1 files changed, 134 insertions, 0 deletions
diff --git a/src/engine/interlace.c b/src/engine/interlace.c
new file mode 100644
index 0000000..0971a5a
--- /dev/null
+++ b/src/engine/interlace.c
@@ -0,0 +1,134 @@
+#include <config.h>
+#ifndef _plan9_
+#ifdef NO_MALLOC_H
+#include <stdlib.h>
+#else
+#include <malloc.h>
+#endif
+#include <stdio.h>		/*for NULL */
+#include <string.h>		/*for memcpy */
+#else
+#include <u.h>
+#include <libc.h>
+#include <stdio.h>
+#endif
+#include <filter.h>
+struct intdata {
+    unsigned char *lastent;
+    int changed;
+    int first;
+};
+static int requirement(struct filter *f, struct requirements *r)
+{
+    r->nimages = 1;
+    r->flags |= IMAGEDATA;
+    return (f->next->action->requirement(f->next, r));
+}
+
+static int initialize(struct filter *f, struct initdata *i)
+{
+    int x;
+    struct intdata *d = (struct intdata *) f->data;
+    pixel_t **lines1 =
+	(pixel_t **) malloc(sizeof(*lines1) * i->image->height / 2),
+	**lines2 =
+	(pixel_t **) malloc(sizeof(*lines2) * i->image->height / 2);
+    if (lines1 == NULL)
+	return 0;
+    inhermisc(f, i);
+    d->first = 1;
+    if (lines2 == NULL) {
+	free(lines1);
+	return 0;
+    }
+    if (f->childimage != NULL)
+	destroy_image(f->childimage);
+    f->image = i->image;
+    f->image->flags |= PROTECTBUFFERS;
+    i->flags |= DATALOST;
+    for (x = 0; x < (i->image->height) / 2; x++) {
+	lines1[x] = i->image->currlines[x * 2];
+	lines2[x] = i->image->currlines[x * 2 + 1];
+    }
+    f->childimage = i->image =
+	create_image_lines(i->image->width, (i->image->height) / 2, 2,
+			   lines1, lines2, i->image->palette, NULL,
+			   FREELINES | PROTECTBUFFERS,
+			   f->image->pixelwidth,
+			   f->image->pixelheight * 2);
+    if (i->image == NULL) {
+	free(lines1);
+	free(lines2);
+	return 0;
+    }
+    return (f->previous->action->initialize(f->previous, i));
+}
+
+static struct filter *getinstance(CONST struct filteraction *a)
+{
+    struct filter *f = createfilter(a);
+    struct intdata *i = (struct intdata *) calloc(1, sizeof(*i));
+    f->data = i;
+    f->name = "Interlace filter";
+    return (f);
+}
+
+static void destroyinstance(struct filter *f)
+{
+    free(f->data);
+    if (f->childimage != NULL)
+	destroy_image(f->childimage);
+    free(f);
+}
+
+static int doit(struct filter *f, int flags, int time)
+{
+    struct intdata *i = (struct intdata *) f->data;
+    int val;
+    if (!(f->req.flags & IMAGEDATA)
+	&& f->childimage->currlines[0] == i->lastent)
+	f->childimage->flip(f->childimage);
+    i->lastent = f->childimage->currlines[0];
+    val = f->previous->action->doit(f->previous, flags, time);
+    if (i->first) {
+	int y;
+	for (y = 0; y < f->childimage->height; y++)
+	    memcpy(f->childimage->oldlines[y], f->childimage->currlines[y],
+		   f->childimage->width * f->childimage->bytesperpixel);
+	i->first = 0;
+    }
+    if (val & CHANGED)
+	i->changed = 1, val |= ANIMATION;
+    else {
+	if (i->changed)
+	    val |= CHANGED;
+	i->changed = 0;
+    }
+    return (val);
+}
+
+static void convertup(struct filter *f, int *x, int *y)
+{
+    *y *= 2;
+    f->next->action->convertup(f->next, x, y);
+}
+
+static void convertdown(struct filter *f, int *x, int *y)
+{
+    *y /= 2;
+    f->previous->action->convertdown(f->previous, x, y);
+}
+
+CONST struct filteraction interlace_filter = {
+    "Interlace filter",
+    "interlace",
+    0,
+    getinstance,
+    destroyinstance,
+    doit,
+    requirement,
+    initialize,
+    convertup,
+    convertdown,
+    NULL
+};