[core] Add `symbol-placement: line-center`

- Remove unused/vestigial 'maxCameraDistance'
- Create a single collision circle for line labels that are less than half the width of a collision circle

2 files changed, 4 insertions, 20 deletions

diff --git a/src/mbgl/renderer/layers/render_symbol_layer.cpp b/src/mbgl/renderer/layers/render_symbol_layer.cpp
index 3a3545122e..861112526b 100644
--- a/src/mbgl/renderer/layers/render_symbol_layer.cpp
+++ b/src/mbgl/renderer/layers/render_symbol_layer.cpp
@@ -130,7 +130,7 @@ void RenderSymbolLayer::render(PaintParameters& parameters, RenderSource*) {
             auto values = iconPropertyValues(layout);
             auto paintPropertyValues = iconPaintProperties();
 
-            const bool alongLine = layout.get<SymbolPlacement>() == SymbolPlacementType::Line &&
+            const bool alongLine = layout.get<SymbolPlacement>() != SymbolPlacementType::Point &&
                 layout.get<IconRotationAlignment>() == AlignmentType::Map;
 
             if (alongLine) {
@@ -191,7 +191,7 @@ void RenderSymbolLayer::render(PaintParameters& parameters, RenderSource*) {
             auto values = textPropertyValues(layout);
             auto paintPropertyValues = textPaintProperties();
 
-            const bool alongLine = layout.get<SymbolPlacement>() == SymbolPlacementType::Line &&
+            const bool alongLine = layout.get<SymbolPlacement>() != SymbolPlacementType::Point &&
                 layout.get<TextRotationAlignment>() == AlignmentType::Map;
 
             if (alongLine) {
@@ -335,24 +335,11 @@ style::SymbolPropertyValues RenderSymbolLayer::iconPropertyValues(const style::S
             evaluated.get<style::IconTranslateAnchor>(),
             evaluated.get<style::IconHaloColor>().constantOr(Color::black()).a > 0 &&
             evaluated.get<style::IconHaloWidth>().constantOr(1),
-            evaluated.get<style::IconColor>().constantOr(Color::black()).a > 0,
-            10.0f
+            evaluated.get<style::IconColor>().constantOr(Color::black()).a > 0
     };
 }
 
 style::SymbolPropertyValues RenderSymbolLayer::textPropertyValues(const style::SymbolLayoutProperties::PossiblyEvaluated& layout_) const {
-    // We hide line labels with viewport alignment as they move into the distance
-    // because the approximations we use for drawing their glyphs get progressively worse
-    // The "1.5" here means we start hiding them when the distance from the label
-    // to the camera is 50% greater than the distance from the center of the map
-    // to the camera. Depending on viewport properties, you might expect this to filter
-    // the top third of the screen at pitch 60, and do almost nothing at pitch 45
-    // "10" is effectively infinite at any pitch we support
-    const bool limitMaxDistance =
-        layout_.get<style::SymbolPlacement>() == style::SymbolPlacementType::Line
-        && layout_.get<style::TextRotationAlignment>() == style::AlignmentType::Map
-        && layout_.get<style::TextPitchAlignment>() == style::AlignmentType::Viewport;
-
     return style::SymbolPropertyValues {
             layout_.get<style::TextPitchAlignment>(),
             layout_.get<style::TextRotationAlignment>(),
@@ -361,8 +348,7 @@ style::SymbolPropertyValues RenderSymbolLayer::textPropertyValues(const style::S
             evaluated.get<style::TextTranslateAnchor>(),
             evaluated.get<style::TextHaloColor>().constantOr(Color::black()).a > 0 &&
             evaluated.get<style::TextHaloWidth>().constantOr(1),
-            evaluated.get<style::TextColor>().constantOr(Color::black()).a > 0,
-            limitMaxDistance ? 1.5f : 10.0f
+            evaluated.get<style::TextColor>().constantOr(Color::black()).a > 0
     };
 }
 
diff --git a/src/mbgl/renderer/layers/render_symbol_layer.hpp b/src/mbgl/renderer/layers/render_symbol_layer.hpp
index 83709b5122..5b73b30294 100644
--- a/src/mbgl/renderer/layers/render_symbol_layer.hpp
+++ b/src/mbgl/renderer/layers/render_symbol_layer.hpp
@@ -48,8 +48,6 @@ public:
 
     bool hasHalo;
     bool hasFill;
-    
-    float maxCameraDistance; // 1.5 for road labels, or 10 (essentially infinite) for everything else
 };
 
 } // namespace style