From d08b4a21baf030ce5923d6b172968406222a651b Mon Sep 17 00:00:00 2001
From: Anand Thakker <github@anandthakker.net>
Date: Wed, 7 Jun 2017 17:38:17 -0400
Subject: [PATCH 1/3] Add regression test for cooperation between
 text-keep-upright & text-anchor

---
 .../expected.png                              | Bin 0 -> 1704 bytes
 .../style.json                                | 128 ++++++++++++++++++
 2 files changed, 128 insertions(+)
 create mode 100644 test/integration/render-tests/text-keep-upright/line-placement-true-text-anchor/expected.png
 create mode 100644 test/integration/render-tests/text-keep-upright/line-placement-true-text-anchor/style.json

diff --git a/test/integration/render-tests/text-keep-upright/line-placement-true-text-anchor/expected.png b/test/integration/render-tests/text-keep-upright/line-placement-true-text-anchor/expected.png
new file mode 100644
index 0000000000000000000000000000000000000000..11358a8fb5cafcab387d07261a8d1c2783e8307d
GIT binary patch
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diff --git a/test/integration/render-tests/text-keep-upright/line-placement-true-text-anchor/style.json b/test/integration/render-tests/text-keep-upright/line-placement-true-text-anchor/style.json
new file mode 100644
index 00000000000..7db2bbf2867
--- /dev/null
+++ b/test/integration/render-tests/text-keep-upright/line-placement-true-text-anchor/style.json
@@ -0,0 +1,128 @@
+{
+  "version": 8,
+  "metadata": {
+    "test": {
+      "height": 64,
+      "operations": [
+          [ "setBearing", 20 ],
+          [ "wait" ]
+      ]
+    }
+  },
+  "center": [ 0, 0 ],
+  "zoom": 0,
+  "sources": {
+    "geojson": {
+      "type": "geojson",
+      "data": {
+        "type": "Feature",
+        "properties": {},
+        "geometry": {
+          "type": "LineString",
+          "coordinates": [
+            [-10, -10],
+            [10, -10],
+            [10, 10],
+            [-10, 10]
+          ]
+        }
+      }
+    }
+  },
+  "glyphs": "local://glyphs/{fontstack}/{range}.pbf",
+  "layers": [
+    {
+      "id": "guid",
+      "type": "line",
+      "source": "geojson"
+    },
+    {
+      "id": "left",
+      "type": "symbol",
+      "source": "geojson",
+      "layout": {
+          "symbol-placement": "line",
+          "symbol-spacing": 50,
+          "text-size": 10,
+          "text-allow-overlap": true,
+          "text-ignore-placement": true,
+          "text-field": "A",
+          "text-font": [
+              "Open Sans Semibold",
+              "Arial Unicode MS Bold"
+          ],
+          "text-keep-upright": true,
+          "text-anchor": "left"
+      },
+      "paint": {
+          "text-color": "red"
+      }
+    },
+    {
+      "id": "right",
+      "type": "symbol",
+      "source": "geojson",
+      "layout": {
+          "symbol-placement": "line",
+          "symbol-spacing": 50,
+          "text-size": 10,
+          "text-allow-overlap": true,
+          "text-ignore-placement": true,
+          "text-field": "A",
+          "text-font": [
+              "Open Sans Semibold",
+              "Arial Unicode MS Bold"
+          ],
+          "text-keep-upright": true,
+          "text-anchor": "right"
+      },
+      "paint": {
+          "text-color": "blue"
+      }
+    },
+    {
+      "id": "top",
+      "type": "symbol",
+      "source": "geojson",
+      "layout": {
+          "symbol-placement": "line",
+          "symbol-spacing": 50,
+          "text-size": 10,
+          "text-allow-overlap": true,
+          "text-ignore-placement": true,
+          "text-field": "A",
+          "text-font": [
+              "Open Sans Semibold",
+              "Arial Unicode MS Bold"
+          ],
+          "text-keep-upright": true,
+          "text-anchor": "top"
+      },
+      "paint": {
+          "text-color": "green"
+      }
+    },
+    {
+      "id": "bottom",
+      "type": "symbol",
+      "source": "geojson",
+      "layout": {
+          "symbol-placement": "line",
+          "symbol-spacing": 50,
+          "text-size": 10,
+          "text-allow-overlap": true,
+          "text-ignore-placement": true,
+          "text-field": "A",
+          "text-font": [
+              "Open Sans Semibold",
+              "Arial Unicode MS Bold"
+          ],
+          "text-keep-upright": true,
+          "text-anchor": "bottom"
+      },
+      "paint": {
+          "text-color": "black"
+      }
+    }
+  ]
+}

