前面说到了inkcanvas的基本操作，这里用一个实例来说明具体应用：绘制矩形和椭圆。
效果图
xaml代码
< window x:class = "wpf_inkcanvas.roi_inkcanvas"
xmlns = "http://schemas.microsoft测试数据/winfx/2006/xaml/presentation"
xmlns:x = "http://schemas.microsoft测试数据/winfx/2006/xaml"
xmlns:d = "http://schemas.microsoft测试数据/expression/blend/2008"
xmlns:mc = "http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local = "clr-namespace:wpf_inkcanvas"
mc:ignorable = "d"
title = "roi_inkcanvas" height = "450" width = "800" >
< grid >
< grid.rowdefinitions >
< rowdefinition />
< rowdefinition height = "auto" />
</ grid.rowdefinitions >
< image name = "imgmeasure" horizontalalignment = "center" stretch = "uniform" />
< inkcanvas name = "inkcanvasmeasure" editingmode = "none" background = "transparent" strokes = "{binding inkstrokes, mode=twoway}" horizontalalignment = "center"
width = "{binding elementname=imgmeasure, path=actualwidth}" height = "{binding elementname=imgmeasure, path=actualheight}"
mousedown = "inkcanvasmeasure_mousedown" mousemove = "inkcanvasmeasure_mousemove" >
< label content = "{binding meainfo}" background = "transparent" horizontalalignment = "left" verticalalignment = "top" margin = "10"
fontsize = "18" foreground = "red" ishittestvisible = "false" />
</ inkcanvas >
< stackpanel grid.row = "1" orientation = "horizontal" >
< button content = "openfile" margin = "5" horizontalalignment = "left" fontsize = "20" click = "openfile_click" />
< togglebutton name = "btnsquare" content = "draw square" margin = "5" horizontalalignment = "left" fontsize = "20" click = "drawsquare_click" />
< togglebutton name = "btnellipse" content = "draw ellipse" margin = "5" horizontalalignment = "left" fontsize = "20" click = "drawellipse_click" />
</ stackpanel >
</ grid >
</ window >
后台代码
using microsoft.win32;
using system;
using system.collections.generic;
using system.linq;
using system.text;
using system.threading.tasks;
using system.windows;
using system.windows.controls;
using system.windows.data;
using system.windows.documents;
using system.windows.ink;
using system.windows.input;
using system.windows.media;
using system.windows.media.imaging;
using system.windows.shapes;
namespace wpf_inkcanvas
{
/// <summary>
/// roi_inkcanvas.xaml 的交互逻辑
/// </summary>
public partial class roi_inkcanvas : window
{
private viewmodel viewmodel;
private system.windows.point inip;
public roi_inkcanvas()
{
initializecomponent();
drawingattributes drawingattributes = new drawingattributes
{
color = colors.red,
width = 2,
height = 2,
stylustip = stylustip.rectangle,
//fittocurve = true,
ishighlighter = false ,
ignorepressure = true ,
};
inkcanvasmeasure.defaultdrawingattributes = drawingattributes;
viewmodel = new viewmodel
{
meainfo = "测试······" ,
inkstrokes = new strokecollection(),
};
datacontext = viewmodel;
}
private void openfile_click( object sender, routedeventargs e)
{
openfiledialog opendialog = new openfiledialog
{
filter = "image files (*.jpg)|*.jpg|image files (*.png)|*.png|image files (*.bmp)|*.bmp" ,
title = "open image file"
};
if (opendialog.showdialog() == true )
{
bitmapimage image = new bitmapimage();
image.begininit();
image.urisource = new uri(opendialog.filename, urikind.relativeorabsolute);
image.endinit();
imgmeasure.source = image;
}
}
private void drawsquare_click( object sender, routedeventargs e)
{
if (btnsquare.ischecked == true )
{
btnellipse.ischecked = false ;
}
}
private void drawellipse_click( object sender, routedeventargs e)
{
if (btnellipse.ischecked == true )
{
btnsquare.ischecked = false ;
}
}
private list<system.windows.point> generateeclipsegeometry(system.windows.point st, system.windows.point ed)
{
double a = 0.5 * (ed.x - st.x);
double b = 0.5 * (ed.y - st.y);
list<system.windows.point> pointlist = new list<system.windows.point>();
for ( double r = 0; r <= 2 * math.pi; r = r + 0.01)
{
pointlist.add( new system.windows.point(0.5 * (st.x + ed.x) + a * math.cos(r), 0.5 * (st.y + ed.y) + b * math.sin(r)));
}
return pointlist;
}
private void inkcanvasmeasure_mousedown( object sender, mousebuttoneventargs e)
{
if (e.leftbutton == mousebuttonstate.pressed)
{
inip = e.getposition(inkcanvasmeasure);
}
}
private void inkcanvasmeasure_mousemove( object sender, mouseeventargs e)
{
if (e.leftbutton == mousebuttonstate.pressed)
{
// draw square
if (btnsquare.ischecked == true )
{
system.windows.point endp = e.getposition(inkcanvasmeasure);
list<system.windows.point> pointlist = new list<system.windows.point>
{
new system.windows.point(inip.x, inip.y),
new system.windows.point(inip.x, endp.y),
new system.windows.point(endp.x, endp.y),
new system.windows.point(endp.x, inip.y),
new system.windows.point(inip.x, inip.y),
};
styluspointcollection point = new styluspointcollection(pointlist);
stroke stroke = new stroke(point)
{
drawingattributes = inkcanvasmeasure.defaultdrawingattributes.clone()
};
viewmodel.inkstrokes.clear();
viewmodel.inkstrokes.add(stroke);
}
// draw eclipse
else if (btnellipse.ischecked == true )
{
system.windows.point endp = e.getposition(inkcanvasmeasure);
list<system.windows.point> pointlist = generateeclipsegeometry(inip, endp);
styluspointcollection point = new styluspointcollection(pointlist);
stroke stroke = new stroke(point)
{
drawingattributes = inkcanvasmeasure.defaultdrawingattributes.clone()
};
viewmodel.inkstrokes.clear();
viewmodel.inkstrokes.add(stroke);
}
}
}
}
}
viewmodel.cs代码
using system;
using system.collections.generic;
using system测试数据ponentmodel;
using system.linq;
using system.text;
using system.threading.tasks;
using system.windows.ink;
namespace wpf_inkcanvas
{
class viewmodel : inotifypropertychanged
{
public event propertychangedeventhandler propertychanged;
protected virtual void onpropertychanged( string propertyname = null )
{
if (propertychanged != null )
propertychanged.invoke( this , new propertychangedeventargs(propertyname));
}
private string meainfo;
public string meainfo
{
get => meainfo;
set
{
meainfo = value;
onpropertychanged( "meainfo" );
}
}
private strokecollection inkstrokes;
public strokecollection inkstrokes
{
get { return inkstrokes; }
set
{
inkstrokes = value;
onpropertychanged( "inkstrokes" );
}
}
}
}
补充说明： 为什么要注释掉画笔属性//fittocurve = true,可以自行体会下不注释会是个什么效果；将inkcanvas的strokes绑定到变量有好处，在别的窗口也能获取到这个对象的哦，因为它是在viewmodel里的，传viewmodel参数就可以了；椭圆绘制完成后设置inkcanvas的edittingmode为select就可以修改大小和形状。
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/u012366767/article/details/81266406
dy("nrwz");
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