lottie: support Tint LayerEffect

issue: https://github.com/thorvg/thorvg/issues/2718

src/loaders/lottie/tvgLottieBuilder.cpp

@@ -1314,6 +1314,13 @@ void LottieBuilder::updateEffect(LottieLayer* layer, float frameNo)
     for (auto ef = layer->effects.begin(); ef < layer->effects.end(); ++ef) {
         if (!(*ef)->enable) continue;
         switch ((*ef)->type) {
+            case LottieEffect::Tint: {
+                auto effect = static_cast<LottieFxTint*>(*ef);
+                auto black = effect->black(frameNo);
+                auto white = effect->white(frameNo);
+                layer->scene->push(SceneEffect::Tint, black.rgb[0], black.rgb[1], black.rgb[2], white.rgb[0], white.rgb[1], white.rgb[2], effect->intensity(frameNo));
+                break;
+            }
             case LottieEffect::Fill: {
                 auto effect = static_cast<LottieFxFill*>(*ef);
                 auto color = effect->color(frameNo);

src/loaders/lottie/tvgLottieModel.h

@@ -82,8 +82,9 @@ struct LottieEffect
     enum Type : uint8_t
     {
         DropShadow = 0,
-        GaussianBlur = 1,
+        GaussianBlur,
-        Fill = 2,
+        Fill,
+        Tint
     };
 
     virtual ~LottieEffect() {}
@@ -109,6 +110,17 @@ struct LottieFxFill : LottieEffect
     }
 };
 
+struct LottieFxTint : LottieEffect
+{
+    LottieColor black;
+    LottieColor white;
+    LottieSlider intensity;
+
+    LottieFxTint()
+    {
+        type = Tint;
+    }
+};
 
 struct LottieFxDropShadow : LottieEffect
 {

src/loaders/lottie/tvgLottieParser.cpp

@@ -60,6 +60,7 @@ static unsigned long _int2str(int num)
 LottieEffect* LottieParser::getEffect(int type)
 {
     switch (type) {
+        case 20: return new LottieFxTint;
         case 21: return new LottieFxFill;
         case 25: return new LottieFxDropShadow;
         case 29: return new LottieFxGaussianBlur;
@@ -1269,6 +1270,30 @@ void LottieParser::parseMasks(LottieLayer* layer)
 }
 
 
+void LottieParser::parseTint(LottieFxTint* effect)
+{
+    int idx = 0;  //black -> white -> intenstiy
+    enterArray();
+    while (nextArrayValue()) {
+        enterObject();
+        while (auto key = nextObjectKey()) {
+            if (KEY_AS("v")) {
+                enterObject();
+                while (auto key = nextObjectKey()) {
+                    if (KEY_AS("k")) {
+                        if (idx == 0) parsePropertyInternal(effect->black);
+                        else if (idx == 1) parsePropertyInternal(effect->white);
+                        else if (idx == 2) parsePropertyInternal(effect->intensity);
+                        else skip();
+                    } else skip();
+                }
+                ++idx;
+            } else skip();
+        }
+    }
+}
+
+
 void LottieParser::parseFill(LottieFxFill* effect)
 {
     int idx = 0;  //fill mask -> all mask -> color -> invert -> h feather -> v feather -> opacity
@@ -1345,6 +1370,10 @@ void LottieParser::parseDropShadow(LottieFxDropShadow* effect)
 void LottieParser::parseEffect(LottieEffect* effect)
 {
     switch (effect->type) {
+        case LottieEffect::Tint: {
+            parseTint(static_cast<LottieFxTint*>(effect));
+            break;
+        }
         case LottieEffect::Fill: {
             parseFill(static_cast<LottieFxFill*>(effect));
             break;

src/loaders/lottie/tvgLottieParser.h

@@ -98,6 +98,7 @@ private:
     LottieFont* parseFont();
     LottieMarker* parseMarker();
 
+    void parseTint(LottieFxTint* effect);
     void parseFill(LottieFxFill* effect);
     void parseGaussianBlur(LottieFxGaussianBlur* effect);
     void parseDropShadow(LottieFxDropShadow* effect);