From 5699d010cfb09ae3eff638904d2f2630d03b04e1 Mon Sep 17 00:00:00 2001
From: Anand Thakker <github@anandthakker.net>
Date: Fri, 2 Jun 2017 17:36:52 -0400
Subject: [PATCH 2/3] Quick/dirty fix: apply rotation after text-offset

---
 src/symbol/quads.js                           |  57 ++++++++++-------
 src/symbol/shaping.js                         |   8 +--
 .../line-placement-true-offset/expected.png   | Bin 0 -> 3050 bytes
 .../line-placement-true-offset/style.json     |  58 ++++++++++++++++++
 4 files changed, 97 insertions(+), 26 deletions(-)
 create mode 100644 test/integration/render-tests/text-keep-upright/line-placement-true-offset/expected.png
 create mode 100644 test/integration/render-tests/text-keep-upright/line-placement-true-offset/style.json

diff --git a/src/symbol/quads.js b/src/symbol/quads.js
index 62e244bd56c..de61e8df504 100644
--- a/src/symbol/quads.js
+++ b/src/symbol/quads.js
@@ -153,8 +153,10 @@ function getIconQuads(anchor, shapedIcon, boxScale, line, layer, alongLine, shap
  */
 function getGlyphQuads(anchor, shaping, boxScale, line, layer, alongLine, globalProperties, featureProperties) {
 
+    const oneEm = 24;
     const textRotate = layer.getLayoutValue('text-rotate', globalProperties, featureProperties) * Math.PI / 180;
     const keepUpright = layer.layout['text-keep-upright'];
+    const textOffset = layer.getLayoutValue('text-offset', globalProperties, featureProperties).map((t)=> t * oneEm);
 
     const positionedGlyphs = shaping.positionedGlyphs;
     const quads = [];
@@ -189,32 +191,19 @@ function getGlyphQuads(anchor, shaping, boxScale, line, layer, alongLine, global
             }];
         }
 
-        const x1 = positionedGlyph.x + glyph.left;
-        const y1 = positionedGlyph.y - glyph.top;
-        const x2 = x1 + rect.w;
-        const y2 = y1 + rect.h;
-
-        const center = new Point(positionedGlyph.x, glyph.advance / 2);
-
-        const otl = new Point(x1, y1);
-        const otr = new Point(x2, y1);
-        const obl = new Point(x1, y2);
-        const obr = new Point(x2, y2);
-
-        if (positionedGlyph.angle !== 0) {
-            otl._sub(center)._rotate(positionedGlyph.angle)._add(center);
-            otr._sub(center)._rotate(positionedGlyph.angle)._add(center);
-            obl._sub(center)._rotate(positionedGlyph.angle)._add(center);
-            obr._sub(center)._rotate(positionedGlyph.angle)._add(center);
-        }
+        const baseQuad = {
+            upright: calculateBaseQuad(positionedGlyph, glyph, rect, textOffset),
+            upsideDown: calculateBaseQuad(positionedGlyph, glyph, rect, [textOffset[0], -textOffset[1]])
+        };
 
         for (let i = 0; i < glyphInstances.length; i++) {
 
             const instance = glyphInstances[i];
-            let tl = otl,
-                tr = otr,
-                bl = obl,
-                br = obr;
+            const base = baseQuad[instance.upsideDown ? 'upsideDown' : 'upright'];
+            let tl = base.tl,
+                tr = base.tr,
+                bl = base.bl,
+                br = base.br;
 
             if (textRotate) {
                 const sin = Math.sin(textRotate),
@@ -240,6 +229,30 @@ function getGlyphQuads(anchor, shaping, boxScale, line, layer, alongLine, global
     return quads;
 }
 
+function calculateBaseQuad(positionedGlyph, glyph, rect, offset) {
+    const x1 = positionedGlyph.x + glyph.left + offset[0];
+    const y1 = positionedGlyph.y - glyph.top + offset[1];
+    const x2 = x1 + rect.w;
+    const y2 = y1 + rect.h;
+
+    const center = new Point(positionedGlyph.x, glyph.advance / 2);
+
+    const tl = new Point(x1, y1);
+    const tr = new Point(x2, y1);
+    const bl = new Point(x1, y2);
+    const br = new Point(x2, y2);
+
+    if (positionedGlyph.angle !== 0) {
+        tl._sub(center)._rotate(positionedGlyph.angle)._add(center);
+        tr._sub(center)._rotate(positionedGlyph.angle)._add(center);
+        bl._sub(center)._rotate(positionedGlyph.angle)._add(center);
+        br._sub(center)._rotate(positionedGlyph.angle)._add(center);
+    }
+
+    return { tl, tr, bl, br };
+}
+
+
 /**
  * We can only render glyph quads that slide along a straight line. To draw
  * curved lines we need an instance of a glyph for each segment it appears on.
diff --git a/src/symbol/shaping.js b/src/symbol/shaping.js
index 20076ea44bc..74410422ff5 100644
--- a/src/symbol/shaping.js
+++ b/src/symbol/shaping.js
@@ -275,7 +275,7 @@ function shapeLines(shaping, glyphs, lines, lineHeight, horizontalAlign, vertica
         y += lineHeight;
     }
 
