkit的WPF宿主UWP控件，默认WPF层面可能开启了性能优先的渲染策略，你可以给MapControl添加渲染优化配置：

XAML配置示例

<wpf:MapControl x:Name="myMap"
                xmlns:wpf="clr-namespace:Microsoft.Toolkit.Wpf.UI.Controls;assembly=Microsoft.Toolkit.Wpf.UI.Controls.MapControl"
                RenderOptions.BitmapScalingMode="HighQuality"
                RenderOptions.EdgeMode="Unspecified"
                RenderOptions.ClearTypeHint="Enabled"
                SnapsToDevicePixels="False"/>

后台代码配置示例

RenderOptions.SetBitmapScalingMode(myMap, BitmapScalingMode.HighQuality);
RenderOptions.SetEdgeMode(myMap, EdgeMode.Unspecified);
RenderOptions.SetClearTypeHint(myMap, ClearTypeHint.Enabled);
myMap.SnapsToDevicePixels = false;

解决方案3（终极兼容方案）：叠加WPF原生Polyline #

如果上述方案依然达不到你旧版本的平滑效果，可以放弃UWP内置的MapPolyline，改用WPF原生的Polyline控件叠加在地图上层，完全复用WPF的抗锯齿渲染管线：

1. 首先调整XAML布局，把MapControl和Polyline放在同一个容器内：

<Grid>
    <wpf:MapControl x:Name="myMap"
                    CenterChanged="MyMap_CenterChanged"
                    ZoomLevelChanged="MyMap_ZoomLevelChanged"/>
    <Polyline x:Name="routePolyline"
              Stroke="#FF0066CC"
              StrokeThickness="5"
              StrokeLineJoin="Round"
              IsHitTestVisible="False"
              SnapsToDevicePixels="False"/>
</Grid>

2. 当地图视角变化时，把地理坐标批量转换为屏幕坐标，更新Polyline的点集合：

// 你的经纬度点集合
private List<Geopoint> _routePoints = new List<Geopoint>();

private void UpdateRouteLine()
{
    var pointCollection = new PointCollection();
    foreach (var geoPoint in _routePoints)
    {
        if (myMap.GetOffsetFromLocation(geoPoint, out Point screenOffset))
        {
            pointCollection.Add(screenOffset);
        }
    }
    routePolyline.Points = pointCollection;
}

// 地图视角变化时触发更新，可添加防抖逻辑避免频繁更新卡顿
private void MyMap_CenterChanged(MapControl sender, object args) => UpdateRouteLine();
private void MyMap_ZoomLevelChanged(MapControl sender, object args) => UpdateRouteLine();

内容的提问来源于stack exchange，提问作者whatthe