refactor: streamline markdown rendering by introducing RenderedSegment and MarkdownSegmentRenderer

android/src/main/java/com/swmansion/enriched/markdown/EnrichedMarkdown.kt

@@ -5,21 +5,18 @@ import android.content.res.Configuration
 import android.os.Build
 import android.os.Handler
 import android.os.Looper
-import android.text.SpannableString
 import android.util.AttributeSet
 import android.util.Log
 import android.view.View
 import android.widget.FrameLayout
 import com.facebook.react.bridge.ReadableMap
-import com.swmansion.enriched.markdown.parser.MarkdownASTNode
 import com.swmansion.enriched.markdown.parser.Md4cFlags
 import com.swmansion.enriched.markdown.parser.Parser
-import com.swmansion.enriched.markdown.renderer.Renderer
-import com.swmansion.enriched.markdown.spans.ImageSpan
 import com.swmansion.enriched.markdown.spoiler.SpoilerOverlay
 import com.swmansion.enriched.markdown.styles.StyleConfig
 import com.swmansion.enriched.markdown.utils.common.FeatureFlags
-import com.swmansion.enriched.markdown.utils.common.MarkdownSegment
+import com.swmansion.enriched.markdown.utils.common.MarkdownSegmentRenderer
+import com.swmansion.enriched.markdown.utils.common.RenderedSegment
 import com.swmansion.enriched.markdown.utils.common.splitASTIntoSegments
 import com.swmansion.enriched.markdown.utils.text.view.emitLinkLongPressEvent
 import com.swmansion.enriched.markdown.utils.text.view.emitLinkPressEvent
@@ -28,23 +25,6 @@ import com.swmansion.enriched.markdown.views.TableContainerView
 import java.util.concurrent.ExecutorService
 import java.util.concurrent.Executors
 
-private sealed interface RenderSegment {
-  data class Text(
-    val styledText: SpannableString,
-    val imageSpans: List<ImageSpan>,
-    val needsJustify: Boolean,
-    val lastElementMarginBottom: Float,
-  ) : RenderSegment
-
-  data class Table(
-    val node: MarkdownASTNode,
-  ) : RenderSegment
-
-  data class Math(
-    val latex: String,
-  ) : RenderSegment
-}
-
 class EnrichedMarkdown
   @JvmOverloads
   constructor(
@@ -200,57 +180,43 @@ class EnrichedMarkdown
               return@execute
             }
 
-          val processedSegments =
-            splitASTIntoSegments(ast).map { segment ->
-              when (segment) {
-                is MarkdownSegment.Text -> renderTextSegment(segment.nodes, style)
-                is MarkdownSegment.Table -> RenderSegment.Table(segment.node)
-                is MarkdownSegment.Math -> RenderSegment.Math(segment.latex)
-              }
-            }
-
-          postToMain(renderId) { applyRenderedSegments(processedSegments, style) }
+          val segments = splitASTIntoSegments(ast)
+          val renderedSegments =
+            MarkdownSegmentRenderer.render(
+              segments,
+              style,
+              context,
+              onLinkPressCallback,
+              onLinkLongPressCallback,
+            )
+
+          postToMain(renderId) { applyRenderedSegments(renderedSegments, style) }
         } catch (e: Exception) {
           Log.e(TAG, "Render failed", e)
           postToMain(renderId) { clearSegments() }
         }
       }
     }
 
-    private fun renderTextSegment(
-      nodes: List<MarkdownASTNode>,
-      style: StyleConfig,
-    ): RenderSegment.Text {
-      val documentWrapper = MarkdownASTNode(type = MarkdownASTNode.NodeType.Document, children = nodes)
-      val renderer = Renderer().apply { configure(style, context) }
-
-      return RenderSegment.Text(
-        styledText = renderer.renderDocument(documentWrapper, onLinkPressCallback, onLinkLongPressCallback),
-        imageSpans = renderer.getCollectedImageSpans().toList(),
-        needsJustify = style.needsJustify,
-        lastElementMarginBottom = renderer.getLastElementMarginBottom(),
-      )
-    }
-
     private fun applyRenderedSegments(
-      renderedSegments: List<RenderSegment>,
+      renderedSegments: List<RenderedSegment>,
       style: StyleConfig,
     ) {
       clearSegments()
       renderedSegments.forEach { segment ->
         val view =
           when (segment) {
-            is RenderSegment.Text -> createTextView(segment)
-            is RenderSegment.Table -> createTableView(segment, style)
-            is RenderSegment.Math -> createMathView(segment, style)
+            is RenderedSegment.Text -> createTextView(segment)
+            is RenderedSegment.Table -> createTableView(segment, style)
+            is RenderedSegment.Math -> createMathView(segment, style)
           }
         segmentViews.add(view)
         addView(view)
       }
       layoutSegments()
     }
 
