Rotate PDF page in Kotlin for Android

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/*
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 *   Copyright © 2020-2025 PSPDFKit GmbH. All rights reserved.
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 *
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 *   The PSPDFKit Sample applications are licensed with a modified BSD license.
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 *   Please see License for details. This notice may not be removed from this file.
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 */
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package com.pspdfkit.catalog.examples.kotlin
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import android.content.Context
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import android.net.Uri
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import android.view.Menu
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import android.view.MenuItem
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import com.pspdfkit.catalog.R
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import com.pspdfkit.catalog.SdkExample
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import com.pspdfkit.catalog.tasks.ExtractAssetTask
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import com.pspdfkit.configuration.activity.PdfActivityConfiguration
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import com.pspdfkit.document.PdfDocument
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import com.pspdfkit.ui.PdfActivity
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import com.pspdfkit.ui.PdfActivityIntentBuilder
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/**
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 * This example shows how to rotate pages in PdfActivity.
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 */
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class RotatePageExample(context: Context) : SdkExample(context, R.string.rotatePageExampleTitle, R.string.rotatePageExampleDescription) {
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    override fun launchExample(context: Context, configuration: PdfActivityConfiguration.Builder) {
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        // This example uses a custom activity which adds some option menu items. The default
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        // menu items are deactivated for simplicity.
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        configuration.searchEnabled(false).outlineEnabled(false)
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        // Start the activity once the example document has been extracted from the app's assets.
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        ExtractAssetTask.extract(WELCOME_DOC, title, context) { documentFile ->
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            val intent = PdfActivityIntentBuilder.fromUri(context, Uri.fromFile(documentFile))
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                .configuration(configuration.build())
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                .activityClass(RotatePageActivity::class.java)
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                .build()
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            // Start the RotatePageActivity for the extracted document.
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            context.startActivity(intent)
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        }
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    }
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}
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class RotatePageActivity : PdfActivity() {
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    /**
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     * Creates custom rotation menu used by this example.
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     */
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    override fun onCreateOptionsMenu(menu: Menu): Boolean {
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        // It's important to call super before inflating the custom menu, or the custom menu won't be shown.
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        super.onCreateOptionsMenu(menu)
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        // Inflate our custom menu items for rotating pages.
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        menuInflater.inflate(R.menu.activity_rotate_example, menu)
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        return true
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    }
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    /**
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     * Handles clicks on the navigation option menu items.
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     */
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    override fun onOptionsItemSelected(item: MenuItem): Boolean {
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        return when (item.itemId) {
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            R.id.rotateClockwise -> {
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                rotatePage(pageIndex, 90)
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                true
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            }
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            R.id.rotateCounterClockwise -> {
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                rotatePage(pageIndex, -90)
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                true
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            }
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            else -> super.onOptionsItemSelected(item)
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        }
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    }
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    private fun rotatePage(pageIndex: Int, rotationToApply: Int) {
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        // Ensure the document is loaded.
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        val document = document ?: return
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        // Get the existing rotation offset of the current page.
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        val currentRotationOffset = document.getRotationOffset(pageIndex)
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        // Add the desired rotation to the current offset.
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        var newRotation = currentRotationOffset + rotationToApply
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        // Make sure that the new rotation offset is in bounds.
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        if (newRotation < 0) {
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            newRotation += 360
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        } else if (newRotation >= 360) {
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            newRotation -= 360
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        }
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        newRotation = when (newRotation) {
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            0 -> PdfDocument.NO_ROTATION
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            90 -> PdfDocument.ROTATION_90
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            180 -> PdfDocument.ROTATION_180
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            270 -> PdfDocument.ROTATION_270
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            else -> return
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        }
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        // Applies a temporary rotation to the specified page of the document.
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        // This will change the size reported by the document to match the new rotation.
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        // The document will not be modified by this call.
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        document.setRotationOffset(newRotation, pageIndex)
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    }
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}