更改WPF画布的坐标系

本文介绍了更改WPF画布的坐标系的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 29岁程序员，3月因学历无情被辞！ 我在写一个使用定位元素的帆布映射应用程序。对于每个元素我要转换编程元素的纬度/龙在画布上'坐标，然后设置Canvas.Top和Canvas.Left属性。 如果我有一个360x180帆布，我可以转换在画布上的坐标去从-180到180，而不是0到360在X轴和90至-90而不是0到180的Y轴 缩放要求： 画布可以是任意大小，因此如果是360x180或5000x100应该仍然工作 的纬度/长区并不总是（-90，-180）×（90,180），它可以是任何东西（即（5，-175）×（89，-174）） 元素，如的PathGeometry这是一点基础的，而不是基于Canvas.Top/Left需要工作。 解决方案 下面是一个全XAML的解决方案。好了，主要是XAML，因为你必须拥有的IValueConverter代码。所以：创建一个新的WPF项目并添加一个类到它。类是MultiplyConverter： 命名空间YourProject {公共类MultiplyConverter：System.Windows.Data。的IValueConverter {公共对象转换（对象的值，System.Type的TARGETTYPE，对象参数，System.Globalization.CultureInfo文化） {返回AsDouble（值）* AsDouble（参数）; } 双AsDouble（对象的值） { VAR valueText =值串; 如果（valueText！= NULL）返回double.Parse（valueText）; ，否则回报（双）值; } 公共对象ConvertBack（对象的值，System.Type的TARGETTYPE，对象参数，System.Globalization.CultureInfo文化） {抛出新System.NotSupportedException（ ）; } } } 然后使用XAML为您窗口。现在你应该可以看到就在你的XAML预览窗口中的结果。 修改：您可以将您的帆布另一个Canvas中修复背景问题。很怪，但它的作品。此外，我添加了翻转Y轴，使Y正达和负面的跌幅为ScaleTransform。仔细注意哪些名字去的地方： <帆布NAME =画布的背景=莫卡辛> <帆布NAME =innerCanvas> < Canvas.RenderTransform> <&的TransformGroup GT; < TranslateTransform X：NAME =翻译> < TranslateTransform.X> <绑定的ElementName =画布PATH =ActualWidth的转换器={StaticResource的mu​​ltiplyConverter}ConverterParameter =0.5/> < /TranslateTransform.X> < TranslateTransform.Y> <绑定的ElementName =画布PATH =的ActualHeight转换器={StaticResource的mu​​ltiplyConverter}ConverterParameter =0.5/> < /TranslateTransform.Y> < / TranslateTransform> < ScaleTransform的ScaleX =1的scaleY = - 1的centerX ={绑定的ElementName =翻译，路径= X} CenterY ={绑定的ElementName =翻译，路径= Y} /> < /&的TransformGroup GT; < /Canvas.RenderTransform> <矩形Canvas.Top = - 50Canvas.Left = - 50HEIGHT =100WIDTH =200填充=蓝/> <矩形Canvas.Top =0Canvas.Left =0HEIGHT =200WIDTH =100填充=绿色/> <矩形Canvas.Top = - 25Canvas.Left = - 25HEIGHT =50WIDTH =50填充=暗粉红/> < /帆布> < /帆布> 至于你需要不同范围的新要求，更复杂的ValueConverter可能会做的伎俩。 I'm writing a mapping app that uses a Canvas for positioning elements. For each element I have to programatically convert element's Lat/Long to the canvas' coordinate, then set the Canvas.Top and Canvas.Left properties.If I had a 360x180 Canvas, can I convert the coordinates on the canvas to go from -180 to 180 rather than 0 to 360 on the X axis and 90 to -90 rather than 0 to 180 on the Y axis?Scaling requirements:The canvas can be any size, so should still work if it's 360x180 or 5000x100.The Lat/Long area may not always be (-90,-180)x(90,180), it could be anything (ie (5,-175)x(89,-174)).Elements such as PathGeometry which are point base, rather than Canvas.Top/Left based need to work. 解决方案 Here's an all-XAML solution. Well, mostly XAML, because you have to have the IValueConverter in code. So: Create a new WPF project and add a class to it. The class is MultiplyConverter:namespace YourProject{ public class MultiplyConverter : System.Windows.Data.IValueConverter { public object Convert(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture) { return AsDouble(value)* AsDouble(parameter); } double AsDouble(object value) { var valueText = value as string; if (valueText != null) return double.Parse(valueText); else return (double)value; } public object ConvertBack(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture) { throw new System.NotSupportedException(); } }}Then use this XAML for your Window. Now you should see the results right in your XAML preview window.EDIT: You can fix the Background problem by putting your Canvas inside another Canvas. Kind of weird, but it works. In addition, I've added a ScaleTransform which flips the Y-axis so that positive Y is up and negative is down. Note carefully which Names go where:<Canvas Name="canvas" Background="Moccasin"> <Canvas Name="innerCanvas"> <Canvas.RenderTransform> <TransformGroup> <TranslateTransform x:Name="translate"> <TranslateTransform.X> <Binding ElementName="canvas" Path="ActualWidth" Converter="{StaticResource multiplyConverter}" ConverterParameter="0.5" /> </TranslateTransform.X> <TranslateTransform.Y> <Binding ElementName="canvas" Path="ActualHeight" Converter="{StaticResource multiplyConverter}" ConverterParameter="0.5" /> </TranslateTransform.Y> </TranslateTransform> <ScaleTransform ScaleX="1" ScaleY="-1" CenterX="{Binding ElementName=translate,Path=X}" CenterY="{Binding ElementName=translate,Path=Y}" /> </TransformGroup> </Canvas.RenderTransform> <Rectangle Canvas.Top="-50" Canvas.Left="-50" Height="100" Width="200" Fill="Blue" /> <Rectangle Canvas.Top="0" Canvas.Left="0" Height="200" Width="100" Fill="Green" /> <Rectangle Canvas.Top="-25" Canvas.Left="-25" Height="50" Width="50" Fill="HotPink" /> </Canvas></Canvas>As for your new requirements that you need varying ranges, a more complex ValueConverter would probably do the trick. 这篇关于更改WPF画布的坐标系的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！