Implement AirPrint/IPP Everywhere printing feature

PRINTING_FEATURE.md

@@ -0,0 +1,57 @@
+# AirPrint/IPP Everywhere Printing Feature Implementation
+
+## Overview
+This implementation adds printing functionality to ScanBridge using Android's Print Framework, which automatically supports AirPrint and IPP Everywhere printers through the system's print services.
+
+## Changes Made
+
+### 1. UI Changes
+- **ExportSettingsPopup.kt**: Added a third print button (🖨️) alongside existing PDF and Archive export buttons
+- **Strings.xml**: Added "Print" text in English and German translations
+
+### 2. Core Functionality
+- **ScanningScreen.kt**: 
+  - Added `doPrint()` function that uses Android PrintManager
+  - Created `ScanDocumentPrintAdapter` class that converts scanned images to PDF for printing
+  - Integrated print callback into export options popup
+
+### 3. Key Features
+- **AirPrint/IPP Everywhere Support**: Uses Android Print Framework which automatically discovers and supports AirPrint and IPP Everywhere printers
+- **Multi-page Printing**: Supports printing multiple scanned pages as a single print job
+- **Page Range Selection**: Users can select which pages to print through the system print dialog
+- **Error Handling**: Same validation as other export functions (no scans, job running, etc.)
+- **PDF Generation**: Converts scanned images to PDF format for printing using existing iText library
+
+### 4. User Experience
+When users tap the share/export button in the scanning screen, they now see three options:
+1. 📄 PDF Export
+2. 🖼️ Archive Export  
+3. 🖨️ Print (NEW)
+
+Selecting print will:
+1. Open the Android system print dialog
+2. Show available printers (including AirPrint/IPP printers)
+3. Allow users to select printer settings, page ranges, etc.
+4. Send the scanned documents to the selected printer
+
+## Technical Implementation
+- Uses `PrintManager.print()` with a custom `PrintDocumentAdapter`
+- Converts scanned images to PDF format using iText library
+- Handles cancellation and error scenarios
+- Supports page range printing
+- Automatic scaling to fit page size (A4 with 1-inch margins)
+
+## Compatibility
+- **Minimum Android Version**: Works with existing app requirements (Android 28+)
+- **Printer Support**: Any printer supported by Android Print Framework, including:
+  - AirPrint printers (Apple ecosystem)
+  - IPP Everywhere printers
+  - Manufacturer-specific print services
+  - Cloud printing services
+
+## Testing
+- Code compiles successfully
+- Maintains compatibility with existing export functionality
+- Ready for manual testing with actual printers
+
+The implementation follows the existing app patterns and provides a seamless user experience for printing scanned documents.

app/src/main/java/io/github/chrisimx/scanbridge/ScanningScreen.kt

@@ -26,6 +26,14 @@ import android.content.Context.MODE_PRIVATE
 import android.content.Intent
 import android.graphics.Bitmap
 import android.graphics.BitmapFactory
+import android.os.Bundle
+import android.os.CancellationSignal
+import android.os.ParcelFileDescriptor
+import android.print.PageRange
+import android.print.PrintAttributes
+import android.print.PrintDocumentAdapter
+import android.print.PrintDocumentInfo
+import android.print.PrintManager
 import androidx.activity.compose.BackHandler
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.core.animateFloatAsState
@@ -352,6 +360,126 @@ fun doPdfExport(scanningViewModel: ScanningScreenViewModel, context: Context, on
     context.startActivity(share)
 }
 
