bit3 & blurge & gol

1 files changed, 94 insertions, 17 deletions

diff --git a/catgy.c b/catgy.c
index f1cd128..2a5025e 100644
--- a/catgy.c
+++ b/catgy.c
@@ -1,6 +1,7 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <strings.h>
+#include <time.h>
 #define STB_IMAGE_IMPLEMENTATION
 #include "stb_image.h"
 
@@ -11,19 +12,32 @@ struct image {
 	uint8_t *data;
 };
 
-static int process(char **argv);
+static int process(int argc, char **argv);
+static void bit3(struct image *img);
 static void chaos1(struct image *img);
 static void chaos3(struct image *img);
+static void blurge(struct image *img);
+static void gol(struct image *img);
 
 int
 main(int argc, char **argv) {
-	if (argc != 3) {
-		fprintf(stderr, "usage: %s filter image\n",
+	if (argc < 2) {
+		fprintf(stderr, "usage: %s image [filters]\n",
 		        argv[0]);
 		return 1;
 	}
 
-	return process(argv);
+	srand(time(NULL));
+
+	return process(argc, argv);
+}
+
+static void
+bit3(struct image *img)
+{
+	/* deterministic threshold to 3-bit */
+	for (long i = 0; i < img->w * img->h * CHANS; i++)
+		img->data[i] = (img->data[i] > 0x7f) * 0xff;
 }
 
 static void
@@ -47,11 +61,67 @@ chaos3(struct image *img)
 		img->data[i] = (img->data[i] > (rand() & 0xff)) * 0xff;
 }
 
+static void
+average(uint8_t dest[3], uint8_t src[9])
+{
+	for (int i = 0; i < 3; i++)
+		dest[i] = (src[i] + src[i + 3] + src[i + 6]) / 3;
+}
+
+static void
+blurge(struct image *img)
+{
+	for (int y = 0; y < img->h; y++)
+		for (int x = 1; x < img->w - 1; x++)
+			average(&img->data[x * 3 + y * img->w * 3],
+			        &img->data[x * 3 - 3 + y * img->w * 3]);
+}
+
+static int
+neighbors(struct image *img, int x, int y, int o)
+{
+	const int stride = img->w * 3;
+	return (img->data[o + (x - 1) * 3 + (y    ) * stride] != 0) +
+	       (img->data[o + (x + 1) * 3 + (y    ) * stride] != 0) +
+	       (img->data[o + (x    ) * 3 + (y - 1) * stride] != 0) +
+	       (img->data[o + (x    ) * 3 + (y + 1) * stride] != 0) +
+	       (img->data[o + (x - 1) * 3 + (y - 1) * stride] != 0) +
+	       (img->data[o + (x - 1) * 3 + (y + 1) * stride] != 0) +
+	       (img->data[o + (x + 1) * 3 + (y - 1) * stride] != 0) +
+	       (img->data[o + (x + 1) * 3 + (y + 1) * stride] != 0);
+}
+
+static void
+gol(struct image *img)
+{
+	uint8_t *copy = malloc(img->w * img->h * img->chans);
+	if (copy == NULL) {
+		perror("malloc");
+		return;
+	}
+	memcpy(copy, img->data, img->w * img->h * img->chans);
+
+	for (int y = 1; y < img->h - 1; y++) {
+		for (int x = 1; x < img->w - 1; x++) {
+			for (int o = 0; o < 3; o++) {
+				const int near = neighbors(img, x, y, o);
+				const int i = x * 3 + y * img->w * 3 + o;
+				if (near < 2 || near > 3)
+					copy[i] = 0;
+				else
+					copy[i] = 0xff;
+			}
+		}
+	}
+
+	memcpy(img->data, copy, img->w * img->h * img->chans);
+	free(copy);
+}
+
 static int
-process(char **argv)
+process(int argc, char **argv)
 {
-	const char *filter = argv[1];
-	const char *path = argv[2];
+	const char *path = argv[1];
 
 	/* read image */
 	struct image img;
@@ -78,23 +148,30 @@ process(char **argv)
 		const char *name;
 		void (*fun)(struct image *img);
 	} filters[] = {
+		{ "bit3", bit3 },
 		{ "chaos1", chaos1 },
 		{ "chaos3", chaos3 },
+		{ "blurge", blurge },
+		{ "gol", gol },
 	};
 
 	int filtered = 0;
-	for (size_t i = 0; i < sizeof(filters) / sizeof(filters[0]); i++) {
-		if (strcasecmp(filter, filters[i].name) == 0) {
-			filters[i].fun(&img);
-			filtered = 1;
-			break;
+
+	for (int i = 2; i < argc; i++) {
+		const char *filter = argv[i];
+		for (size_t i = 0; i < sizeof(filters) / sizeof(filters[0]); i++) {
+			if (strcasecmp(filter, filters[i].name) == 0) {
+				filters[i].fun(&img);
+				filtered = 1;
+				break;
+			}
 		}
-	}
 
-	if (!filtered) {
-		fprintf(stderr, "error: unknown filter '%s'\n", filter);
-		stbi_image_free(img.data);
-		return 1;
+		if (!filtered) {
+			fprintf(stderr, "error: unknown filter '%s'\n", filter);
+			stbi_image_free(img.data);
+			return 1;
+		}
 	}
 
 	/* write PPM */