From 646e35484f88c768eae4716cdd99e1d7ba421368 Mon Sep 17 00:00:00 2001
From: Jinny You <jinny@lottiefiles.com>
Date: Thu, 20 Feb 2025 12:42:41 +0900
Subject: [PATCH] loaders: added lottie, svg font fallback mechanism

fallback for allowing any available fonts.

Co-Authored-By: Hermet Park <hermet@lottiefiles.com>
---
 src/loaders/lottie/tvgLottieBuilder.cpp | 15 +++++++++------
 src/loaders/svg/tvgSvgSceneBuilder.cpp  |  8 +++++---
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/src/loaders/lottie/tvgLottieBuilder.cpp b/src/loaders/lottie/tvgLottieBuilder.cpp
index 519eb923..4fc81527 100644
--- a/src/loaders/lottie/tvgLottieBuilder.cpp
+++ b/src/loaders/lottie/tvgLottieBuilder.cpp
@@ -889,18 +889,21 @@ void LottieBuilder::updateImage(LottieGroup* layer)
 }
 
 
-void _fontURLText(LottieText* text, Scene* main, float frameNo, Tween& tween, LottieExpressions* exps)
+static void _fontText(LottieText* text, Scene* scene, float frameNo, LottieExpressions* exps)
 {
     auto& doc = text->doc(frameNo, exps);
     if (!doc.text) return;
 
-    const float ptPerPx = 0.75f; //1 pt = 1/72; 1 in = 96 px; -> 72/96 = 0.75
+    auto size = doc.size * 75.0f; //1 pt = 1/72; 1 in = 96 px; -> 72/96 = 0.75
     auto txt = Text::gen();
-    txt->font(doc.name, doc.size * 100.0f * ptPerPx);
+    if (txt->font(doc.name, size) != Result::Success) {
+        //fallback to any available font
+        txt->font(nullptr, size);
+    }
     txt->translate(0.0f, -doc.size * 100.0f);
     txt->text(doc.text);
     txt->fill(doc.color.rgb[0], doc.color.rgb[1], doc.color.rgb[2]);
-    main->push(txt);
+    scene->push(txt);
 }
 
 
@@ -913,8 +916,8 @@ void LottieBuilder::updateText(LottieLayer* layer, float frameNo)
 
     if (!p || !text->font) return;
 
-    if (text->font->origin == LottieFont::Origin::FontURL) {
-        _fontURLText(text, layer->scene, frameNo, tween, exps);
+    if (text->font->origin != LottieFont::Origin::Embedded) {
+        _fontText(text, layer->scene, frameNo, exps);
         return;
     }
 
diff --git a/src/loaders/svg/tvgSvgSceneBuilder.cpp b/src/loaders/svg/tvgSvgSceneBuilder.cpp
index b1880024..dbd5dede 100644
--- a/src/loaders/svg/tvgSvgSceneBuilder.cpp
+++ b/src/loaders/svg/tvgSvgSceneBuilder.cpp
@@ -886,9 +886,11 @@ static Paint* _textBuildHelper(SvgLoaderData& loaderData, const SvgNode* node, c
     text->transform(textTransform);
 
     //TODO: handle def values of font and size as used in a system?
-    const float ptPerPx = 0.75f; //1 pt = 1/72; 1 in = 96 px; -> 72/96 = 0.75
-    auto fontSizePt = textNode->fontSize * ptPerPx;
-    if (textNode->fontFamily) text->font(textNode->fontFamily, fontSizePt);
+    auto size = textNode->fontSize * 0.75f; //1 pt = 1/72; 1 in = 96 px; -> 72/96 = 0.75
+    if (text->font(textNode->fontFamily, size) != Result::Success) {
+        //fallback to any available font
+        text->font(nullptr, size);
+    }
     text->text(textNode->text);
 
     _applyTextFill(node->style, text, vBox);