common: added blending factor to tritone post-effect

- introduced a blending factor to control the mix between the original color and the tritone effect.
- improved Lottie compliance with this enhancement.
- implemented the spec by all engines

CAPI:
* Tvg_Result tvg_scene_push_effect_tritone(Tvg_Paint* scene, int shadow_r, int shadow_g, int shadow_b, int midtone_r, int midtone_g, int midtone_b, int highlight_r, int highlight_g, int highlight_b);
 -> TVG_API Tvg_Result tvg_scene_push_effect_tritone(Tvg_Paint* scene, int shadow_r, int shadow_g, int shadow_b, int midtone_r, int midtone_g, int midtone_b, int highlight_r, int highlight_g, int highlight_b, int blend);

examples/SceneEffects.cpp

@@ -115,9 +115,9 @@ struct UserExample : tvgexam::Example
         tint->push(tvg::SceneEffect::ClearAll);
         tint->push(tvg::SceneEffect::Tint, 0, 0, 0, 0, (int)(progress * 255), 0, (double)(progress * 100.0f));
 
-        //Apply Trintone post effect (shadow:rgb, midtone:rgb, highlight:rgb)
+        //Apply Tritone post effect (shadow:rgb, midtone:rgb, highlight:rgb, blending with original)
         trintone->push(tvg::SceneEffect::ClearAll);
-        trintone->push(tvg::SceneEffect::Tritone, 0, (int)(progress * 255), 0, 199, 110, 36, 255, 255, 255);
+        trintone->push(tvg::SceneEffect::Tritone, 0, (int)(progress * 255), 0, 199, 110, 36, 255, 255, 255, 0);
 
         canvas->update();
 

inc/thorvg.h

@@ -233,9 +233,9 @@ enum class SceneEffect : uint8_t
     ClearAll = 0,      ///< Reset all previously applied scene effects, restoring the scene to its original state.
     GaussianBlur,      ///< Apply a blur effect with a Gaussian filter. Param(4) = {sigma(double)[> 0], direction(int)[both: 0 / horizontal: 1 / vertical: 2], border(int)[duplicate: 0 / wrap: 1], quality(int)[0 - 100]}
     DropShadow,        ///< Apply a drop shadow effect with a Gaussian Blur filter. Param(8) = {color_R(int)[0 - 255], color_G(int)[0 - 255], color_B(int)[0 - 255], opacity(int)[0 - 255], angle(double)[0 - 360], distance(double), blur_sigma(double)[> 0], quality(int)[0 - 100]}
-    Fill,              ///< Override the scene content color with a given fill information (Experimental API). Param(4) = {color_R(int)[0 - 255], color_G(int)[0 - 255], color_B(int)[0 - 255], opacity(int)[0 - 255]}
-    Tint,              ///< Tinting the current scene color with a given black, white color parameters (Experimental API). Param(7) = {black_R(int)[0 - 255], black_G(int)[0 - 255], black_B(int)[0 - 255], white_R(int)[0 - 255], white_G(int)[0 - 255], white_B(int)[0 - 255], intensity(double)[0 - 100]}
-    Tritone            ///< Apply a tritone color effect to the scene using three color parameters for shadows, midtones, and highlights (Experimental API). Param(9) = {Shadow_R(int)[0 - 255], Shadow_G(int)[0 - 255], Shadow_B(int)[0 - 255], Midtone_R(int)[0 - 255], Midtone_G(int)[0 - 255], Midtone_B(int)[0 - 255], Highlight_R(int)[0 - 255], Highlight_G(int)[0 - 255], Highlight_B(int)[0 - 255]}
+    Fill,              ///< Override the scene content color with a given fill information. Param(4) = {color_R(int)[0 - 255], color_G(int)[0 - 255], color_B(int)[0 - 255], opacity(int)[0 - 255]}
+    Tint,              ///< Tinting the current scene color with a given black, white color parameters. Param(7) = {black_R(int)[0 - 255], black_G(int)[0 - 255], black_B(int)[0 - 255], white_R(int)[0 - 255], white_G(int)[0 - 255], white_B(int)[0 - 255], intensity(double)[0 - 100]}
+    Tritone            ///< Apply a tritone color effect to the scene using three color parameters for shadows, midtones, and highlights. A blending factor determines the mix between the original color and the tritone colors. Param(9) = {Shadow_R(int)[0 - 255], Shadow_G(int)[0 - 255], Shadow_B(int)[0 - 255], Midtone_R(int)[0 - 255], Midtone_G(int)[0 - 255], Midtone_B(int)[0 - 255], Highlight_R(int)[0 - 255], Highlight_G(int)[0 - 255], Highlight_B(int)[0 - 255], Blend(int)[0 - 255]}
 };
 
