Added stylus-only mode for PDF drawing and annotations. (#27)

This change introduces a "Stylus Only Mode" toggle in the annotation dock, allowing users to restrict drawing input to stylus pens while maintaining touch support for scrolling and navigation.

Key changes include:
- Added `isStylusOnlyMode` state and persistence logic in `PdfViewerScreen`.
- Updated `AnnotationDock` with a toggle button for the new mode.
- Modified pointer input handling in `PdfPageComposable` and `PdfVerticalReader` to filter touch events when stylus-only mode is active.
- Adjusted tap gesture detection to ensure scrolling and page clicks still function correctly under various input modes.

CONTRIBUTING.md

@@ -21,10 +21,10 @@ This allows the open-source version to thrive while keeping the project sustaina
 
 ## How to Submit a Pull Request
 
-1. Fork the repository and create your branch from `main`.
+1. Fork the repository.
 2. Make your changes and commit them with clear, descriptive messages.
 3. Open a Pull Request!
-4. **Sign the CLA:** When you open your first PR, the [CLA Assistant](https://cla-assistant.io/) bot will automatically comment with a link. Simply click the link, sign in with GitHub, and click "I agree." **This is a one-time process** — once signed, it covers all your future contributions to Episteme.
+4. **Sign the CLA:** When you open your first PR, the [CLA Assistant](https://cla-assistant.io/) bot will automatically comment with a link. Simply click the link, sign in with GitHub, and click "I agree." **This is a one-time process**, once signed, it covers all your future contributions to Episteme.
 
 ## Questions?
 

app/src/main/java/com/aryan/reader/pdf/AnnotationDock.kt

@@ -35,6 +35,8 @@ import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.Redo
 import androidx.compose.material.icons.automirrored.filled.Undo
 import androidx.compose.material.icons.filled.Close
+import androidx.compose.material.icons.filled.DoNotTouch
+import androidx.compose.material.icons.filled.TouchApp
 import androidx.compose.material.icons.filled.Visibility
 import androidx.compose.material.icons.filled.VisibilityOff
 import androidx.compose.material3.Icon
@@ -68,7 +70,9 @@ fun AnnotationDock(
     modifier: Modifier = Modifier,
     isSticky: Boolean = false,
     isMinimized: Boolean,
-    onToggleMinimize: () -> Unit
+    onToggleMinimize: () -> Unit,
+    isStylusOnlyMode: Boolean,
+    onToggleStylusOnlyMode: () -> Unit
 ) {
     val showFullDock = isSticky || !isMinimized
 
@@ -141,6 +145,29 @@ fun AnnotationDock(
                     horizontalArrangement = Arrangement.spacedBy(spacing),
                     modifier = Modifier.alpha(toolsAlpha)
                 ) {
+
+                    // Stylus Only Toggle
+                    if (!isMinimized) {
+                        val iconVector = if (isStylusOnlyMode) Icons.Default.DoNotTouch else Icons.Default.TouchApp
+                        val iconTint = if (isStylusOnlyMode) Color(0xFFE57373) else Color.White
+
+                        Box(
+                            modifier = Modifier
+                                .size(buttonSize)
+                                .clip(CircleShape)
+                                .background(Color.White.copy(alpha = if (isStylusOnlyMode) 0.15f else 0f))
+                                .clickable(onClick = onToggleStylusOnlyMode),
+                            contentAlignment = Alignment.Center
+                        ) {
+                            Icon(
+                                imageVector = iconVector,
+                                contentDescription = "Stylus Only Mode",
+                                tint = iconTint,
+                                modifier = Modifier.size(iconSize)
+                            )
+                        }
+                    }
+
                     // Pen Group
                     val isPenActive = !isMinimized && (selectedTool == InkType.PEN ||
                             selectedTool == InkType.FOUNTAIN_PEN ||

