Implement render quality and scroll to top listener

miseke-ffw · rschattauer · commit c9263a8a9926 · 2025-05-20T11:41:51.000+02:00
diff --git a/pdfViewer/src/main/java/com/rajat/pdfviewer/PdfRendererView.kt b/pdfViewer/src/main/java/com/rajat/pdfviewer/PdfRendererView.kt
@@ -76,7 +76,9 @@ class PdfRendererView @JvmOverloads constructor(
     // endregion
 
     var zoomListener: ZoomListener? = null
+    var scrollListener: ScrollListener? = null
     var statusListener: StatusCallBack? = null
+    var renderQuality: RenderQuality = RenderQuality.NORMAL
 
     //region Public APIs
     fun isZoomedIn(): Boolean = this::recyclerView.isInitialized && recyclerView.isZoomedIn()
@@ -217,7 +219,8 @@ class PdfRendererView @JvmOverloads constructor(
             pdfRendererCore,
             this,
             pageMargin,
-            enableLoadingForPages
+            enableLoadingForPages,
+            renderQuality,
         )
 
         recyclerView.apply {
@@ -230,6 +233,7 @@ class PdfRendererView @JvmOverloads constructor(
                 }.let { addItemDecoration(it) }
             }
             setZoomEnabled(isZoomEnabled)
+            setRenderQuality(renderQuality)
         }
 
         recyclerView.addOnScrollListener(
@@ -253,6 +257,9 @@ class PdfRendererView @JvmOverloads constructor(
         recyclerView.setOnZoomChangeListener { isZoomedIn, scale ->
             zoomListener?.onZoomChanged(isZoomedIn, scale)
         }
+        recyclerView.setScrollListener { isScrolledToTop ->
+            scrollListener?.onScroll(isScrolledToTop)
+        }
 
         recyclerView.post {
             postInitializationAction?.invoke()
@@ -478,4 +485,8 @@ class PdfRendererView @JvmOverloads constructor(
     interface ZoomListener {
         fun onZoomChanged(isZoomedIn: Boolean, scale: Float)
     }
+
+    interface ScrollListener {
+        fun onScroll(isScrolledToTop: Boolean)
+    }
 }
diff --git a/pdfViewer/src/main/java/com/rajat/pdfviewer/PdfViewAdapter.kt b/pdfViewer/src/main/java/com/rajat/pdfviewer/PdfViewAdapter.kt
@@ -25,7 +25,8 @@ internal class PdfViewAdapter(
     private val renderer: PdfRendererCore,
     private val parentView: PdfRendererView,
     private val pageSpacing: Rect,
-    private val enableLoadingForPages: Boolean
+    private val enableLoadingForPages: Boolean,
+    private val renderQuality: RenderQuality,
 ) : RecyclerView.Adapter<PdfViewAdapter.PdfPageViewHolder>() {
 
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PdfPageViewHolder =
@@ -75,6 +76,11 @@ internal class PdfViewAdapter(
 
                 if (cached != null && currentBoundPage == position) {
                     if (DEBUG_LOGS_ENABLED) Log.d("PdfViewAdapter", "✅ Loaded page $position from cache")
+                    val aspectRatio = runCatching {
+                        cached.width.toFloat() / cached.height.toFloat()
+                    }.getOrElse { 1f }
+                    val height = (displayWidth / aspectRatio).toInt()
+                    itemBinding.updateLayoutParams(height)
                     itemBinding.pageView.setImageBitmap(cached)
                     hasRealBitmap = true
                     applyFadeInAnimation(itemBinding.pageView)
@@ -89,7 +95,9 @@ internal class PdfViewAdapter(
                     val height = (displayWidth / aspectRatio).toInt()
                     itemBinding.updateLayoutParams(height)
 
-                    renderAndApplyBitmap(position, displayWidth, height)
+                    val bitmapWidth = (displayWidth * renderQuality.qualityMultiplier).toInt()
+                    val bitmapHeight = (height * renderQuality.qualityMultiplier).toInt()
+                    renderAndApplyBitmap(position, bitmapWidth, bitmapHeight)
                 }
             }
 
