我只是希望用户能够用某种指针在屏幕上绘图。
我已经有了捕获指针位置的代码,但我不知道如何将像素或形状或任何东西放在屏幕上。
我发现了这个有用的教程:
http://www.dotnetspeaks.com/DisplayArticle.aspx?ID=137
我一直在看这里的文档:
http://msdn.microsoft.com/en-us/library/windows/apps/hh465055 (v = VS.85) . aspx
到目前为止还没有运气。这个教程是针对Windows Phone 7的,所以有点不同。请帮忙?=)
这是我目前得到的。
绘图部分:
private void Image_PointerPressed(object sender, PointerEventArgs e)
{
Debug.WriteLine("Image_PointerPressed");
isTracing = true;
}
private void Image_PointerReleased(object sender, PointerEventArgs e)
{
Debug.WriteLine("Image_PointerReleased");
isTracing = false;
}
private void Image_PointerMoved(object sender, PointerEventArgs e)
{
Debug.WriteLine("Image_PointerMoved");
Debug.WriteLine(e.GetCurrentPoint(this).Position);
if (isTracing)
{
Debug.WriteLine("isTracing");
Point pos = e.GetCurrentPoint(this).Position;
Color color = Colors.Green;
Line line = new Line() { X1 = pos.X, X2 = pos.X + 1, Y1 = pos.Y, Y2 = pos.Y + 1 };
line.Stroke = new SolidColorBrush(color);
line.StrokeThickness = 15;
//// So how do I draw this line onto the screen?? ////
}
}
作为参考,代码中其他地方的东西:
<>之前使用系统;使用System.Collections.Generic;使用System.Diagnostics;使用先;使用来;使用System.Threading.Tasks;使用Multimedia.FFmpeg;使用Windows.Foundation;使用Windows.Storage;使用Windows.Storage.Pickers;使用Windows.Storage.Streams;使用Windows.UI.Xaml;使用Windows.UI.Xaml.Controls;使用Windows.UI.Xaml.Shapes;使用Windows.UI.Xaml.Media;使用Windows.UI.Xaml.Input;使用Windows.UI.Input;bool istring = false;简写:
- 添加
Line
s和Rectangle
s到面板 - 直接操作位图
- 在JavaScript/HTML项目中使用HTML5 Canvas元素
- 用c++/DirectX编写整个程序
OnRender()
方法或类似的方法。你的选择是将现有的图形元素(例如从形状命名空间)添加到画布或其他面板,或者直接操作位图中的像素并将该位图推入图像元素。
Metro/c#只有保留模式的图形绘制,这意味着它只会渲染已经添加到视图层次结构中的对象。你要找的是某种即时模式的图形绘制,例如
myCanvas.DrawLine( fromPoint, toPoint );
这可以在JavaScript/HTML项目中使用HTML5的Canvas对象完成。可悲的是,这就是我对这样一个项目的学习方式。不幸的是,微软没有为XAML项目提供即时模式元素,但这就是它的方式。c++/DirectX也是一个自定义绘图的选项,但需要大量的重做你在应用程序中所做的一切。
这里有一个很好的代码示例,说明如何使用XAML形状来做到这一点。
http://www.codeproject.com/Articles/416878/Metro-Paint您应该将Line添加到UI元素中,例如Canvas
在你的代码的主要问题是,你没有附加,行到任何XAML元素,我建议你做一个画布元素,更少像这样:
newCanvas.Children.Add(line);
另一种选择是使用Modern Components Drawing Library,它可以在WinRT上工作,使用。net Graphics类(如调用)并直接在XAML Canvas上绘制,注意如果你想将图像保存为位图,你可能还需要使用WritableBitmapEx,因为XAML Canvas不能渲染为位图。
这个示例项目用c#/XAML在屏幕上绘制win8 Store应用程序的代码:
http://code.msdn.microsoft.com/windowsapps/drawing——一个画布上-和- 33510 - ae6
下面是相关的c#文件:
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Windows.Devices.Input;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI;
using Windows.UI.Input;
using Windows.UI.Input.Inking; //we need to add this name space in order to have many functions
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
using Windows.UI.Xaml.Shapes;
// The Blank Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234238
namespace DrawingOnCanvasWithInkPen
{
/// <summary>
/// An empty page that can be used on its own or navigated to within a Frame.