 

src/bindings/capi/thorvg_capi.h

@@ -2091,10 +2091,11 @@ TVG_API Tvg_Result tvg_scene_push_effect_tint(Tvg_Paint* scene, int black_r, int
  * @param[in] highlight_r Red component of the highlight color [0 - 255].
  * @param[in] highlight_g Green component of the highlight color [0 - 255].
  * @param[in] highlight_b Blue component of the highlight color [0 - 255].
+ * @param[in] blend A blending factor that determines the mix between the original color and the tritone colors [0 - 255].
  *
  * @since 1.0
  */
-TVG_API Tvg_Result tvg_scene_push_effect_tritone(Tvg_Paint* scene, int shadow_r, int shadow_g, int shadow_b, int midtone_r, int midtone_g, int midtone_b, int highlight_r, int highlight_g, int highlight_b);
+TVG_API Tvg_Result tvg_scene_push_effect_tritone(Tvg_Paint* scene, int shadow_r, int shadow_g, int shadow_b, int midtone_r, int midtone_g, int midtone_b, int highlight_r, int highlight_g, int highlight_b, int blend);
 
 /** \} */   // end defgroup ThorVGCapi_Scene
 

src/bindings/capi/tvgCapi.cpp

@@ -813,9 +813,9 @@ TVG_API Tvg_Result tvg_scene_push_effect_tint(Tvg_Paint* scene, int black_r, int
 }
 
 
-TVG_API Tvg_Result tvg_scene_push_effect_tritone(Tvg_Paint* scene, int shadow_r, int shadow_g, int shadow_b, int midtone_r, int midtone_g, int midtone_b, int highlight_r, int highlight_g, int highlight_b)
+TVG_API Tvg_Result tvg_scene_push_effect_tritone(Tvg_Paint* scene, int shadow_r, int shadow_g, int shadow_b, int midtone_r, int midtone_g, int midtone_b, int highlight_r, int highlight_g, int highlight_b, int blend)
 {
-    if (scene) return (Tvg_Result) reinterpret_cast<Scene*>(scene)->push(SceneEffect::Tritone, shadow_r, shadow_g, shadow_b, midtone_r, midtone_g, midtone_b, highlight_r, highlight_g, highlight_b);
+    if (scene) return (Tvg_Result) reinterpret_cast<Scene*>(scene)->push(SceneEffect::Tritone, shadow_r, shadow_g, shadow_b, midtone_r, midtone_g, midtone_b, highlight_r, highlight_g, highlight_b, blend);
     return TVG_RESULT_INVALID_ARGUMENT;
 }
 

src/loaders/lottie/tvgLottieBuilder.cpp

@@ -1343,7 +1343,7 @@ void LottieBuilder::updateEffect(LottieLayer* layer, float frameNo)
                 auto dark = effect->dark(frameNo);
                 auto midtone = effect->midtone(frameNo);
                 auto bright = effect->bright(frameNo);
-                layer->scene->push(SceneEffect::Tritone, dark.rgb[0], dark.rgb[1], dark.rgb[2], midtone.rgb[0], midtone.rgb[1], midtone.rgb[2], bright.rgb[0], bright.rgb[1], bright.rgb[2]);
+                layer->scene->push(SceneEffect::Tritone, dark.rgb[0], dark.rgb[1], dark.rgb[2], midtone.rgb[0], midtone.rgb[1], midtone.rgb[2], bright.rgb[0], bright.rgb[1], bright.rgb[2], (int)effect->blend(frameNo));
                 break;
             }
             case LottieEffect::DropShadow: {

src/loaders/lottie/tvgLottieModel.h

@@ -204,6 +204,7 @@ struct LottieFxTritone : LottieEffect
     LottieColor bright;
     LottieColor midtone;
     LottieColor dark;
+    LottieOpacity blend;
 
     LottieFxTritone()
     {

src/loaders/lottie/tvgLottieParser.cpp

@@ -1338,6 +1338,7 @@ void LottieParser::parseTritone(LottieEffect* effect, int idx)
     if (idx == 0) parsePropertyInternal(tritone->bright);
     else if (idx == 1) parsePropertyInternal(tritone->midtone);
     else if (idx == 2) parsePropertyInternal(tritone->dark);
+    else if (idx == 3) parsePropertyInternal(tritone->blend);
     else skip();
 }
 

src/renderer/gl_engine/tvgGlCommon.h

@@ -177,7 +177,7 @@ struct GlDropShadow: GlGaussianBlur {
 struct GlEffectParams {
     // fill:          [0..3]: color
     // tint:          [0..2]: black,  [4..6]: white,   [8]: intensity
-    // tritone:       [0..2]: shadow, [4..6]: midtone, [8..10]: highlight
+    // tritone:       [0..2]: shadow, [4..6]: midtone, [8..10]: highlight [11]: blender
     float params[4+4+4];
 };
 