@@ -127,7 +135,7 @@ internal class PdfViewAdapter(
         }
 
         private fun retryRenderOnce(page: Int, width: Int, height: Int) {
-            val retryBitmap = CommonUtils.Companion.BitmapPool.getBitmap(width, height)
+            val retryBitmap = CommonUtils.Companion.BitmapPool.getBitmap(width, maxOf(1, height))
             renderer.renderPage(page, retryBitmap) { success, retryPageNo, rendered ->
                 scope.launch {
                     if (success && retryPageNo == currentBoundPage && !hasRealBitmap) {
diff --git a/pdfViewer/src/main/java/com/rajat/pdfviewer/PinchZoomRecyclerView.kt b/pdfViewer/src/main/java/com/rajat/pdfviewer/PinchZoomRecyclerView.kt
@@ -23,11 +23,13 @@ class PinchZoomRecyclerView @JvmOverloads constructor(
     private val gestureDetector = GestureDetector(context, GestureListener())
 
     // Zoom and pan state
+    private var renderQuality = RenderQuality.NORMAL
     private var scaleFactor = 1f
     private var isZoomEnabled = true
-    private var maxZoom = MAX_ZOOM
+    private val maxZoom get() = MAX_ZOOM * renderQuality.qualityMultiplier
     private var zoomDuration = ZOOM_DURATION
     private var isZoomingInProgress = false
+    private var isOnTop = true
 
     // Panning offsets and touch memory
     private var lastTouchX = 0f
@@ -36,6 +38,7 @@ class PinchZoomRecyclerView @JvmOverloads constructor(
     private var posY = 0f
 
     private var zoomChangeListener: ((Boolean, Float) -> Unit)? = null
+    private var scrollListener: ((Boolean) -> Unit)? = null
 
     init {
         setWillNotDraw(false)
@@ -53,6 +56,14 @@ class PinchZoomRecyclerView @JvmOverloads constructor(
         zoomChangeListener = listener
     }
 
+    fun setScrollListener(listener: (isScrolledToTop: Boolean) -> Unit) {
+        scrollListener = listener
+    }
+
+    fun setRenderQuality(quality: RenderQuality) {
+        renderQuality = quality
+    }
+
     /**
      * Handles touch interactions — zoom, pan, and scroll.
      */
@@ -67,42 +78,10 @@ class PinchZoomRecyclerView @JvmOverloads constructor(
         }
 
         when (ev.actionMasked) {
-            MotionEvent.ACTION_DOWN -> {
-                lastTouchX = ev.x
-                lastTouchY = ev.y
-                activePointerId = ev.getPointerId(0)
-            }
-            MotionEvent.ACTION_MOVE -> {
-                if (!scaleDetector.isInProgress && scaleFactor > 1f) {
-                    val pointerIndex = ev.findPointerIndex(activePointerId)
-                    if (pointerIndex != -1) {
-                        val x = ev.getX(pointerIndex)
-                        val y = ev.getY(pointerIndex)
-                        val dx = x - lastTouchX
-                        val dy = y - lastTouchY
-                        posX += dx
-                        posY += dy
-                        clampPosition()
-                        invalidate()
-
-                        lastTouchX = x
-                        lastTouchY = y
-                    }
-                }
-            }
-            MotionEvent.ACTION_POINTER_UP -> {
-                val pointerIndex = ev.actionIndex
-                val pointerId = ev.getPointerId(pointerIndex)
-                if (pointerId == activePointerId) {
-                    val newPointerIndex = if (pointerIndex == 0) 1 else 0
-                    lastTouchX = ev.getX(newPointerIndex)
-                    lastTouchY = ev.getY(newPointerIndex)
-                    activePointerId = ev.getPointerId(newPointerIndex)
-                }
-            }
-            MotionEvent.ACTION_CANCEL -> {
-                activePointerId = INVALID_POINTER_ID
-            }
+            MotionEvent.ACTION_DOWN -> onDown(ev = ev)
+            MotionEvent.ACTION_MOVE -> onMove(ev = ev)
+            MotionEvent.ACTION_POINTER_UP -> onUp(ev = ev)
+            MotionEvent.ACTION_CANCEL -> onCancel(ev = ev)
         }
 
         return if (scaleFactor > 1f) true else super.onTouchEvent(ev)
@@ -171,13 +150,65 @@ class PinchZoomRecyclerView @JvmOverloads constructor(
         return (averageHeight * itemCount * scaleFactor).toInt()
     }
 