/// </summary>
public sealed partial class MainPage : Page
{
InkManager _inkKhaled = new Windows.UI.Input.Inking.InkManager();
private uint _penID;
private uint _touchID;
private Point _previousContactPt;
private Point currentContactPt;
private double x1;
private double y1;
private double x2;
private double y2;
public MainPage()
{
this.InitializeComponent();
MyCanvas.PointerPressed += new PointerEventHandler(MyCanvas_PointerPressed);
MyCanvas.PointerMoved += new PointerEventHandler(MyCanvas_PointerMoved);
MyCanvas.PointerReleased += new PointerEventHandler(MyCanvas_PointerReleased);
MyCanvas.PointerExited += new PointerEventHandler(MyCanvas_PointerReleased);
}
#region PointerEvents
private void MyCanvas_PointerReleased(object sender, PointerRoutedEventArgs e)
{
if (e.Pointer.PointerId == _penID)
{
Windows.UI.Input.PointerPoint pt = e.GetCurrentPoint(MyCanvas);
// Pass the pointer information to the InkManager.
_inkKhaled.ProcessPointerUp(pt);
}
else if (e.Pointer.PointerId == _touchID)
{
// Process touch input
}
_touchID = 0;
_penID = 0;
// Call an application-defined function to render the ink strokes.
e.Handled = true;
}
private void MyCanvas_PointerMoved(object sender, PointerRoutedEventArgs e)
{
if (e.Pointer.PointerId == _penID)
{
PointerPoint pt = e.GetCurrentPoint(MyCanvas);
// Render a red line on the canvas as the pointer moves.
// Distance() is an application-defined function that tests
// whether the pointer has moved far enough to justify
// drawing a new line.
currentContactPt = pt.Position;
x1 = _previousContactPt.X;
y1 = _previousContactPt.Y;
x2 = currentContactPt.X;
y2 = currentContactPt.Y;
if (Distance(x1, y1, x2, y2) > 2.0) // We need to developp this method now
{
Line line = new Line()
{
X1 = x1,
Y1 = y1,
X2 = x2,
Y2 = y2,
StrokeThickness = 4.0,
Stroke = new SolidColorBrush(Colors.Green)
};
_previousContactPt = currentContactPt;
// Draw the line on the canvas by adding the Line object as
// a child of the Canvas object.
MyCanvas.Children.Add(line);
// Pass the pointer information to the InkManager.
_inkKhaled.ProcessPointerUpdate(pt);
}
}
else if (e.Pointer.PointerId == _touchID)
{
// Process touch input
}
}
private double Distance(double x1, double y1, double x2, double y2)
{
double d = 0;
d = Math.Sqrt(Math.Pow((x2 - x1), 2) + Math.Pow((y2 - y1), 2));
return d;
}
private void MyCanvas_PointerPressed(object sender, PointerRoutedEventArgs e)
{
// Get information about the pointer location.
PointerPoint pt = e.GetCurrentPoint(MyCanvas);
_previousContactPt = pt.Position;
// Accept input only from a pen or mouse with the left button pressed.
PointerDeviceType pointerDevType = e.Pointer.PointerDeviceType;
if (pointerDevType == PointerDeviceType.Pen ||
pointerDevType == PointerDeviceType.Mouse &&
pt.Properties.IsLeftButtonPressed)
{
// Pass the pointer information to the InkManager.
_inkKhaled.ProcessPointerDown(pt);
_penID = pt.PointerId;
e.Handled = true;
}
else if (pointerDevType == PointerDeviceType.Touch)
{
// Process touch input
}
}
#endregion
/// <summary>
/// Invoked when this page is about to be displayed in a Frame.
/// </summary>
/// <param name="e">Event data that describes how this page was reached. The Parameter
/// property is typically used to configure the page.</param>
protected override void OnNavigatedTo(NavigationEventArgs e)
{
}
}
}
and
<Page
x:Class="DrawingOnCanvasWithInkPen.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:DrawingOnCanvasWithInkPen"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
<Canvas Name="MyCanvas" Background="White" HorizontalAlignment="Left" Height="513" Margin="83,102,0,0" VerticalAlignment="Top" Width="1056"/>
</Grid>
在目前的状态下,它只能处理笔或鼠标输入——但我也让它在触摸时工作,只需要稍微修改一下。