src/renderer/gl_engine/tvgGlRenderer.cpp

@@ -1001,6 +1001,9 @@ void GlRenderer::effectFillUpdate(RenderEffectFill* effect, const Matrix& transf
 
 void GlRenderer::effectTintUpdate(RenderEffectTint* effect, const Matrix& transform)
 {
+    effect->valid = (effect->intensity > 0);
+    if (!effect->valid) return;
+
     auto params = (GlEffectParams*)effect->rd;
     if (!params) params = tvg::malloc<GlEffectParams*>(sizeof(GlEffectParams));
     params->params[0] = effect->black[0] / 255.0f;
@@ -1013,12 +1016,14 @@ void GlRenderer::effectTintUpdate(RenderEffectTint* effect, const Matrix& transf
     params->params[7] = 0.0f;
     params->params[8] = effect->intensity / 255.0f;
     effect->rd = params;
-    effect->valid = (effect->intensity > 0);
 }
 
 
 void GlRenderer::effectTritoneUpdate(RenderEffectTritone* effect, const Matrix& transform)
 {
+    effect->valid = (effect->blender < 255);
+    if (!effect->valid) return;
+
     auto params = (GlEffectParams*)effect->rd;
     if (!params) params = tvg::malloc<GlEffectParams*>(sizeof(GlEffectParams));
     params->params[0] = effect->shadow[0] / 255.0f;
@@ -1032,9 +1037,8 @@ void GlRenderer::effectTritoneUpdate(RenderEffectTritone* effect, const Matrix&
     params->params[8] = effect->highlight[0] / 255.0f;
     params->params[9] = effect->highlight[1] / 255.0f;
     params->params[10] = effect->highlight[2] / 255.0f;
-    params->params[11] = 0.0f;
+    params->params[11] = effect->blender / 255.0f;
     effect->rd = params;
-    effect->valid = true;
 }
 
 

src/renderer/gl_engine/tvgGlShaderSrc.cpp

@@ -889,11 +889,15 @@ void main()
     vec4 midtone = uParams.params[1];
     vec4 highlight = uParams.params[2];
 
-    FragColor = vec4(
+    vec4 tmp = vec4(
         luma >= 0.5f ? mix(midtone.r, highlight.r, (luma - 0.5f)*2.0f) : mix(shadow.r, midtone.r, luma * 2.0f),
         luma >= 0.5f ? mix(midtone.g, highlight.g, (luma - 0.5f)*2.0f) : mix(shadow.g, midtone.g, luma * 2.0f),
         luma >= 0.5f ? mix(midtone.b, highlight.b, (luma - 0.5f)*2.0f) : mix(shadow.b, midtone.b, luma * 2.0f),
         luma >= 0.5f ? mix(midtone.a, highlight.a, (luma - 0.5f)*2.0f) : mix(shadow.a, midtone.a, luma * 2.0f)
-    ) * orig.a;
+    );
+
+    //blender
+    if (highlight.a > 0.0f) tmp = mix(tmp, orig, highlight.a);
+    FragColor = tmp * orig.a;
 } 
 )";

src/renderer/sw_engine/tvgSwPostEffect.cpp

@@ -540,7 +540,7 @@ static uint32_t _trintone(uint32_t s, uint32_t m, uint32_t h, int l)
 
 void effectTritoneUpdate(RenderEffectTritone* params)
 {
-    params->valid = true;
+    params->valid = (params->blender < 255);
 }
 
 
@@ -555,7 +555,7 @@ bool effectTritone(SwCompositor* cmp, const RenderEffectTritone* params, bool di
     auto opacity = cmp->opacity;
     auto luma = cmp->recoverSfc->alphas[2];  //luma function
 
-    TVGLOG("SW_ENGINE", "Tritone region(%d, %d, %d, %d), param(%d %d %d, %d %d %d, %d %d %d)", bbox.min.x, bbox.min.y, bbox.max.x, bbox.max.y, params->shadow[0], params->shadow[1], params->shadow[2], params->midtone[0], params->midtone[1], params->midtone[2], params->highlight[0], params->highlight[1], params->highlight[2]);
+    TVGLOG("SW_ENGINE", "Tritone region(%d, %d, %d, %d), param(%d %d %d, %d %d %d, %d %d %d, %d)", bbox.min.x, bbox.min.y, bbox.max.x, bbox.max.y, params->shadow[0], params->shadow[1], params->shadow[2], params->midtone[0], params->midtone[1], params->midtone[2], params->highlight[0], params->highlight[1], params->highlight[2], params->blender);
 
