[core] Export placement types

6 files changed, 122 insertions, 94 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 417336341b..3411afa17d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -246,6 +246,7 @@ add_library(
     ${PROJECT_SOURCE_DIR}/include/mbgl/sourcemanager/raster_dem_source_factory.hpp
     ${PROJECT_SOURCE_DIR}/include/mbgl/sourcemanager/raster_source_factory.hpp
     ${PROJECT_SOURCE_DIR}/include/mbgl/sourcemanager/vector_source_factory.hpp
+    ${PROJECT_SOURCE_DIR}/include/mbgl/text/placement_types.hpp
     ${PROJECT_SOURCE_DIR}/src/mbgl/sourcemanager/source_manager.cpp
     ${PROJECT_SOURCE_DIR}/src/mbgl/sourcemanager/annotation_source_factory.cpp
     ${PROJECT_SOURCE_DIR}/src/mbgl/sourcemanager/custom_geometry_source_factory.cpp
@@ -751,6 +752,7 @@ add_library(
     ${PROJECT_SOURCE_DIR}/src/mbgl/text/local_glyph_rasterizer.hpp
     ${PROJECT_SOURCE_DIR}/src/mbgl/text/placement.cpp
     ${PROJECT_SOURCE_DIR}/src/mbgl/text/placement.hpp
+    ${PROJECT_SOURCE_DIR}/src/mbgl/text/placement_types.cpp
     ${PROJECT_SOURCE_DIR}/src/mbgl/text/quads.cpp
     ${PROJECT_SOURCE_DIR}/src/mbgl/text/quads.hpp
     ${PROJECT_SOURCE_DIR}/src/mbgl/text/shaping.cpp
diff --git a/include/mbgl/renderer/renderer.hpp b/include/mbgl/renderer/renderer.hpp
index b72cc847c9..87dd014412 100644
--- a/include/mbgl/renderer/renderer.hpp
+++ b/include/mbgl/renderer/renderer.hpp
@@ -1,7 +1,8 @@
 #pragma once
 
-#include <mbgl/renderer/query.hpp>
 #include <mbgl/annotation/annotation.hpp>
+#include <mbgl/renderer/query.hpp>
+#include <mbgl/text/placement_types.hpp>
 #include <mbgl/util/geo.hpp>
 #include <mbgl/util/geojson.hpp>
 
