Maths support (MSC2191)

changelog.d/2133.feature

@@ -0,0 +1 @@
+Add labs support for rendering LaTeX maths (MSC2191)

dependencies.gradle

@@ -14,7 +14,7 @@ def kotlinCoroutines = "1.5.1"
 def dagger = "2.38.1"
 def retrofit = "2.9.0"
 def arrow = "0.8.2"
-def markwon = "4.6.2"
+def markwon = "4.3.1"
 def moshi = "1.12.0"
 def lifecycle = "2.2.0"
 def rxBinding = "3.1.0"
@@ -90,6 +90,8 @@ ext.libs = [
         ],
         markwon     : [
                 'core'                   : "io.noties.markwon:core:$markwon",
+                'extLatex'               : "io.noties.markwon:ext-latex:$markwon",
+                'inlineParser'           : "io.noties.markwon:inline-parser:$markwon",
                 'html'                   : "io.noties.markwon:html:$markwon"
         ],
         airbnb      : [

matrix-sdk-android/src/main/java/org/commonmark/ext/maths/DisplayMaths.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2021 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.commonmark.ext.maths
+
+import org.commonmark.node.CustomBlock
+
+class DisplayMaths(private val delimiter: DisplayDelimiter) : CustomBlock() {
+    enum class DisplayDelimiter {
+        DOUBLE_DOLLAR, SQUARE_BRACKET_ESCAPED
+    }
+}

matrix-sdk-android/src/main/java/org/commonmark/ext/maths/InlineMaths.kt

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2021 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.commonmark.ext.maths
+
+import org.commonmark.node.CustomNode
+import org.commonmark.node.Delimited
+
+class InlineMaths(private val delimiter: InlineDelimiter) : CustomNode(), Delimited {
+    enum class InlineDelimiter {
+        SINGLE_DOLLAR, ROUND_BRACKET_ESCAPED
+    }
+
+    override fun getOpeningDelimiter(): String {
+        return when (delimiter) {
+            InlineDelimiter.SINGLE_DOLLAR         -> "$"
+            InlineDelimiter.ROUND_BRACKET_ESCAPED -> "\\("
+        }
+    }
+
+    override fun getClosingDelimiter(): String {
+        return when (delimiter) {
+            InlineDelimiter.SINGLE_DOLLAR         -> "$"
+            InlineDelimiter.ROUND_BRACKET_ESCAPED -> "\\)"
+        }
+    }
+}

matrix-sdk-android/src/main/java/org/commonmark/ext/maths/MathsExtension.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2021 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.commonmark.ext.maths
+
+import org.commonmark.Extension
+import org.commonmark.ext.maths.internal.DollarMathsDelimiterProcessor
+import org.commonmark.ext.maths.internal.MathsHtmlNodeRenderer
+import org.commonmark.parser.Parser
+import org.commonmark.renderer.html.HtmlRenderer
+
+class MathsExtension private constructor() : Parser.ParserExtension, HtmlRenderer.HtmlRendererExtension {
+    override fun extend(parserBuilder: Parser.Builder) {
+        parserBuilder.customDelimiterProcessor(DollarMathsDelimiterProcessor())
+    }
+
+    override fun extend(rendererBuilder: HtmlRenderer.Builder) {
+        rendererBuilder.nodeRendererFactory { context -> MathsHtmlNodeRenderer(context) }
+    }
+
+    companion object {
+        fun create(): Extension {
+            return MathsExtension()
+        }
+    }
+}

matrix-sdk-android/src/main/java/org/commonmark/ext/maths/internal/DollarMathsDelimiterProcessor.kt

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2021 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.commonmark.ext.maths.internal
+
+import org.commonmark.ext.maths.DisplayMaths
+import org.commonmark.ext.maths.InlineMaths
+import org.commonmark.node.Text
+import org.commonmark.parser.delimiter.DelimiterProcessor
+import org.commonmark.parser.delimiter.DelimiterRun
+
+class DollarMathsDelimiterProcessor : DelimiterProcessor {
+    override fun getOpeningCharacter(): Char {
+        return '$'
+    }
+
+    override fun getClosingCharacter(): Char {
+        return '$'
+    }
+
+    override fun getMinLength(): Int {
+        return 1
+    }
+
+    override fun getDelimiterUse(opener: DelimiterRun, closer: DelimiterRun): Int {
+        return if (opener.length() == 1 && closer.length() == 1) 1 // inline
+        else if (opener.length() == 2 && closer.length() == 2) 2 // display
+        else 0
+    }
+
+    override fun process(opener: Text, closer: Text, delimiterUse: Int) {
+        val maths = if (delimiterUse == 1) InlineMaths(InlineMaths.InlineDelimiter.SINGLE_DOLLAR) else DisplayMaths(DisplayMaths.DisplayDelimiter.DOUBLE_DOLLAR)
+        var tmp = opener.next
+        while (tmp != null && tmp !== closer) {
+            val next = tmp.next
+            maths.appendChild(tmp)
+            tmp = next
+        }
+        opener.insertAfter(maths)
+    }
+}

matrix-sdk-android/src/main/java/org/commonmark/ext/maths/internal/MathsHtmlNodeRenderer.kt

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2021 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.commonmark.ext.maths.internal
+
+import org.commonmark.ext.maths.DisplayMaths
+import org.commonmark.node.Node
+import org.commonmark.node.Text
+import org.commonmark.renderer.html.HtmlNodeRendererContext
+import org.commonmark.renderer.html.HtmlWriter
+import java.util.Collections
+
+class MathsHtmlNodeRenderer(private val context: HtmlNodeRendererContext) : MathsNodeRenderer() {
+    private val html: HtmlWriter = context.writer
+    override fun render(node: Node) {
+        val display = node.javaClass == DisplayMaths::class.java
+        val contents = node.firstChild // should be the only child
+        val latex = (contents as Text).literal
+        val attributes = context.extendAttributes(node, if (display) "div" else "span", Collections.singletonMap("data-mx-maths",
+                latex))
+        html.tag(if (display) "div" else "span", attributes)
+        html.tag("code")
+        context.render(contents)
+        html.tag("/code")
+        html.tag(if (display) "/div" else "/span")
+    }
+}

matrix-sdk-android/src/main/java/org/commonmark/ext/maths/internal/MathsNodeRenderer.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2021 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.commonmark.ext.maths.internal
+
+import org.commonmark.ext.maths.InlineMaths
+import org.commonmark.ext.maths.DisplayMaths
+import org.commonmark.ext.maths.internal.MathsNodeRenderer
+import org.commonmark.node.Node
+import org.commonmark.renderer.NodeRenderer
+import java.util.HashSet
+
+abstract class MathsNodeRenderer : NodeRenderer {
+    override fun getNodeTypes(): Set<Class<out Node>> {
+        val types: MutableSet<Class<out Node>> = HashSet()
+        types.add(InlineMaths::class.java)
+        types.add(DisplayMaths::class.java)
+        return types
+    }
+}

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/RoomModule.kt

@@ -19,6 +19,8 @@ package org.matrix.android.sdk.internal.session.room
 import dagger.Binds
 import dagger.Module
 import dagger.Provides
+import org.commonmark.Extension
+import org.commonmark.ext.maths.MathsExtension
 import org.commonmark.parser.Parser
 import org.commonmark.renderer.html.HtmlRenderer
 import org.matrix.android.sdk.api.session.file.FileService
@@ -104,6 +106,7 @@ internal abstract class RoomModule {
 
     @Module
     companion object {
+        private val extensions : List<Extension> = listOf(MathsExtension.create())
         @Provides
         @JvmStatic
         @SessionScope
@@ -121,14 +124,15 @@ internal abstract class RoomModule {
         @Provides
         @JvmStatic
         fun providesParser(): Parser {
-            return Parser.builder().build()
+            return Parser.builder().extensions(extensions).build()
         }
 
         @Provides
         @JvmStatic
         fun providesHtmlRenderer(): HtmlRenderer {
             return HtmlRenderer
                     .builder()
+                    .extensions(extensions)
                     .softbreak("<br />")
                     .build()
         }

