sample, add wysiwyg sample

app-sample/samples.json

@@ -1,4 +1,16 @@
 [
+  {
+    "javaClassName": "io.noties.markwon.app.samples.editor.WYSIWYGEditorSample",
+    "id": "20200908133515",
+    "title": "WYSIWG editor",
+    "description": "A possible direction to implement what-you-see-is-what-you-get editor",
+    "artifacts": [
+      "EDITOR"
+    ],
+    "tags": [
+      "rendering"
+    ]
+  },
   {
     "javaClassName": "io.noties.markwon.app.samples.tasklist.ListTaskListSample",
     "id": "20200902174132",

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

@@ -0,0 +1,134 @@
+package io.noties.markwon.app.samples.editor;
+
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.text.method.LinkMovementMethod;
+import android.text.style.ReplacementSpan;
+import android.view.View;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import io.noties.debug.Debug;
+import io.noties.markwon.Markwon;
+import io.noties.markwon.SoftBreakAddsNewLinePlugin;
+import io.noties.markwon.app.sample.Tags;
+import io.noties.markwon.app.samples.editor.shared.BlockQuoteEditHandler;
+import io.noties.markwon.app.samples.editor.shared.CodeEditHandler;
+import io.noties.markwon.app.samples.editor.shared.HeadingEditHandler;
+import io.noties.markwon.app.samples.editor.shared.LinkEditHandler;
+import io.noties.markwon.app.samples.editor.shared.MarkwonEditTextSample;
+import io.noties.markwon.app.samples.editor.shared.StrikethroughEditHandler;
+import io.noties.markwon.editor.MarkwonEditor;
+import io.noties.markwon.editor.MarkwonEditorTextWatcher;
+import io.noties.markwon.editor.PersistedSpans;
+import io.noties.markwon.editor.handler.EmphasisEditHandler;
+import io.noties.markwon.editor.handler.StrongEmphasisEditHandler;
+import io.noties.markwon.sample.annotations.MarkwonArtifact;
+import io.noties.markwon.sample.annotations.MarkwonSampleInfo;
+
+@MarkwonSampleInfo(
+  id = "20200908133515",
+  title = "WYSIWG editor",
+  description = "A possible direction to implement what-you-see-is-what-you-get editor",
+  artifacts = MarkwonArtifact.EDITOR,
+  tags = Tags.rendering
+)
+public class WYSIWYGEditorSample extends MarkwonEditTextSample {
+  @Override
+  public void render() {
+
+    // when automatic line break is inserted and text is inside margin span (blockquote, list, etc)
+    //  be prepared to encounter selection bugs (selection would be drawn at the place as is no margin
+    //  span is present)
+
+    final Markwon markwon = Markwon.builder(context)
+      .usePlugin(SoftBreakAddsNewLinePlugin.create())
+      .build();
+
+    final MarkwonEditor editor = MarkwonEditor.builder(markwon)
+      .punctuationSpan(HidePunctuationSpan.class, new PersistedSpans.SpanFactory<HidePunctuationSpan>() {
+        @NonNull
+        @Override
+        public HidePunctuationSpan create() {
+          return new HidePunctuationSpan();
+        }
+      })
+      .useEditHandler(new EmphasisEditHandler())
+      .useEditHandler(new StrongEmphasisEditHandler())
+      .useEditHandler(new StrikethroughEditHandler())
+      .useEditHandler(new CodeEditHandler())
+      .useEditHandler(new BlockQuoteEditHandler())
+      .useEditHandler(new LinkEditHandler(new LinkEditHandler.OnClick() {
+        @Override
+        public void onClick(@NonNull View widget, @NonNull String link) {
+          Debug.e("clicked: %s", link);
+        }
+      }))
+      .useEditHandler(new HeadingEditHandler())
+      .build();
+
+    // for links to be clickable
+    //   NB! markwon MovementMethodPlugin cannot be used here as editor do not execute `beforeSetText`)
+    editText.setMovementMethod(LinkMovementMethod.getInstance());
+
+    editText.addTextChangedListener(MarkwonEditorTextWatcher.withProcess(editor));
+  }
+
+  private static class HidePunctuationSpan extends ReplacementSpan {
+
+    @Override
+    public int getSize(@NonNull Paint paint, CharSequence text, int start, int end, @Nullable Paint.FontMetricsInt fm) {
+      // last space (which is swallowed until next non-space character appears)
+      // block quote
+      // code tick
+
+//      Debug.i("text: '%s', %d-%d (%d)", text.subSequence(start, end), start, end, text.length());
+      if (end == text.length()) {
+        // TODO: find first non-space character (not just first one because commonmark allows
+        //  arbitrary (0-3) white spaces before content starts
+
+        //  TODO: if all white space - render?
+        final char c = text.charAt(start);
+        if ('#' == c
+          || '>' == c
+          || '-' == c // TODO: not thematic break
+          || '+' == c
+          // `*` is fine but only for a list
+          || isBulletList(text, c, start, end)
+          || Character.isDigit(c) // assuming ordered list (replacement should only happen for ordered lists)
+          || Character.isWhitespace(c)) {
+          return (int) (paint.measureText(text, start, end) + 0.5F);
+        }
+      }
+      return 0;
+    }
+
+    @Override
+    public void draw(@NonNull Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, @NonNull Paint paint) {
+      // will be called only when getSize is not 0 (and if it was once reported as 0...)
+      if (end == text.length()) {
+
+        // if first non-space is `*` then check for is bullet
+        //  else `**` would be still rendered at the end of the emphasis
+        if (text.charAt(start) == '*'
+          && !isBulletList(text, '*', start, end)) {
+          return;
+        }
+
+        // TODO: inline code last tick received here, handle it (do not highlight)
+        //  why can't we have reported width in this method for supplied text?
+
+        // let's use color to make it distinct from the rest of the text for demonstration purposes
+        paint.setColor(0xFFff0000);
+
+        canvas.drawText(text, start, end, x, y, paint);
+      }
+    }
+
+    private static boolean isBulletList(@NonNull CharSequence text, char firstChar, int start, int end) {
+      return '*' == firstChar
+        && ((end - start == 1) || (Character.isWhitespace(text.charAt(start + 1))));
+    }
+  }
+}