feat: add ThumbHash support alongside BlurHash across events, uploads, and UI

Adds a parallel ThumbHash placeholder everywhere BlurHash is already used. Remote events now carry both hashes; renderers prefer thumbhash when available and fall back to blurhash. The MIP-04 `thumbhash` imeta field that was previously reserved-but-unused is now wired end-to-end. - New ThumbHash encoder/decoder in commons/commonMain (no new Gradle dep) - New ThumbhashTag and thumbhash accessors/builders across NIP-17, 68, 71, 94, 95, 99, the experimental profile gallery, and MIP-04 - RichTextParser + MediaContentModels carry a thumbhash field alongside blurhash so every downstream composable can pick its preferred placeholder - New ThumbHashFetcher (Android + Desktop) registered with Coil, plus a small placeholderModel(thumbhash, blurhash) helper centralising the "prefer thumbhash, fall back to blurhash" rule - Rename BlurhashMetadataCalculator -> PreviewMetadataCalculator; the calculator decodes the bitmap / video thumbnail once and runs both encoders on the same pixels to keep upload cost flat - DesktopMediaMetadata, MediaUploadResult, and FileHeader now surface both hashes through the NIP-96, Blossom, NIP-95, MIP-04, NIP-17 DM, Classifieds, picture, video, and long-form upload paths - Round-trip unit test for the ThumbHash port
2026-04-20 00:12:28 +00:00
parent 2d5097e8b0
commit b2f297b3bb
68 changed files with 1203 additions and 120 deletions
@@ -0,0 +1,91 @@
+/*
+ * 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
+
+import com.vitorpamplona.amethyst.commons.thumbhash.ThumbHashDecoder
+import com.vitorpamplona.amethyst.commons.thumbhash.ThumbHashEncoder
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class ThumbHashTest {
+    @Test
+    fun `encode and decode a solid color produces a hash with matching aspect`() {
+        val w = 32
+        val h = 24
+        val pixels = IntArray(w * h) { 0xFFFF8040.toInt() } // opaque warm orange
+
+        val hashBytes = ThumbHashEncoder.encode(pixels, w, h)
+        assertTrue("hash should have at least header bytes", hashBytes.size >= 5)
+
+        val decoded = ThumbHashDecoder.decode(hashBytes)
+        assertNotNull(decoded)
+        decoded!!
+        assertTrue("decoded width should be positive", decoded.width > 0)
+        assertTrue("decoded height should be positive", decoded.height > 0)
+
+        val originalRatio = w.toFloat() / h.toFloat()
+        val decodedRatio = decoded.width.toFloat() / decoded.height.toFloat()
+        // ThumbHash loses some precision, but landscape vs portrait should be preserved.
+        assertTrue(
+            "decoded ratio ($decodedRatio) should be on the same side of 1 as original ($originalRatio)",
+            (originalRatio > 1f) == (decodedRatio > 1f) || originalRatio == decodedRatio,
+        )
+    }
+
+    @Test
+    fun `base64 round-trip preserves decoded dimensions`() {
+        val w = 40
+        val h = 40
+        // A simple gradient so the image isn't entirely flat.
+        val pixels =
+            IntArray(w * h) { i ->
+                val x = i % w
+                val y = i / w
+                val r = (x * 255 / (w - 1))
+                val g = (y * 255 / (h - 1))
+                (0xFF shl 24) or (r shl 16) or (g shl 8) or 0x40
+            }
+
+        val encoded = ThumbHashEncoder.encodeToBase64(pixels, w, h)
+        assertTrue("base64 string should be non-empty", encoded.isNotEmpty())
+        assertTrue("base64 string should not contain padding", !encoded.contains('='))
+
+        val viaBase64 = ThumbHashDecoder.decode(encoded)
+        assertNotNull(viaBase64)
+        viaBase64!!
+
+        val viaBytes = ThumbHashDecoder.decode(ThumbHashEncoder.encode(pixels, w, h))
+        assertNotNull(viaBytes)
+        viaBytes!!
+
+        assertEquals("base64 path and raw path should agree on width", viaBytes.width, viaBase64.width)
+        assertEquals("base64 path and raw path should agree on height", viaBytes.height, viaBase64.height)
+    }
+
+    @Test
+    fun `decoding a malformed hash returns null`() {
+        assertEquals(null, ThumbHashDecoder.decode(ByteArray(3)))
+        assertEquals(null, ThumbHashDecoder.decode(null as String?))
+        assertEquals(null, ThumbHashDecoder.decode(""))
+    }
+}