Fix originGeometry value generation
This should fix #979
diff --git a/coders/json.c b/coders/json.c
index ef8d9a8..eda1206 100644
--- a/coders/json.c
+++ b/coders/json.c
@@ -1449,7 +1449,7 @@
(double) image->page.width,(double) image->page.height,
(double) image->page.x,(double) image->page.y);
if ((image->page.x != 0) || (image->page.y != 0))
- (void) FormatLocaleFile(file," \"originGeometry\": %+.20g%+.20g,\n",
+ (void) FormatLocaleFile(file," \"originGeometry\": \"%+.20g%+.20g\",\n",
(double) image->page.x,(double) image->page.y);
JSONFormatLocaleFile(file," \"dispose\": %s,\n",
CommandOptionToMnemonic(MagickDisposeOptions,(ssize_t) image->dispose));