Add bit-plane slicing

Makefile

@@ -4,7 +4,7 @@ LDIR = /opt/local/lib/
 LIBS = -lc -lpng16
 CFLAGS = -Wall -march=native -Ofast -Wa,-q
 OUT_DIR = build
-LABS = lab1_1 lab1_2 lab1_3 lab1_4 lab1_5 lab1_6 lab1_7 lab2_1 lab2_2 lab3 lab4_1 lab4_2 lab5 lab6 lab7
+LABS = lab1_1 lab1_2 lab1_3 lab1_4 lab1_5 lab1_6 lab1_7 lab1_8 lab2_1 lab2_2 lab3 lab4_1 lab4_2 lab5 lab6 lab7
 BINS = $(addprefix $(OUT_DIR)/,${LABS})
 OBJS = $(addsuffix .o,${BINS})
 

README.md

@@ -10,6 +10,7 @@ Here are the programs that I wrote during the Digital Image Processing class in
     5. [Ordered dithering](#ordered-dithering-lab1_5c)
     6. [Random dithering](#random-dithering-lab1_6c)
     7. [Clustered dithering](#clustered-dithering-lab1_7c)
+    8. [Bit-plane slicing](#bit-plane-slicing-lab1_8c)
 2. Image scaling
     1. [Nearest-neighbor interpolation](#nearest-neighbor-interpolation-lab2_1c)
     2. [Bilinear interpolation](#bilinear-interpolation-lab2_2c)
@@ -63,6 +64,16 @@ Here are the programs that I wrote during the Digital Image Processing class in
 | ----- | ------ |
 | ![Input](images/Lena.png) | ![Output](lab1_7/Lena_out.png) |
 
+---
+## Bit-plane slicing ([lab1_8.c](lab1_8/lab1_8.c))
+| Output (bit 6) | Output (bit 5) |
+| ----- | ------ |
+| ![Output](lab1_8/Lena_out_6.png) | ![Output](lab1_8/Lena_out_5.png) |
+
+| Output (bit 4) | Output (bit 3) |
+| ----- | ------ |
+| ![Output](lab1_8/Lena_out_4.png) | ![Output](lab1_8/Lena_out_3.png) |
+
 ---
 ## Nearest-neighbor interpolation ([lab2_1.c](lab2_1/lab2_1.c))
 | Input | Output (N = 5, cropped) |

lab1_8/lab1_8.c

@@ -0,0 +1,45 @@
+#include <stdlib.h>
+#include "png_wrapper.h"
+
+static void process_image(struct Image in, struct Image out[8])
+{
+	for (size_t y = 0; y < in.height; y++)
+		for (size_t x = 0; x < in.width; x++)
+			for (int b = 0; b < 8; b++)
+				out[b].pixels[y][x] = in.pixels[y][x] & 1 << b ? 255 : 0;
+}
+
+int main(int argc, char * const argv[])
+{
+	if (argc != 10)
+		error("usage: %s <in_file> <out0_file> <out1_file> <out2_file> <out3_file> "
+			  "<out4_file> <out5_file> <out6_file> <out7_file> ", argv[0]);
+
+	char *input_filename = argv[1];
+	char *output_filenames[8];
+	for (int i = 0; i < 8; i++)
+		output_filenames[i] = argv[i + 2];
+
+	struct Image in = read_grayscale_png(input_filename);
+	printf("Input file \"%s\" opened (width = %u, height = %u)\n",
+		   input_filename, in.width, in.height);
+
+	struct Image out[8];
+	for (int i = 0; i < 8; i++)
+	{
+		out[i].width  = in.width;
+		out[i].height = in.height;
+		alloc_pixels(&out[i]);
+	}
+
+	process_image(in, out);
+	free_pixels(in);
+
+	for (int i = 0; i < 8; i++)
+	{
+		write_grayscale_png(out[i], output_filenames[i]);
+		free_pixels(out[i]);
+	}
+
+	return 0;
+}