我已经进行了子类化Canvas
,以便我可以覆盖它的Render
功能。我需要知道如何在 WPF 中加载位图并将其渲染到画布上。我对 WPF 完全陌生,我还没有找到任何教程来告诉你如何做一些看似微不足道的事情。带有示例的分步说明会很棒。
问问题
33667 次
3 回答
15
In WPF it is a rare case that you would need to override OnRender
especially if all you wanted to do was draw a BMP to a background:
<Canvas>
<Canvas.Background>
<ImageBrush ImageSource="Resources\background.bmp" />
</Canvas.Background>
<!-- ... -->
</Canvas>
于 2010-01-30T16:12:40.293 回答
11
这应该让你开始:
class MyCanvas : Canvas {
protected override void OnRender (DrawingContext dc) {
BitmapImage img = new BitmapImage (new Uri ("c:\\demo.jpg"));
dc.DrawImage (img, new Rect (0, 0, img.PixelWidth, img.PixelHeight));
}
}
于 2010-01-30T15:45:13.490 回答
3
如果您确实想绘制画布的背景,我建议您使用ImageBrush
as Background
,'因为这很简单,因为您不需要子类Canvas
来覆盖Onender
。
但我会给你一个演示源代码来满足你的要求:
创建一个类(我称之为ImageCanvas
)
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
namespace WpfApplication1
{
public class ImageCanvas : Canvas
{
public ImageSource CanvasImageSource
{
get { return (ImageSource)GetValue(CanvasImageSourceProperty); }
set { SetValue(CanvasImageSourceProperty, value); }
}
public static readonly DependencyProperty CanvasImageSourceProperty =
DependencyProperty.Register("CanvasImageSource", typeof(ImageSource),
typeof(ImageCanvas), new FrameworkPropertyMetadata(default(ImageSource)));
protected override void OnRender(System.Windows.Media.DrawingContext dc)
{
dc.DrawImage(CanvasImageSource, new Rect(this.RenderSize));
base.OnRender(dc);
}
}
}
现在你可以像这样使用它:
<Window x:Class="WpfApplication1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication1" Title="Window1" Height="300" Width="300">
<Grid>
<local:ImageCanvas CanvasImageSource="/Splash.png">
<TextBlock Text="Hello From Mihir!" />
</local:ImageCanvas>
</Grid>
</Window>
于 2010-01-30T16:06:17.813 回答