app/src/main/java/com/aryan/reader/pdf/PdfPageComposable.kt

@@ -81,6 +81,7 @@ import androidx.compose.ui.graphics.graphicsLayer
 import androidx.compose.ui.graphics.nativeCanvas
 import androidx.compose.ui.graphics.toArgb
 import androidx.compose.ui.input.pointer.PointerEventTimeoutCancellationException
+import androidx.compose.ui.input.pointer.PointerType
 import androidx.compose.ui.input.pointer.changedToUp
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.input.pointer.positionChanged
@@ -416,6 +417,7 @@ internal fun PdfPageComposable(
     draggingBoxId: String? = null,
     isScrollLocked: Boolean = false,
     isVisible: Boolean = true,
+    isStylusOnlyMode: Boolean = false
 ) {
     SideEffect { Timber.tag("PdfDrawPerf").v("PdfPageComposable Recompose: Page $pageIndex") }
     val pdfDocumentItem = pdfDocument.item
@@ -2237,9 +2239,14 @@ internal fun PdfPageComposable(
                 isZoomEnabled,
                 isVerticalScroll,
                 isEditMode,
-                selectedTool
+                selectedTool,
+                isStylusOnlyMode
             ) {
-                if (isEditMode && selectedTool != InkType.TEXT) return@pointerInput
+                val isTapDetectionAllowed = !isEditMode ||
+                        selectedTool == InkType.TEXT ||
+                        isStylusOnlyMode
+
+                if (!isTapDetectionAllowed) return@pointerInput
 
                 detectTapGestures(onTap = { tapOffset ->
                     Timber.d(
@@ -2600,7 +2607,8 @@ internal fun PdfPageComposable(
                 offset,
                 isScrolling,
                 isVerticalScroll,
-                selectedTool
+                selectedTool,
+                isStylusOnlyMode
             ) {
                 val canDraw = isEditMode && selectedTool != InkType.TEXT && !isScrolling && !isVerticalScroll && actualBitmapWidthPx > 0 && actualBitmapHeightPx > 0
 
@@ -2611,6 +2619,13 @@ internal fun PdfPageComposable(
                 try {
                     awaitEachGesture {
                         val down = awaitFirstDown(requireUnconsumed = false)
+
+                        Timber.tag("PointerTypeDebug").d("Page $pageIndex: Input Type detected: ${down.type}")
+
+                        if (isStylusOnlyMode && down.type == PointerType.Touch) {
+                            return@awaitEachGesture
+                        }
+
                         val dragPointerId = down.id
                         val startPos = down.position
                         var dragStarted = false

app/src/main/java/com/aryan/reader/pdf/PdfVerticalReader.kt

@@ -88,6 +88,7 @@ import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.TransformOrigin
 import androidx.compose.ui.graphics.drawscope.Stroke
 import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.input.pointer.PointerType
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.input.pointer.positionChanged
 import androidx.compose.ui.input.pointer.util.VelocityTracker
@@ -216,7 +217,8 @@ internal fun PdfVerticalReader(
     isAutoScrollTempPaused: Boolean = false,
     isScrollLocked: Boolean = false,
     autoScrollSpeed: Float = 1.0f,
-    onInteractionListener: () -> Unit = {}
+    onInteractionListener: () -> Unit = {},
+    isStylusOnlyMode: Boolean = false
 ) {
     SideEffect { Timber.tag("PdfDrawPerf").v("LIST: PdfVerticalReader Recomposing.") }
     var globalEraserPosition by remember { mutableStateOf<Offset?>(null) }
@@ -726,13 +728,17 @@ internal fun PdfVerticalReader(
             }
         }
 
-        val globalDrawingModifier = Modifier.pointerInput(isEditMode, layoutInfo, selectedTool) {
+        val globalDrawingModifier = Modifier.pointerInput(isEditMode, layoutInfo, selectedTool, isStylusOnlyMode) {
             if (!isEditMode) return@pointerInput
             if (selectedTool == InkType.TEXT) return@pointerInput
 
             awaitEachGesture {
                 val down = awaitFirstDown(requireUnconsumed = false)
 