-    private fun createTextView(segment: RenderSegment.Text) =
+    private fun createTextView(segment: RenderedSegment.Text) =
       EnrichedMarkdownInternalText(context).apply {
         spoilerOverlay = this@EnrichedMarkdown.spoilerOverlay
         setIsSelectable(selectable)
@@ -271,7 +237,7 @@ class EnrichedMarkdown
       }
 
     private fun createTableView(
-      segment: RenderSegment.Table,
+      segment: RenderedSegment.Table,
       style: StyleConfig,
     ) = TableContainerView(context, style).apply {
       allowFontScaling = this@EnrichedMarkdown.allowFontScaling
@@ -282,7 +248,7 @@ class EnrichedMarkdown
     }
 
     private fun createMathView(
-      segment: RenderSegment.Math,
+      segment: RenderedSegment.Math,
       style: StyleConfig,
     ): android.view.View {
       if (!FeatureFlags.IS_MATH_ENABLED) return android.view.View(context)

android/src/main/java/com/swmansion/enriched/markdown/MeasurementStore.kt

@@ -12,7 +12,6 @@ import com.facebook.react.bridge.ReadableMap
 import com.facebook.react.uimanager.PixelUtil
 import com.facebook.yoga.YogaMeasureMode
 import com.facebook.yoga.YogaMeasureOutput
-import com.swmansion.enriched.markdown.parser.MarkdownASTNode
 import com.swmansion.enriched.markdown.parser.Md4cFlags
 import com.swmansion.enriched.markdown.parser.Parser
 import com.swmansion.enriched.markdown.renderer.Renderer
@@ -21,7 +20,8 @@ import com.swmansion.enriched.markdown.spans.MathMetrics
 import com.swmansion.enriched.markdown.spans.MathRenderMode
 import com.swmansion.enriched.markdown.styles.StyleConfig
 import com.swmansion.enriched.markdown.utils.common.FeatureFlags
-import com.swmansion.enriched.markdown.utils.common.MarkdownSegment
+import com.swmansion.enriched.markdown.utils.common.MarkdownSegmentRenderer
+import com.swmansion.enriched.markdown.utils.common.RenderedSegment
 import com.swmansion.enriched.markdown.utils.common.getBooleanOrDefault
 import com.swmansion.enriched.markdown.utils.common.getMapOrNull
 import com.swmansion.enriched.markdown.utils.common.getStringOrDefault
@@ -307,12 +307,13 @@ object MeasurementStore {
 
       val style = StyleConfig(styleMap, context, allowFontScaling, maxFontSizeMultiplier)
       val segments = splitASTIntoSegments(ast)
+      val renderedSegments = MarkdownSegmentRenderer.render(segments, style, context, null, null)
 
       val mathHeightByIndex = HashMap<Int, Float>()
       val mathSegmentIndices = mutableListOf<Int>()
       val mathRequests = mutableListOf<MathMeasureRequest>()
-      for ((i, segment) in segments.withIndex()) {
-        if (segment is MarkdownSegment.Math) {
+      for ((i, segment) in renderedSegments.withIndex()) {
+        if (segment is RenderedSegment.Math) {
           mathSegmentIndices.add(i)
           mathRequests.add(
             MathMeasureRequest(
@@ -333,33 +334,30 @@ object MeasurementStore {
       }
 
       val widthPx = width.toInt().coerceAtLeast(1)
-      val lastIndex = segments.lastIndex
+      val lastIndex = renderedSegments.lastIndex
       var totalHeightPx = 0f
       var maxContentWidthPx = 0f
 
