Extend "fade in immediately" for line labels to labels that were previously outside the range of the CollisionIndex.upstream/viewport-collision-no-fade-line-labels

Otherwise there's a weird mix on panning of some labels fading in vs. some popping in.

4 files changed, 30 insertions, 18 deletions

diff --git a/src/mbgl/text/collision_index.cpp b/src/mbgl/text/collision_index.cpp
index 17663363b6..7cfa39099e 100644
--- a/src/mbgl/text/collision_index.cpp
+++ b/src/mbgl/text/collision_index.cpp
@@ -73,7 +73,8 @@ std::pair<bool,bool> CollisionIndex::placeFeature(CollisionFeature& feature,
                                       const float fontSize,
                                       const bool allowOverlap,
                                       const bool pitchWithMap,
-                                      const bool collisionDebug) {
+                                      const bool collisionDebug,
+                                      bool& outsideGrid) {
     if (!feature.alongLine) {
         CollisionBox& box = feature.boxes.front();
         const auto projectedPoint = projectAndGetPerspectiveRatio(posMatrix, box.anchor);
@@ -82,6 +83,8 @@ std::pair<bool,bool> CollisionIndex::placeFeature(CollisionFeature& feature,
         box.py1 = box.y1 / tileToViewport + projectedPoint.first.y;
         box.px2 = box.x2 / tileToViewport + projectedPoint.first.x;
         box.py2 = box.y2 / tileToViewport + projectedPoint.first.y;
+        
+        outsideGrid &= !isInsideGrid(box);
 
         if (!isInsideGrid(box) ||
             (!allowOverlap && collisionGrid.hitTest({{ box.px1, box.py1 }, { box.px2, box.py2 }}))) {
@@ -90,7 +93,7 @@ std::pair<bool,bool> CollisionIndex::placeFeature(CollisionFeature& feature,
 
         return {true, isOffscreen(box)};
     } else {
-        return placeLineFeature(feature, posMatrix, labelPlaneMatrix, textPixelRatio, symbol, scale, fontSize, allowOverlap, pitchWithMap, collisionDebug);
+        return placeLineFeature(feature, posMatrix, labelPlaneMatrix, textPixelRatio, symbol, scale, fontSize, allowOverlap, pitchWithMap, collisionDebug, outsideGrid);
     }
 }
 
@@ -103,7 +106,8 @@ std::pair<bool,bool> CollisionIndex::placeLineFeature(CollisionFeature& feature,
                                       const float fontSize,
                                       const bool allowOverlap,
                                       const bool pitchWithMap,
-                                      const bool collisionDebug) {
+                                      const bool collisionDebug,
+                                      bool& outsideGrid) {
 
     const auto tileUnitAnchorPoint = symbol.anchorPoint;
     const auto projectedAnchor = projectAnchor(posMatrix, tileUnitAnchorPoint);
@@ -213,6 +217,7 @@ std::pair<bool,bool> CollisionIndex::placeLineFeature(CollisionFeature& feature,
         }
     }
 
+    outsideGrid &= !inGrid;
     return {!collisionDetected && firstAndLastGlyph && inGrid, entirelyOffscreen};
 }
 
diff --git a/src/mbgl/text/collision_index.hpp b/src/mbgl/text/collision_index.hpp
index 8653c1d76c..2521dac1f6 100644
--- a/src/mbgl/text/collision_index.hpp
+++ b/src/mbgl/text/collision_index.hpp
@@ -26,7 +26,8 @@ public:
                                       const float fontSize,
                                       const bool allowOverlap,
                                       const bool pitchWithMap,
-                                      const bool collisionDebug);
+                                      const bool collisionDebug,
+                                      bool& outsideGrid);
 
     void insertFeature(CollisionFeature& feature, bool ignorePlacement);
 
@@ -46,7 +47,8 @@ private:
                                   const float fontSize,
                                   const bool allowOverlap,
                                   const bool pitchWithMap,
-                                  const bool collisionDebug);
+                                  const bool collisionDebug,
+                                  bool& outsideGrid);
     
     float approximateTileDistance(const TileDistance& tileDistance, const float lastSegmentAngle, const float pixelsToTileUnits, const float cameraToAnchorDistance, const bool pitchWithMap);
     
diff --git a/src/mbgl/text/placement.cpp b/src/mbgl/text/placement.cpp
index 112d641be0..4652654148 100644
--- a/src/mbgl/text/placement.cpp
+++ b/src/mbgl/text/placement.cpp
@@ -22,9 +22,11 @@ bool OpacityState::isHidden() const {
     return opacity == 0 && !placed;
 }
 
-JointOpacityState::JointOpacityState(bool placedIcon, bool placedText, bool skipFadeIn) :
+JointOpacityState::JointOpacityState(bool placedIcon, bool placedText, bool skipFadeIn, bool outsideGrid_) :
     icon(OpacityState(placedIcon, skipFadeIn)),
-    text(OpacityState(placedText, skipFadeIn)) {}
+    text(OpacityState(placedText, skipFadeIn)),
+    outsideGrid(outsideGrid_)
+{}
 