+                if (isStylusOnlyMode && down.type == PointerType.Touch) {
+                    return@awaitEachGesture
+                }
+
                 fun getPageAndPoint(screenOffset: Offset): Pair<Int, PdfPoint>? {
                     val zoom = zoomAnimatable.value
                     val panX = panXAnimatable.value
@@ -814,31 +820,31 @@ internal fun PdfVerticalReader(
             modifier = Modifier
                 .fillMaxSize()
                 .then(globalDrawingModifier)
-                .pointerInput(isEditMode, selectedTool) {
+                .pointerInput(isEditMode, selectedTool, isStylusOnlyMode) {
                     Timber.tag("PdfTouchDebug").v(
                         "VerticalReader: TapPointerInput init. isEditMode=$isEditMode"
                     )
-                    if (isEditMode && selectedTool != InkType.TEXT) return@pointerInput
+
+                    val isTapDetectionAllowed = !isEditMode ||
+                            selectedTool == InkType.TEXT ||
+                            isStylusOnlyMode
+
+                    if (!isTapDetectionAllowed) return@pointerInput
 
                     detectTapGestures(onTap = {
                         if (!isEditMode) {
-                            Timber.tag("PdfTouchDebug").d(
+                            Timber.tag("PdfTouchDebug").d("VerticalReader: Tap detected")
-                                "VerticalReader: Tap detected (Toggling bars)"
-                            )
                             selectionClearTrigger++
                             onPageClick()
                         } else if (selectedTool == InkType.TEXT) {
                             onPageClick()
                         }
                     }, onDoubleTap = { offset ->
-                        if (!isEditMode) {
                         Timber.tag("PdfTouchDebug").d("VerticalReader: DoubleTap detected")
                         onDoubleTapToZoom(offset)
-                        }
                     })
                 }
-
+                .pointerInput(totalDocHeight, isEditMode, selectedTool, isScrollLocked, isStylusOnlyMode) {
-                .pointerInput(totalDocHeight, isEditMode, selectedTool, isScrollLocked) {
                     val tracker = VelocityTracker()
                     val decay = exponentialDecay<Float>()
                     val touchSlop = viewConfiguration.touchSlop
@@ -849,11 +855,14 @@ internal fun PdfVerticalReader(
                         )
 
                         val down = awaitFirstDown(requireUnconsumed = false)
-                        Timber.tag("PdfTouchDebug").v(
-                            "VerticalReader: DOWN received. Pressed=${down.pressed}, Consumed=${down.isConsumed}"
-                        )
 
-                        if (isEditMode && selectedTool != InkType.TEXT && down.pressed) {
+                        Timber.tag("PointerTypeDebug").d("VerticalReader: Input Type detected: ${down.type}")
+
+                        val isDrawingGesture = isEditMode &&
+                                selectedTool != InkType.TEXT &&
+                                (!isStylusOnlyMode || down.type != PointerType.Touch)
+
+                        if (isDrawingGesture && down.pressed) {
                             val event = awaitPointerEvent()
                             Timber.tag("PdfTouchDebug").v(
                                 "VerticalReader: EditMode check. Event changes: ${event.changes.size}"
@@ -959,8 +968,9 @@ internal fun PdfVerticalReader(
                                     }
                                 }
 
-                                val shouldScroll =
+                                val isTouchInput = event.changes.all { it.type == PointerType.Touch }
-                                    (panLocked || gestureDisambiguationMode != 0) && (!isEditMode || selectedTool == InkType.TEXT || isMultiTouch)
+                                val shouldScroll = (panLocked || gestureDisambiguationMode != 0) &&
+                                        (!isEditMode || selectedTool == InkType.TEXT || isMultiTouch || (isStylusOnlyMode && isTouchInput))
 
