1 files changed, 38 insertions, 0 deletions
diff --git a/helium/tracer.cpp b/helium/tracer.cpp
new file mode 100644
index 0000000..4e7d54d
--- /dev/null
+++ b/helium/tracer.cpp
@@ -0,0 +1,38 @@
+// Copyright 2006 Google Inc.
+// All Rights Reserved.
+// Author: <renn@google.com> (Marius Renn)
+//
+#include "debugging.h"
+#include "image.h"
+#include "trace.h"
+#include "tracer.h"
+
+using namespace helium;
+
+const uint8 kMark = 0x01;
+
+Tracer::Tracer() : scrap_(NULL), trace_map_(NULL) {
+}
+
+void Tracer::SetScrap(Image* scrap) {
+  scrap_ = scrap;
+  ASSERT(scrap_);
+  
+  int w = scrap->width();
+  neighbor_[0] = 1;
+  neighbor_[1] = w + 1;
+  neighbor_[2] = w;
+  neighbor_[3] = w - 1;
+  neighbor_[4] = -1;
+  neighbor_[5] = -w - 1;
+  neighbor_[6] = -w;
+  neighbor_[7] = -w + 1;
+}
+
+void Tracer::Engrave(const Trace& trace, Color* scrap_ptr) const {
+  for (unsigned i = 0; i < trace.size(); i++) {
+    SetAlphaAt(scrap_ptr, kMark);
+    scrap_ptr += neighbor_[trace.ValueAt(i)];
+  }
+  SetAlphaAt(scrap_ptr, kMark);
+}