OneOCR settings

OneOcrService (EngineId: oneocr) exposes engine settings through SettingDescriptor for UI hosts, and accepts the same keys as a dictionary in CreateSessionAsync.

Typed helper: OneOcrConfig → ToDictionary().

Keys

Key	Type	Default	Required when	Description
source	enum string	auto	always	Where to load oneocr.dll / model from
directoryPath	directory path	—	source = directory	Folder with oneocr.dll, onnxruntime.dll, oneocr.onemodel
downloadUrl	URL	Zaya.External OneOCR.zip	source = url	Zip package URL; also used as auto fallback
cacheDirectory	directory path	%TEMP%\Zaya\OneOcr	—	Writable cache for copy/extract (auto / snippingtool / url)
minConfidence	int 0–100	70	—	Drop words with confidence below this percent

source values

Value	Behavior
auto	Use cache if complete; else try SnippingTool; on OneOcrSnippingToolNotFoundException download via downloadUrl
snippingtool	Use cache if complete; else resolve from Windows 11 SnippingTool and copy into cacheDirectory
directory	Load from directoryPath
url	Use cache if complete; else download zip from downloadUrl into cacheDirectory

A cache directory is treated as complete when it contains oneocr.dll, onnxruntime.dll, and oneocr.onemodel.

Visibility (UI)

Hosts should honor SettingDescriptor.IsVisible / IsRequired:

• directoryPath — visible only when source is directory
• downloadUrl — visible and required only when source is url (still used as auto fallback when needed)
• cacheDirectory — visible for auto, snippingtool, and url

Some hosts (for example ScreenTranslator) treat cacheDirectory as host-managed and inject a path under %AppData% instead of showing the field.

Example

using Zaya.OCR.Impl.OneOcr;
using Zaya.OCR.Impl.OneOcr;

using var ocr = new OneOcrService();

// Dictionary form
using var session = await ocr.CreateSessionAsync(new Dictionary<string, object>
{
    ["source"] = "auto",
    ["minConfidence"] = 40,
});

// Or typed config
var config = new OneOcrConfig
{
    Source = OneOcrSource.Directory,
    DirectoryPath = @"C:\tools\oneocr",
    MinConfidence = 40,
};
var settings = config.ToDictionary()
    .Where(kv => kv.Value is not null)
    .ToDictionary(kv => kv.Key, kv => kv.Value!);
using var session2 = await ocr.CreateSessionAsync(settings);

See also API remarks on OneOcrService.