Add support for displaying spoiler text in compose.

app/src/main/java/org/thoughtcrime/securesms/components/spoiler/SpoilerPaint.kt

@@ -28,9 +28,18 @@ object SpoilerPaint {
    */
   var shader: BitmapShader? = null
 
-  private val WIDTH = if (Util.isLowMemory(AppDependencies.application)) 50.dp else 100.dp
-  private val HEIGHT = if (Util.isLowMemory(AppDependencies.application)) 20.dp else 40.dp
-  private val PARTICLES_PER_PIXEL = if (Util.isLowMemory(AppDependencies.application)) 0.001f else 0.002f
+  private val WIDTH = if (isLowMemory()) 50.dp else 100.dp
+  private val HEIGHT = if (isLowMemory()) 20.dp else 40.dp
+  private val PARTICLES_PER_PIXEL = if (isLowMemory()) 0.001f else 0.002f
+
+  private fun isLowMemory(): Boolean {
+    return try {
+      Util.isLowMemory(AppDependencies.application)
+    } catch (e: Throwable) {
+      // In preview mode or when AppDependencies is not initialized, default to low memory mode
+      true
+    }
+  }
 
   private var shaderBitmap: Bitmap = Bitmap.createBitmap(WIDTH, HEIGHT, Bitmap.Config.ALPHA_8)
   private var bufferBitmap: Bitmap = Bitmap.createBitmap(WIDTH, HEIGHT, Bitmap.Config.ALPHA_8)

app/src/main/java/org/thoughtcrime/securesms/components/spoiler/compose/SpoilerModifier.kt

