sample, add copy code block

app-sample/samples.json

@@ -1,4 +1,19 @@
 [
+  {
+    "javaClassName": "io.noties.markwon.app.samples.CopyCodeBlockSample",
+    "id": "20210315112847",
+    "title": "Copy code block",
+    "description": "Copy contents of fenced code blocks",
+    "artifacts": [
+      "CORE"
+    ],
+    "tags": [
+      "block",
+      "rendering",
+      "span",
+      "spanFactory"
+    ]
+  },
   {
     "javaClassName": "io.noties.markwon.app.samples.parser.RedditSuperscriptSample",
     "id": "20210224091506",

app-sample/src/main/java/io/noties/markwon/app/samples/CopyCodeBlockSample.kt

@@ -0,0 +1,119 @@
+package io.noties.markwon.app.samples
+
+import android.graphics.Canvas
+import android.graphics.Paint
+import android.graphics.drawable.Drawable
+import android.text.Layout
+import android.text.Spanned
+import android.text.TextPaint
+import android.text.style.ClickableSpan
+import android.text.style.LeadingMarginSpan
+import android.view.View
+import android.widget.TextView
+import io.noties.debug.Debug
+import io.noties.markwon.AbstractMarkwonPlugin
+import io.noties.markwon.Markwon
+import io.noties.markwon.MarkwonSpansFactory
+import io.noties.markwon.app.R
+import io.noties.markwon.app.sample.ui.MarkwonTextViewSample
+import io.noties.markwon.sample.annotations.MarkwonArtifact
+import io.noties.markwon.sample.annotations.MarkwonSampleInfo
+import io.noties.markwon.sample.annotations.Tag
+import io.noties.markwon.utils.LeadingMarginUtils
+import org.commonmark.node.FencedCodeBlock
+
+@MarkwonSampleInfo(
+        id = "20210315112847",
+        title = "Copy code block",
+        description = "Copy contents of fenced code blocks",
+        artifacts = [MarkwonArtifact.CORE],
+        tags = [Tag.rendering, Tag.block, Tag.spanFactory, Tag.span]
+)
+class CopyCodeBlockSample : MarkwonTextViewSample() {
+
+    override fun render() {
+        val md = """
+            # Hello code blocks!
+            ```java
+            final int i = 0;
+            final Type t = Type.init()
+              .filter(i -> i.even)
+              .first(null);
+            ```
+            bye bye!
+        """.trimIndent()
+
+        val markwon = Markwon.builder(context)
+                .usePlugin(object : AbstractMarkwonPlugin() {
+                    override fun configureSpansFactory(builder: MarkwonSpansFactory.Builder) {
+                        builder.appendFactory(FencedCodeBlock::class.java) { _, _ ->
+                            CopyContentsSpan()
+                        }
+                        builder.appendFactory(FencedCodeBlock::class.java) { _, _ ->
+                            CopyIconSpan(context.getDrawable(R.drawable.ic_code_white_24dp)!!)
+                        }
+                    }
+                })
+                .build()
+
+        markwon.setMarkdown(textView, md)
+    }
+
+    class CopyContentsSpan : ClickableSpan() {
+        override fun onClick(widget: View) {
+            val spanned = (widget as? TextView)?.text as? Spanned ?: return
+            val start = spanned.getSpanStart(this)
+            val end = spanned.getSpanEnd(this)
+            // by default code blocks have new lines before and after content
+            val contents = spanned.subSequence(start, end).toString().trim()
+            // copy code here
+            Debug.i(contents)
+        }
+
+        override fun updateDrawState(ds: TextPaint) {
+            // do not apply link styling
+        }
+    }
+
+    class CopyIconSpan(val icon: Drawable) : LeadingMarginSpan {
+
+        init {
+            if (icon.bounds.isEmpty) {
+                icon.setBounds(0, 0, icon.intrinsicWidth, icon.intrinsicHeight)
+            }
+        }
+
+        override fun getLeadingMargin(first: Boolean): Int = 0
+
+        override fun drawLeadingMargin(
+                c: Canvas,
+                p: Paint,
+                x: Int,
+                dir: Int,
+                top: Int,
+                baseline: Int,
+                bottom: Int,
+                text: CharSequence,
+                start: Int,
+                end: Int,
+                first: Boolean,
+                layout: Layout
+        ) {
+
+            // called for each line of text, we are interested only in first one
+            if (!LeadingMarginUtils.selfStart(start, text, this)) return
+
+            val save = c.save()
+            try {
+                // horizontal position for icon
+                val w = icon.bounds.width().toFloat()
+                // minus quarter width as padding
+                val left = layout.width - w - (w / 4F)
+                c.translate(left, top.toFloat())
+                icon.draw(c)
+            } finally {
+                c.restoreToCount(save)
+            }
+        }
+    }
+}

app-sample/src/main/java/io/noties/markwon/app/samples/GithubUserIssueInlineParsingSample.java

@@ -34,7 +34,7 @@ public class GithubUserIssueInlineParsingSample extends MarkwonTextViewSample {
       "# Custom Extension 2\n" +
       "\n" +
       "This is an issue #1\n" +
-      "Done by @noties";
+      "Done by @noties and other @dude";
 
     final InlineParserFactory inlineParserFactory = MarkwonInlineParser.factoryBuilder()
       // include all current defaults (otherwise will be empty - contain only our inline-processors)

app-sample/src/main/java/io/noties/markwon/app/samples/GithubUserIssueOnTextAddedSample.java

@@ -36,7 +36,7 @@ public class GithubUserIssueOnTextAddedSample extends MarkwonTextViewSample {
       "# Custom Extension 2\n" +
       "\n" +
       "This is an issue #1\n" +
-      "Done by @noties";
+      "Done by @noties and other @dude";
 
     final Markwon markwon = Markwon.builder(context)
       .usePlugin(new AbstractMarkwonPlugin() {