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/send/MarkdownParser.kt

@@ -32,7 +32,7 @@ internal class MarkdownParser @Inject constructor(
         private val textPillsUtils: TextPillsUtils
 ) {
 
-    private val mdSpecialChars = "[`_\\-*>.\\[\\]#~]".toRegex()
+    private val mdSpecialChars = "[`_\\-*>.\\[\\]#~$]".toRegex()
 
     fun parse(text: CharSequence): TextContent {
         val source = textPillsUtils.processSpecialSpansToMarkdown(text) ?: text.toString()

vector/build.gradle

@@ -390,6 +390,8 @@ dependencies {
     implementation libs.google.material
     implementation 'me.gujun.android:span:1.7'
     implementation libs.markwon.core
+    implementation libs.markwon.extLatex
+    implementation libs.markwon.inlineParser
     implementation libs.markwon.html
     implementation 'com.googlecode.htmlcompressor:htmlcompressor:1.5.2'
     implementation 'me.saket:better-link-movement-method:2.2.0'

vector/src/main/java/im/vector/app/features/home/room/detail/timeline/factory/MessageItemFactory.kt

@@ -484,6 +484,7 @@ class MessageItemFactory @Inject constructor(
         }
                 .useBigFont(linkifiedBody.length <= MAX_NUMBER_OF_EMOJI_FOR_BIG_FONT * 2 && containsOnlyEmojis(linkifiedBody.toString()))
                 .canUseTextFuture(canUseTextFuture)
+                .markwonPlugins(htmlRenderer.get().plugins)
                 .searchForPills(isFormatted)
                 .previewUrlRetriever(callback?.getPreviewUrlRetriever())
                 .imageContentRenderer(imageContentRenderer)

vector/src/main/java/im/vector/app/features/home/room/detail/timeline/item/MessageTextItem.kt

@@ -16,6 +16,7 @@
 
 package im.vector.app.features.home.room.detail.timeline.item
 
+import android.text.Spanned
 import android.text.method.MovementMethod
 import androidx.appcompat.widget.AppCompatTextView
 import androidx.core.text.PrecomputedTextCompat
@@ -31,6 +32,7 @@ import im.vector.app.features.home.room.detail.timeline.url.PreviewUrlRetriever
 import im.vector.app.features.home.room.detail.timeline.url.PreviewUrlUiState
 import im.vector.app.features.home.room.detail.timeline.url.PreviewUrlView
 import im.vector.app.features.media.ImageContentRenderer
+import io.noties.markwon.MarkwonPlugin
 
 @EpoxyModelClass(layout = R.layout.item_timeline_event_base)
 abstract class MessageTextItem : AbsMessageItem<MessageTextItem.Holder>() {
@@ -59,6 +61,9 @@ abstract class MessageTextItem : AbsMessageItem<MessageTextItem.Holder>() {
     @EpoxyAttribute(EpoxyAttribute.Option.DoNotHash)
     var movementMethod: MovementMethod? = null
 
+    @EpoxyAttribute(EpoxyAttribute.Option.DoNotHash)
+    var markwonPlugins: (List<MarkwonPlugin>)? = null
+
     private val previewUrlViewUpdater = PreviewUrlViewUpdater()
 
     override fun bind(holder: Holder) {
@@ -92,6 +97,7 @@ abstract class MessageTextItem : AbsMessageItem<MessageTextItem.Holder>() {
         } else {
             null
         }
+        markwonPlugins?.forEach { plugin -> plugin.beforeSetText(holder.messageView, message as Spanned) }
         super.bind(holder)
         holder.messageView.movementMethod = movementMethod
 
@@ -104,6 +110,7 @@ abstract class MessageTextItem : AbsMessageItem<MessageTextItem.Holder>() {
         } else {
             holder.messageView.text = message
         }
+        markwonPlugins?.forEach { plugin -> plugin.afterSetText(holder.messageView) }
     }
 
     override fun unbind(holder: Holder) {