我想要一个具有背景的面板,其显示重复的图案(例如,点,均匀分开30个像素)。
到目前为止,我设法创建了一个XamlCompositionBrushBase的子类,允许我们创建自己的形状(例如一个点)。但我不明白如何重复这种模式。
这是我的自定义画笔:
public sealed class DottedBackgroundBrush : XamlCompositionBrushBase
{
public DottedBackgroundBrush()
{
}
protected override void OnConnected()
{
// Delay creating composition resources until they're required.
if (CompositionBrush == null)
{
var compositor = Window.Current.Compositor;
// Actual Width/Height are going to be returned in effective pixels which
// is going to differ from the size of the bitmap that we'll render from the XAML.
var width = 400;
var height = 400;
// Make our visual:
var spriteVisual = compositor.CreateSpriteVisual();
spriteVisual.Size = new Vector2(width, height);
CanvasDevice device = CanvasDevice.GetSharedDevice();
var graphicsDevice = CanvasComposition.CreateCompositionGraphicsDevice(compositor, device);
CompositionSurfaceBrush drawingBrush = compositor.CreateSurfaceBrush();
var drawingSurface = graphicsDevice.CreateDrawingSurface(
new Size(width, height),
DirectXPixelFormat.B8G8R8A8UIntNormalized,
DirectXAlphaMode.Premultiplied);
using (var ds = CanvasComposition.CreateDrawingSession(drawingSurface))
{
ds.Clear(Colors.Transparent);
ds.DrawCircle(new Vector2(10, 10), 5, Colors.Black, 3);
}
drawingBrush.Surface = drawingSurface;
CompositionBrush = drawingBrush;
}
}
protected override void OnDisconnected()
{
// Dispose of composition resources when no longer in use.
if (CompositionBrush != null)
{
CompositionBrush.Dispose();
CompositionBrush = null;
}
}
}
如何才能无限期地复制圆圈,而不是单个实例?
为此,你想创建一个CompositionEffectBrush作为你的主刷,使用Win2D BorderEffect - 它进行实际的平铺 - 并将它的源设置为SurfaceBrush。
示例(改编自我的repo所以它可能有点环形交叉口)
public class TilingBrush : XamlCompositionBrushBase
{
protected Compositor _compositor => Window.Current.Compositor;
protected CompositionBrush _imageBrush = null;
protected IDisposable _surfaceSource = null;
protected override void OnConnected()
{
base.OnConnected();
if (CompositionBrush == null)
{
CreateEffectBrush();
Render();
}
}
protected override void OnDisconnected()
{
base.OnDisconnected();
this.CompositionBrush?.Dispose();
this.CompositionBrush = null;
ClearResources();
}
private void ClearResources()
{
_imageBrush?.Dispose();
_imageBrush = null;
_surfaceSource?.Dispose();
_surfaceSource = null;
}
private void UpdateBrush()
{
if (CompositionBrush != null && _imageBrush != null)
{
((CompositionEffectBrush)CompositionBrush).SetSourceParameter(nameof(BorderEffect.Source), _imageBrush);
}
}
protected ICompositionSurface CreateSurface()
{
double width = 20;
double height = 20;
CanvasDevice device = CanvasDevice.GetSharedDevice();
var graphicsDevice = CanvasComposition.CreateCompositionGraphicsDevice(_compositor, device);
var drawingSurface = graphicsDevice.CreateDrawingSurface(
new Size(width, height),
DirectXPixelFormat.B8G8R8A8UIntNormalized,
DirectXAlphaMode.Premultiplied);
/* Create Drawing Session is not thread safe - only one can ever be active at a time per app */
using (var ds = CanvasComposition.CreateDrawingSession(drawingSurface))
{
ds.Clear(Colors.Transparent);
ds.DrawCircle(new Vector2(10, 10), 5, Colors.Black, 3);
}
return drawingSurface;
}
private void Render()
{
ClearResources();
try
{
var src = CreateSurface();
_surfaceSource = src as IDisposable;
var surfaceBrush = _compositor.CreateSurfaceBrush(src);
surfaceBrush.VerticalAlignmentRatio = 0.0f;
surfaceBrush.HorizontalAlignmentRatio = 0.0f;
surfaceBrush.Stretch = CompositionStretch.None;
_imageBrush = surfaceBrush;
UpdateBrush();
}
catch
{
// no image for you, soz.
}
}
private void CreateEffectBrush()
{
using (var effect = new BorderEffect
{
Name = nameof(BorderEffect),
ExtendY = CanvasEdgeBehavior.Wrap,
ExtendX = CanvasEdgeBehavior.Wrap,
Source = new CompositionEffectSourceParameter(nameof(BorderEffect.Source))
})
using (var _effectFactory = _compositor.CreateEffectFactory(effect))
{
this.CompositionBrush = _effectFactory.CreateBrush();
}
}
}
最长的时间我打算将它添加到WindowsCommunityToolkit中,但是最长的时间我一直在用可视化层来阻止我。但这个特殊情况应该可以正常工作。