THotPDF.AddPageLayer Method
Registers a reusable background, header, footer, or foreground callback for stable page composition
声明
function AddPageLayer(Kind: THPDFPageLayerKind; Handler: THPDFPageLayerEvent): Integer;单元
HPDFDoc
参数
| 名称 | 用途 |
|---|---|
Kind | Composition position for the reusable page layer |
Handler | Object-method callback invoked once for each generated page |
返回值
Returns a stable positive identifier for later removal
使用说明
- Register page layers before BeginDoc
- Callbacks execute once per page in background, header, content, footer, and foreground order
- Each callback is isolated by a graphics-state save and restore pair