+/**
+ * Print scanned documents using Android Print Framework (supports AirPrint/IPP Everywhere)
+ */
+fun doPrint(scanningViewModel: ScanningScreenViewModel, context: Context, onError: (String) -> Unit) {
+    if (scanningViewModel.scanningScreenData.currentScansState.isEmpty()) {
+        onError(context.getString(R.string.no_scans_yet))
+        return
+    }
+    if (scanningViewModel.scanningScreenData.scanJobRunning) {
+        onError(context.getString(R.string.job_still_running))
+        return
+    }
+
+    val printManager = context.getSystemService(Context.PRINT_SERVICE) as PrintManager
+    val printAdapter = ScanDocumentPrintAdapter(
+        context,
+        scanningViewModel.scanningScreenData.currentScansState.map { File(it.first) }
+    )
+
+    val jobName = "ScanBridge - ${
+        LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"))
+    }"
+
+    printManager.print(jobName, printAdapter, null)
+}
+
+/**
+ * PrintDocumentAdapter for printing scanned documents
+ */
+class ScanDocumentPrintAdapter(
+    private val context: Context,
+    private val imageFiles: List<File>
+) : PrintDocumentAdapter() {
+
+    override fun onLayout(
+        oldAttributes: PrintAttributes?,
+        newAttributes: PrintAttributes,
+        cancellationSignal: CancellationSignal?,
+        callback: LayoutResultCallback,
+        extras: Bundle?
+    ) {
+        if (cancellationSignal?.isCanceled == true) {
+            callback.onLayoutCancelled()
+            return
+        }
+
+        val info = PrintDocumentInfo.Builder("ScanBridge_Print")
+            .setContentType(PrintDocumentInfo.CONTENT_TYPE_PHOTO)
+            .setPageCount(imageFiles.size)
+            .build()
+
+        callback.onLayoutFinished(info, true)
+    }
+
+    override fun onWrite(
+        pages: Array<out PageRange>?,
+        destination: ParcelFileDescriptor,
+        cancellationSignal: CancellationSignal?,
+        callback: WriteResultCallback
+    ) {
+        try {
+            if (cancellationSignal?.isCanceled == true) {
+                callback.onWriteCancelled()
+                return
+            }
+
+            // Create a temporary file for the PDF
+            val tempFile = File.createTempFile("print_document", ".pdf")
+            val pdfWriter = PdfWriter(tempFile)
+            val pdfDocument = PdfDocument(pdfWriter)
+            val document = Document(pdfDocument)
+
+            imageFiles.forEachIndexed { index, imageFile ->
+                if (cancellationSignal?.isCanceled == true) {
+                    document.close()
+                    callback.onWriteCancelled()
+                    return
+                }
+
+                // Check if this page should be printed based on the page ranges
+                val shouldPrintPage = pages?.any { range ->
+                    index >= range.start && index <= range.end
+                } ?: true
+
+                if (shouldPrintPage) {
+                    val imageData = ImageDataFactory.create(imageFile.absolutePath)
+                    val image = Image(imageData)
+
+                    // Scale image to fit page
+                    val pageSize = PageSize.A4
+                    image.scaleToFit(pageSize.width - 72, pageSize.height - 72) // 1 inch margins
+                    image.setFixedPosition(36f, 36f) // Center on page
+
+                    if (index > 0) {
+                        document.add(com.itextpdf.layout.element.AreaBreak())
+                    }
+                    document.add(image)
+                }
+            }
+
+            document.close()
+
+            // Copy the temporary file to the destination
+            tempFile.inputStream().use { input ->
+                ParcelFileDescriptor.AutoCloseOutputStream(destination).use { output ->
+                    input.copyTo(output)
+                }
+            }
+
+            // Clean up temporary file
+            tempFile.delete()
+
+            callback.onWriteFinished(arrayOf(PageRange.ALL_PAGES))
+
+        } catch (e: Exception) {
+            callback.onWriteFailed(e.message)
+        }
+    }
+}
+
 @OptIn(ExperimentalUuidApi::class)
 fun doScan(
     esclRequestClient: ESCLRequestClient,
@@ -834,6 +962,22 @@ fun ScanningScreen(
                                 }
                             )
                         }
+                    },
+                    onPrint = {
+                        scanningViewModel.setShowExportOptionsPopup(false)
+                        doPrint(
+                            scanningViewModel,
+                            context,
+                            { error ->
+                                snackBarError(
+                                    error,
+                                    scope,
+                                    context,
+                                    snackbarHostState,
+                                    false
+                                )
+                            }
+                        )
                     }
                 )
             }

app/src/main/java/io/github/chrisimx/scanbridge/uicomponents/ExportSettingsPopup.kt

@@ -25,7 +25,8 @@ fun ExportSettingsPopup(
     onDismiss: () -> Unit,
     updateWidth: (Int) -> Unit,
     onExportPdf: () -> Unit,
-    onExportArchive: () -> Unit
+    onExportArchive: () -> Unit,
+    onPrint: () -> Unit
 ) {
     Popup(
         alignment = Alignment.TopStart,
@@ -58,6 +59,12 @@ fun ExportSettingsPopup(
                         contentDescription = stringResource(R.string.export_as_archive)
                     )
                 }
+                IconButton(onClick = { onPrint() }) {
+                    Icon(
+                        painterResource(R.drawable.round_print_36),
+                        contentDescription = stringResource(R.string.print)
+                    )
+                }
             }
         }
     }

app/src/main/res/values-de/strings.xml

@@ -21,6 +21,7 @@
     <string name="swap_with_next_page">Nach rechts verschieben</string>
     <string name="page_x_of_y">Seite %1$s von %2$s</string>
     <string name="export">Exportieren</string>
+    <string name="print">Drucken</string>
     <string name="retrieving_page">Seite wird abgerufen</string>
     <string name="exporting">Wird exportiert…</string>
     <string name="no_scans_yet">Bisher keine Seiten. Klicke den Scanbutton :)</string>

app/src/main/res/values/strings.xml

@@ -21,6 +21,7 @@
     <string name="swap_with_next_page">Swap with next</string>
     <string name="page_x_of_y">Page %1$s of %2$s</string>
     <string name="export">Export</string>
+    <string name="print">Print</string>
     <string name="retrieving_page">Retrieving page</string>
     <string name="exporting">Exporting…</string>
     <string name="no_scans_yet">No pages were scanned yet. Click the scan button :)</string>