# FVideoCanvas (/zh-CN/api-reference/rtc/unreal-blueprint/class-videocanvas)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

<a id="class_videocanvas__prototype"></a>

```cpp
USTRUCT(BlueprintType)
struct FVideoCanvas
{
	GENERATED_BODY()
public:
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	int64 uid = 0;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	int64 subviewUid = 0;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	UImage* view = nullptr;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	int64 backgroundColor = 0;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	ERENDER_MODE_TYPE renderMode = ERENDER_MODE_TYPE::RENDER_MODE_HIDDEN;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	EVIDEO_MIRROR_MODE_TYPE mirrorMode = EVIDEO_MIRROR_MODE_TYPE::VIDEO_MIRROR_MODE_AUTO;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	EVIDEO_VIEW_SETUP_MODE setupMode = EVIDEO_VIEW_SETUP_MODE::VIDEO_VIEW_SETUP_REPLACE;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	EVIDEO_SOURCE_TYPE sourceType = EVIDEO_SOURCE_TYPE::VIDEO_SOURCE_CAMERA_PRIMARY;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	int mediaPlayerId = 0;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	FRectangle cropArea;

	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	bool enableAlphaMask = false;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Agora|VideoCanvas")
	EVIDEO_MODULE_POSITION position = EVIDEO_MODULE_POSITION::POSITION_POST_CAPTURER;

	FVideoCanvas(){}
	FVideoCanvas(const agora::rtc::VideoCanvas & AgoraData){
		view = nullptr; 		uid = AgoraData.uid;
		subviewUid = AgoraData.subviewUid;
		backgroundColor = AgoraData.backgroundColor;
		renderMode = static_cast<ERENDER_MODE_TYPE>(AgoraData.renderMode);
		mirrorMode = static_cast<EVIDEO_MIRROR_MODE_TYPE>(AgoraData.mirrorMode);
		setupMode = static_cast<EVIDEO_VIEW_SETUP_MODE>(AgoraData.setupMode);
		sourceType = static_cast<EVIDEO_SOURCE_TYPE>(AgoraData.sourceType);
		mediaPlayerId = AgoraData.mediaPlayerId;
		cropArea = FRectangle(AgoraData.cropArea);
		enableAlphaMask = AgoraData.enableAlphaMask;
		position = static_cast<EVIDEO_MODULE_POSITION>(AgoraData.position);
	}
	agora::rtc::VideoCanvas CreateAgoraData() const {
		agora::rtc::VideoCanvas AgoraData;
		AgoraData.view = (agora::view_t) view;
		AgoraData.uid = uid;
		AgoraData.subviewUid = subviewUid;
		AgoraData.backgroundColor = backgroundColor;
		AgoraData.renderMode = static_cast<agora::media::base::RENDER_MODE_TYPE>(renderMode);
		AgoraData.mirrorMode = static_cast<agora::rtc::VIDEO_MIRROR_MODE_TYPE>(mirrorMode);
		AgoraData.setupMode = static_cast<agora::rtc::VIDEO_VIEW_SETUP_MODE>(setupMode);
		AgoraData.sourceType = static_cast<agora::rtc::VIDEO_SOURCE_TYPE>(sourceType);
		AgoraData.mediaPlayerId = AgoraData.mediaPlayerId;
		AgoraData.cropArea = cropArea.CreateAgoraData();
		AgoraData.enableAlphaMask = enableAlphaMask;
		AgoraData.position = static_cast<agora::media::base::VIDEO_MODULE_POSITION>(position);
		return AgoraData;
	}
	void FreeAgoraData(agora::rtc::VideoCanvas& AgoraData) const {
		cropArea.FreeAgoraData(AgoraData.cropArea);
	}
};
```

<a id="class_videocanvas__detailed_desc"></a>

<a id="class_videocanvas__parameters"></a>

## 属性 [#属性]

<ParameterList>
<a id="uid"></a>
<Parameter name="uid">

发布视频源的用户 ID。

</Parameter>
<a id="subviewuid"></a>
<Parameter name="subviewUid">

发布某一路合图子视频流的用户 ID。

</Parameter>
<a id="view"></a>
<Parameter name="view">

视频图像。你需要定义 UImage 类型的指针，并传入该参数，示例代码如下：

```text
agora::rtc::VideoCanvas videoCanvas;
    UImage* LocalVideo;
    videoCanvas.view = LocalVideo;
```

</Parameter>
<a id="rendermode"></a>
<Parameter name="renderMode">

视频渲染模式，详见 [ERENDER_MODE_TYPE](/zh-CN/api-reference/rtc/unreal-blueprint/enum-rendermodetype)。

</Parameter>
<a id="mirrormode"></a>
<Parameter name="mirrorMode">

视图镜像模式，详见 [EUABT_VIDEO_MIRROR_MODE_TYPE](/zh-CN/api-reference/rtc/unreal-blueprint/enum-videomirrormodetype)。

:::caution
注意： 该参数不生效。如需实现镜像显示效果，请在 Unreal Engine 中进行镜像设置。
:::

:::caution
注意：

- 本地视图镜像模式：如果你使用前置摄像头，默认启动本地视图镜像模式；如果你使用后置摄像头，默认关闭本地视图镜像模式。
- 远端用户视图镜像模式：默认关闭远端用户的镜像模式。
:::

</Parameter>
<a id="sourcetype"></a>
<Parameter name="sourceType">

视频源的类型，详见 [EUABT_VIDEO_SOURCE_TYPE](/zh-CN/api-reference/rtc/unreal-blueprint/enum-videosourcetype)。

</Parameter>
<a id="setupmode"></a>
<Parameter name="setupMode">

视图设置模式。详见 [EVIDEO_VIEW_SETUP_MODE](/zh-CN/api-reference/rtc/unreal-blueprint/enum-videoviewsetupmode)。

</Parameter>
<a id="croparea"></a>
<Parameter name="cropArea">

（可选）视频帧的展示区域，详见 [FRectangle](/zh-CN/api-reference/rtc/unreal-blueprint/class-rectangle)。其中，width 和 height 表示该区域的视频像素宽度和高度。默认值为空值 (宽或高为 0)，表示展示实际分辨率的视频帧。

</Parameter>
<a id="backgroundcolor"></a>
<Parameter name="backgroundColor">

视频画布的背景颜色，格式为 RGBA。默认值为 0x00000000，代表完全透明的黑色。

</Parameter>
<a id="enablealphamask"></a>
<Parameter name="enableAlphaMask">

（可选）是否开启 Alpha 遮罩渲染：

- `true`：开启 Alpha 遮罩渲染。
- `false`：（默认）关闭 Alpha 遮罩渲染。

Alpha 遮罩渲染可以创建具有透明效果的图像，还可以提取视频中的人像。与其他方法结合使用时，可以实现人像画中画、添加水印等效果。

:::caution
注意：

- 仅当发送端开启 Alpha 传输功能时，接收端才能渲染 Alpha 通道的信息。
- 如需开启 Alpha 传输功能，请[联系技术支持](https://ticket.shengwang.cn/)。
:::

</Parameter>
<a id="position"></a>
<Parameter name="position">

视频帧在视频链路中的位置。详见 [EUABT_VIDEO_MODULE_POSITION](/zh-CN/api-reference/rtc/unreal-blueprint/enum-videomoduleposition)。

</Parameter>
</ParameterList>