Add CustomTypefaceSpan

markwon-core/src/main/java/ru/noties/markwon/core/spans/CustomTypefaceSpan.java

@@ -0,0 +1,43 @@
+package ru.noties.markwon.core.spans;
+
+import android.graphics.Typeface;
+import android.support.annotation.NonNull;
+import android.text.TextPaint;
+import android.text.style.MetricAffectingSpan;
+
+/**
+ * A span implementation that allow applying custom Typeface. Although it is
+ * not used directly by the library, it\'s helpful for customizations.
+ * <p>
+ * Please note that this implementation does not validate current paint state
+ * and won\'t be updating/modifying supplied Typeface.
+ *
+ * @since 3.0.0
+ */
+public class CustomTypefaceSpan extends MetricAffectingSpan {
+
+    @NonNull
+    public static CustomTypefaceSpan create(@NonNull Typeface typeface) {
+        return new CustomTypefaceSpan(typeface);
+    }
+
+    private final Typeface typeface;
+
+    public CustomTypefaceSpan(@NonNull Typeface typeface) {
+        this.typeface = typeface;
+    }
+
+    @Override
+    public void updateMeasureState(@NonNull TextPaint p) {
+        updatePaint(p);
+    }
+
+    @Override
+    public void updateDrawState(TextPaint tp) {
+        updatePaint(tp);
+    }
+
+    private void updatePaint(@NonNull TextPaint paint) {
+        paint.setTypeface(typeface);
+    }
+}