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tomasr78 merged 1 commit into from
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README: sections for the most-used APIs it did not cover, OCR first #94

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215 changes: 214 additions & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -75,10 +75,16 @@ Each task links to its C# code in this README and, where there is one, to a comp
| [Convert PDF to Word (DOCX)](#convert-pdf-to-word-in-c) | [ConvertPdfToDocx](https://github.com/ConvertAPI/convertapi-library-dotnet/blob/main/Examples/ConvertPdfToDocx/Program.cs) |
| [Convert PDF to JPG or PNG](#convert-pdf-to-jpg-or-png-in-c) | [CreatePdfThumbnail](https://github.com/ConvertAPI/convertapi-library-dotnet/blob/main/Examples/CreatePdfThumbnail/Program.cs) |
| [Extract text from PDF](#extract-text-from-pdf-in-c) | |
| [OCR a scanned PDF to make it searchable](#ocr-a-scanned-pdf-in-c) | |
| [Compress PDF](#compress-pdf-in-c) | |
| [Convert HTML to Word (DOCX)](#convert-html-to-docx-in-c) | |
| [Convert PowerPoint (PPTX) to PDF](#powerpoint-to-pdf) | [ConvertRemoteFile](https://github.com/ConvertAPI/convertapi-library-dotnet/blob/main/Examples/ConvertRemoteFile/Program.cs) |
| [Convert an image to PDF](#image-to-pdf) | |
| [Combine images into one PDF](#combine-images-into-one-pdf) | |
| [Convert a text file (TXT) to PDF](#text-to-pdf) | |
| [Convert HEIC photos to JPG](#heic-to-jpg) | |
| [Take a screenshot of a web page](#web-page-screenshot) | |
| [Convert PDF, Word, PowerPoint, Excel or HTML to Markdown, and Markdown to PDF](#markdown-conversion) | |
| [Convert PDF to PowerPoint (PPTX)](#pdf-to-powerpoint) | [ConvertPdfToPptx](https://github.com/ConvertAPI/convertapi-library-dotnet/blob/main/Examples/ConvertPdfToPptx/Program.cs) |
| [Convert an eBook (EPUB) to PDF](#ebook-conversion) | |
| [Convert an email (EML, MSG) to PDF](#email-conversion) | |
Expand All @@ -94,12 +100,17 @@ Each task links to its C# code in this README and, where there is one, to a comp
| [Remove a PDF password](#remove-pdf-password) | |
| [Redact a PDF](#redact-pdf) | |
| [Convert PDF to PDF/A](#convert-to-pdfa) | [ConvertPdfToPdfA](https://github.com/ConvertAPI/convertapi-library-dotnet/blob/main/Examples/ConvertPdfToPdfA/Program.cs) |
| [Make a PDF accessible (PDF/UA)](#make-a-pdf-accessible-pdfua) | |
| [Read PDF metadata](#read-pdf-metadata) | |
| [Remove PDF metadata](#remove-metadata) | |
| [Extract tables from PDF to Excel](#extract-tables-from-pdf) | [ConvertPdfToXlsx](https://github.com/ConvertAPI/convertapi-library-dotnet/blob/main/Examples/ConvertPdfToXlsx/Program.cs) |
| [Extract data from invoices and other documents with AI](#extract-data-with-ai) | |
| [Extract images from PDF](#extract-images-from-pdf) | |
| [Extract PDF form data](#extract-form-data) | |
| [Read email metadata: sender, recipients, subject and attachments](#read-email-metadata) | |
| [Extract email attachments](#extract-email-attachments) | |
| [Generate a document from a template](#generate-document-from-template) | |
| [Update a Word table of contents](#update-a-word-table-of-contents) | |
| [Compare Word documents](#compare-documents) | |
| [Create a ZIP archive](#create-zip-archive) | [Workflow](https://github.com/ConvertAPI/convertapi-library-dotnet/blob/main/Examples/Workflow/Program.cs) |
| [Save, stream and delete result files](#work-with-the-result) | [DeleteFiles](https://github.com/ConvertAPI/convertapi-library-dotnet/blob/main/Examples/DeleteFiles/Program.cs) |
Expand Down Expand Up @@ -144,7 +155,7 @@ Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

The PDF is saved as `output/document.pdf`.
The PDF is saved as `output/document.pdf`. For plain text or HTML, use `"txt"` or `"html"` in place of `"pdf"`.