@@ -0,0 +1,149 @@
+package org.thoughtcrime.securesms.components.spoiler.compose
+
+import android.graphics.Paint
+import android.graphics.PorterDuff
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.drawWithCache
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
+import androidx.compose.ui.graphics.nativeCanvas
+import androidx.compose.ui.graphics.toArgb
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.TextLayoutResult
+import org.thoughtcrime.securesms.components.spoiler.SpoilerPaint
+
+/**
+ * Annotation tag used to mark spoiler text ranges in an AnnotatedString.
+ */
+const val SPOILER_ANNOTATION_TAG = "spoiler"
+
+/**
+ * Modifier that draws the spoiler effect over specific text regions.
+ *
+ * @param spoilerState State holder for revealed spoilers
+ * @param annotatedString The text with spoiler annotations
+ * @param textLayoutResult The result of text layout measurement
+ * @param textColor Color to tint the particles
+ */
+fun Modifier.drawSpoilers(
+  spoilerState: SpoilerState,
+  annotatedString: AnnotatedString,
+  textLayoutResult: TextLayoutResult?,
+  textColor: Color
+): Modifier = this.then(
+  Modifier.drawWithCache {
+    val paint = Paint()
+    val colorFilter = android.graphics.PorterDuffColorFilter(
+      textColor.toArgb(),
+      PorterDuff.Mode.SRC_IN
+    )
+
+    onDrawWithContent {
+      drawContent()
+
+      val layout = textLayoutResult ?: return@onDrawWithContent
+
+      // Get all spoiler annotations
+      val spoilerAnnotations = annotatedString.getStringAnnotations(
+        tag = SPOILER_ANNOTATION_TAG,
+        start = 0,
+        end = annotatedString.length
+      )
+
+      if (spoilerAnnotations.isEmpty()) {
+        return@onDrawWithContent
+      }
+
+      val shader = SpoilerPaint.shader
+
+      drawIntoCanvas { canvas ->
+        val nativeCanvas = canvas.nativeCanvas
+
+        // Update paint properties for this draw
+        if (shader != null) {
+          paint.shader = shader
+          paint.colorFilter = colorFilter
+        } else {
+          paint.shader = null
+          paint.color = android.graphics.Color.TRANSPARENT
+        }
+
+        for (annotation in spoilerAnnotations) {
+          if (spoilerState.isRevealed(annotation.item)) {
+            continue
+          }
+
+          val start = annotation.start
+          val end = annotation.end
+
+          if (start >= end) {
+            continue
+          }
+
+          val startLine = layout.getLineForOffset(start)
+          val endLine = layout.getLineForOffset(end)
+
+          if (startLine == endLine) {
+            val left = layout.getHorizontalPosition(start, true)
+            val right = layout.getHorizontalPosition(end, true)
+            val top = layout.getLineTop(startLine)
+            val bottom = layout.getLineBottom(startLine)
+
+            nativeCanvas.drawRect(
+              left.coerceAtMost(right),
+              top,
+              left.coerceAtLeast(right),
+              bottom,
+              paint
+            )
+          } else {
+            val firstLineLeft = layout.getHorizontalPosition(start, true)
+            val firstLineRight = if (layout.getParagraphDirection(startLine) == androidx.compose.ui.text.style.ResolvedTextDirection.Rtl) {
+              layout.getLineLeft(startLine)
+            } else {
+              layout.getLineRight(startLine)
+            }
+            nativeCanvas.drawRect(
+              firstLineLeft.coerceAtMost(firstLineRight),
+              layout.getLineTop(startLine),
+              firstLineLeft.coerceAtLeast(firstLineRight),
+              layout.getLineBottom(startLine),
+              paint
+            )
+
+            for (line in startLine + 1 until endLine) {
+              nativeCanvas.drawRect(
+                layout.getLineLeft(line),
+                layout.getLineTop(line),
+                layout.getLineRight(line),
+                layout.getLineBottom(line),
+                paint
+              )
+            }
+
+            val lastLineLeft = if (layout.getParagraphDirection(endLine) == androidx.compose.ui.text.style.ResolvedTextDirection.Rtl) {
+              layout.getLineRight(endLine)
+            } else {
+              layout.getLineLeft(endLine)
+            }
+            val lastLineRight = layout.getHorizontalPosition(end, true)
+            nativeCanvas.drawRect(
+              lastLineLeft.coerceAtMost(lastLineRight),
+              layout.getLineTop(endLine),
+              lastLineLeft.coerceAtLeast(lastLineRight),
+              layout.getLineBottom(endLine),
+              paint
+            )
+          }
+        }
+      }
+    }
+  }
+)
+
+/**
+ * Find which spoiler annotation (if any) contains the given offset in the text.
+ */
+fun AnnotatedString.findSpoilerAt(offset: Int): AnnotatedString.Range<String>? {
+  return getStringAnnotations(SPOILER_ANNOTATION_TAG, offset, offset).firstOrNull()
+}

app/src/main/java/org/thoughtcrime/securesms/components/spoiler/compose/SpoilerState.kt

@@ -0,0 +1,46 @@
+package org.thoughtcrime.securesms.components.spoiler.compose
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Stable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+
+/**
+ * State holder for managing which spoilers have been revealed in Compose.
+ * Similar to the View-based SpoilerAnnotation, but uses Compose state management.
+ */
+@Stable
+class SpoilerState {
+  private var revealedSpoilers by mutableStateOf(setOf<String>())
+
+  /**
+   * Check if a spoiler with the given ID has been revealed.
+   */
+  fun isRevealed(spoilerId: String): Boolean {
+    return spoilerId in revealedSpoilers
+  }
+
+  /**
+   * Reveal a spoiler with the given ID.
+   */
+  fun reveal(spoilerId: String) {
+    revealedSpoilers = revealedSpoilers + spoilerId
+  }
+
+  /**
+   * Reset all revealed spoilers.
+   */
+  fun reset() {
+    revealedSpoilers = emptySet()
+  }
+}
+
+/**
+ * Remember a [SpoilerState] instance.
+ */
+@Composable
+fun rememberSpoilerState(): SpoilerState {
+  return remember { SpoilerState() }
+}

app/src/main/java/org/thoughtcrime/securesms/components/spoiler/compose/SpoilerText.kt