+    private fun onDown(ev: MotionEvent) {
+        lastTouchX = ev.x
+        lastTouchY = ev.y
+        activePointerId = ev.getPointerId(0)
+    }
+
+    private fun onMove(ev: MotionEvent) {
+        val pointerIndex = ev.findPointerIndex(activePointerId)
+        if (pointerIndex != -1) {
+            if (!scaleDetector.isInProgress && scaleFactor > 1f) {
+                val x = ev.getX(pointerIndex)
+                val y = ev.getY(pointerIndex)
+                val dx = x - lastTouchX
+                val dy = y - lastTouchY
+                posX += dx
+                posY += dy
+                clampPosition()
+                invalidate()
+
+                lastTouchX = x
+                lastTouchY = y
+            }
+
+            val isScrolledOut = !scaleDetector.isInProgress && scaleFactor == 1f
+            val currentScrollOffset = computeVerticalScrollOffset()
+            if (currentScrollOffset == 0 && isScrolledOut && !isOnTop) {
+                scrollListener?.invoke(true)
+                isOnTop = true
+            } else if ((currentScrollOffset != 0 || isScrolledOut.not()) && isOnTop) {
+                scrollListener?.invoke(false)
+                isOnTop = false
+            }
+        }
+    }
+
+    private fun onUp(ev: MotionEvent) {
+        val pointerIndex = ev.actionIndex
+        val pointerId = ev.getPointerId(pointerIndex)
+        if (pointerId == activePointerId) {
+            val newPointerIndex = if (pointerIndex == 0) 1 else 0
+            lastTouchX = ev.getX(newPointerIndex)
+            lastTouchY = ev.getY(newPointerIndex)
+            activePointerId = ev.getPointerId(newPointerIndex)
+        }
+    }
+
+    private fun onCancel(ev: MotionEvent) {
+        activePointerId = INVALID_POINTER_ID
+    }
+
     /**
      * Handles pinch-to-zoom scaling with focal-point centering.
      */
     private inner class ScaleListener : ScaleGestureDetector.SimpleOnScaleGestureListener() {
         override fun onScaleBegin(detector: ScaleGestureDetector): Boolean {
             isZoomingInProgress = true
             suppressLayout(true)
+            scrollListener?.invoke(false)
+            isOnTop = false
             return true
         }
 
diff --git a/pdfViewer/src/main/java/com/rajat/pdfviewer/RenderQuality.kt b/pdfViewer/src/main/java/com/rajat/pdfviewer/RenderQuality.kt
@@ -0,0 +1,5 @@
+package com.rajat.pdfviewer
+
+enum class RenderQuality(val qualityMultiplier: Float) {
+    NORMAL(qualityMultiplier = 1f), HIGH(qualityMultiplier = 2f), ULTRA(qualityMultiplier = 3f)
+}
diff --git a/pdfViewer/src/main/java/com/rajat/pdfviewer/compose/PdfRendererCompose.kt b/pdfViewer/src/main/java/com/rajat/pdfviewer/compose/PdfRendererCompose.kt
@@ -14,6 +14,7 @@ import androidx.lifecycle.compose.LocalLifecycleOwner
 import androidx.lifecycle.lifecycleScope
 import com.rajat.pdfviewer.HeaderData
 import com.rajat.pdfviewer.PdfRendererView
+import com.rajat.pdfviewer.RenderQuality
 import com.rajat.pdfviewer.util.CacheStrategy
 import com.rajat.pdfviewer.util.FileUtils.fileFromAsset
 import com.rajat.pdfviewer.util.PdfSource
@@ -23,12 +24,14 @@ import java.io.File
 fun PdfRendererViewCompose(
     source: PdfSource,
     modifier: Modifier = Modifier,
+    renderQuality: RenderQuality = RenderQuality.NORMAL,
     headers: HeaderData = HeaderData(),
     cacheStrategy: CacheStrategy = CacheStrategy.MAXIMIZE_PERFORMANCE,
     lifecycleOwner: LifecycleOwner = LocalLifecycleOwner.current,
     jumpToPage: Int? = null,
     statusCallBack: PdfRendererView.StatusCallBack? = null,
     zoomListener: PdfRendererView.ZoomListener? = null,
+    scrollListener: PdfRendererView.ScrollListener? = null,
     onReady: ((PdfRendererView) -> Unit)? = null,
 ) {
     val context = LocalContext.current
@@ -69,6 +72,8 @@ fun PdfRendererViewCompose(
         update = { view ->
             view.statusListener = combinedCallback
             view.zoomListener = zoomListener
+            view.scrollListener = scrollListener
+            view.renderQuality = renderQuality
 
             if (!initialized) {
                 when (source) {
