WPF+SkiaSharp实现自绘弹幕效果_开发_开发者

SkiaSharp 自绘弹幕效果

框架使用.NET60；

Visual Studio 2022;

项目使用 MIT 开源许可协议；

接着上一篇 wpF 弹幕

上期有网友建议使用Skia实现弹幕。

弹幕消息使用SKElement做弹幕展现，然后在SKCanvas进行绘制弹幕。
由于需要绘制矩形与文本所以需要使用到SKBitmap进行绘制弹幕类。
创建SKBitmap设置宽（根据文本的长度定义宽度）与高度40。
创建对象SKCanvas并实例化的时候将SKBitmap传入，然后对SKCanvas进行绘制背景DrawRoundRect 与文本DrawText ，使用属性记录X与Y的值方便在动画的时候让弹幕动起来。
Barrage在Render的时候进行绘制弹幕图片DrawImage（SKBitmap,x,y） 。
弹幕每次移动多少值等于SKCanvas的宽除以弹幕的宽。
当弹幕移动Move()时如超过-Width则通过out返回GUID 就移除弹幕对象。

实现代码

1）准备 MsgInfo 弹幕消息类如下：

usingSystem;
usingSkiaSharp;

namespaceSkiaSharpBarrage
{
///<summary>
///msginfo
///</summary>
publicclassMsgInfo
{
privatestring_msg;

publicstringGUID;

publicmsgInfo(stringmsg,SKTypeface_font,floatWindowsWidth)
{
_msg=msg;
var_random=newRandom();
varskColor=newSKColor((byte)_random.Next(1,255),
(byte)_random.Next(1,255),(byte)_random.Next(1,233));
usingvarpaint=newSKPaint
{
Color=skColor,
Style=SKPaintStyle.Fill,
IsAntialias=true,
StrokeWidth=2
};
paint.Shader=SKShader.CreateLinearGradient(
newSKPoint(0,0),
newSKPoint(1,1),
new[]{SKColors.Transparent,skColor},
newfloat[]{0,1},
SKShaderTileMode.Repeat);

usingvarpaintText=newSKPaint
{
Color=SKColors.White,
IsAntialias=true,
Typeface=_font,
TextSize=24
};
vartextBounds=newSKRect();
paintText.MeasureText(msg,reftextBounds);
varwidth=textBounds.Width+100;
SKImageskImage;
using(varbitmap=newSKBitmap((int)width,40,true))
using(varcanvas=newSKCanvas(bitmap))
{
canvas.DrawRoundRect(0,0,width,40,20,20,paint);
canvas.DrawText(msg,width/2-textBounds.Width/2,bitmap.Height/2+textBounds.HeigampRUht/2,
paintText);
varimage=SKImage.FromBitmap(bitmap);
skImage=image;
}

SKImage=skImage;
Width=width;
X=windowsWidth+Width;
CanvasWidth=windowsWidth;
CostTime=TimeSpan.FromMilliseconds(Width);
GUID=Guid.NewGuid().ToString("N");
}

publicfloatX{get;set;}
publicfloatY{get;set;}
publicfloatWidth{get;set;}
publicfloatCanvasWidth{get;set;}
publicSKImageSKImage{get;set;}
publicfloatMoveNum=>CanvasWidth/(float)CostTime.TotalMilliseconds;
publicTimeSpanCostTime{get;set;}

///<summary>
///定时调用，移动指定距离
///</summary>
publicvoidMove(outstringguid)
{
guid=string.Empty;
X=X-MoveNum;
if(X<=-Width)
guid=GUID;
}
}
}

2）新建 Barrage.cs 类如下：

usingSystem.Collections.Generic;
usingSystem.Linq;
usingSkiaSharp;

namespaceSkiaSharpBarrage
{
publicclassBarrage
{
privatereadonlySKTypeface_font;
privatereadonlyList<MsgInfo>_MsgInfo;
privateint_num,_index;
privatedouble_right,_top;
privatefloat_width;
privatereadonlyandroidfloat_height;

publicBarrage(SKTypefacefont,floatwidth,floatheight,List<string>strList)
{
_width=width;
_height=height;
_font=font;
_num=(int)height/40;
_MsgInfo=newList<MsgInfo>();
foreach(variteminstrList)BuildMsgInfo(item);
}