@@ -0,0 +1,213 @@
+package org.thoughtcrime.securesms.components.spoiler.compose
+
+import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.foundation.text.InlineTextContent
+import androidx.compose.material3.LocalContentColor
+import androidx.compose.material3.LocalTextStyle
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableLongStateOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.runtime.withFrameNanos
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.TextLayoutResult
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.text.style.TextDecoration
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.TextUnit
+import org.thoughtcrime.securesms.components.spoiler.SpoilerPaint
+
+/**
+ * A Text composable that supports spoiler annotations with particle effects.
+ *
+ * Text ranges marked with [SPOILER_ANNOTATION_TAG] annotations will be rendered with
+ * an animated particle effect until revealed by tapping.
+ *
+ * Example usage:
+ * ```
+ * val spoilerState = rememberSpoilerState()
+ * val text = buildAnnotatedString {
+ *   append("This is normal text. ")
+ *   withAnnotation(SPOILER_ANNOTATION_TAG, "spoiler-1") {
+ *     append("This is a spoiler!")
+ *   }
+ *   append(" More normal text.")
+ * }
+ * SpoilerText(
+ *   text = text,
+ *   spoilerState = spoilerState
+ * )
+ * ```
+ *
+ * @param text The annotated string with optional spoiler annotations
+ * @param spoilerState State holder for managing revealed spoilers
+ * @param modifier Modifier to be applied to the Text
+ * @param color Color to apply to the text
+ * @param fontSize Font size to apply to the text
+ * @param textAlign Text alignment
+ * @param textDecoration Text decoration
+ * @param overflow How to handle text overflow
+ * @param softWrap Whether the text should break at soft line breaks
+ * @param maxLines Maximum number of lines
+ * @param minLines Minimum number of lines
+ * @param onTextLayout Callback for text layout results
+ * @param style Text style to apply
+ * @param inlineContent Map of inline content for the text
+ */
+@Composable
+fun SpoilerText(
+  text: AnnotatedString,
+  spoilerState: SpoilerState,
+  modifier: Modifier = Modifier,
+  color: Color = Color.Unspecified,
+  fontSize: TextUnit = TextUnit.Unspecified,
+  textAlign: TextAlign? = null,
+  textDecoration: TextDecoration? = null,
+  overflow: TextOverflow = TextOverflow.Clip,
+  softWrap: Boolean = true,
+  maxLines: Int = Int.MAX_VALUE,
+  minLines: Int = 1,
+  onTextLayout: (TextLayoutResult) -> Unit = {},
+  style: TextStyle = LocalTextStyle.current,
+  inlineContent: Map<String, InlineTextContent> = mapOf()
+) {
+  var textLayoutResult by remember { mutableStateOf<TextLayoutResult?>(null) }
+  var frameTime by remember { mutableLongStateOf(0L) }
+
+  // Get all spoiler annotations
+  val spoilerAnnotations = remember(text) {
+    text.getStringAnnotations(SPOILER_ANNOTATION_TAG, 0, text.length)
+  }
+
+  // Check if there are any unrevealed spoilers
+  val hasUnrevealedSpoilers = remember(spoilerAnnotations, spoilerState, frameTime) {
+    spoilerAnnotations.any { !spoilerState.isRevealed(it.item) }
+  }
+
+  // Animate when there are unrevealed spoilers
+  LaunchedEffect(hasUnrevealedSpoilers) {
+    if (hasUnrevealedSpoilers) {
+      while (true) {
+        withFrameNanos { nanos ->
+          SpoilerPaint.update()
+          frameTime = nanos
