> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# BlockLayerTypeEnum

BlockLayerTypeEnum enumeration constants are used to describe the layers to which blocks belong. Blocks may be overlaid, for example, a text block may lay over a background picture block.

```
typedef enum {
 BLT_Background,
 BLT_Foreground,
 BLT_Hidden
} BlockLayerTypeEnum;
```

## Elements

| Name              | Description                                                                                                                                                                                                                                                                                                                                     |
| ----------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| BLT\\\_Background | The block belongs to background of the page.                                                                                                                                                                                                                                                                                                    |
| BLT\\\_Foreground | The block is on foreground of the page.                                                                                                                                                                                                                                                                                                         |
| BLT\\\_Hidden     | The block is hidden. Such blocks appear in the layout, if the [IPageAnalysisParams::DetectTextOnPictures](/fine-reader/engine/api-reference/parameter-objects/preprocessing-analysis-recognition-and-synthesis-parameters/pageanalysisparams#detecttextonpictures) property was set to TRUE during recognition and text was found on a picture. |

## Used in

[IBlock::BlockLayerType](/fine-reader/engine/api-reference/layout-related-objects/block#blocklayertype)

[RasterPictureBlock::SetBlockLayerType](/fine-reader/engine/api-reference/layout-related-objects/vectorpictureblock/setblocklayertype-method)

[VectorPictureBlock::SetBlockLayerType](/fine-reader/engine/api-reference/layout-related-objects/vectorpictureblock/setblocklayertype-method)