                                 if (shouldScroll) {
                                     if (!isInteracting) {
@@ -1432,6 +1442,7 @@ internal fun PdfVerticalReader(
                                     onOcrModelDownloading = onOcrModelDownloading,
                                     selectedTool = selectedTool,
                                     richTextController = richTextController,
+                                    isStylusOnlyMode = isStylusOnlyMode,
                                     textBoxes = textBoxes.filter { it.pageIndex == page.index },
                                     selectedTextBoxId = selectedTextBoxId,
                                     onTextBoxChange = onTextBoxChange,

app/src/main/java/com/aryan/reader/pdf/PdfViewerScreen.kt

@@ -291,12 +291,23 @@ private const val PDF_AUTO_SCROLL_LOCKED_KEY = "pdf_auto_scroll_locked"
 private const val PDF_AUTO_SCROLL_USE_SLIDER_KEY = "pdf_auto_scroll_use_slider"
 private const val PDF_AUTO_SCROLL_MIN_SPEED_KEY = "pdf_auto_scroll_min_speed"
 private const val PDF_AUTO_SCROLL_MAX_SPEED_KEY = "pdf_auto_scroll_max_speed"
+private const val STYLUS_ONLY_MODE_KEY = "stylus_only_mode"
 
 private fun savePdfAutoScrollMinSpeed(context: Context, speed: Float) {
     val prefs = context.getSharedPreferences(SETTINGS_PREFS_NAME, Context.MODE_PRIVATE)
     prefs.edit { putFloat(PDF_AUTO_SCROLL_MIN_SPEED_KEY, speed) }
 }
 
+private fun saveStylusOnlyMode(context: Context, isEnabled: Boolean) {
+    val prefs = context.getSharedPreferences(SETTINGS_PREFS_NAME, Context.MODE_PRIVATE)
+    prefs.edit { putBoolean(STYLUS_ONLY_MODE_KEY, isEnabled) }
+}
+
+private fun loadStylusOnlyMode(context: Context): Boolean {
+    val prefs = context.getSharedPreferences(SETTINGS_PREFS_NAME, Context.MODE_PRIVATE)
+    return prefs.getBoolean(STYLUS_ONLY_MODE_KEY, false)
+}
+
 private fun loadPdfAutoScrollMinSpeed(context: Context): Float {
     val prefs = context.getSharedPreferences(SETTINGS_PREFS_NAME, Context.MODE_PRIVATE)
     return prefs.getFloat(PDF_AUTO_SCROLL_MIN_SPEED_KEY, 0.1f)
@@ -649,6 +660,7 @@ fun PdfViewerScreen(
 
     var isAutoScrollLocked by remember { mutableStateOf(loadPdfAutoScrollLocked(context)) }
     var autoScrollUseSlider by remember { mutableStateOf(loadPdfAutoScrollUseSlider(context)) }
+    var isStylusOnlyMode by remember { mutableStateOf(loadStylusOnlyMode(context)) }
     var currentTtsMode by remember { mutableStateOf(loadTtsMode(context)) }
     var showTtsSettingsSheet by remember { mutableStateOf(false) }
 
@@ -3298,6 +3310,7 @@ fun PdfViewerScreen(
                                                     }
                                                 },
                                                 richTextController = richTextController,
+                                                isStylusOnlyMode = isStylusOnlyMode,
                                                 isEditMode = isDrawingActive,
                                                 textBoxes = textBoxes.filter { it.pageIndex == pageIndex },
                                                 selectedTextBoxId = selectedTextBoxId,
@@ -3649,6 +3662,7 @@ fun PdfViewerScreen(
                                             },
                                             selectedTool = selectedTool,
                                             richTextController = richTextController,
+                                            isStylusOnlyMode = isStylusOnlyMode,
                                             isEditMode = isDrawingActive,
                                             textBoxes = textBoxes,
                                             selectedTextBoxId = selectedTextBoxId,
@@ -4894,6 +4908,11 @@ fun PdfViewerScreen(
                                     activePenColor = dockPenColor,
                                     activeHighlighterColor = dockHighlighterColor,
                                     lastPenTool = lastPenTool,
+                                    isStylusOnlyMode = isStylusOnlyMode,
+                                    onToggleStylusOnlyMode = {
+                                        isStylusOnlyMode = !isStylusOnlyMode
+                                        saveStylusOnlyMode(context, isStylusOnlyMode)
+                                    },
                                     onToolClick = { clickedTool ->
                                         if (clickedTool == InkType.ERASER) {
                                             annotationSettingsRepo.updateSelectedTool(