+        }
+      }
+    }
+  }
+
+  val originalTextColor = if (color != Color.Unspecified) {
+    color
+  } else if (style.color != Color.Unspecified) {
+    style.color
+  } else {
+    LocalContentColor.current
+  }
+
+  val displayText = remember(text, spoilerAnnotations, spoilerState, frameTime) {
+    AnnotatedString.Builder(text).apply {
+      for (annotation in spoilerAnnotations) {
+        if (!spoilerState.isRevealed(annotation.item)) {
+          addStyle(
+            style = androidx.compose.ui.text.SpanStyle(color = Color.Transparent),
+            start = annotation.start,
+            end = annotation.end
+          )
+        }
+      }
+    }.toAnnotatedString()
+  }
+
+  Text(
+    text = displayText,
+    modifier = modifier
+      .drawSpoilers(
+        spoilerState = spoilerState,
+        annotatedString = text,
+        textLayoutResult = textLayoutResult,
+        textColor = originalTextColor
+      )
+      .pointerInput(text, spoilerState) {
+        detectTapGestures { offset ->
+          val layout = textLayoutResult ?: return@detectTapGestures
+          val position = layout.getOffsetForPosition(offset)
+          val spoiler = text.findSpoilerAt(position)
+          if (spoiler != null && !spoilerState.isRevealed(spoiler.item)) {
+            spoilerState.reveal(spoiler.item)
+          }
+        }
+      },
+    color = color,
+    fontSize = fontSize,
+    textAlign = textAlign,
+    textDecoration = textDecoration,
+    overflow = overflow,
+    softWrap = softWrap,
+    maxLines = maxLines,
+    minLines = minLines,
+    onTextLayout = { result ->
+      textLayoutResult = result
+      onTextLayout(result)
+    },
+    style = style,
+    inlineContent = inlineContent
+  )
+}
+
+/**
+ * A Text composable that supports spoiler annotations, using a simple string with builder.
+ *
+ * @param text The plain text to display
+ * @param spoilerState State holder for managing revealed spoilers
+ * @param modifier Modifier to be applied to the Text
+ * @param color Color to apply to the text
+ * @param fontSize Font size to apply to the text
+ * @param textAlign Text alignment
+ * @param textDecoration Text decoration
+ * @param overflow How to handle text overflow
+ * @param softWrap Whether the text should break at soft line breaks
+ * @param maxLines Maximum number of lines
+ * @param minLines Minimum number of lines
+ * @param onTextLayout Callback for text layout results
+ * @param style Text style to apply
+ */
+@Composable
+fun SpoilerText(
+  text: String,
+  spoilerState: SpoilerState,
+  modifier: Modifier = Modifier,
+  color: Color = Color.Unspecified,
+  fontSize: TextUnit = TextUnit.Unspecified,
+  textAlign: TextAlign? = null,
+  textDecoration: TextDecoration? = null,
+  overflow: TextOverflow = TextOverflow.Clip,
+  softWrap: Boolean = true,
+  maxLines: Int = Int.MAX_VALUE,
+  minLines: Int = 1,
+  onTextLayout: (TextLayoutResult) -> Unit = {},
+  style: TextStyle = LocalTextStyle.current
+) {
+  SpoilerText(
+    text = AnnotatedString(text),
+    spoilerState = spoilerState,
+    modifier = modifier,
+    color = color,
+    fontSize = fontSize,
+    textAlign = textAlign,
+    textDecoration = textDecoration,
+    overflow = overflow,
+    softWrap = softWrap,
+    maxLines = maxLines,
+    minLines = minLines,
+    onTextLayout = onTextLayout,
+    style = style
+  )
+}

