ignore flipped glyphs when placing labels for perf

2 files changed, 37 insertions, 25 deletions

diff --git a/src/text/collision.cpp b/src/text/collision.cpp
index d1488cb29e..0da50f2809 100644
--- a/src/text/collision.cpp
+++ b/src/text/collision.cpp
@@ -53,7 +53,7 @@ Collision::Collision() : cTree(new Tree()), hTree(new Tree()) {
            CollisionAnchor{m, m}, 1, {{M_PI * 2, 0}}, false, 2);
 }
 
-GlyphBox getMergedGlyphs(const PlacedGlyphs &placed_glyphs, bool horizontal,
+GlyphBox getMergedGlyphs(const GlyphBoxes &boxes, bool horizontal,
                          const CollisionAnchor &anchor) {
     GlyphBox mergedGlyphs;
     const float inf = std::numeric_limits<float>::infinity();
@@ -62,28 +62,28 @@ GlyphBox getMergedGlyphs(const PlacedGlyphs &placed_glyphs, bool horizontal,
     mergedGlyphs.anchor = anchor;
 
     CollisionRect &box = mergedGlyphs.box;
-    for (const PlacedGlyph &placed_glyph : placed_glyphs) {
-        const CollisionRect &gbox = placed_glyph.glyphBox.box;
+    for (const GlyphBox &glyph : boxes) {
+        const CollisionRect &gbox = glyph.box;
         box.tl.x = util::min(box.tl.x, gbox.tl.x);
         box.tl.y = util::min(box.tl.y, gbox.tl.y);
         box.br.x = util::max(box.br.x, gbox.br.x);
         box.br.y = util::max(box.br.y, gbox.br.y);
         mergedGlyphs.minScale =
-            util::max(mergedGlyphs.minScale, placed_glyph.glyphBox.minScale);
+            util::max(mergedGlyphs.minScale, glyph.minScale);
     }
 
     return mergedGlyphs;
 }
 
-PlacementProperty Collision::place(const PlacedGlyphs &placed_glyphs,
+PlacementProperty Collision::place(const GlyphBoxes &boxes,
                                    const CollisionAnchor &anchor,
                                    float minPlacementScale,
                                    float maxPlacementScale, float padding,
                                    bool horizontal, bool alwaysVisible) {
 
     float minScale = std::numeric_limits<float>::infinity();
-    for (const PlacedGlyph &placed_glyph : placed_glyphs) {
-        minScale = util::min(minScale, placed_glyph.glyphBox.minScale);
+    for (const GlyphBox &glyphBox : boxes) {
+        minScale = util::min(minScale, glyphBox.minScale);
     }
     minPlacementScale = util::max(minPlacementScale, minScale);
 
@@ -92,11 +92,9 @@ PlacementProperty Collision::place(const PlacedGlyphs &placed_glyphs,
     // for horizontal labels.
     GlyphBoxes glyphs;
     if (horizontal) {
-        glyphs.push_back(getMergedGlyphs(placed_glyphs, horizontal, anchor));
+        glyphs.push_back(getMergedGlyphs(boxes, horizontal, anchor));
     } else {
-        for (const PlacedGlyph &placed_glyph : placed_glyphs) {
-            glyphs.push_back(placed_glyph.glyphBox);
-        }
+        glyphs = boxes;
     }
 
     // Calculate bboxes for all the glyphs
diff --git a/src/text/placement.cpp b/src/text/placement.cpp
index 237fd05d76..dbf7286e52 100644
--- a/src/text/placement.cpp
+++ b/src/text/placement.cpp
@@ -72,6 +72,14 @@ struct GlyphInstance {
     const float angle = 0.0f;
 };
 
+struct GlyphsAndBoxes {
+    explicit GlyphsAndBoxes(const PlacedGlyphs &glyphs, const GlyphBoxes &boxes)
+        : glyphs(glyphs), boxes(boxes) {}
+
+    const PlacedGlyphs glyphs;
+    const GlyphBoxes boxes;
+};
+
 typedef std::vector<GlyphInstance> GlyphInstances;
 
 void getSegmentGlyphs(std::back_insert_iterator<GlyphInstances> glyphs,
@@ -145,7 +153,7 @@ void getSegmentGlyphs(std::back_insert_iterator<GlyphInstances> glyphs,
     }
 }
 
-PlacedGlyphs getGlyphs(Anchor &anchor, float advance, const Shaping &shaping,
+GlyphsAndBoxes getGlyphs(Anchor &anchor, float advance, const Shaping &shaping,
                        const IndexedFaces &faces, float fontScale,
                        bool horizontal, const std::vector<Coordinate> &line,
                        float maxAngleDelta, float rotate) {
@@ -163,6 +171,7 @@ PlacedGlyphs getGlyphs(Anchor &anchor, float advance, const Shaping &shaping,
     // }
 
     PlacedGlyphs glyphs;
+    GlyphBoxes boxes;
 
     const uint32_t buffer = 3;
 
@@ -235,23 +244,28 @@ PlacedGlyphs getGlyphs(Anchor &anchor, float advance, const Shaping &shaping,
                     fontScale * util::max(tl.y, tr.y, bl.y, br.y)};
             }
 
+            GlyphBox glyphBox = GlyphBox{
+                box,
+                // Prevent label from extending past the end of the line
+                util::max(instance.minScale, anchor.scale),
+                instance.maxScale,
+                instance.anchor,
+                horizontal};
+
             // Remember the glyph for later insertion.
             glyphs.emplace_back(PlacedGlyph{
                 tl, tr, bl, br, glyph.rect,
                 static_cast<float>(
-                    std::fmod((anchor.angle + rotate + instance.offset + 2 * M_PI),
-                         (2 * M_PI))),
-                GlyphBox{box,             instance.minScale, instance.maxScale,
-                         instance.anchor, horizontal}});
-        }
-    }
+                    std::fmod((anchor.angle + rotate + instance.offset + 2 * M_PI), (2 * M_PI))),
+                glyphBox});
 
-    // Prevent label from extending past the end of the line
-    for (PlacedGlyph &g : glyphs) {
-        g.glyphBox.minScale = util::max(g.glyphBox.minScale, anchor.scale);
+            if (instance.offset == 0.0f) {
+                boxes.emplace_back(glyphBox);
+            }
+        }
     }
 
-    return glyphs;
+    return GlyphsAndBoxes{glyphs, boxes};
 }
 
 void Placement::addFeature(TextBucket& bucket,
@@ -289,14 +303,14 @@ void Placement::addFeature(TextBucket& bucket,
     }
 
     for (Anchor anchor : anchors) {
-        PlacedGlyphs glyphs =
+        GlyphsAndBoxes glyphsAndBoxes =
             getGlyphs(anchor, advance, shaping, faces, fontScale, horizontal,
                       line, maxAngleDelta, rotate);
         PlacementProperty place =
-            collision.place(glyphs, anchor, anchor.scale, maxPlacementScale,
+            collision.place(glyphsAndBoxes.boxes, anchor, anchor.scale, maxPlacementScale,
                             padding, horizontal, info.alwaysVisible);
         if (place) {
-            bucket.addGlyphs(glyphs, place.zoom, place.rotationRange,
+            bucket.addGlyphs(glyphsAndBoxes.glyphs, place.zoom, place.rotationRange,
                              zoom - zOffset);
         }
     }