[skotty] Color opacity support

TBR=
Change-Id: I21dd6dda211d17c5de1b815fd43eac713a8e8ccc
Reviewed-on: https://skia-review.googlesource.com/92840
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>

3 files changed, 40 insertions, 3 deletions

diff --git a/experimental/skotty/Skotty.cpp b/experimental/skotty/Skotty.cpp
index d118516d16..8d43d46b45 100644
--- a/experimental/skotty/Skotty.cpp
+++ b/experimental/skotty/Skotty.cpp
@@ -297,12 +297,17 @@ sk_sp<sksg::Color> AttachColorPaint(const Json::Value& obj, AttachContext* ctx)
     auto color_node = sksg::Color::Make(SK_ColorBLACK);
     color_node->setAntiAlias(true);
 
-    auto color_attached = BindProperty<VectorValue>(obj["c"], ctx, color_node,
-        [](sksg::Color* node, const VectorValue& c) {
+    auto composite = sk_make_sp<CompositeColor>(color_node);
+    auto color_attached = BindProperty<VectorValue>(obj["c"], ctx, composite,
+        [](CompositeColor* node, const VectorValue& c) {
             node->setColor(ValueTraits<VectorValue>::As<SkColor>(c));
         });
+    auto opacity_attached = BindProperty<ScalarValue>(obj["o"], ctx, composite,
+        [](CompositeColor* node, const ScalarValue& o) {
+            node->setOpacity(o);
+        });
 
-    return color_attached ? color_node : nullptr;
+    return (color_attached || opacity_attached) ? color_node : nullptr;
 }
 
 sk_sp<sksg::PaintNode> AttachFillPaint(const Json::Value& jfill, AttachContext* ctx) {
diff --git a/experimental/skotty/SkottyProperties.cpp b/experimental/skotty/SkottyProperties.cpp
index 3bd95d8969..579823b24c 100644
--- a/experimental/skotty/SkottyProperties.cpp
+++ b/experimental/skotty/SkottyProperties.cpp
@@ -10,6 +10,7 @@
 #include "SkColor.h"
 #include "SkottyPriv.h"
 #include "SkPath.h"
+#include "SkSGColor.h"
 #include "SkSGPath.h"
 #include "SkSGRect.h"
 #include "SkSGTransform.h"
@@ -177,6 +178,20 @@ SkPath ValueTraits<ShapeValue>::As<SkPath>(const ShapeValue& path) {
     return path;
 }
 
+CompositeColor::CompositeColor(sk_sp<sksg::Color> wrapped_node)
+    : fColorNode(std::move(wrapped_node)) {
+    SkASSERT(fColorNode);
+}
+
+void CompositeColor::apply() {
+    // 'opacity' is [0..100]
+    const auto a = SkScalarRoundToInt(SkTPin<float>(fOpacity * .01f, 0, 1) * SkColorGetA(fColor));
+    fColorNode->setColor(SkColorSetARGB(a,
+                                        SkColorGetR(fColor),
+                                        SkColorGetG(fColor),
+                                        SkColorGetB(fColor)));
+}
+
 CompositeRRect::CompositeRRect(sk_sp<sksg::RRect> wrapped_node)
     : fRRectNode(std::move(wrapped_node)) {}
 
diff --git a/experimental/skotty/SkottyProperties.h b/experimental/skotty/SkottyProperties.h
index 4357367b3f..cb64ed748b 100644
--- a/experimental/skotty/SkottyProperties.h
+++ b/experimental/skotty/SkottyProperties.h
@@ -8,6 +8,7 @@
 #ifndef SkottyProperties_DEFINED
 #define SkottyProperties_DEFINED
 
+#include "SkColor.h"
 #include "SkPath.h"
 #include "SkPoint.h"
 #include "SkSize.h"
@@ -20,6 +21,7 @@
 #include <vector>
 
 namespace sksg {
+class Color;
 class Matrix;
 class Path;
 class RRect;
@@ -53,6 +55,21 @@ using ShapeValue  = SkPath;
     p_type f##p_name = p_default;                     \
   public:
 
+class CompositeColor final : public SkRefCnt {
+public:
+    explicit CompositeColor(sk_sp<sksg::Color>);
+
+     COMPOSITE_PROPERTY(Color  , SkColor , SK_ColorBLACK)
+     COMPOSITE_PROPERTY(Opacity, SkScalar, 100          )
+
+private:
+    void apply();
+
+    sk_sp<sksg::Color> fColorNode;
+
+    using INHERITED = SkRefCnt;
+};
+
 class CompositeRRect final : public SkRefCnt {
 public:
     explicit CompositeRRect(sk_sp<sksg::RRect>);