app/src/main/java/org/thoughtcrime/securesms/components/spoiler/compose/SpoilerTextPreviews.kt

@@ -0,0 +1,289 @@
+package org.thoughtcrime.securesms.components.spoiler.compose
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.SpanStyle
+import androidx.compose.ui.text.buildAnnotatedString
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.withStyle
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import org.signal.core.ui.compose.DayNightPreviews
+import org.signal.core.ui.compose.Previews
+
+@DayNightPreviews
+@Composable
+private fun SingleSpoilerPreview() {
+  val spoilerState = rememberSpoilerState()
+  val text = buildAnnotatedString {
+    append("This is some normal text and ")
+    val start = length
+    append("this part is hidden")
+    addStringAnnotation(SPOILER_ANNOTATION_TAG, "spoiler-1", start, length)
+    append(" until you tap it!")
+  }
+
+  Previews.Preview {
+    Column(
+      modifier = Modifier
+        .padding(16.dp)
+        .fillMaxWidth()
+    ) {
+      SpoilerText(
+        text = text,
+        spoilerState = spoilerState,
+        style = MaterialTheme.typography.bodyLarge
+      )
+    }
+  }
+}
+
+@DayNightPreviews
+@Composable
+private fun MultipleSpoilersPreview() {
+  val spoilerState = rememberSpoilerState()
+  val text = buildAnnotatedString {
+    append("The answer to question 1 is ")
+    val start1 = length
+    append("42")
+    addStringAnnotation(SPOILER_ANNOTATION_TAG, "answer-1", start1, length)
+    append(" and the answer to question 2 is ")
+    val start2 = length
+    append("the meaning of life")
+    addStringAnnotation(SPOILER_ANNOTATION_TAG, "answer-2", start2, length)
+    append(".")
+  }
+
+  Previews.Preview {
+    Column(
+      modifier = Modifier
+        .padding(16.dp)
+        .fillMaxWidth()
+    ) {
+      SpoilerText(
+        text = text,
+        spoilerState = spoilerState,
+        style = MaterialTheme.typography.bodyLarge
+      )
+    }
+  }
+}
+
+@DayNightPreviews
+@Composable
+private fun MultilineSpoilerPreview() {
+  val spoilerState = rememberSpoilerState()
+  val text = buildAnnotatedString {
+    append("Here's a really long spoiler: ")
+    val start = length
+    append("This is a very long piece of text that will definitely span multiple lines when displayed in a narrow container. It contains important plot details that you might not want to see until you're ready!")
+    addStringAnnotation(SPOILER_ANNOTATION_TAG, "long-spoiler", start, length)
+    append(" Tap to reveal.")
+  }
+
+  Previews.Preview {
+    Column(
+      modifier = Modifier
+        .padding(16.dp)
+        .fillMaxWidth()
+    ) {
+      SpoilerText(
+        text = text,
+        spoilerState = spoilerState,
+        style = MaterialTheme.typography.bodyLarge
+      )
+    }
+  }
+}
+
+@DayNightPreviews
+@Composable
+private fun StyledSpoilersPreview() {
+  val spoilerState = rememberSpoilerState()
+  val text = buildAnnotatedString {
+    append("Normal text, ")
+    withStyle(SpanStyle(fontWeight = FontWeight.Bold)) {
+      append("bold text, ")
+    }
+    val start1 = length
+    withStyle(SpanStyle(fontWeight = FontWeight.Bold, fontSize = 18.sp)) {
+      append("bold spoiler")
+    }
+    addStringAnnotation(SPOILER_ANNOTATION_TAG, "styled-spoiler-1", start1, length)
+    append(", and ")
+    val start2 = length
+    withStyle(SpanStyle(fontWeight = FontWeight.Light, fontSize = 14.sp)) {
+      append("light spoiler")
+    }
+    addStringAnnotation(SPOILER_ANNOTATION_TAG, "styled-spoiler-2", start2, length)
+    append(".")
+  }
+
+  Previews.Preview {
+    Column(
+      modifier = Modifier
+        .padding(16.dp)
+        .fillMaxWidth()
+    ) {
+      SpoilerText(
+        text = text,
+        spoilerState = spoilerState,
+        style = MaterialTheme.typography.bodyLarge
+      )
+    }
+  }
+}
+