     if (direct) {
         auto dbuffer = cmp->recoverSfc->buf32 + (bbox.min.y * cmp->recoverSfc->stride + bbox.min.x);
@@ -563,9 +563,14 @@ bool effectTritone(SwCompositor* cmp, const RenderEffectTritone* params, bool di
         for (size_t y = 0; y < h; ++y) {
             auto dst = dbuffer;
             auto src = sbuffer;
-            for (size_t x = 0; x < w; ++x, ++dst, ++src) {
-                auto tmp = rasterUnpremultiply(*src);
-                *dst = INTERPOLATE(_trintone(shadow, midtone, highlight, luma((uint8_t*)&tmp)), *dst, MULTIPLY(opacity, A(tmp)));
+            if (params->blender == 0) {
+                for (size_t x = 0; x < w; ++x, ++dst, ++src) {
+                    *dst = INTERPOLATE(_trintone(shadow, midtone, highlight, luma((uint8_t*)src)), *dst, MULTIPLY(opacity, A(*src)));
+                }
+            } else {
+                for (size_t x = 0; x < w; ++x, ++dst, ++src) {
+                    *dst = INTERPOLATE(INTERPOLATE(*src, _trintone(shadow, midtone, highlight, luma((uint8_t*)src)), params->blender), *dst, MULTIPLY(opacity, A(*src)));
+                }
             }
             dbuffer += cmp->image.stride;
             sbuffer += cmp->recoverSfc->stride;
@@ -575,9 +580,14 @@ bool effectTritone(SwCompositor* cmp, const RenderEffectTritone* params, bool di
         auto dbuffer = cmp->image.buf32 + (bbox.min.y * cmp->image.stride + bbox.min.x);
         for (size_t y = 0; y < h; ++y) {
             auto dst = dbuffer;
-            for (size_t x = 0; x < w; ++x, ++dst) {
-                auto tmp = rasterUnpremultiply(*dst);
-                *dst = ALPHA_BLEND(_trintone(shadow, midtone, highlight, luma((uint8_t*)&tmp)), A(tmp));
+            if (params->blender == 0) {
+                for (size_t x = 0; x < w; ++x, ++dst) {
+                    *dst = ALPHA_BLEND(_trintone(shadow, midtone, highlight, luma((uint8_t*)dst)), MULTIPLY(A(*dst), opacity));
+                }
+            } else {
+                for (size_t x = 0; x < w; ++x, ++dst) {
+                    *dst = ALPHA_BLEND(INTERPOLATE(*dst, _trintone(shadow, midtone, highlight, luma((uint8_t*)dst)), params->blender), MULTIPLY(A(*dst), opacity));
+                }
             }
             dbuffer += cmp->image.stride;
         }

src/renderer/tvgRender.h

@@ -479,6 +479,7 @@ struct RenderEffectTritone : RenderEffect
     uint8_t shadow[3];       //rgb
     uint8_t midtone[3];      //rgb
     uint8_t highlight[3];    //rgb
+    uint8_t blender = 0;     //0 ~ 255
 
     static RenderEffectTritone* gen(va_list& args)
     {
@@ -492,6 +493,7 @@ struct RenderEffectTritone : RenderEffect
         inst->highlight[0] = va_arg(args, int);
         inst->highlight[1] = va_arg(args, int);
         inst->highlight[2] = va_arg(args, int);
+        inst->blender = va_arg(args, int);
         inst->type = SceneEffect::Tritone;
         return inst;
     }

src/renderer/wg_engine/tvgWgShaderSrc.cpp

@@ -874,11 +874,14 @@ fn cs_main_tritone(@builtin(global_invocation_id) gid: vec3u) {
     let shadow = settings[0];
     let midtone = settings[1];
     let highlight = settings[2];
-    let color = select(
-        mix(shadow, midtone, luma * 2.0f),
-        mix(midtone, highlight, (luma - 0.5f)*2.0f),
-        luma >= 0.5f
-    ) * orig.a;
-    textureStore(imageTrg, uid.xy, color);
+
+    var color = select(mix(shadow, midtone, luma * 2.0f), mix(midtone, highlight, (luma - 0.5f)*2.0f), luma >= 0.5f);
+
+    // blending
+    if (highlight.a > 0.0f) {
+        color = mix(color, orig, highlight.a);
+    }
+
+    textureStore(imageTrg, uid.xy, color * orig.a);
 }
 )";

src/renderer/wg_engine/tvgWgShaderTypes.cpp

@@ -294,8 +294,8 @@ bool WgShaderTypeEffectParams::update(RenderEffectTritone* tritone)
     params[8] = tritone->highlight[0] / 255.0f;
     params[9] = tritone->highlight[1] / 255.0f;
     params[10] = tritone->highlight[2] / 255.0f;
-    params[11] = 0.0f;
+    params[11] = tritone->blender / 255.0f;
 
-    tritone->valid = true;
+    tritone->valid = tritone->blender < 255;
     return true;
 }