@@ -21,26 +22,6 @@ namespace gfx {
 class RendererBackend;
 } // namespace gfx
 
-struct PlacedSymbolData {
-    // Contents of the label
-    std::u16string key;
-    // If symbol contains text, text collision box in viewport coordinates
-    optional<mapbox::geometry::box<float>> textCollisionBox;
-    // If symbol contains icon, icon collision box in viewport coordinates
-    optional<mapbox::geometry::box<float>> iconCollisionBox;
-    // Symbol text was placed
-    bool textPlaced;
-    // Symbol icon was placed
-    bool iconPlaced;
-    // Symbol text or icon collision box intersects tile borders
-    // (initialized only in tile mode)
-    optional<bool> intersectsTileBorder;
-    // Viewport padding ({viewportPadding, viewportPadding} is a coordinate of the tile's top-left corner)
-    float viewportPadding;
-    // Layer id (leader of the symbol layout group)
-    std::string layer;
-};
-
 class Renderer {
 public:
     Renderer(gfx::RendererBackend&, float pixelRatio_, const optional<std::string>& localFontFamily = {});
diff --git a/include/mbgl/text/placement_types.hpp b/include/mbgl/text/placement_types.hpp
new file mode 100644
index 0000000000..54ea0251cb
--- /dev/null
+++ b/include/mbgl/text/placement_types.hpp
@@ -0,0 +1,77 @@
+#pragma once
+
+#include <mapbox/geometry/box.hpp>
+#include <mbgl/style/types.hpp>
+#include <mbgl/util/optional.hpp>
+
+#include <array>
+
+namespace mbgl {
+
+class OpacityState {
+public:
+    OpacityState(bool placed, bool skipFade);
+    OpacityState(const OpacityState& prevState, float increment, bool placed);
+    bool isHidden() const;
+    float opacity;
+    bool placed;
+};
+
+class JointOpacityState {
+public:
+    JointOpacityState(bool placedText, bool placedIcon, bool skipFade);
+    JointOpacityState(const JointOpacityState& prevOpacityState, float increment, bool placedText, bool placedIcon);
+    bool isHidden() const;
+    OpacityState icon;
+    OpacityState text;
+};
+
+class VariableOffset {
+public:
+    std::array<float, 2> offset;
+    float width;
+    float height;
+    style::TextVariableAnchorType anchor;
+    float textBoxScale;
+    optional<style::TextVariableAnchorType> prevAnchor;
+};
+
+class JointPlacement {
+public:
+    JointPlacement(bool text_, bool icon_, bool skipFade_) : text(text_), icon(icon_), skipFade(skipFade_) {}
+
+    bool placed() const { return text || icon; }
+
+    const bool text;
+    const bool icon;
+    // skipFade = outside viewport, but within CollisionIndex::viewportPadding px of the edge
+    // Because these symbols aren't onscreen yet, we can skip the "fade in" animation,
+    // and if a subsequent viewport change brings them into view, they'll be fully
+    // visible right away.
+    const bool skipFade;
+};
+
+struct PlacedSymbolData {
+    // Contents of the label
+    std::u16string key;
+    // If symbol contains text, text collision box in viewport coordinates
+    optional<mapbox::geometry::box<float>> textCollisionBox;
+    // If symbol contains icon, icon collision box in viewport coordinates
+    optional<mapbox::geometry::box<float>> iconCollisionBox;
+    // Symbol text was placed
+    bool textPlaced;
+    // Symbol icon was placed
+    bool iconPlaced;
+    // Symbol text or icon collision box intersects tile borders
+    // (initialized only in tile mode)
+    optional<bool> intersectsTileBorder;
+    // Viewport padding ({viewportPadding, viewportPadding} is a coordinate of the tile's top-left corner)
+    float viewportPadding;
+    // Layer id (leader of the symbol layout group)
+    std::string layer;
+    // In Continous mode, contains the previous opacity of the symbol,
+    // in case it was already placed.
+    optional<JointOpacityState> prevOpacity;
+};
+
+} // namespace mbgl
\ No newline at end of file
diff --git a/src/mbgl/text/placement.cpp b/src/mbgl/text/placement.cpp
index 1a2971e16e..a55d372c62 100644
--- a/src/mbgl/text/placement.cpp
+++ b/src/mbgl/text/placement.cpp
@@ -12,32 +12,6 @@
 
 namespace mbgl {
 
-OpacityState::OpacityState(bool placed_, bool skipFade)
-    : opacity((skipFade && placed_) ? 1 : 0)
-    , placed(placed_)
-{
-}
-
-OpacityState::OpacityState(const OpacityState& prevState, float increment, bool placed_) :
-    opacity(::fmax(0, ::fmin(1, prevState.opacity + (prevState.placed ? increment : -increment)))),
-    placed(placed_) {}
-
-bool OpacityState::isHidden() const {
-    return opacity == 0 && !placed;
-}
-
-JointOpacityState::JointOpacityState(bool placedText, bool placedIcon, bool skipFade) :
-    icon(OpacityState(placedIcon, skipFade)),
-    text(OpacityState(placedText, skipFade)) {}
-
-JointOpacityState::JointOpacityState(const JointOpacityState& prevOpacityState, float increment, bool placedText, bool placedIcon) :
-    icon(OpacityState(prevOpacityState.icon, increment, placedIcon)),
-    text(OpacityState(prevOpacityState.text, increment, placedText)) {}
-
-bool JointOpacityState::isHidden() const {
-    return icon.isHidden() && text.isHidden();
-}
-    
 const CollisionGroups::CollisionGroup& CollisionGroups::get(const std::string& sourceID) {
     // The predicate/groupID mechanism allows for arbitrary grouping,
     // but the current interface defines one source == one group when
@@ -1224,6 +1198,13 @@ bool Placement::recordSymbolPlacement(const SymbolInstance& symbol,
         assert(box.isBox());
         iconCollisionBox = box.box();
     }
+    optional<JointOpacityState> prevOpacity;
+    if (getPrevPlacement()) {
+        auto it = getPrevPlacement()->opacities.find(symbol.crossTileID);
+        if (it != getPrevPlacement()->opacities.end()) {
+            prevOpacity = it->second;
+        }
+    }
     PlacedSymbolData symbolData{symbol.key,
                                 textCollisionBox,
                                 iconCollisionBox,
@@ -1231,7 +1212,8 @@ bool Placement::recordSymbolPlacement(const SymbolInstance& symbol,
                                 placement.icon,
                                 nullopt,
                                 collisionIndex.getViewportPadding(),
-                                ctx.getBucket().bucketLeaderID};
+                                ctx.getBucket().bucketLeaderID,
+                                prevOpacity};
     placedSymbolsData.emplace_back(std::move(symbolData));
     return true;
 }
@@ -1239,7 +1221,7 @@ bool Placement::recordSymbolPlacement(const SymbolInstance& symbol,
 const CollisionIndex& Placement::getCollisionIndex() const {
     return collisionIndex;
 }
-    
+
 const RetainedQueryData& Placement::getQueryData(uint32_t bucketInstanceId) const {
     auto it = retainedQueryData.find(bucketInstanceId);
     if (it == retainedQueryData.end()) {
diff --git a/src/mbgl/text/placement.hpp b/src/mbgl/text/placement.hpp
index 864f195c80..28296115ee 100644
--- a/src/mbgl/text/placement.hpp
+++ b/src/mbgl/text/placement.hpp
@@ -4,6 +4,7 @@
 #include <mbgl/renderer/renderer.hpp>
 #include <mbgl/style/transition_options.hpp>
 #include <mbgl/text/collision_index.hpp>
+#include <mbgl/text/placement_types.hpp>
 #include <mbgl/util/chrono.hpp>
 #include <string>
 #include <unordered_map>
@@ -17,51 +18,6 @@ using SymbolInstanceReferences = std::vector<std::reference_wrapper<const Symbol
 class UpdateParameters;
 enum class PlacedSymbolOrientation : bool;
 