 JointOpacityState::JointOpacityState(const JointOpacityState& prevOpacityState, float increment, bool placedIcon, bool placedText) :
     icon(OpacityState(prevOpacityState.icon, increment, placedIcon)),
@@ -105,6 +107,7 @@ void Placement::placeLayerBucket(
             bool placeIcon = false;
             bool offscreen = true;
             bool lineLabel = false;
+            bool outsideGrid = true;
 
             if (symbolInstance.placedTextIndex) {
                 PlacedSymbol& placedSymbol = bucket.text.placedSymbols.at(*symbolInstance.placedTextIndex);
@@ -115,7 +118,7 @@ void Placement::placeLayerBucket(
                         placedSymbol, scale, fontSize,
                         bucket.layout.get<TextAllowOverlap>(),
                         bucket.layout.get<TextPitchAlignment>() == style::AlignmentType::Map,
-                        showCollisionBoxes);
+                        showCollisionBoxes, outsideGrid);
                 placeText = placed.first;
                 offscreen &= placed.second;
                 lineLabel = symbolInstance.textCollisionFeature.alongLine;
@@ -130,7 +133,7 @@ void Placement::placeLayerBucket(
                         placedSymbol, scale, fontSize,
                         bucket.layout.get<IconAllowOverlap>(),
                         bucket.layout.get<IconPitchAlignment>() == style::AlignmentType::Map,
-                        showCollisionBoxes);
+                        showCollisionBoxes, outsideGrid);
                 placeIcon = placed.first;
                 offscreen &= placed.second;
             }
@@ -154,7 +157,7 @@ void Placement::placeLayerBucket(
 
             assert(symbolInstance.crossTileID != 0);
 
-            placements.emplace(symbolInstance.crossTileID, JointPlacement(placeText, placeIcon, offscreen, lineLabel));
+            placements.emplace(symbolInstance.crossTileID, JointPlacement(placeText, placeIcon, offscreen, lineLabel, outsideGrid));
             seenCrossTileIDs.insert(symbolInstance.crossTileID);
         }
     } 
@@ -172,13 +175,13 @@ bool Placement::commit(const Placement& prevPlacement, TimePoint now) {
     // add the opacities from the current placement, and copy their current values from the previous placement
     for (auto& jointPlacement : placements) {
         auto prevOpacity = prevPlacement.opacities.find(jointPlacement.first);
-        if (prevOpacity != prevPlacement.opacities.end()) {
+        if (prevOpacity != prevPlacement.opacities.end() && !prevOpacity->second.outsideGrid) {
             opacities.emplace(jointPlacement.first, JointOpacityState(prevOpacity->second, increment, jointPlacement.second.icon, jointPlacement.second.text));
             placementChanged = placementChanged ||
                 jointPlacement.second.icon != prevOpacity->second.icon.placed ||
                 jointPlacement.second.text != prevOpacity->second.text.placed;
         } else {
-            opacities.emplace(jointPlacement.first, JointOpacityState(jointPlacement.second.icon, jointPlacement.second.text, jointPlacement.second.offscreen || jointPlacement.second.lineLabel));
+            opacities.emplace(jointPlacement.first, JointOpacityState(jointPlacement.second.icon, jointPlacement.second.text, jointPlacement.second.offscreen || jointPlacement.second.lineLabel, jointPlacement.second.outsideGrid));
             placementChanged = placementChanged || jointPlacement.second.icon || jointPlacement.second.text;
         }
     }
@@ -220,7 +223,7 @@ void Placement::updateBucketOpacities(SymbolBucket& bucket, std::set<uint32_t>&
     for (SymbolInstance& symbolInstance : bucket.symbolInstances) {
         auto opacityState = seenCrossTileIDs.count(symbolInstance.crossTileID) == 0 ?
             getOpacity(symbolInstance.crossTileID) :
-            JointOpacityState(false, false, false);
+            JointOpacityState(false, false, false, false);
 
         seenCrossTileIDs.insert(symbolInstance.crossTileID);
 
@@ -282,7 +285,7 @@ JointOpacityState Placement::getOpacity(uint32_t crossTileSymbolID) const {
     if (it != opacities.end()) {
         return it->second;
     } else {
-        return JointOpacityState(false, false, false);
+        return JointOpacityState(false, false, false, false);
     }
 
 }
diff --git a/src/mbgl/text/placement.hpp b/src/mbgl/text/placement.hpp
index 68de16a358..8b3cbda86d 100644
--- a/src/mbgl/text/placement.hpp
+++ b/src/mbgl/text/placement.hpp
@@ -14,7 +14,7 @@ class SymbolBucket;
 
 class OpacityState {
 public:
-    OpacityState(bool placed, bool offscreen);
+    OpacityState(bool placed, bool skipFadeIn);
     OpacityState(const OpacityState& prevOpacityState, float increment, bool placed);
     bool isHidden() const;
     float opacity;
@@ -23,17 +23,18 @@ public:
 
 class JointOpacityState {
 public:
-    JointOpacityState(bool placedIcon, bool placedText, bool offscreen);
+    JointOpacityState(bool placedIcon, bool placedText, bool skipFadeIn, bool outsideGrid);
     JointOpacityState(const JointOpacityState& prevOpacityState, float increment, bool placedIcon, bool placedText);
     bool isHidden() const;
     OpacityState icon;
     OpacityState text;
+    bool outsideGrid;
 };
 
 class JointPlacement {
 public:
-    JointPlacement(bool text_, bool icon_, bool offscreen_, bool lineLabel_)
-        : text(text_), icon(icon_), offscreen(offscreen_), lineLabel(lineLabel_)
+    JointPlacement(bool text_, bool icon_, bool offscreen_, bool lineLabel_, bool outsideGrid_)
+        : text(text_), icon(icon_), offscreen(offscreen_), lineLabel(lineLabel_), outsideGrid(outsideGrid_)
     {}
 
     const bool text;
@@ -44,6 +45,7 @@ public:
     // visible right away.
     const bool offscreen;
     const bool lineLabel;
+    const bool outsideGrid;
 };
 
 class Placement {