privatevoidBuildMsgInfo(stringtext)
{
_index++;
if(_right!=0)
_width=(float)_right;
varmodel=newMsgInfo(text,_font,_width);
_right=_right==0?_height+model.Width:_right;
vary=_height-40;
_top=_top+40>=y?40:_top;
model.Y=(float)_top;
_MsgInfo.Add(model);
_top+=60;
}

publicvoidAddBarrage(stringtext)
{
BuildMsgInfo(text);
}

publicvoidRender(SKCanvascanvas,SKTypefacefont,intwidth,intheight,List<string>strList)
{
for(vari=0;i<_MsgInfo.Count;i++)
{
varinfo=_MsgInfo[i];
varguid=string.Empty;
info.Move(outguid);
if(!string.IsNullOrEmpty(guid))
{
varmodel=_MsgInfo.FirstOrDefault(x=>x.GUID==guid);
_MsgInfo.Remove(model);
}

canvas.DrawImage(info.SKImage,info.X,info.Y);
}
}
}
}

3） MainWind开发者_开发入门ow.xaml.cs 如下：

<wpfdev:Windowx:Class="SkiaSharpBarrage.MainWindow"
XMLns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:wpfdev="https://github.com/WPFDevelopersOrg/WPFDevelopers"
xmlns:skia="clr-namespace:SkiaSharp.Views.WPF;assembly=SkiaSharp.Views.WPF"
mc:Ignorable="d"WindowStartupLocation="CenterScreen"
ResizeMode="CanMinimize"
Title="SkiaSharpBarrage-弹幕篇"Height="450"Width="800">
<GridMargin="4">
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinitionHeight="Auto"/>
</Grid.RowDefinitions>
<MediaElementStretch="Uniform"Grid.RowSpan="2"
Name="myMediaElement"/>
<skia:SKElementx:Name="skElement"/>
<GridGrid.Row="1"Name="MyGrid">
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinitionWidth="Auto"/>
</Grid.ColumnDefinitions>
<TextBoxwpfdev:ElementHelper.IsWatermark="True"
x:Name="tbBarrage"
wpfdev:ElementHelper.Watermark="请弹幕内容"/>
<ButtonGrid.Column="1"Style="{StaticResourcePrimaryButton}"
Content="发射弹幕"Margin="4,0,0,0"
Click="ButtonBase_OnClick"/>
</Grid>
</Grid>
</wpfdev:Window>

3）逻辑 MainWinandroiddow.xaml.cs 如下：

usingSystem;
usingSystem.Collections.Generic;
usingSystem.IO;
usingSystem.Linq;
usingSystem.Threading;
usingSystem.Threading.Tasks;
usingSystem.Windows;
usingSkiaSharp;
usingSkiaSharp.Views.Desktop;

namespaceSkiaSharpBarrage
{
///<summary>
///InteractionlogicforMainWindow.xaml
///</summary>
publicpartialclassMainWindow
{
privatereadonlyBarrage_barrage;
privatereadonlySKTypeface_font;
privatereadonlyList<string>list=newList<string>();

publicMainWindow()
{
list.Add("2333");
list.Add("测试弹幕公众号：WPF开发者");
list.Add("很难开心");
list.Add("LOL~");
list.Add("青春记忆");
list.Add("bing");
list.Add("Microsoft"python);
InitializeComponent();
varindex=SKFontManager.Default.FontFamilies.ToList().IndexOf("微软雅黑");
_font=SKFontManager.Default.GetFontStyles(index).CreateTypeface(0);
_barrage=newBarrage(_font,(float)Width,(float)Height-(float)MyGrid.ActualHeight,list);
skElement.PaintSurface+=SkElement_PaintSurface;
Loaded+=delegate
{
myMediaElement.Source=
newUri(Path.Combine(AppDomain.CurrentDomain.BaseDirectory,"Leagueoflegends.mp4"));
};
_=Task.Run(()=>
{
try
{
while(true)
{
www.devze.comDispatcher.Invoke(()=>{skElement.InvalidateVisual();});
_=SpinWait.SpinUntil(()=>false,1000/60);//每秒60帧
}
}
catch(Exceptione)
{
}
});
}


privatevoidSkElement_PaintSurface(object?sender,SKPaintSurfaceEventArgse)
{
varcanvas=e.Surface.Canvas;
canvas.Clear();
_barrage.Render(canvas,_font,e.Info.Width,e.Info.Height,list);
}

privatevoidButtonBase_OnClick(objectsender,RoutedEventArgse)
{
_barrage.AddBarrage(tbBarrage.Text);
}
}
}

实现效果

WPF+SkiaSharp实现自绘弹幕效果