-    align(positionedGlyphs, justify, horizontalAlign, verticalAlign, maxLineLength, lineHeight, lines.length, translate);
+    align(positionedGlyphs, justify, horizontalAlign, verticalAlign, maxLineLength, lineHeight, lines.length);
 
     // Calculate the bounding box
     const height = lines.length * lineHeight;
@@ -299,9 +299,9 @@ function justifyLine(positionedGlyphs, glyphs, start, end, justify) {
     }
 }
 
-function align(positionedGlyphs, justify, horizontalAlign, verticalAlign, maxLineLength, lineHeight, lineCount, translate) {
-    const shiftX = (justify - horizontalAlign) * maxLineLength + translate[0];
-    const shiftY = (-verticalAlign * lineCount + 0.5) * lineHeight + translate[1];
+function align(positionedGlyphs, justify, horizontalAlign, verticalAlign, maxLineLength, lineHeight, lineCount) {
+    const shiftX = (justify - horizontalAlign) * maxLineLength;
+    const shiftY = (-verticalAlign * lineCount + 0.5) * lineHeight;
 
     for (let j = 0; j < positionedGlyphs.length; j++) {
         positionedGlyphs[j].x += shiftX;
diff --git a/test/integration/render-tests/text-keep-upright/line-placement-true-offset/expected.png b/test/integration/render-tests/text-keep-upright/line-placement-true-offset/expected.png
new file mode 100644
index 0000000000000000000000000000000000000000..3c6dfef6d7d611ea1f152740203fefa4924118a9
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HcmV?d00001

diff --git a/test/integration/render-tests/text-keep-upright/line-placement-true-offset/style.json b/test/integration/render-tests/text-keep-upright/line-placement-true-offset/style.json
new file mode 100644
index 00000000000..b587263ccf1
--- /dev/null
+++ b/test/integration/render-tests/text-keep-upright/line-placement-true-offset/style.json
@@ -0,0 +1,58 @@
+{
+  "version": 8,
+  "metadata": {
+    "test": {
+      "height": 64,
+      "operations": [
+          [ "setBearing", 20 ],
+          [ "wait" ]
+        ]
+    }
+  },
+  "center": [ 0, 0 ],
+  "zoom": 0,
+  "sources": {
+    "geojson": {
+      "type": "geojson",
+      "data": {
+        "type": "Feature",
+        "properties": {},
+        "geometry": {
+          "type": "LineString",
+          "coordinates": [
+            [-20, -20],
+            [20, -20],
+            [20, 20],
+            [-20, 20]
+          ]
+        }
+      }
+    }
+  },
+  "glyphs": "local://glyphs/{fontstack}/{range}.pbf",
+  "layers": [
+    {
+      "id": "guid",
+      "type": "line",
+      "source": "geojson"
+    },
+    {
+      "id": "text",
+      "type": "symbol",
+      "source": "geojson",
+      "layout": {
+        "symbol-placement": "line",
+        "symbol-spacing": 3,
+        "text-allow-overlap": true,
+        "text-ignore-placement": true,
+        "text-field": "A",
+        "text-font": [
+          "Open Sans Semibold",
+          "Arial Unicode MS Bold"
+        ],
+        "text-keep-upright": true,
+        "text-offset": [0, -1]
+      }
+    }
+  ]
+}

From 5561213656143d01c43fa3b160ab2060883019d6 Mon Sep 17 00:00:00 2001
From: Anand Thakker <github@anandthakker.net>
Date: Fri, 2 Jun 2017 17:49:52 -0400
Subject: [PATCH 3/3] Add explanatory comment

---
 src/symbol/quads.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/symbol/quads.js b/src/symbol/quads.js
index de61e8df504..c1120354d9c 100644
--- a/src/symbol/quads.js
+++ b/src/symbol/quads.js
@@ -193,6 +193,10 @@ function getGlyphQuads(anchor, shaping, boxScale, line, layer, alongLine, global
 
         const baseQuad = {
             upright: calculateBaseQuad(positionedGlyph, glyph, rect, textOffset),
+            // The quad coordinates represent an offset from the anchor.  Since
+            // we use the same anchor for both the 'upright' and 'upside-down'
+            // copies of each glyph, invert the y dimension of text-offset for the
+            // upside-down case.
             upsideDown: calculateBaseQuad(positionedGlyph, glyph, rect, [textOffset[0], -textOffset[1]])
         };