[core] Add DDS support for {text,icon}-size (#8593)

* Update gl-js and generate style code

* Factor out packUint8Pair() helper function

* Draft implementation of DDS for {text,icon}-size

Ports https://github.com/mapbox/mapbox-gl-js/pull/4455

* Fix text-size/composite-function-line-placement test

* Refactor to PaintPropertyBinders-like strategy

* Dedupe gl::Program construction

* Use exponential function base for interpolation

* Dedupe coveringZoomStops method

* Fixup tests

* Fix CI errors (hidden within #if block)

4 files changed, 18 insertions, 9 deletions

diff --git a/include/mbgl/style/conversion/make_property_setters.hpp b/include/mbgl/style/conversion/make_property_setters.hpp
index 85bcd44cf3..105cca99d6 100644
--- a/include/mbgl/style/conversion/make_property_setters.hpp
+++ b/include/mbgl/style/conversion/make_property_setters.hpp
@@ -37,7 +37,7 @@ auto makeLayoutPropertySetters() {
     result["icon-ignore-placement"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<bool>, &SymbolLayer::setIconIgnorePlacement>;
     result["icon-optional"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<bool>, &SymbolLayer::setIconOptional>;
     result["icon-rotation-alignment"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<AlignmentType>, &SymbolLayer::setIconRotationAlignment>;
-    result["icon-size"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<float>, &SymbolLayer::setIconSize>;
+    result["icon-size"] = &setLayoutProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setIconSize>;
     result["icon-text-fit"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<IconTextFitType>, &SymbolLayer::setIconTextFit>;
     result["icon-text-fit-padding"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<std::array<float, 4>>, &SymbolLayer::setIconTextFitPadding>;
     result["icon-image"] = &setLayoutProperty<V, SymbolLayer, DataDrivenPropertyValue<std::string>, &SymbolLayer::setIconImage>;
@@ -49,7 +49,7 @@ auto makeLayoutPropertySetters() {
     result["text-rotation-alignment"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<AlignmentType>, &SymbolLayer::setTextRotationAlignment>;
     result["text-field"] = &setLayoutProperty<V, SymbolLayer, DataDrivenPropertyValue<std::string>, &SymbolLayer::setTextField>;
     result["text-font"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<std::vector<std::string>>, &SymbolLayer::setTextFont>;
-    result["text-size"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<float>, &SymbolLayer::setTextSize>;
+    result["text-size"] = &setLayoutProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextSize>;
     result["text-max-width"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<float>, &SymbolLayer::setTextMaxWidth>;
     result["text-line-height"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<float>, &SymbolLayer::setTextLineHeight>;
     result["text-letter-spacing"] = &setLayoutProperty<V, SymbolLayer, PropertyValue<float>, &SymbolLayer::setTextLetterSpacing>;
diff --git a/include/mbgl/style/data_driven_property_value.hpp b/include/mbgl/style/data_driven_property_value.hpp
index 3f9ac69436..5acf800840 100644
--- a/include/mbgl/style/data_driven_property_value.hpp
+++ b/include/mbgl/style/data_driven_property_value.hpp
@@ -45,6 +45,15 @@ public:
     bool isDataDriven() const {
         return value.template is<SourceFunction<T>>() || value.template is<CompositeFunction<T>>();
     }
+    
+    bool isZoomConstant() const {
+        return !value.template is<CameraFunction<T>>() && !value.template is<CompositeFunction<T>>();
+    }
+    
+    template <class... Ts>
+    auto match(Ts&&... ts) const {
+        return value.match(std::forward<Ts>(ts)...);
+    }
 
     template <typename Evaluator>
     auto evaluate(const Evaluator& evaluator) const {
diff --git a/include/mbgl/style/function/camera_function.hpp b/include/mbgl/style/function/camera_function.hpp
index 5636b1663c..2e4aac2238 100644
--- a/include/mbgl/style/function/camera_function.hpp
+++ b/include/mbgl/style/function/camera_function.hpp
@@ -28,7 +28,7 @@ public:
             return s.evaluate(Value(double(zoom))).value_or(T());
         });
     }
-
+    
     friend bool operator==(const CameraFunction& lhs,
                            const CameraFunction& rhs) {
         return lhs.stops == rhs.stops;
diff --git a/include/mbgl/style/layers/symbol_layer.hpp b/include/mbgl/style/layers/symbol_layer.hpp
index 853a71bef2..6e29faa949 100644
--- a/include/mbgl/style/layers/symbol_layer.hpp
+++ b/include/mbgl/style/layers/symbol_layer.hpp
@@ -59,9 +59,9 @@ public:
     PropertyValue<AlignmentType> getIconRotationAlignment() const;
     void setIconRotationAlignment(PropertyValue<AlignmentType>);
 
-    static PropertyValue<float> getDefaultIconSize();
-    PropertyValue<float> getIconSize() const;
-    void setIconSize(PropertyValue<float>);
+    static DataDrivenPropertyValue<float> getDefaultIconSize();
+    DataDrivenPropertyValue<float> getIconSize() const;
+    void setIconSize(DataDrivenPropertyValue<float>);
 
     static PropertyValue<IconTextFitType> getDefaultIconTextFit();
     PropertyValue<IconTextFitType> getIconTextFit() const;
@@ -107,9 +107,9 @@ public:
     PropertyValue<std::vector<std::string>> getTextFont() const;
     void setTextFont(PropertyValue<std::vector<std::string>>);
 
-    static PropertyValue<float> getDefaultTextSize();
-    PropertyValue<float> getTextSize() const;
-    void setTextSize(PropertyValue<float>);
+    static DataDrivenPropertyValue<float> getDefaultTextSize();
+    DataDrivenPropertyValue<float> getTextSize() const;
+    void setTextSize(DataDrivenPropertyValue<float>);
 
     static PropertyValue<float> getDefaultTextMaxWidth();
     PropertyValue<float> getTextMaxWidth() const;