Merge pull request #4307 from vitorpamplona/claude/cool-einstein-mkv9i8

Drop blank lines after block-level rich text segments
2026-10-05 19:28:25 +00:00 · 2026-10-02 10:12:41 -04:00
parent 9b435f287b 487269e54f
commit 4b63c87c94
3 changed files with 161 additions and 1 deletions
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.richtext
+
+/**
+ * True when [segment] renders as a full-width block (a link-preview card, an image, a video,
+ * a PDF) instead of an inline word. Media always draws as a block; a [LinkSegment] only does
+ * when previews are on, otherwise it is an inline clickable URL.
+ */
+fun rendersAsBlock(
+    segment: Segment,
+    canPreview: Boolean,
+): Boolean =
+    when (segment) {
+        is ImageSegment, is VideoSegment, is PdfSegment, is Base64Segment -> true
+        is LinkSegment -> canPreview
+        else -> false
+    }
+
+/** A paragraph that renders as an empty line: no words, or only blank text. */
+fun ParagraphState.isBlankLine(): Boolean = words.all { it is RegularTextSegment && it.segmentText.isBlank() }
+
+/**
+ * Drops the one blank line that directly follows a paragraph ending in a block (see
+ * [rendersAsBlock]). The block already ends its row, so the `\n\n` the author typed to separate
+ * the URL from the next sentence would otherwise render as an extra empty text line under the
+ * card, doubling the gap. Standalone image paragraphs get the same treatment in [GalleryParser].
+ *
+ * Returns [paragraphs] itself when nothing is dropped.
+ */
+fun dropBlankLineAfterBlocks(
+    paragraphs: List<ParagraphState>,
+    canPreview: Boolean,
+): List<ParagraphState> {
+    var result: ArrayList<ParagraphState>? = null
+
+    for (i in paragraphs.indices) {
+        val paragraph = paragraphs[i]
+        val previous = paragraphs.getOrNull(i - 1)
+        val drop =
+            previous != null &&
+                paragraph.isBlankLine() &&
+                !previous.isBlankLine() &&
+                rendersAsBlock(previous.words.last(), canPreview)
+
+        if (drop) {
+            if (result == null) result = ArrayList<ParagraphState>(paragraphs.size).apply { addAll(paragraphs.subList(0, i)) }
+        } else {
+            result?.add(paragraph)
+        }
+    }
+
+    return result ?: paragraphs
+}
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.richtext
+
+import com.vitorpamplona.amethyst.commons.model.EmptyTagList
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertSame
+import kotlin.test.assertTrue
+
+class BlockParagraphSpacingTest {
+    private fun parse(text: String) = RichTextParser().parseText(text, EmptyTagList, null).paragraphs
+
+    @Test
+    fun blankLineAfterTrailingLinkPreviewIsDropped() {
+        val paragraphs = parse("See if you can restore your follow list here: https://metadata.nostr.com/#\n\nSomething zeroed it out.")
+
+        // The parser keeps the author's blank line as its own paragraph...
+        assertEquals(3, paragraphs.size)
+        assertTrue(paragraphs[0].words.last() is LinkSegment)
+        assertTrue(paragraphs[1].isBlankLine())
+
+        // ...which the renderer drops under the card.
+        val rendered = dropBlankLineAfterBlocks(paragraphs, canPreview = true)
+        assertEquals(2, rendered.size)
+        assertSame(paragraphs[0], rendered[0])
+        assertSame(paragraphs[2], rendered[1])
+    }
+
+    @Test
+    fun blankLineAfterInlineLinkIsKeptWithoutPreviews() {
+        val paragraphs = parse("here: https://metadata.nostr.com/\n\nSomething zeroed it out.")
+
+        assertSame(paragraphs, dropBlankLineAfterBlocks(paragraphs, canPreview = false))
+    }
+
+    @Test
+    fun blankLineAfterTrailingImageIsDropped() {
+        val paragraphs = parse("look at this https://example.com/cat.jpg\n\nnice, right?")
+
+        assertEquals(3, paragraphs.size)
+        val rendered = dropBlankLineAfterBlocks(paragraphs, canPreview = false)
+        assertEquals(listOf(paragraphs[0], paragraphs[2]), rendered)
+    }
+
+    @Test
+    fun onlyOneBlankLineIsDropped() {
+        val paragraphs = parse("here: https://metadata.nostr.com/\n\n\nSomething zeroed it out.")
+
+        assertEquals(4, paragraphs.size)
+        val rendered = dropBlankLineAfterBlocks(paragraphs, canPreview = true)
+        assertEquals(listOf(paragraphs[0], paragraphs[2], paragraphs[3]), rendered)
+    }
+
+    @Test
+    fun linkInTheMiddleOfALineKeepsTheBlankLine() {
+        val paragraphs = parse("here: https://metadata.nostr.com/ is the site\n\nSomething zeroed it out.")
+
+        assertSame(paragraphs, dropBlankLineAfterBlocks(paragraphs, canPreview = true))
+    }
+
+    @Test
+    fun blankLineBeforeAPreviewIsKept() {
+        val paragraphs = parse("Something zeroed it out.\n\nhttps://metadata.nostr.com/")
+
+        assertSame(paragraphs, dropBlankLineAfterBlocks(paragraphs, canPreview = true))
+    }
+}
@@ -81,6 +81,7 @@ import com.vitorpamplona.amethyst.commons.richtext.SecretEmoji
 import com.vitorpamplona.amethyst.commons.richtext.Segment
 import com.vitorpamplona.amethyst.commons.richtext.VideoSegment
 import com.vitorpamplona.amethyst.commons.richtext.WithdrawSegment
+import com.vitorpamplona.amethyst.commons.richtext.dropBlankLineAfterBlocks

 /**
 * Cross-platform rich-text renderer. Owns everything identical on every front
@@ -104,9 +105,10 @@ fun RichTextViewer(
    val renderer = LocalRichTextSegmentRenderer.current
    val baseStyle = LocalTextStyle.current
    val paragraphStyle = remember(baseStyle) { baseStyle.copy(lineHeight = 1.3.em) }
+    val paragraphs = remember(state, canPreview) { dropBlankLineAfterBlocks(state.paragraphs, canPreview) }

    Column(modifier) {
-        state.paragraphs.forEach { paragraph ->
+        paragraphs.forEach { paragraph ->
            val align = if (paragraph.isRTL) Alignment.End else Alignment.Start
            if (paragraph is ImageGalleryParagraph) {
                renderer.Gallery(paragraph, state, Modifier.align(align))