-      for ((index, segment) in segments.withIndex()) {
+      for ((index, segment) in renderedSegments.withIndex()) {
         val isLastSegment = index == lastIndex
         val includeBottomMargin = if (isLastSegment) allowTrailingMargin else true
 
         when (segment) {
-          is MarkdownSegment.Text -> {
-            val segmentRenderer = Renderer().apply { configure(style, context) }
-            val tempDoc = MarkdownASTNode(type = MarkdownASTNode.NodeType.Document, children = segment.nodes)
-            val styledText = segmentRenderer.renderDocument(tempDoc, null)
-            styledText.replaceMathSpansWithPlaceholders(context)
+          is RenderedSegment.Text -> {
+            segment.styledText.replaceMathSpansWithPlaceholders(context)
 
-            val layout = createStaticLayout(styledText, fontSize, widthPx)
+            val layout = createStaticLayout(segment.styledText, fontSize, widthPx)
             totalHeightPx += layout.height
 
             val segmentMaxLineWidth = (0 until layout.lineCount).maxOfOrNull { layout.getLineWidth(it) } ?: 0f
             maxContentWidthPx = maxOf(maxContentWidthPx, ceil(segmentMaxLineWidth))
 
             if (includeBottomMargin) {
-              totalHeightPx += segmentRenderer.getLastElementMarginBottom()
+              totalHeightPx += segment.lastElementMarginBottom
             }
           }
 
-          is MarkdownSegment.Table -> {
+          is RenderedSegment.Table -> {
             totalHeightPx += style.tableStyle.marginTop
             totalHeightPx += TableContainerView.measureTableNodeHeight(segment.node, style, context)
             maxContentWidthPx = width
@@ -368,7 +366,7 @@ object MeasurementStore {
             }
           }
 
-          is MarkdownSegment.Math -> {
+          is RenderedSegment.Math -> {
             totalHeightPx += style.mathStyle.marginTop
             totalHeightPx += mathHeightByIndex[index] ?: 0f
             maxContentWidthPx = width

android/src/main/java/com/swmansion/enriched/markdown/utils/common/RenderedSegment.kt

@@ -0,0 +1,60 @@
+package com.swmansion.enriched.markdown.utils.common
+
+import android.content.Context
+import android.text.SpannableString
+import com.swmansion.enriched.markdown.parser.MarkdownASTNode
+import com.swmansion.enriched.markdown.renderer.Renderer
+import com.swmansion.enriched.markdown.spans.ImageSpan
+import com.swmansion.enriched.markdown.styles.StyleConfig
+
+sealed interface RenderedSegment {
+  data class Text(
+    val styledText: SpannableString,
+    val imageSpans: List<ImageSpan>,
+    val needsJustify: Boolean,
+    val lastElementMarginBottom: Float,
+  ) : RenderedSegment
+
+  data class Table(
+    val node: MarkdownASTNode,
+  ) : RenderedSegment
+
+  data class Math(
+    val latex: String,
+  ) : RenderedSegment
+}
+
+object MarkdownSegmentRenderer {
+  fun render(
+    segments: List<MarkdownSegment>,
+    style: StyleConfig,
+    context: Context,
+    onLinkPress: ((String) -> Unit)?,
+    onLinkLongPress: ((String) -> Unit)?,
+  ): List<RenderedSegment> =
+    segments.map { segment ->
+      when (segment) {
+        is MarkdownSegment.Text -> renderTextSegment(segment.nodes, style, context, onLinkPress, onLinkLongPress)
+        is MarkdownSegment.Table -> RenderedSegment.Table(segment.node)
+        is MarkdownSegment.Math -> RenderedSegment.Math(segment.latex)
+      }
+    }
+
+  private fun renderTextSegment(
+    nodes: List<MarkdownASTNode>,
+    style: StyleConfig,
+    context: Context,
+    onLinkPress: ((String) -> Unit)?,
+    onLinkLongPress: ((String) -> Unit)?,
+  ): RenderedSegment.Text {
+    val documentWrapper = MarkdownASTNode(type = MarkdownASTNode.NodeType.Document, children = nodes)
+    val renderer = Renderer().apply { configure(style, context) }
+
+    return RenderedSegment.Text(
+      styledText = renderer.renderDocument(documentWrapper, onLinkPress, onLinkLongPress),
+      imageSpans = renderer.getCollectedImageSpans().toList(),
+      needsJustify = style.needsJustify,
+      lastElementMarginBottom = renderer.getLastElementMarginBottom(),
+    )
+  }
+}