Merge pull request #2133 from NickHu/maths

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 = "1.5.2"
 def dagger = "2.40.5"
 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 = "2.4.0"
 def flowBinding = "1.2.0"
@@ -95,6 +95,8 @@ 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
@@ -121,7 +124,7 @@ internal abstract class RoomModule {
         @Provides
         @JvmStatic
         fun providesParser(): Parser {
-            return Parser.builder().build()
+            return Parser.builder().extensions(extensions).build()
         }
 
         @Provides
@@ -129,6 +132,7 @@ internal abstract class RoomModule {
         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

@@ -389,6 +389,8 @@ 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

@@ -511,6 +511,7 @@ class MessageItemFactory @Inject constructor(
         }
                 .useBigFont(linkifiedBody.length <= MAX_NUMBER_OF_EMOJI_FOR_BIG_FONT * 2 && containsOnlyEmojis(linkifiedBody.toString()))
                 .bindingOptions(bindingOptions)
+                .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
@@ -33,6 +34,7 @@ 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
 import org.matrix.android.sdk.api.extensions.orFalse
 
 @EpoxyModelClass(layout = R.layout.item_timeline_event_base)
@@ -62,6 +64,9 @@ 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) {
@@ -95,6 +100,7 @@ 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
         renderSendState(holder.messageView, holder.messageView)
@@ -110,6 +116,7 @@ abstract class MessageTextItem : AbsMessageItem<MessageTextItem.Holder>() {
                 message
             }
         }
+        markwonPlugins?.forEach { plugin -> plugin.afterSetText(holder.messageView) }
     }
 
     override fun unbind(holder: Holder) {

vector/src/main/java/im/vector/app/features/html/EventHtmlRenderer.kt

@@ -20,8 +20,15 @@ import android.content.Context
 import android.text.Spannable
 import androidx.core.text.toSpannable
 import im.vector.app.core.resources.ColorProvider
+import im.vector.app.features.settings.VectorPreferences
+import io.noties.markwon.AbstractMarkwonPlugin
 import io.noties.markwon.Markwon
+import io.noties.markwon.MarkwonPlugin
+import io.noties.markwon.PrecomputedFutureTextSetterCompat
+import io.noties.markwon.ext.latex.JLatexMathPlugin
+import io.noties.markwon.ext.latex.JLatexMathTheme
 import io.noties.markwon.html.HtmlPlugin
+import io.noties.markwon.inlineparser.MarkwonInlineParserPlugin
 import org.commonmark.node.Node
 import timber.log.Timber
 import javax.inject.Inject
@@ -29,15 +36,39 @@ import javax.inject.Singleton
 
 @Singleton
 class EventHtmlRenderer @Inject constructor(htmlConfigure: MatrixHtmlPluginConfigure,
-                                            context: Context) {
+                                            context: Context,
+                                            private val vectorPreferences: VectorPreferences) {
 
     interface PostProcessor {
         fun afterRender(renderedText: Spannable)
     }
 
-    private val markwon = Markwon.builder(context)
+    private val builder = Markwon.builder(context)
             .usePlugin(HtmlPlugin.create(htmlConfigure))
-            .build()
+
+    private val markwon = if (vectorPreferences.latexMathsIsEnabled()) {
+        builder
+                .usePlugin(object : AbstractMarkwonPlugin() { // Markwon expects maths to be in a specific format: https://noties.io/Markwon/docs/v4/ext-latex
+                    override fun processMarkdown(markdown: String): String {
+                        return markdown
+                                .replace(Regex("""<span\s+data-mx-maths="([^"]*)">.*?</span>""")) {
+                                    matchResult -> "$$" + matchResult.groupValues[1] + "$$"
+                                }
+                                .replace(Regex("""<div\s+data-mx-maths="([^"]*)">.*?</div>""")) {
+                                    matchResult -> "\n$$\n" + matchResult.groupValues[1] + "\n$$\n"
+                                }
+                    }
+                })
+                .usePlugin(MarkwonInlineParserPlugin.create())
+                .usePlugin(JLatexMathPlugin.create(44F) { builder ->
+                    builder.inlinesEnabled(true)
+                    builder.theme().inlinePadding(JLatexMathTheme.Padding.symmetric(24, 8))
+                })
+    } else {
+        builder
+    }.textSetter(PrecomputedFutureTextSetterCompat.create()).build()
+
+    val plugins: List<MarkwonPlugin> = markwon.plugins
 
     fun parse(text: String): Node {
         return markwon.parse(text)

vector/src/main/java/im/vector/app/features/settings/VectorPreferences.kt

@@ -97,6 +97,7 @@ class VectorPreferences @Inject constructor(private val context: Context) {
         private const val SETTINGS_SEND_MESSAGE_WITH_ENTER = "SETTINGS_SEND_MESSAGE_WITH_ENTER"
         private const val SETTINGS_ENABLE_CHAT_EFFECTS = "SETTINGS_ENABLE_CHAT_EFFECTS"
         private const val SETTINGS_SHOW_EMOJI_KEYBOARD = "SETTINGS_SHOW_EMOJI_KEYBOARD"
+        private const val SETTINGS_LABS_ENABLE_LATEX_MATHS = "SETTINGS_LABS_ENABLE_LATEX_MATHS"
 
         // Room directory
         private const val SETTINGS_ROOM_DIRECTORY_SHOW_ALL_PUBLIC_ROOMS = "SETTINGS_ROOM_DIRECTORY_SHOW_ALL_PUBLIC_ROOMS"
@@ -334,6 +335,10 @@ class VectorPreferences @Inject constructor(private val context: Context) {
         return defaultPrefs.getBoolean(SETTINGS_LABS_UNREAD_NOTIFICATIONS_AS_TAB, false)
     }
 
+    fun latexMathsIsEnabled(): Boolean {
+        return defaultPrefs.getBoolean(SETTINGS_LABS_ENABLE_LATEX_MATHS, false)
+    }
+
     fun failFast(): Boolean {
         return BuildConfig.DEBUG || (developerMode() && defaultPrefs.getBoolean(SETTINGS_DEVELOPER_MODE_FAIL_FAST_PREFERENCE_KEY, false))
     }

vector/src/main/res/values/strings.xml

@@ -3661,6 +3661,8 @@
     <!-- %s will be replaced by the value of link_this_email_settings_link and styled as a link -->
     <string name="link_this_email_with_your_account">%s in Settings to receive invites directly in Element.</string>
 
+   <string name="labs_enable_latex_maths">Enable LaTeX mathematics</string>
+
     <!-- Poll -->
     <string name="create_poll_title">Create Poll</string>
     <string name="create_poll_question_title">Poll question or topic</string>

vector/src/main/res/xml/vector_settings_labs.xml

@@ -49,6 +49,11 @@
         android:key="SETTINGS_LABS_USE_RESTRICTED_JOIN_RULE"
         android:title="@string/labs_use_restricted_join_rule"
         android:summary="@string/labs_use_restricted_join_rule_desc"/>
+
+    <im.vector.app.core.preference.VectorSwitchPreference
+        android:defaultValue="false"
+        android:key="SETTINGS_LABS_ENABLE_LATEX_MATHS"
+        android:title="@string/labs_enable_latex_maths"/>
     <!--</im.vector.app.core.preference.VectorPreferenceCategory>-->
 
     <im.vector.app.core.preference.VectorSwitchPreference