1 files changed, 60 insertions, 0 deletions
diff --git a/libfonts_calculate_subpixel_order.c b/libfonts_calculate_subpixel_order.c
new file mode 100644
index 0000000..6d26921
--- /dev/null
+++ b/libfonts_calculate_subpixel_order.c
@@ -0,0 +1,60 @@
+/* See LICENSE file for copyright and license details. */
+#include "libfonts.h"
+
+
+enum libfonts_subpixel_order
+libfonts_calculate_subpixel_order(enum libfonts_subpixel_order unrotated, enum libfonts_orientation rotation)
+{
+	int rot;
+
+	switch (rotation) {
+	case LIBFONTS_ORIENTATION_UNKNOWN:
+	default:
+		switch (unrotated) {
+		case LIBFONTS_SUBPIXEL_ORDER_UNKNOWN:
+		case LIBFONTS_SUBPIXEL_ORDER_NONRGB:
+		case LIBFONTS_SUBPIXEL_ORDER_NONLINEAR:
+		case LIBFONTS_SUBPIXEL_ORDER_OTHER:
+			return unrotated;
+		default:
+			return LIBFONTS_SUBPIXEL_ORDER_UNKNOWN;
+		}
+		break;
+
+	case LIBFONTS_ORIENTATION_0_DEGREES_CLOCKWISE:
+		return unrotated;
+
+	case LIBFONTS_ORIENTATION_90_DEGREES_CLOCKWISE:
+		rot = 1;
+		break;
+
+	case LIBFONTS_ORIENTATION_180_DEGREES_CLOCKWISE:
+		rot = 2;
+		break;
+
+	case LIBFONTS_ORIENTATION_270_DEGREES_CLOCKWISE:
+		rot = 3;
+		break;
+
+	case LIBFONTS_ORIENTATION_OTHER:
+		switch (unrotated) {
+		case LIBFONTS_SUBPIXEL_ORDER_UNKNOWN:
+		case LIBFONTS_SUBPIXEL_ORDER_NONRGB:
+		case LIBFONTS_SUBPIXEL_ORDER_NONLINEAR:
+			return unrotated;
+		default:
+			return LIBFONTS_SUBPIXEL_ORDER_NONLINEAR;
+		}
+		break;
+	}
+
+	switch (unrotated) {
+	case LIBFONTS_SUBPIXEL_ORDER_UNKNOWN:
+	case LIBFONTS_SUBPIXEL_ORDER_NONRGB:
+	case LIBFONTS_SUBPIXEL_ORDER_NONLINEAR:
+	case LIBFONTS_SUBPIXEL_ORDER_OTHER:
+		return unrotated;
+	default:
+		return ((unrotated + rot) & 3) + (unrotated & ~3);
+	}
+}