OCRPageEx

OCR, rendering, document editing

Description

Checks the existing-text policy, renders one page to PNG when needed, invokes the selected OCR provider, and applies the result as an owned invisible text layer

Syntax

Delphi

Function TPDFlib.OCRPageEx(Page: Integer; DPI: Double; Const Language,
  FontName: WideString; MinConfidence: Double; Options: Integer): Integer;

ActiveX

Function PDFlib::OCRPageEx(Page As Long, DPI As Double, Language As String,
  FontName As String, MinConfidence As Double, Options As Long) As Long

DLL

int DLOCRPageEx(int InstanceID, int Page, double DPI, const wchar_t* Language,
  const wchar_t* FontName, double MinConfidence, int Options);
int DLOCRPageExA(int InstanceID, int Page, double DPI, const char* Language,
  const char* FontName, double MinConfidence, int Options);

Parameters

Page	The one-based target page
DPI	The finite positive raster resolution supplied to the provider
Language	A provider-defined language hint; the configured Tesseract provider uses trained-data names such as `eng`
FontName	An embeddable TrueType font or an empty string for fallback selection
MinConfidence	The inclusive word-confidence threshold from 0 through 1
Options	The bitwise layer policies defined by ApplyOCRTextLayerEx; zero appends, 1 skips existing non-owned text, and 2 replaces owned OCR layers

Return values

1	The result was applied, the page was skipped, or no word met the threshold
0	Rendering, provider execution, result validation, layer writing, or cancellation prevented completion

Remarks

Use ConfigureTesseractOCR for the supplied engine adapter or assign an application-owned OnOCRPage callback

The existing-text check runs before rendering and provider execution, so a skipped page does not require an OCR engine

Only owned old OCR streams are ignored by that check; a foreign invisible text layer or hidden text in an invoked Form XObject still counts as existing text

Enable orientation detection explicitly for scans that need a verified quarter-turn correction; low orientation confidence fails without changing the OCR layer

Read GetOCRDiagnosticsJSON for the layer action and configured engine's latest recognition and orientation reports