Generating PDF Reports in Kotlin: iText 7 Library

Generating PDF Reports in Kotlin with iText 7

In modern development, there is often a need to create structured PDF documents: reports, invoices, contracts, or analytical summaries. The Kotlin language, thanks to its conciseness and compatibility with Java, is well-suited for this task. One of the most powerful and popular libraries for working with PDF is iText 7 (formerly iTextSharp for .NET). In this article, we will explore how to use it to generate professional PDF reports in Kotlin.

Why iText 7?

• Full control over content: text, tables, images, fonts.
• Performance: the library is optimized for working with large documents.
• Cross-platform: works on JVM, Android, and the web.
• Licensing: AGPL for open-source projects or a commercial license.

Installation (Gradle)

Add the dependency to build.gradle.kts:

dependencies {    implementation("com.itextpdf:itext7-core:7.2.5")}

Basic Example: "Hello, PDF!"

Let's create a simple PDF document with text:

import com.itextpdf.kernel.pdf.PdfDocumentimport com.itextpdf.kernel.pdf.PdfWriterimport com.itextpdf.layout.Documentimport com.itextpdf.layout.element.Paragraph

fun main() {    val writer = PdfWriter("hello.pdf")    val pdf = PdfDocument(writer)    val document = Document(pdf)

    document.add(Paragraph("Hello, PDF world in Kotlin!"))    document.close()    println("PDF created: hello.pdf")}

Creating a Report with Tables and Styles

A real report requires more than just text. Let's add a table, headers, and styles:

import com.itextpdf.kernel.colors.ColorConstantsimport com.itextpdf.kernel.pdf.PdfDocumentimport com.itextpdf.kernel.pdf.PdfWriterimport com.itextpdf.layout.Documentimport com.itextpdf.layout.element.Cellimport com.itextpdf.layout.element.Paragraphimport com.itextpdf.layout.element.Tableimport com.itextpdf.layout.properties.UnitValue

fun generateReport() {    val writer = PdfWriter("report.pdf")    val pdf = PdfDocument(writer)    val document = Document(pdf)

    // Title    val title = Paragraph("Monthly Sales Report")        .setFontSize(20)        .setBold()        .setTextAlignment(com.itextpdf.layout.properties.TextAlignment.CENTER)    document.add(title)

    // Table    val table = Table(UnitValue.createPercentArray(floatArrayOf(1f, 2f, 1.5f, 1.5f)))    table.setWidth(UnitValue.createPercentValue(100))

    // Table headers    val headers = listOf("ID", "Product", "Quantity", "Price")    headers.forEach { header ->        val cell = Cell().add(Paragraph(header).setBold())        cell.setBackgroundColor(ColorConstants.LIGHT_GRAY)        table.addCell(cell)    }

    // Data    val data = listOf(        listOf("1", "Laptop", "3", "150000"),        listOf("2", "Mouse", "10", "5000"),        listOf("3", "Keyboard", "5", "12500")    )    data.forEach { row ->        row.forEach { value ->            table.addCell(Cell().add(Paragraph(value)))        }    }

    document.add(table)    document.close()    println("Report created: report.pdf")}

fun main() {    generateReport()}

Adding Images and Styles

Reports often need to include logos or charts. iText 7 supports images:

import com.itextpdf.kernel.pdf.PdfDocumentimport com.itextpdf.kernel.pdf.PdfWriterimport com.itextpdf.layout.Documentimport com.itextpdf.layout.element.Imageimport com.itextpdf.io.image.ImageDataFactory

fun addImageExample() {    val writer = PdfWriter("report_with_image.pdf")    val pdf = PdfDocument(writer)    val document = Documen