> ## 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.

# StraightenLinesModeEnum

StraightenLinesModeEnum Controls which algorithm is used to straighten text lines during text extraction.

```
typedef enum {
 SLM_Auto,
 SLM_Fast
} StraightenLinesModeEnum;
```

## Elements

| Name        | Description                                                                                                                                                                                                                                                                                                                                                                     |
| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| SLM\\\_Auto | Uses the new neural-network–based method for the best average quality (slower).                                                                                                                                                                                                                                                                                                 |
| SLM\\\_Fast | Uses the legacy non-NN method for maximum speed (lower average quality on average; may be better on some pages). For end users, prefer the [TextExtraction\\\_Speed or DocumentArchiving\\\_Speed](/fine-reader/engine/specifications/predefined-profiles-specification) presets, which set all related options consistently; toggling this flag alone isn’t always sufficient. |

## Used in

[PagePreprocessingParams::StraightenLinesMode](/fine-reader/engine/api-reference/parameter-objects/preprocessing-analysis-recognition-and-synthesis-parameters/pagepreprocessingparams)