### Convert HTML to PDF in C#

Expand Down Expand Up @@ -201,6 +212,8 @@ Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

To save each worksheet as a CSV file, use `"csv"` in place of `"pdf"`.

### Convert PDF to Word in C#

Convert a PDF to an editable Word document (DOCX):
Expand Down Expand Up @@ -247,6 +260,23 @@ var text = await reader.ReadToEndAsync();
Console.WriteLine(text);
```

### OCR a scanned PDF in C#

Make a scanned PDF searchable. OCR adds an invisible text layer, so the text can be found, selected and copied; pages that already have text are skipped. `OcrLanguage` is the language of the text, such as `de` or `es`. The [PDF OCR page](https://www.convertapi.com/pdf-to-ocr) lists all languages.

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("pdf", "ocr",
new ConvertApiFileParam("scanned.pdf"),
new ConvertApiParam("OcrLanguage", "en"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

The searchable PDF is saved as `output/scanned.pdf`. If text is missed, for example in tables, low-quality scans, photos or small print, add `new ConvertApiParam("OcrQuality", "enhanced")`: it is slower but reads more.

### Compress PDF in C#

Make a PDF smaller. The `Preset` parameter accepts `lossless`, `text`, `archive`, `web`, `ebook` and `printer`.
Expand Down Expand Up @@ -278,6 +308,8 @@ await result.SaveFilesAsync("output");

### More conversions and PDF tools

Every other format pair works the same way: pass its source and target format to `ConvertAsync`. All formats and conversions are listed in the [API reference](https://www.convertapi.com/api).

#### PowerPoint to PDF

Convert a PowerPoint presentation (PPTX or PPT) to PDF:
Expand Down Expand Up @@ -306,6 +338,99 @@ Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

PNG, TIFF, GIF, HEIC and WEBP images work the same way with `"png"`, `"tiff"`, `"gif"`, `"heic"` or `"webp"` in place of `"jpg"`; `"tiff"` also takes TIF files.

#### Combine images into one PDF

Combine several images, such as scanned pages or photos, into one PDF with one page per image, in the order you pass them. Here every page is A4:

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("images", "pdf",
new ConvertApiFileParam("Files", "page1.jpg"),
new ConvertApiFileParam("Files", "page2.jpg"),
new ConvertApiParam("PageSize", "a4"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

The PDF takes the name of the first image: `output/page1.pdf`. All pages get the same size and orientation; `PageOrientation` sets `portrait` or `landscape`.

#### Text to PDF

Convert a plain text file to PDF. `FontName`, `FontSize` and `PageSize` change the layout.

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("txt", "pdf",
new ConvertApiFileParam("notes.txt"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

#### HEIC to JPG

Convert a HEIC photo, the format iPhones save, to JPG. For PNG, use `"png"` in place of `"jpg"`.

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("heic", "jpg",
new ConvertApiFileParam("photo.heic"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

#### Web page screenshot

Take a screenshot of a whole web page as a PNG image. For JPG, use `"jpg"` in place of `"png"`.

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("html", "png",
new ConvertApiParam("Url", "https://cdn.convertapi.com/public/files/demo"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

The image is named after the site: `output/cdn_convertapi_com.png`.

#### Markdown conversion

Convert a PDF to Markdown, for example to feed it to an LLM or a search index. Word, PowerPoint, Excel and HTML files work the same way with `"docx"`, `"pptx"`, `"xlsx"` or `"html"` in place of `"pdf"`.

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("pdf", "md",
new ConvertApiFileParam("document.pdf"),
new ConvertApiParam("Images", "remove"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

`Images` set to `remove` keeps the Markdown compact by replacing images with their alt text. Without it, images are embedded as base64 data; `describe` replaces each image with a description written by AI.

Convert a Markdown file to PDF:

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("md", "pdf",
new ConvertApiFileParam("document.md"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

#### PDF to PowerPoint

Convert a PDF to a PowerPoint presentation (PPTX):
Expand Down Expand Up @@ -524,6 +649,36 @@ Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

#### Make a PDF accessible (PDF/UA)

Convert a PDF to PDF/UA, the standard for accessible PDF files that screen readers can navigate. The result is a tagged PDF marked as PDF/UA:

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("pdf", "pdfua",
new ConvertApiFileParam("document.pdf"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

#### Read PDF metadata

Read the title, subject, author, keywords, producer, creation and modification dates and page count of a PDF as JSON:

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("pdf", "meta",
new ConvertApiFileParam("document.pdf"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

The JSON is saved as `output/document.json`.

#### Remove metadata

Remove the title, subject, author, creator and keywords from a PDF. A space in single quotes clears a field.
Expand Down Expand Up @@ -557,6 +712,23 @@ Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

#### Extract data with AI

Extract structured data from a PDF with AI, such as the number, dates, totals and line items of an invoice. Besides `invoice`, `DocumentType` takes `receipt`, `contract`, `identification`, `financial`, `form` and `manual`, or `auto` to let the AI decide.

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("pdf", "extract",
new ConvertApiFileParam("invoice.pdf"),
new ConvertApiParam("DocumentType", "invoice"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

The result, `output/invoice.json`, lists each field with its name, value and a confidence score. To choose the fields yourself, see `CustomExtractionData` on the [AI data extraction page](https://www.convertapi.com/pdf-to-extract).

#### Extract images from PDF

Save the images inside a PDF as PNG files:
Expand Down Expand Up @@ -586,6 +758,22 @@ Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

#### Read email metadata

Read the sender, recipients, subject, sent time, text and HTML body, and attachment list of an EML or MSG email as JSON:

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("email", "metadata",
new ConvertApiFileParam("email.eml"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

The JSON is saved as `output/email.json`. To leave inline images, such as a logo in the signature, out of the attachment list, add `new ConvertApiParam("IgnoreInlineAttachments", "true")`.

#### Extract email attachments

Save the attachments of an EML or MSG email:
Expand Down Expand Up @@ -616,6 +804,22 @@ Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

#### Update a Word table of contents

Update the table of contents, its page numbers and the cross-references of a Word document, for example after your code has filled in a template:

