From 205ae7b47a66d7bd33a0b21c7c9105929cd8a117 Mon Sep 17 00:00:00 2001
From: Dimitry Ivanov <di@noties.io>
Date: Wed, 24 Feb 2021 12:36:11 +0300
Subject: [PATCH] sample, add reddit superscript

---
 app-sample/samples.json                       | 13 +++
 .../samples/parser/RedditSuperscriptSample.kt | 91 +++++++++++++++++++
 .../markwon/sample/annotations/Tag.java       |  1 +
 3 files changed, 105 insertions(+)
 create mode 100644 app-sample/src/main/java/io/noties/markwon/app/samples/parser/RedditSuperscriptSample.kt

diff --git a/app-sample/samples.json b/app-sample/samples.json
index c6c5938d..ea8bf2d5 100644
--- a/app-sample/samples.json
+++ b/app-sample/samples.json
@@ -1,4 +1,17 @@
 [
+  {
+    "javaClassName": "io.noties.markwon.app.samples.parser.RedditSuperscriptSample",
+    "id": "20210224091506",
+    "title": "Reddit superscript",
+    "description": "",
+    "artifacts": [
+      "HTML"
+    ],
+    "tags": [
+      "html",
+      "reddit"
+    ]
+  },
   {
     "javaClassName": "io.noties.markwon.app.samples.image.ImageSizeResolverSample",
     "id": "20210201165512",
diff --git a/app-sample/src/main/java/io/noties/markwon/app/samples/parser/RedditSuperscriptSample.kt b/app-sample/src/main/java/io/noties/markwon/app/samples/parser/RedditSuperscriptSample.kt
new file mode 100644
index 00000000..70dc705a
--- /dev/null
+++ b/app-sample/src/main/java/io/noties/markwon/app/samples/parser/RedditSuperscriptSample.kt
@@ -0,0 +1,91 @@
+package io.noties.markwon.app.samples.parser
+
+import android.text.TextPaint
+import android.text.style.MetricAffectingSpan
+import io.noties.markwon.AbstractMarkwonPlugin
+import io.noties.markwon.Markwon
+import io.noties.markwon.MarkwonConfiguration
+import io.noties.markwon.RenderProps
+import io.noties.markwon.app.sample.ui.MarkwonTextViewSample
+import io.noties.markwon.html.HtmlPlugin
+import io.noties.markwon.html.HtmlTag
+import io.noties.markwon.html.tag.SimpleTagHandler
+import io.noties.markwon.sample.annotations.MarkwonArtifact
+import io.noties.markwon.sample.annotations.MarkwonSampleInfo
+import io.noties.markwon.sample.annotations.Tag.html
+import io.noties.markwon.sample.annotations.Tag.reddit
+import java.util.regex.Pattern
+
+@MarkwonSampleInfo(
+  id = "20210224091506",
+  title = "Reddit superscript",
+  artifacts = [MarkwonArtifact.HTML],
+  tags = [html, reddit]
+)
+class RedditSuperscriptSample : MarkwonTextViewSample() {
+  override fun render() {
+    val md = """
+      The greatest thing you'll ever learn is just to ^reddit and be ^(reddited here) in ^return and ^(hey hey hye) something something^? daaagw
+    """.trimIndent()
+
+    val markwon = Markwon.builder(context)
+      .usePlugin(HtmlPlugin.create {
+        it.addHandler(SmallerSuperScriptTagHandler())
+      })
+      .usePlugin(ProcessRedditSuperscript)
+      .build()
+
+    markwon.setMarkdown(textView, md)
+  }
+
+  object ProcessRedditSuperscript : AbstractMarkwonPlugin() {
+
+    val re = Pattern.compile("(?:\\^\\((.+?)\\))|(?:\\^(\\S+))")
+
+    override fun processMarkdown(markdown: String): String {
+      val builder = StringBuilder()
+      val matcher = re.matcher(markdown)
+
+      var start = 0
+
+      while (matcher.find()) {
+        // if one of them, otherwise matcher should not report a match
+        val match = matcher.group(1) ?: matcher.group(2)!!
+        builder
+          .append(markdown.substring(start, matcher.start()))
+          .append("<sup>")
+          .append(match)
+          .append("</sup>")
+        start = matcher.end()
+      }
+
+      // append the rest of markwon
+      if (start < markdown.length) {
+        builder.append(markdown.substring(start))
+      }
+
+      // if no match is found (thus builder is empty), then return original
+      return if (builder.isEmpty()) markdown else builder.toString()
+    }
+  }
+
+  class SmallerSuperScriptSpan(val ratio: Float) : MetricAffectingSpan() {
+    override fun updateDrawState(tp: TextPaint?): Unit = tp?.let(::update) ?: Unit
+    override fun updateMeasureState(textPaint: TextPaint) = update(textPaint)
+
+    fun update(paint: TextPaint) = paint.run {
+      textSize *= ratio
+      baselineShift += (ascent() / 2F).toInt()
+    }
+  }
+
+  class SmallerSuperScriptTagHandler : SimpleTagHandler() {
+    override fun supportedTags(): Collection<String> = setOf("sup")
+
+    override fun getSpans(configuration: MarkwonConfiguration, renderProps: RenderProps, tag: HtmlTag): Any {
+      // 0.5 makes half the original textSize
+      // default value (for library SuperscriptSpan is `HtmlPlugin.SCRIPT_DEF_TEXT_SIZE_RATIO`
+      return SmallerSuperScriptSpan(0.5F)
+    }
+  }
+}
\ No newline at end of file
diff --git a/sample-utils/annotations/io/noties/markwon/sample/annotations/Tag.java b/sample-utils/annotations/io/noties/markwon/sample/annotations/Tag.java
index 58039316..5352241c 100644
--- a/sample-utils/annotations/io/noties/markwon/sample/annotations/Tag.java
+++ b/sample-utils/annotations/io/noties/markwon/sample/annotations/Tag.java
@@ -35,4 +35,5 @@ public enum Tag {
     precomputedText,
     cache,
     spanFactory,
+    reddit
 }