1 files changed, 30 insertions, 0 deletions
diff --git a/src/fontsize-expansion.cpp b/src/fontsize-expansion.cpp
new file mode 100644
index 000000000..50169c3c2
--- /dev/null
+++ b/src/fontsize-expansion.cpp
@@ -0,0 +1,30 @@
+#include "libnr/nr-matrix-ops.h"
+
+/**
+ * Returns the distance from the transformed baseline to the
+ * transformation of a point at (0, 1); or 0 if \a m has no inverse.
+ */
+double
+fontsize_expansion(NR::Matrix const &m)
+{
+    double const denom(hypot(m[0], m[1]));
+    if (!(denom > 1e-100)) {
+        return 0.;
+    }
+    double const numer(m.descrim2());
+    if (!(numer > 1e-100)) {
+        return 0.;
+    }
+    return numer / denom;
+}
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :