diff --git a/djvu.c b/djvu.c
index 0171d3a06..a09e036b7 100644
--- a/djvu.c
+++ b/djvu.c
@@ -18,6 +18,7 @@
 #include <math.h>
 #include <string.h>
 #include <errno.h>
+#include <pthread.h>
 #include <libdjvu/miniexp.h>
 #include <libdjvu/ddjvuapi.h>
 
@@ -476,7 +477,6 @@ static int reflowPage(lua_State *L) {
 	DjvuPage *page = (DjvuPage*) luaL_checkudata(L, 1, "djvupage");
 	KOPTContext *kctx = (KOPTContext*) luaL_checkudata(L, 2, "koptcontext");
 	ddjvu_render_mode_t mode = (int) luaL_checkint(L, 3);
-	WILLUSBITMAP _src, *src;
 	ddjvu_rect_t prect;
 	ddjvu_rect_t rrect;
 
@@ -510,7 +510,7 @@ static int reflowPage(lua_State *L) {
 		dpi *= kctx->shrink_factor;
 	} while (rrect.w > kctx->read_max_width | rrect.h > kctx->read_max_height);
 
-	src = &_src;
+	WILLUSBITMAP *src = malloc(sizeof(WILLUSBITMAP));
 	bmp_init(src);
 	src->width = rrect.w;
 	src->height = rrect.h;
@@ -528,8 +528,13 @@ static int reflowPage(lua_State *L) {
 	status = ddjvu_page_render(page->page_ref, mode, &prect, &rrect, page->doc->pixelformat,
 			bmp_bytewidth(src), (char *) src->data);
 
-	k2pdfopt_reflow_bmp(kctx, src);
-	bmp_free(src);
+	kctx->src = src;
+	if (kctx->precache) {
+		pthread_t rf_thread;
+		pthread_create(&rf_thread, NULL, k2pdfopt_reflow_bmp, (void*) kctx);
+	} else {
+		k2pdfopt_reflow_bmp(kctx);
+	}
 
 	return 0;
 }
diff --git a/koptcontext.c b/koptcontext.c
index 408ca7f71..0a810d310 100644
--- a/koptcontext.c
+++ b/koptcontext.c
@@ -46,6 +46,8 @@ static int newKOPTContext(lua_State *L) {
 
 	uint8_t *data = NULL;
 	BBox bbox = {0, 0, 0, 0};
+	WILLUSBITMAP *src;
+	int precache = 0;
 
 	KOPTContext *kc = (KOPTContext*) lua_newuserdata(L, sizeof(KOPTContext));
 
@@ -76,6 +78,8 @@ static int newKOPTContext(lua_State *L) {
 
 	kc->data = data;
 	kc->bbox = bbox;
+	kc->src = src;
+	kc->precache = precache;
 
 	luaL_getmetatable(L, "koptcontext");
 	lua_setmetatable(L, -2);
@@ -216,6 +220,18 @@ static int kcSetWordSpacing(lua_State *L) {
 	return 0;
 }
 
+static int kcSetPreCache(lua_State *L) {
+	KOPTContext *kc = (KOPTContext*) luaL_checkudata(L, 1, "koptcontext");
+	kc->precache = 1;
+	return 0;
+}
+
+static int kcIsPreCache(lua_State *L) {
+	KOPTContext *kc = (KOPTContext*) luaL_checkudata(L, 1, "koptcontext");
+	lua_pushinteger(L, kc->precache);
+	return 1;
+}
+
 static const struct luaL_Reg koptcontext_meth[] = {
 	{"setBBox", kcSetBBox},
 	{"setTrim", kcSetTrim},
@@ -239,6 +255,9 @@ static const struct luaL_Reg koptcontext_meth[] = {
 	{"setDefectSize", kcSetDefectSize},
 	{"setLineSpacing", kcSetLineSpacing},
 	{"setWordSpacing", kcSetWordSpacing},
+
+	{"setPreCache", kcSetPreCache},
+	{"isPreCache", kcIsPreCache},
 	{NULL, NULL}
 };
 
diff --git a/pdf.c b/pdf.c
index 111576055..b8f35a68c 100644
--- a/pdf.c
+++ b/pdf.c
@@ -15,6 +15,11 @@
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
+
+#include <stdio.h>
+#include <math.h>
+#include <stddef.h>
+#include <pthread.h>
 #include <fitz/fitz-internal.h>
 
 #include "blitbuffer.h"
@@ -22,10 +27,6 @@
 #include "koptcontext.h"
 #include "k2pdfopt.h"
 #include "pdf.h"
-#include <stdio.h>
-#include <math.h>
-#include <stddef.h>
-
 
 typedef struct PdfDocument {
 	fz_document *xref;
@@ -563,7 +564,6 @@ static int reflowPage(lua_State *L) {
 	fz_rect bounds,bounds2;
 	fz_matrix ctm;
 	fz_bbox bbox;
-	WILLUSBITMAP _src, *src;
 
 	pix = NULL;
 	fz_var(pix);
@@ -606,14 +606,19 @@ static int reflowPage(lua_State *L) {
 	fz_run_page(page->doc->xref, page->page, dev, ctm, NULL);
 	fz_free_device(dev);
 
-	src = &_src;
+	WILLUSBITMAP *src = malloc(sizeof(WILLUSBITMAP));
 	bmp_init(src);
 
 	int status = bmpmupdf_pixmap_to_bmp(src, page->doc->context, pix);
 	fz_drop_pixmap(page->doc->context, pix);
 
-	k2pdfopt_reflow_bmp(kctx, src);
-	bmp_free(src);
+	kctx->src = src;
+	if (kctx->precache) {
+		pthread_t rf_thread;
+		pthread_create( &rf_thread, NULL, k2pdfopt_reflow_bmp, (void*) kctx);
+	} else {
+		k2pdfopt_reflow_bmp(kctx);
+	}
 
 	return 0;
 }