1 files changed, 82 insertions, 0 deletions
diff --git a/libskrift_create_context.c b/libskrift_create_context.c
new file mode 100644
index 0000000..16c215e
--- /dev/null
+++ b/libskrift_create_context.c
@@ -0,0 +1,82 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+#define IMPLEMENTED_FLAGS (LIBSKRIFT_CORRECT_GAMMA |\
+                           LIBSKRIFT_REMOVE_GAMMA) /* libschrift does not add gamma, so not handling is required */
+
+#define HAVE_MULTIPLE_FLAGS(HAVE, CHECK) (((HAVE) & (CHECK)) & (((HAVE) & (CHECK)) - 1))
+
+#define COPY_ARRAY(DEST_STRUCT, SRC_STRUCT, FIELD)\
+	memcpy((DEST_STRUCT).FIELD, (SRC_STRUCT).FIELD, sizeof((SRC_STRUCT).FIELD))
+
+static const struct libskrift_rendering default_rendering = LIBSKRIFT_DEFAULT_RENDERING;
+
+int
+libskrift_create_context(LIBSKRIFT_CONTEXT **ctxp, LIBSKRIFT_FONT *font, const struct libskrift_rendering *rendering, double height)
+{
+	if (rendering) {
+		if (HAVE_MULTIPLE_FLAGS(rendering->flags, LIBSKRIFT_CORRECT_GAMMA | LIBSKRIFT_REMOVE_GAMMA)) {
+			errno = EINVAL;
+			return -1;
+		}
+	}
+
+	*ctxp = calloc(1, sizeof(**ctxp));
+	if (!*ctxp)
+		return -1;
+
+	(*ctxp)->font               = font;
+	(*ctxp)->schrift_ctx.font   = font->font;
+	(*ctxp)->schrift_ctx.yScale = height;
+
+	if (rendering) {
+		memcpy(&(*ctxp)->rendering, rendering, sizeof(*rendering));
+
+		COPY_ARRAY((*ctxp)->rendering, default_rendering, prestroke_transformation_rotation);
+		COPY_ARRAY((*ctxp)->rendering, default_rendering, left_transformation);
+		COPY_ARRAY((*ctxp)->rendering, default_rendering, right_transformation);
+		COPY_ARRAY((*ctxp)->rendering, default_rendering, top_transformation);
+		COPY_ARRAY((*ctxp)->rendering, default_rendering, bottom_transformation);
+		COPY_ARRAY((*ctxp)->rendering, default_rendering, poststroke_transformation_rotation);
+		COPY_ARRAY((*ctxp)->rendering, default_rendering, char_transformation);
+		COPY_ARRAY((*ctxp)->rendering, default_rendering, text_transformation);
+	} else {
+		memcpy(&(*ctxp)->rendering, &default_rendering, sizeof(default_rendering));
+	}
+
+	(*ctxp)->rendering.struct_version      = LIBSKRIFT_RENDERING_STRUCT_VERSION;
+	(*ctxp)->rendering.hinting             = LIBSKRIFT_NONE;
+	(*ctxp)->rendering.flags              &= IMPLEMENTED_FLAGS;
+	(*ctxp)->rendering.kerning             = 0;
+	(*ctxp)->rendering.interletter_spacing = 0;
+
+	if (!(*ctxp)->rendering.smoothing)
+		(*ctxp)->rendering.smoothing = LIBSKRIFT_GREYSCALE;
+
+	(*ctxp)->schrift_ctx.xScale = (*ctxp)->schrift_ctx.yScale;
+	(*ctxp)->schrift_ctx.xScale *= (*ctxp)->rendering.horizontal_dpi / (*ctxp)->rendering.vertical_dpi;
+
+	if ((*ctxp)->rendering.smoothing == LIBSKRIFT_SUBPIXEL) {
+		if ((*ctxp)->rendering.subpixel_order == LIBSKRIFT_RGB) {
+			(*ctxp)->schrift_ctx.xScale   *= 3;
+			(*ctxp)->subpixel_horizontally = 1;
+		} else if ((*ctxp)->rendering.subpixel_order == LIBSKRIFT_BGR) {
+			(*ctxp)->schrift_ctx.xScale   *= 3;
+			(*ctxp)->subpixel_horizontally = 1;
+			(*ctxp)->subpixel_bgr          = 1;
+		} else if ((*ctxp)->rendering.subpixel_order == LIBSKRIFT_VRGB) {
+			(*ctxp)->schrift_ctx.yScale   *= 3;
+			(*ctxp)->subpixel_vertically   = 1;
+		} else if ((*ctxp)->rendering.subpixel_order == LIBSKRIFT_VBGR) {
+			(*ctxp)->schrift_ctx.yScale   *= 3;
+			(*ctxp)->subpixel_vertically   = 1;
+			(*ctxp)->subpixel_bgr          = 1;
+		} else {
+			(*ctxp)->rendering.subpixel_order = LIBSKRIFT_NONE;
+			(*ctxp)->rendering.smoothing = LIBSKRIFT_GREYSCALE;
+		}
+	}
+
+	font->refcount += 1;
+	return 0;
+}