-class OpacityState {
-public:
-    OpacityState(bool placed, bool skipFade);
-    OpacityState(const OpacityState& prevState, float increment, bool placed);
-    bool isHidden() const;
-    float opacity;
-    bool placed;
-};
-
-class JointOpacityState {
-public:
-    JointOpacityState(bool placedText, bool placedIcon, bool skipFade);
-    JointOpacityState(const JointOpacityState& prevOpacityState, float increment, bool placedText, bool placedIcon);
-    bool isHidden() const;
-    OpacityState icon;
-    OpacityState text;
-};
-
-class VariableOffset {
-public:
-    std::array<float, 2> offset;
-    float width;
-    float height;
-    style::TextVariableAnchorType anchor;
-    float textBoxScale;
-    optional<style::TextVariableAnchorType> prevAnchor;
-};
-
-class JointPlacement {
-public:
-    JointPlacement(bool text_, bool icon_, bool skipFade_)
-        : text(text_), icon(icon_), skipFade(skipFade_)
-    {}
-
-    bool placed() const { return text || icon; }
-
-    const bool text;
-    const bool icon;
-    // skipFade = outside viewport, but within CollisionIndex::viewportPadding px of the edge
-    // Because these symbols aren't onscreen yet, we can skip the "fade in" animation,
-    // and if a subsequent viewport change brings them into view, they'll be fully
-    // visible right away.
-    const bool skipFade;
-};
-  
 struct RetainedQueryData {
     uint32_t bucketInstanceId;
     std::shared_ptr<FeatureIndex> featureIndex;
diff --git a/src/mbgl/text/placement_types.cpp b/src/mbgl/text/placement_types.cpp
new file mode 100644
index 0000000000..02cf90e11a
--- /dev/null
+++ b/src/mbgl/text/placement_types.cpp
@@ -0,0 +1,30 @@
+#include <mbgl/text/placement_types.hpp>
+
+#include <cmath>
+
+namespace mbgl {
+
+OpacityState::OpacityState(bool placed_, bool skipFade) : opacity((skipFade && placed_) ? 1 : 0), placed(placed_) {}
+
+OpacityState::OpacityState(const OpacityState& prevState, float increment, bool placed_)
+    : opacity(::fmax(0, ::fmin(1, prevState.opacity + (prevState.placed ? increment : -increment)))), placed(placed_) {}
+
+bool OpacityState::isHidden() const {
+    return opacity == 0 && !placed;
+}
+
+JointOpacityState::JointOpacityState(bool placedText, bool placedIcon, bool skipFade)
+    : icon(OpacityState(placedIcon, skipFade)), text(OpacityState(placedText, skipFade)) {}
+
+JointOpacityState::JointOpacityState(const JointOpacityState& prevOpacityState,
+                                     float increment,
+                                     bool placedText,
+                                     bool placedIcon)
+    : icon(OpacityState(prevOpacityState.icon, increment, placedIcon)),
+      text(OpacityState(prevOpacityState.text, increment, placedText)) {}
+
+bool JointOpacityState::isHidden() const {
+    return icon.isHidden() && text.isHidden();
+}
+
+} // namespace mbgl
\ No newline at end of file