Instant JSON Attachment

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/*
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 *   Copyright © 2022-2026 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.graphics.Bitmap
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import android.graphics.BitmapFactory
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import android.graphics.RectF
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import android.net.Uri
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import androidx.activity.viewModels
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import com.pspdfkit.annotations.StampAnnotation
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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.document.providers.InputStreamDataProvider
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import com.pspdfkit.ui.PdfActivity
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import com.pspdfkit.ui.PdfActivityIntentBuilder
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import kotlinx.coroutines.runBlocking
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import java.io.File
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import java.io.FileOutputStream
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import java.io.FileWriter
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import java.io.IOException
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import java.io.InputStream
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import kotlin.getValue
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/**
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 * Example showing how to export and import instant JSON attachment binaries.
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 *
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 */
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class InstantJsonAttachmentExample(context: Context) : SdkExample(
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    context,
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    R.string.instantJsonAttachmentTitle,
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    R.string.instantJsonAttachmentDescription
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) {
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    override fun launchExample(context: Context, configuration: PdfActivityConfiguration.Builder) {
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        // We turn off auto save to avoid saving redundant annotations.
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        configuration.autosaveEnabled(false)
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        // We use a custom utility class to extract the example document from the assets.
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        ExtractAssetTask.extract(WELCOME_DOC, title, context) { documentFile ->
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            // To start the `InstantJsonAttachmentExampleActivity` create a launch intent using the builder.
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            val intent = PdfActivityIntentBuilder.fromUri(context, Uri.fromFile(documentFile))
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                .configuration(configuration.build())
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                .activityClass(InstantJsonAttachmentExampleActivity::class)
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                .build()
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            context.startActivity(intent)
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        }
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    }
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}
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/**
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 * This example activity subclasses [PdfActivity], and it demonstrates how to export and import instant JSON attachment binaries using
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 * instant JSON Attachment APIs.
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 */
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class InstantJsonAttachmentExampleActivity : PdfActivity() {
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    private val viewModel: AnnotationCreationViewModel by viewModels()
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    override fun onDocumentLoaded(document: PdfDocument) {
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        super.onDocumentLoaded(document)
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        viewModel.createObjects {
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            // Create a stamp annotation from an image bitmap.
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            val annotationBitmap = getBitmapFromAsset()
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            val stampAnnotation = StampAnnotation(
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                0,
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                RectF(100f, (annotationBitmap.height / 2) + 100f, (annotationBitmap.width / 2) + 100f, 100f),
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                annotationBitmap
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            )
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            // Add the stamp annotation to the document.
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            runBlocking { document.annotationProvider.addAnnotationToPage(stampAnnotation) }
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            // Export START.
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            // Convert annotation to instant JSON.
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            val jsonData = stampAnnotation.toInstantJson()
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            // Prepare a file to store the image attachment.
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            val tempBinaryAttachmentJsonFile = File.createTempFile("tmp_", "stampAnnotationBinaryJsonAttachment.jpeg")
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            val outputStream = FileOutputStream(tempBinaryAttachmentJsonFile)
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            // Write the Instant JSON attachment data to the file.
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            if (stampAnnotation.hasBinaryInstantJsonAttachment()) {
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                stampAnnotation.fetchBinaryInstantJsonAttachment(outputStream)
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            }
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            // Save the JSON data in a file.
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            val tempJsonFile = File.createTempFile("tmp_", "stampAnnotationJson.txt")
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            FileWriter(tempJsonFile).use { w -> w.write(jsonData) }
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            // Export END.
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            // Let's remove the annotation to try the import feature.
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            runBlocking { document.annotationProvider.removeAnnotationFromPage(stampAnnotation) }
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            // Import START.
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            val anotherStampAnnotation = runBlocking { document.annotationProvider.createAnnotationFromInstantJson(jsonData) }
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            anotherStampAnnotation.attachBinaryInstantJsonAttachment(FileDataProvider(tempBinaryAttachmentJsonFile), "image/jpeg")
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            // Import END.
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        }
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    }
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    /** Decodes bitmap from application's assets. */
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    private fun getBitmapFromAsset(): Bitmap {
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        return try {
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            val inputStream = assets.open("images/android.png")
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            BitmapFactory.decodeStream(inputStream)
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        } catch (ioException: IOException) {
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            throw RuntimeException("Error while trying to load PNG from assets: images/android.png", ioException)
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        }
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    }
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}
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/**
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 * Data provider that handles serving data from [File].
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 */
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open class FileDataProvider(val file: File) : InputStreamDataProvider() {
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    override fun getSize(): Long {
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        return file.length()
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    }
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    override fun getUid(): String {
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        return file.canonicalPath
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    }
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    override fun openInputStream(): InputStream {
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        return file.inputStream()
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    }
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    override fun getTitle(): String? {
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        return file.nameWithoutExtension
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    }
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}