[core] Encapsulate placement code handling symbols sort ranges

2 files changed, 25 insertions, 12 deletions

diff --git a/src/mbgl/renderer/buckets/symbol_bucket.cpp b/src/mbgl/renderer/buckets/symbol_bucket.cpp
index 7b8eec4471..af2a479c26 100644
--- a/src/mbgl/renderer/buckets/symbol_bucket.cpp
+++ b/src/mbgl/renderer/buckets/symbol_bucket.cpp
@@ -275,8 +275,8 @@ void SymbolBucket::sortFeatures(const float angle) {
     featureSortOrder = std::move(symbolsSortOrder);
 }
 
-std::vector<std::reference_wrapper<const SymbolInstance>> SymbolBucket::getSortedSymbols(const float angle) const {
-    std::vector<std::reference_wrapper<const SymbolInstance>> result(symbolInstances.begin(), symbolInstances.end());
+SymbolInstanceReferences SymbolBucket::getSortedSymbols(const float angle) const {
+    SymbolInstanceReferences result(symbolInstances.begin(), symbolInstances.end());
     const float sin = std::sin(angle);
     const float cos = std::cos(angle);
 
@@ -292,6 +292,15 @@ std::vector<std::reference_wrapper<const SymbolInstance>> SymbolBucket::getSorte
     return result;
 }
 
+SymbolInstanceReferences SymbolBucket::getSymbols(const optional<SortKeyRange>& range) const {
+    if (!range) return SymbolInstanceReferences(symbolInstances.begin(), symbolInstances.end());
+    assert(range->start < range->end);
+    assert(range->end <= symbolInstances.size());
+    auto begin = symbolInstances.begin() + range->start;
+    auto end = symbolInstances.begin() + range->end;
+    return SymbolInstanceReferences(begin, end);
+}
+
 bool SymbolBucket::hasFormatSectionOverrides() const {
     if (!hasFormatSectionOverrides_) {
         hasFormatSectionOverrides_= SymbolLayerPaintPropertyOverrides::hasOverrides(layout->get<TextField>());
diff --git a/src/mbgl/renderer/buckets/symbol_bucket.hpp b/src/mbgl/renderer/buckets/symbol_bucket.hpp
index 2b41ac9295..3cdea1310c 100644
--- a/src/mbgl/renderer/buckets/symbol_bucket.hpp
+++ b/src/mbgl/renderer/buckets/symbol_bucket.hpp
@@ -1,16 +1,17 @@
 #pragma once
 
-#include <mbgl/renderer/bucket.hpp>
-#include <mbgl/map/mode.hpp>
-#include <mbgl/gfx/vertex_buffer.hpp>
 #include <mbgl/gfx/index_buffer.hpp>
+#include <mbgl/gfx/vertex_buffer.hpp>
+#include <mbgl/layout/symbol_feature.hpp>
+#include <mbgl/layout/symbol_instance.hpp>
+#include <mbgl/map/mode.hpp>
+#include <mbgl/programs/collision_box_program.hpp>
 #include <mbgl/programs/segment.hpp>
 #include <mbgl/programs/symbol_program.hpp>
-#include <mbgl/programs/collision_box_program.hpp>
-#include <mbgl/text/glyph_range.hpp>
+#include <mbgl/renderer/bucket.hpp>
 #include <mbgl/style/layers/symbol_layer_properties.hpp>
-#include <mbgl/layout/symbol_feature.hpp>
-#include <mbgl/layout/symbol_instance.hpp>
+#include <mbgl/text/glyph_range.hpp>
+#include <mbgl/text/placement.hpp>
 
 #include <vector>
 
@@ -97,8 +98,11 @@ public:
 
 
     void sortFeatures(const float angle);
-    // The result contains references to the `symbolInstances` items, sorted by viewport Y.
-    std::vector<std::reference_wrapper<const SymbolInstance>> getSortedSymbols(const float angle) const;
+    // Returns references to the `symbolInstances` items, sorted by viewport Y.
+    SymbolInstanceReferences getSortedSymbols(const float angle) const;
+    // Returns references to the `symbolInstances` items, which belong to the `sortKeyRange` range;
+    // returns references to all the symbols if |sortKeyRange| is `nullopt`.
+    SymbolInstanceReferences getSymbols(const optional<SortKeyRange>& sortKeyRange = nullopt) const;
 
     Immutable<style::SymbolLayoutProperties::PossiblyEvaluated> layout;
     const std::string bucketLeaderID;
@@ -118,7 +122,7 @@ public:
     bool hasUninitializedSymbols : 1;
 
     std::vector<SymbolInstance> symbolInstances;
-    std::vector<SortKeyRange> sortKeyRanges;
+    const std::vector<SortKeyRange> sortKeyRanges;
 
     struct PaintProperties {
         SymbolIconProgram::Binders iconBinders;