From 1617ec0ec421282452bfc3f5b2b52febc8145379 Mon Sep 17 00:00:00 2001
From: Tomek Zawadzki <tomekzawadzki98@gmail.com>
Date: Thu, 18 Jan 2024 22:31:48 +0100
Subject: [PATCH] Support custom font family for codeblocks and inline code on
 Android (#133)

---
 .../livemarkdown/MarkdownFontFamilySpan.java  | 36 ++++++++++++++++---
 .../MarkdownTextInputDecoratorView.java       |  6 ++--
 .../expensify/livemarkdown/MarkdownUtils.java | 11 ++++--
 3 files changed, 45 insertions(+), 8 deletions(-)

diff --git a/android/src/main/java/com/expensify/livemarkdown/MarkdownFontFamilySpan.java b/android/src/main/java/com/expensify/livemarkdown/MarkdownFontFamilySpan.java
index a948f1a8..facecb82 100644
--- a/android/src/main/java/com/expensify/livemarkdown/MarkdownFontFamilySpan.java
+++ b/android/src/main/java/com/expensify/livemarkdown/MarkdownFontFamilySpan.java
@@ -1,11 +1,39 @@
 package com.expensify.livemarkdown;
 
-import android.text.style.TypefaceSpan;
+import android.content.res.AssetManager;
+import android.graphics.Paint;
+import android.graphics.Typeface;
+import android.text.TextPaint;
+import android.text.style.MetricAffectingSpan;
 
 import androidx.annotation.NonNull;
 
-public class MarkdownFontFamilySpan extends TypefaceSpan implements MarkdownSpan {
-  public MarkdownFontFamilySpan(@NonNull String fontFamily) {
-    super(fontFamily);
+import com.facebook.react.views.text.ReactFontManager;
+
+public class MarkdownFontFamilySpan extends MetricAffectingSpan implements MarkdownSpan {
+
+  private final @NonNull String mFontFamily;
+  private final @NonNull AssetManager mAssetManager;
+
+  public MarkdownFontFamilySpan(@NonNull String fontFamily, @NonNull AssetManager assetManager) {
+    mFontFamily = fontFamily;
+    mAssetManager = assetManager;
+  }
+
+  @Override
+  public void updateMeasureState(@NonNull TextPaint textPaint) {
+    apply(textPaint);
+  }
+
+  @Override
+  public void updateDrawState(TextPaint tp) {
+    apply(tp);
+  }
+
+  private void apply(@NonNull TextPaint textPaint) {
+    int style = textPaint.getTypeface().getStyle();
+    Typeface typeface = ReactFontManager.getInstance().getTypeface(mFontFamily, style, mAssetManager);
+    textPaint.setTypeface(typeface);
+    textPaint.setFlags(textPaint.getFlags() | Paint.SUBPIXEL_TEXT_FLAG);
   }
 }
diff --git a/android/src/main/java/com/expensify/livemarkdown/MarkdownTextInputDecoratorView.java b/android/src/main/java/com/expensify/livemarkdown/MarkdownTextInputDecoratorView.java
index a17bb0a5..9ea57457 100644
--- a/android/src/main/java/com/expensify/livemarkdown/MarkdownTextInputDecoratorView.java
+++ b/android/src/main/java/com/expensify/livemarkdown/MarkdownTextInputDecoratorView.java
@@ -3,6 +3,7 @@
 import androidx.annotation.Nullable;
 
 import android.content.Context;
+import android.content.res.AssetManager;
 import android.text.TextWatcher;
 import android.util.AttributeSet;
 
@@ -51,8 +52,9 @@ protected void onAttachedToWindow() {
     }
 
     if (previousSibling instanceof ReactEditText) {
-      MarkdownUtils.maybeInitializeRuntime(getContext().getAssets());
-      mMarkdownUtils = new MarkdownUtils();
+      AssetManager assetManager = getContext().getAssets();
+      MarkdownUtils.maybeInitializeRuntime(assetManager);
+      mMarkdownUtils = new MarkdownUtils(assetManager);
       mMarkdownUtils.setMarkdownStyle(mMarkdownStyle);
       mReactEditText = (ReactEditText) previousSibling;
       mTextWatcher = new MarkdownTextWatcher(mMarkdownUtils);
diff --git a/android/src/main/java/com/expensify/livemarkdown/MarkdownUtils.java b/android/src/main/java/com/expensify/livemarkdown/MarkdownUtils.java
index 686e61e5..5ab87bfb 100644
--- a/android/src/main/java/com/expensify/livemarkdown/MarkdownUtils.java
+++ b/android/src/main/java/com/expensify/livemarkdown/MarkdownUtils.java
@@ -8,6 +8,7 @@
 
 import androidx.annotation.NonNull;
 
+import com.facebook.infer.annotation.Assertions;
 import com.facebook.infer.annotation.ThreadConfined;
 import com.facebook.react.bridge.UiThreadUtil;
 import com.facebook.react.views.text.CustomLineHeightSpan;
@@ -56,6 +57,12 @@ private static String parseMarkdown(String input) {
 
   private static native String nativeParseMarkdown(String input);
 
+  public MarkdownUtils(@NonNull AssetManager assetManager) {
+    mAssetManager = assetManager;
+  }
+
+  private final @NonNull AssetManager mAssetManager;
+
   private String mPrevInput;
 
   private String mPrevOutput;
@@ -124,12 +131,12 @@ private void applyRange(SpannableStringBuilder ssb, String type, int start, int
         setSpan(ssb, new MarkdownForegroundColorSpan(mMarkdownStyle.getLinkColor()), start, end);
         break;
       case "code":
-        setSpan(ssb, new MarkdownFontFamilySpan(mMarkdownStyle.getCodeFontFamily()), start, end);
+        setSpan(ssb, new MarkdownFontFamilySpan(mMarkdownStyle.getCodeFontFamily(), mAssetManager), start, end);
         setSpan(ssb, new MarkdownForegroundColorSpan(mMarkdownStyle.getCodeColor()), start, end);
         setSpan(ssb, new MarkdownBackgroundColorSpan(mMarkdownStyle.getCodeBackgroundColor()), start, end);
         break;
       case "pre":
-        setSpan(ssb, new MarkdownFontFamilySpan(mMarkdownStyle.getPreFontFamily()), start, end);
+        setSpan(ssb, new MarkdownFontFamilySpan(mMarkdownStyle.getPreFontFamily(), mAssetManager), start, end);
         setSpan(ssb, new MarkdownForegroundColorSpan(mMarkdownStyle.getPreColor()), start, end);
         setSpan(ssb, new MarkdownBackgroundColorSpan(mMarkdownStyle.getPreBackgroundColor()), start, end);
         break;