improve snapping in agg backend

leejjoon · mdboom · commit a6e700694ff8 · 2013-03-01T12:31:24.000-05:00
diff --git a/src/path_converters.h b/src/path_converters.h
@@ -514,8 +514,8 @@ class PathSnapper
         code = m_source->vertex(x, y);
         if (m_snap && agg::is_vertex(code))
         {
-            *x = floor(*x - m_snap_value) + m_snap_value;
-            *y = floor(*y - m_snap_value) + m_snap_value;
+            *x = floor(*x + 0.5 - m_snap_value) + m_snap_value;
+            *y = floor(*y + 0.5 - m_snap_value) + m_snap_value;
         }
         return code;
     }

Original file line number	Diff line number	Diff line change
`@@ -514,8 +514,8 @@ class PathSnapper`
`514`	`514`	`code = m_source->vertex(x, y);`
`515`	`515`	`if (m_snap && agg::is_vertex(code))`
`516`	`516`	`{`
`517`		`- x = floor(x - m_snap_value) + m_snap_value;`
`518`		`- y = floor(y - m_snap_value) + m_snap_value;`
	`517`	`+ x = floor(x + 0.5 - m_snap_value) + m_snap_value;`
	`518`	`+ y = floor(y + 0.5 - m_snap_value) + m_snap_value;`
`519`	`519`	`}`
`520`	`520`	`return code;`
`521`	`521`	`}`