[haiku-commits] r40172 - haiku/trunk/src/servers/app
- From: mmlr@xxxxxxxx
- To: haiku-commits@xxxxxxxxxxxxx
- Date: Sun, 9 Jan 2011 00:17:19 +0100 (CET)
Author: mmlr
Date: 2011-01-09 00:17:18 +0100 (Sun, 09 Jan 2011)
New Revision: 40172
Changeset: http://dev.haiku-os.org/changeset/40172
Ticket: http://dev.haiku-os.org/ticket/7075
Modified:
haiku/trunk/src/servers/app/GlyphLayoutEngine.h
Log:
LayoutGlyphs() was broken in various ways when encountering missing glyphs:
* The code used continue to restart the loop when encountering a missing glyph,
but in that case the index wouldn't be incremented, meaning the consumers
would received the same index for ConsumeEmptyGlphy() and ConsumeGlyph() and
at the end there was not necessarily a call for every index, resulting in
uninitialized array elements for GetHasGlyphs, GetEdges, GetEscapements and
GetBoundingBoxes.
* Since the advance values were not reset in case of a missing glyph but still
added for the next char, the coordinates the consumers would get were advanced
by the advance values of the glyph preceeding the missing glyph(s). This made
StringWidth return wrong widths.
* The loop end condition was skipped by the continue as well, which would have
resulted in overruns when there were problematic chars at the end of a string.
Fixes #7075 where the uninitialized array elements caused random truncation
errors. The problematic character in this case is a tab, that has no glyph as
it is a dynamic spacer. Previously this was resolved to the "missing glyph"
(the box) which had a width.
I find it highly problematic not to fall back to such a glyph, because there is
no real way to see that you're using a font that has missing glyphs. Instead
those are simply collapsed to nothing with this change (instead of being
random). This whole problem is only brought up by not guaranteeing that there
always is a glyph as was the case before where a missing glyph was replaced by
the box.
Modified: haiku/trunk/src/servers/app/GlyphLayoutEngine.h
===================================================================
--- haiku/trunk/src/servers/app/GlyphLayoutEngine.h 2011-01-08 23:05:09 UTC
(rev 40171)
+++ haiku/trunk/src/servers/app/GlyphLayoutEngine.h 2011-01-08 23:17:18 UTC
(rev 40172)
@@ -55,7 +55,7 @@
fCacheEntry->WriteUnlock();
else
fCacheEntry->ReadUnlock();
-
+
FontCache::Default()->Recycle(fCacheEntry);
}
@@ -275,22 +275,22 @@
const GlyphCache* glyph = entry->Glyph(charCode, fallbackEntry);
if (glyph == NULL) {
- consumer.ConsumeEmptyGlyph(index, charCode, x, y);
- continue;
+ consumer.ConsumeEmptyGlyph(index++, charCode, x, y);
+ advanceX = 0;
+ advanceY = 0;
} else {
- if (!consumer.ConsumeGlyph(index, charCode, glyph,
entry, x, y)) {
+ if (!consumer.ConsumeGlyph(index++, charCode, glyph,
entry, x, y)) {
advanceX = 0;
advanceY = 0;
break;
}
+
+ // get next increment for pen position
+ advanceX = glyph->advance_x;
+ advanceY = glyph->advance_y;
}
- // get next increment for pen position
- advanceX = glyph->advance_x;
- advanceY = glyph->advance_y;
-
lastCharCode = charCode;
- index++;
if (utf8String - start + 1 > length)
break;
}
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