From 72f1e9a8014690e0d4b96341077cd988f523d51f Mon Sep 17 00:00:00 2001
From: Alexander Shalamov <alexander.shalamov@mapbox.com>
Date: Fri, 6 Sep 2019 12:19:21 +0300
Subject: [core] Swap offset values for vertical POI labels

---
 src/mbgl/text/quads.cpp   | 10 ++++++++--
 src/mbgl/text/shaping.cpp | 12 ++++++++++--
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/mbgl/text/quads.cpp b/src/mbgl/text/quads.cpp
index 281c5d99de..91b4d723a3 100644
--- a/src/mbgl/text/quads.cpp
+++ b/src/mbgl/text/quads.cpp
@@ -58,7 +58,7 @@ SymbolQuad getIconQuad(const PositionedIcon& shapedIcon,
 }
 
 SymbolQuads getGlyphQuads(const Shaping& shapedText,
-                          const std::array<float, 2> textOffset,
+                          const std::array<float, 2> textOffset_,
                           const SymbolLayoutProperties::Evaluated& layout,
                           const style::SymbolPlacementType placement,
                           const GlyphPositions& positions,
@@ -67,6 +67,7 @@ SymbolQuads getGlyphQuads(const Shaping& shapedText,
     const bool alongLine = layout.get<TextRotationAlignment>() == AlignmentType::Map && placement != SymbolPlacementType::Point;
 
     SymbolQuads quads;
+    std::array<float, 2> textOffset = textOffset_;
 
     for (const PositionedGlyph &positionedGlyph: shapedText.positionedGlyphs) {
         auto fontPositions = positions.find(positionedGlyph.font);
@@ -85,6 +86,12 @@ SymbolQuads getGlyphQuads(const Shaping& shapedText,
         const float rectBuffer = 3.0f + glyphPadding;
 
         const float halfAdvance = glyph.metrics.advance * positionedGlyph.scale / 2.0;
+        const bool rotateVerticalGlyph = (alongLine || allowVerticalPlacement) && positionedGlyph.vertical;
+
+        // Swap offsets for vertical POI labels
+        if (rotateVerticalGlyph) {
+            textOffset = {{textOffset_[1], -textOffset_[0]}};
+        }
 
         const Point<float> glyphOffset = alongLine ?
             Point<float>{ positionedGlyph.x + halfAdvance, positionedGlyph.y } :
@@ -95,7 +102,6 @@ SymbolQuads getGlyphQuads(const Shaping& shapedText,
             Point<float>{ positionedGlyph.x + halfAdvance + textOffset[0], positionedGlyph.y + textOffset[1] };
 
         Point<float> verticalizedLabelOffset = { 0.0f, 0.0f };
-        const bool rotateVerticalGlyph = (alongLine || allowVerticalPlacement) && positionedGlyph.vertical;
         if (rotateVerticalGlyph) {
             // Vertical POI labels, that are rotated 90deg CW and whose glyphs must preserve upright orientation
             // need to be rotated 90deg CCW. After quad is rotated, it is translated to the original built-in offset.
diff --git a/src/mbgl/text/shaping.cpp b/src/mbgl/text/shaping.cpp
index d6d9a3d34e..a454fc6506 100644
--- a/src/mbgl/text/shaping.cpp
+++ b/src/mbgl/text/shaping.cpp
@@ -432,10 +432,18 @@ const Shaping getShaping(const TaggedString& formattedString,
             reorderedLines.emplace_back(line, formattedString.getSections());
         }
     }
-    Shaping shaping(translate[0], translate[1], writingMode, reorderedLines.size());
+
+    Shaping shaping;
+    // Swap text-offset for vertical POI labels.
+    if (allowVerticalPlacement && writingMode == WritingModeType::Vertical) {
+        shaping = Shaping(translate[1], -translate[0], writingMode, reorderedLines.size());
+    } else {
+        shaping = Shaping(translate[0], translate[1], writingMode, reorderedLines.size());
+    }
+
     shapeLines(shaping, reorderedLines, spacing, lineHeight, textAnchor,
                textJustify, writingMode, glyphs, allowVerticalPlacement);
-    
+
     return shaping;
 }
 
-- 
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