```csharp
using ConvertApiDotNet;

var convertApi = new ConvertApi(Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN"));
var result = await convertApi.ConvertAsync("docx", "docx",
new ConvertApiFileParam("report.docx"),
new ConvertApiParam("UpdateTableOfContents", "true"),
new ConvertApiParam("UpdateReferences", "true"));
Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

#### Compare documents

Compare two Word documents. The result is a DOCX that marks the differences as tracked changes.
Expand Down Expand Up @@ -646,6 +850,15 @@ Directory.CreateDirectory("output");
await result.SaveFilesAsync("output");
```

#### Also available

These converters are documented, with their parameters, on their own pages:

- E-invoices: [PDF to ZUGFeRD](https://www.convertapi.com/pdf-to-zugferd), [PDF to Factur-X](https://www.convertapi.com/pdf-to-facturx), [ZUGFeRD to Peppol](https://www.convertapi.com/zugferd-to-peppol) and [Factur-X to Peppol](https://www.convertapi.com/facturx-to-peppol)
- QR codes and barcodes: [create a QR code](https://www.convertapi.com/data-to-qrcode), [create a barcode](https://www.convertapi.com/data-to-barcode), [read QR codes](https://www.convertapi.com/qrcode-to-data) and [read barcodes](https://www.convertapi.com/barcode-to-data)
- [Crop PDF](https://www.convertapi.com/pdf-to-crop)
- [Validate PDF/A](https://www.convertapi.com/pdfa-to-validate)

### Work with the result

`ConvertAsync` returns the conversion cost and the result files. Each file is a `ConvertApiFile` with a name, a size and a download URL. Save the files, read them as streams, and delete them from the server when you are done:
Expand Down
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