+@DayNightPreviews
+@Composable
+private fun ColoredSpoilersPreview() {
+  val spoilerState = rememberSpoilerState()
+  val text = buildAnnotatedString {
+    append("This text has ")
+    val start1 = length
+    withStyle(SpanStyle(color = Color.Red)) {
+      append("red spoiler")
+    }
+    addStringAnnotation(SPOILER_ANNOTATION_TAG, "red-spoiler", start1, length)
+    append(" and ")
+    val start2 = length
+    withStyle(SpanStyle(color = Color.Blue)) {
+      append("blue spoiler")
+    }
+    addStringAnnotation(SPOILER_ANNOTATION_TAG, "blue-spoiler", start2, length)
+    append(".")
+  }
+
+  Previews.Preview {
+    Column(
+      modifier = Modifier
+        .padding(16.dp)
+        .fillMaxWidth()
+    ) {
+      SpoilerText(
+        text = text,
+        spoilerState = spoilerState,
+        style = MaterialTheme.typography.bodyLarge
+      )
+    }
+  }
+}
+
+@DayNightPreviews
+@Composable
+private fun SharedStatePreview() {
+  val spoilerState = rememberSpoilerState()
+
+  val text1 = buildAnnotatedString {
+    append("First message with ")
+    val start = length
+    append("shared spoiler")
+    addStringAnnotation(SPOILER_ANNOTATION_TAG, "shared-spoiler", start, length)
+  }
+
+  val text2 = buildAnnotatedString {
+    append("Second message with the same ")
+    val start = length
+    append("shared spoiler")
+    addStringAnnotation(SPOILER_ANNOTATION_TAG, "shared-spoiler", start, length)
+  }
+
+  Previews.Preview {
+    Column(
+      modifier = Modifier
+        .padding(16.dp)
+        .fillMaxWidth(),
+      verticalArrangement = Arrangement.spacedBy(16.dp)
+    ) {
+      SpoilerText(
+        text = text1,
+        spoilerState = spoilerState,
+        style = MaterialTheme.typography.bodyLarge
+      )
+      SpoilerText(
+        text = text2,
+        spoilerState = spoilerState,
+        style = MaterialTheme.typography.bodyLarge
+      )
+    }
+  }
+}
+
+@DayNightPreviews
+@Composable
+private fun EntireMessageSpoilerPreview() {
+  val spoilerState = rememberSpoilerState()
+  val text = buildAnnotatedString {
+    val start = length
+    append("This entire message is a spoiler! You need to tap anywhere on it to reveal the content.")
+    addStringAnnotation(SPOILER_ANNOTATION_TAG, "entire-message", start, length)
+  }
+
+  Previews.Preview {
+    Column(
+      modifier = Modifier
+        .padding(16.dp)
+        .fillMaxWidth()
+    ) {
+      SpoilerText(
+        text = text,
+        spoilerState = spoilerState,
+        style = MaterialTheme.typography.bodyLarge
+      )
+    }
+  }
+}
+
+@DayNightPreviews
+@Composable
+private fun DifferentSizesPreview() {
+  val spoilerState = rememberSpoilerState()
+
+  Previews.Preview {
+    Column(
+      modifier = Modifier
+        .padding(16.dp)
+        .fillMaxWidth(),
+      verticalArrangement = Arrangement.spacedBy(12.dp)
+    ) {
+      SpoilerText(
+        text = buildAnnotatedString {
+          append("Small text with ")
+          val start = length
+          append("small spoiler")
+          addStringAnnotation(SPOILER_ANNOTATION_TAG, "small", start, length)
+        },
+        spoilerState = spoilerState,
+        fontSize = 12.sp
+      )
+
+      SpoilerText(
+        text = buildAnnotatedString {
+          append("Medium text with ")
+          val start = length
+          append("medium spoiler")
+          addStringAnnotation(SPOILER_ANNOTATION_TAG, "medium", start, length)
+        },
+        spoilerState = spoilerState,
+        fontSize = 16.sp
+      )
+
+      SpoilerText(
+        text = buildAnnotatedString {
+          append("Large text with ")
+          val start = length
+          append("large spoiler")
+          addStringAnnotation(SPOILER_ANNOTATION_TAG, "large", start, length)
+        },
+        spoilerState = spoilerState,
+        fontSize = 24.sp
+      )
+    }
+  }
+}