From 689a166f6d0fb265a1fcddbeac098a9343734a64 Mon Sep 17 00:00:00 2001
From: Alex Wood <abwood@gmail.com>
Date: Sun, 29 Dec 2013 13:13:49 -0500
Subject: [PATCH] Initial support for newlines in labels.

---
 Apps/Sandcastle/gallery/Labels.html |  2 +-
 Source/Scene/LabelCollection.js     | 45 +++++++++++++++++++++++------
 2 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/Apps/Sandcastle/gallery/Labels.html b/Apps/Sandcastle/gallery/Labels.html
index 0a155c95e3c9..550ce10b00ad 100644
--- a/Apps/Sandcastle/gallery/Labels.html
+++ b/Apps/Sandcastle/gallery/Labels.html
@@ -110,7 +110,7 @@
 
             labels.add({
                 position : ellipsoid.cartographicToCartesian(Cesium.Cartographic.fromDegrees(-75.10, 39.57)),
-                text     : 'Label on top of scaling billboard',
+                text     : 'Label on top\nof scaling billboard',
                 font : '20px sans-serif',
                 horizontalOrigin : Cesium.HorizontalOrigin.CENTER,
                 pixelOffset : new Cesium.Cartesian2(0.0, image.height),
diff --git a/Source/Scene/LabelCollection.js b/Source/Scene/LabelCollection.js
index a135c62a1c9f..4d41bb6573d7 100644
--- a/Source/Scene/LabelCollection.js
+++ b/Source/Scene/LabelCollection.js
@@ -202,44 +202,71 @@ define([
 
     function repositionAllGlyphs(label) {
         var glyphs = label._glyphs;
+        var text = label._text;
         var glyph;
         var dimensions;
-        var totalWidth = 0;
+        var lineWidth = 0;
+        var maxWidth = 0;
         var maxHeight = 0;
+        var numberNewlines = 0;
 
         var glyphIndex = 0;
         var glyphLength = glyphs.length;
         for (glyphIndex = 0; glyphIndex < glyphLength; ++glyphIndex) {
             glyph = glyphs[glyphIndex];
             dimensions = glyph.dimensions;
-            totalWidth += dimensions.width;
-            maxHeight = Math.max(maxHeight, dimensions.height);
+            lineWidth += dimensions.width;
+            maxWidth = Math.max(maxWidth, lineWidth);
+            maxHeight = Math.max(maxHeight, dimensions.height + dimensions.descent);
+            if (text.charAt(glyphIndex) === '\n') {
+                numberNewlines += 1;
+                lineWidth = 0;
+            }
         }
 
         var scale = label._scale;
         var horizontalOrigin = label._horizontalOrigin;
         var widthOffset = 0;
         if (horizontalOrigin === HorizontalOrigin.CENTER) {
-            widthOffset -= totalWidth / 2 * scale;
+            widthOffset -= maxWidth / 2 * scale;
         } else if (horizontalOrigin === HorizontalOrigin.RIGHT) {
-            widthOffset -= totalWidth * scale;
+            widthOffset -= maxWidth * scale;
+        }
+
+        var heightOffset = 0;
+        var totalHeight = maxHeight * numberNewlines;
+        var verticalOrigin = label._verticalOrigin;
+        if (verticalOrigin === VerticalOrigin.CENTER) {
+            heightOffset -= totalHeight / 2 * scale;
+        } else if (verticalOrigin === VerticalOrigin.TOP) {
+            heightOffset -= totalHeight * scale;
+        }
+        else if (verticalOrigin === VerticalOrigin.BOTTOM) {
+            heightOffset += totalHeight * scale;
         }
 
         glyphPixelOffset.x = widthOffset;
         glyphPixelOffset.y = 0;
 
-        var verticalOrigin = label._verticalOrigin;
+        var glyphNewlineOffset = 0;
         for (glyphIndex = 0; glyphIndex < glyphLength; ++glyphIndex) {
             glyph = glyphs[glyphIndex];
             dimensions = glyph.dimensions;
 
             if (verticalOrigin === VerticalOrigin.BOTTOM || dimensions.height === maxHeight) {
-                glyphPixelOffset.y = -dimensions.descent * scale;
+                glyphPixelOffset.y = heightOffset - dimensions.descent * scale;
             } else if (verticalOrigin === VerticalOrigin.TOP) {
-                glyphPixelOffset.y = -(maxHeight - dimensions.height) * scale - dimensions.descent * scale;
+                glyphPixelOffset.y = heightOffset - (maxHeight - dimensions.height) * scale - dimensions.descent * scale;
             } else if (verticalOrigin === VerticalOrigin.CENTER) {
-                glyphPixelOffset.y = -(maxHeight - dimensions.height) / 2 * scale - dimensions.descent * scale;
+                glyphPixelOffset.y = heightOffset - (maxHeight - dimensions.height) / 2 * scale - dimensions.descent * scale;
+            }
+
+            if (text.charAt(glyphIndex) === '\n') {
+                glyphNewlineOffset += maxHeight * scale;
+                glyphPixelOffset.x = widthOffset;
+                continue;
             }
+            glyphPixelOffset.y -= glyphNewlineOffset;
 
             if (defined(glyph.billboard)) {
                 glyph.billboard._setTranslate(glyphPixelOffset);