From 2abe0bb681044d972e171189395a2afdbc39bf28 Mon Sep 17 00:00:00 2001
From: Khaled Hosny <khaledhosny@eglug.org>
Date: Tue, 15 Aug 2017 22:39:32 +0200
Subject: Fix inverted y sign for glyph positioning

This is causing vertical glyph positioning to move in the wrong
direction e.g. marks go below base glyph instead of above. Seems to be a
regression introduced in:

commit 83dac189ff21c59be9b4f912e0d0e9690e710a4d
Author: Tavmjong Bah <tavmjong@free.fr>
Date:   Tue Nov 3 13:19:36 2015 +0100

    Rearrange code to make handling of baseline clearer.

    (bzr r14430.1.3)
---
 src/libnrtype/Layout-TNG-Compute.cpp               |   4 ++--
 testfiles/rendering_tests/CMakeLists.txt           |   1 +
 .../expected_rendering/test-glyph-y-pos-large.png  | Bin 0 -> 73316 bytes
 .../expected_rendering/test-glyph-y-pos.png        | Bin 0 -> 13723 bytes
 testfiles/rendering_tests/test-glyph-y-pos.svg     |  26 +++++++++++++++++++++
 5 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 testfiles/rendering_tests/expected_rendering/test-glyph-y-pos-large.png
 create mode 100644 testfiles/rendering_tests/expected_rendering/test-glyph-y-pos.png
 create mode 100644 testfiles/rendering_tests/test-glyph-y-pos.svg

diff --git a/src/libnrtype/Layout-TNG-Compute.cpp b/src/libnrtype/Layout-TNG-Compute.cpp
index 63364ab34..5d0c5c3ce 100644
--- a/src/libnrtype/Layout-TNG-Compute.cpp
+++ b/src/libnrtype/Layout-TNG-Compute.cpp
@@ -767,7 +767,7 @@ void Layout::Calculator::_outputLine(ParagraphInfo const &para,
                             if( dominant_baseline == SP_CSS_BASELINE_AUTO ) dominant_baseline = SP_CSS_BASELINE_ALPHABETIC;
                         }
 
-                        new_glyph.y += delta_y;
+                        new_glyph.y -= delta_y;
 
                         // TODO: Should also check 'glyph_orientation_vertical' if 'text-orientation' is unset...
                         if( new_span.text_orientation == SP_CSS_TEXT_ORIENTATION_SIDEWAYS ||
@@ -801,7 +801,7 @@ void Layout::Calculator::_outputLine(ParagraphInfo const &para,
 
                         if( dominant_baseline == SP_CSS_BASELINE_AUTO ) dominant_baseline = SP_CSS_BASELINE_ALPHABETIC;
 
-                        new_glyph.y -= delta_y;
+                        new_glyph.y += delta_y;
                         new_glyph.y += new_span.font_size * para.pango_items[unbroken_span.pango_item_index].font->GetBaselines()[ dominant_baseline ];
                         
                         new_glyph.width = unbroken_span_glyph_info->geometry.width * font_size_multiplier;
diff --git a/testfiles/rendering_tests/CMakeLists.txt b/testfiles/rendering_tests/CMakeLists.txt
index 3f838628a..739f9789d 100644
--- a/testfiles/rendering_tests/CMakeLists.txt
+++ b/testfiles/rendering_tests/CMakeLists.txt
@@ -2,6 +2,7 @@
 #add your test here (do not put the .svg extension)
 set(RENDERING_TESTS 
     test-empty
+    test-glyph-y-pos
 )
 
 
diff --git a/testfiles/rendering_tests/expected_rendering/test-glyph-y-pos-large.png b/testfiles/rendering_tests/expected_rendering/test-glyph-y-pos-large.png
new file mode 100644
index 000000000..0bd76e68e
Binary files /dev/null and b/testfiles/rendering_tests/expected_rendering/test-glyph-y-pos-large.png differ
diff --git a/testfiles/rendering_tests/expected_rendering/test-glyph-y-pos.png b/testfiles/rendering_tests/expected_rendering/test-glyph-y-pos.png
new file mode 100644
index 000000000..27833a1bb
Binary files /dev/null and b/testfiles/rendering_tests/expected_rendering/test-glyph-y-pos.png differ
diff --git a/testfiles/rendering_tests/test-glyph-y-pos.svg b/testfiles/rendering_tests/test-glyph-y-pos.svg
new file mode 100644
index 000000000..28200c79b
--- /dev/null
+++ b/testfiles/rendering_tests/test-glyph-y-pos.svg
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+
+<svg width="600" height="600"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:xlink="http://www.w3.org/1999/xlink"
+   version="1.1"
+   viewBox="0 0 600 600">
+  <style type="text/css">
+    text {
+      font-family: DejaVu Sans;
+      font-size: 36px;
+    }
+    .title {
+      text-anchor: middle;
+    }
+  </style>
+
+  <g>
+    <text x="50"  y="200">G̃g̃X̃x̃</text>
+    <text x="300" y="200" style="writing-mode:vertical-lr;">G̃g̃X̃x̃</text>
+    <text x="500" y="200" style="writing-mode:vertical-lr;text-orientation:upright">G̃g̃X̃x̃</text>
+  </g>
+
+  <text class="title" x="50%" y="120">Composed Glyphs</text>
+
+</svg>
-- 
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