From d9be58d4b7ade6329965180d3b9468b15ecb03a2 Mon Sep 17 00:00:00 2001
From: Mira Grudzinska <mira@lottiefiles.com>
Date: Mon, 21 Oct 2024 21:36:23 +0700
Subject: [PATCH] lottie: fix transformations in text range selector

Since the translate API was used while text updating,
the subsequent range selector transformations gets overwritten
when updating the shape (scale and rotate, adding another
translation will persist). This caused unexpected results.
Fixed by using the transform API when additional transformations
are needed - also fixes applying more than one range selector.
---
 src/loaders/lottie/tvgLottieBuilder.cpp | 59 ++++++++++++++-----------
 src/renderer/tvgPaint.h                 |  2 +-
 2 files changed, 34 insertions(+), 27 deletions(-)

diff --git a/src/loaders/lottie/tvgLottieBuilder.cpp b/src/loaders/lottie/tvgLottieBuilder.cpp
index b4ac15fd..22a6a5e9 100644
--- a/src/loaders/lottie/tvgLottieBuilder.cpp
+++ b/src/loaders/lottie/tvgLottieBuilder.cpp
@@ -1060,41 +1060,48 @@ void LottieBuilder::updateText(LottieLayer* layer, float frameNo)
                     shape->strokeFill(doc.stroke.color.rgb[0], doc.stroke.color.rgb[1], doc.stroke.color.rgb[2]);
                 }
 
-                //text range process
-                for (auto s = text->ranges.begin(); s < text->ranges.end(); ++s) {
-                    float start, end;
-                    (*s)->range(frameNo, float(totalChars), start, end);
+                if (!text->ranges.empty()) {
+                    Point scaling = {1.0f, 1.0f};
+                    auto rotation = 0.0f;
+                    auto translation = cursor;
 
-                    auto basedIdx = idx;
-                    if ((*s)->based == LottieTextRange::Based::CharsExcludingSpaces) basedIdx = idx - space;
-                    else if ((*s)->based == LottieTextRange::Based::Words) basedIdx = line + space;
-                    else if ((*s)->based == LottieTextRange::Based::Lines) basedIdx = line;
+                    //text range process
+                    for (auto s = text->ranges.begin(); s < text->ranges.end(); ++s) {
+                        float start, end;
+                        (*s)->range(frameNo, float(totalChars), start, end);
 
-                    if (basedIdx < start || basedIdx >= end) continue;
-                    auto& matrix = shape->transform();
+                        auto basedIdx = idx;
+                        if ((*s)->based == LottieTextRange::Based::CharsExcludingSpaces) basedIdx = idx - space;
+                        else if ((*s)->based == LottieTextRange::Based::Words) basedIdx = line + space;
+                        else if ((*s)->based == LottieTextRange::Based::Lines) basedIdx = line;
 
-                    shape->opacity((*s)->style.opacity(frameNo));
+                        if (basedIdx < start || basedIdx >= end) continue;
 
-                    auto color = (*s)->style.fillColor(frameNo);
-                    shape->fill(color.rgb[0], color.rgb[1], color.rgb[2], (*s)->style.fillOpacity(frameNo));
+                        translation = translation + (*s)->style.position(frameNo);
+                        scaling = scaling * (*s)->style.scale(frameNo) * 0.01f;
+                        rotation += (*s)->style.rotation(frameNo);
 
-                    rotate(&matrix, (*s)->style.rotation(frameNo));
+                        shape->opacity((*s)->style.opacity(frameNo));
 
-                    auto glyphScale = (*s)->style.scale(frameNo) * 0.01f;
-                    tvg::scale(&matrix, glyphScale.x, glyphScale.y);
+                        auto color = (*s)->style.fillColor(frameNo);
+                        shape->fill(color.rgb[0], color.rgb[1], color.rgb[2], (*s)->style.fillOpacity(frameNo));
 
-                    auto position = (*s)->style.position(frameNo);
-                    translate(&matrix, position.x, position.y);
+                        if (doc.stroke.render) {
+                            auto strokeColor = (*s)->style.strokeColor(frameNo);
+                            shape->strokeWidth((*s)->style.strokeWidth(frameNo) / scale);
+                            shape->strokeFill(strokeColor.rgb[0], strokeColor.rgb[1], strokeColor.rgb[2], (*s)->style.strokeOpacity(frameNo));
+                        }
+                        cursor.x += (*s)->style.letterSpacing(frameNo);
 
-                    if (doc.stroke.render) {
-                        auto strokeColor = (*s)->style.strokeColor(frameNo);
-                        shape->strokeWidth((*s)->style.strokeWidth(frameNo) / scale);
-                        shape->strokeFill(strokeColor.rgb[0], strokeColor.rgb[1], strokeColor.rgb[2], (*s)->style.strokeOpacity(frameNo));
+                        auto spacing = (*s)->style.lineSpacing(frameNo);
+                        if (spacing > lineSpacing) lineSpacing = spacing;
                     }
-                    cursor.x += (*s)->style.letterSpacing(frameNo);
-
-                    auto spacing = (*s)->style.lineSpacing(frameNo);
-                    if (spacing > lineSpacing) lineSpacing = spacing;
+                    auto& matrix = shape->transform();
+                    identity(&matrix);
+                    translate(&matrix, translation.x, translation.y);
+                    tvg::scale(&matrix, scaling.x, scaling.y);
+                    rotate(&matrix, rotation);
+                    shape->transform(matrix);
                 }
 
                 scene->push(cast(shape));
diff --git a/src/renderer/tvgPaint.h b/src/renderer/tvgPaint.h
index 5454dcbd..95124fb9 100644
--- a/src/renderer/tvgPaint.h
+++ b/src/renderer/tvgPaint.h
@@ -107,7 +107,7 @@ namespace tvg
 
         bool transform(const Matrix& m)
         {
-            tr.m = m;
+            if (&tr.m != &m) tr.m = m;
             tr.overriding = true;
             renderFlag |= RenderUpdateFlag::Transform;