Don't include trailing newline in width for line breaking

In a paragraph with a trailing newline, the width of the newline
character was included in the line width for breaking purposes,
basically as if it were a non-breaking space. This caused a
discrepancy, where Layout.getDesiredWidth() suggested that the text
would fit in a single line, but StaticLayout would break it because of
the added width of the newline character.

The proposed fix is simply to consider newline to be a space that
disappears at the end of a line.

Bug: 20152308
Change-Id: I539574c5b8ea892c8ed6aca6c59e90ccdf74a680

1 files changed, 4 insertions, 3 deletions

diff --git a/libs/minikin/LineBreaker.cpp b/libs/minikin/LineBreaker.cpp
index f4201cb..88190ff 100644
--- a/libs/minikin/LineBreaker.cpp
+++ b/libs/minikin/LineBreaker.cpp
@@ -84,11 +84,12 @@ void LineBreaker::setIndents(const std::vector<float>& indents) {
 }
 
 // This function determines whether a character is a space that disappears at end of line.
-// It is the Unicode set: [[:General_Category=Space_Separator:]-[:Line_Break=Glue:]]
+// It is the Unicode set: [[:General_Category=Space_Separator:]-[:Line_Break=Glue:]],
+// plus '\n'.
 // Note: all such characters are in the BMP, so it's ok to use code units for this.
 static bool isLineEndSpace(uint16_t c) {
-    return c == ' ' || c == 0x1680 || (0x2000 <= c && c <= 0x200A && c != 0x2007) || c == 0x205F ||
-            c == 0x3000;
+    return c == '\n' || c == ' ' || c == 0x1680 || (0x2000 <= c && c <= 0x200A && c != 0x2007) ||
+            c == 0x205F || c == 0x3000;
 }
 
 // Ordinarily, this method measures the text in the range given. However, when paint