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octoantoctoant
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Clone the assignment-image-rotation
1 parent 14e0803 commit f072eef

16 files changed

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lines changed

‎README.md

+4-2
Original file line numberDiff line numberDiff line change
@@ -18,13 +18,15 @@ stands for transposition). *B*, *G*, *R* stand for blue, green, and red levels.
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In vector from the transformation can be described as follows:
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2020
<p align="center">
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<img src="docs/transform-matrix.png" alt="transform-pixel" />
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<img src="docs/transform-matrix.png" alt="transform-pixel"
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width="250" height="70" />
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</p>
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In scalar form, we can rewrite it as
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<p align="center">
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<img src="docs/transform-system.png" alt="transform-system" />
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<img src="docs/transform-system.png" alt="transform-system"
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width="250" height="70" />
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</p>
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We will have to use saturation arithmetic. It means, that all operations such as

‎include/bmp.h

+12
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@@ -0,0 +1,12 @@
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#ifndef BMP_H
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#define BMP_H
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#include <stdio.h>
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#include "image.h"
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#include "iostatus.h"
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enum read_status from_bmp(FILE *, struct image *);
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enum write_status to_bmp(FILE *, struct image const *);
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#endif

‎include/dimensions.h

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@@ -0,0 +1,13 @@
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#ifndef DIMENSIONS_H
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#define DIMENSIONS_H
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#include <stdint.h>
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struct dimensions {
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uint32_t width, height;
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};
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struct dimensions dimensions_create(uint32_t, uint32_t);
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struct dimensions dimensions_reverse(struct dimensions);
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#endif

‎include/file.h

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@@ -0,0 +1,12 @@
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#ifndef FILE_H
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#define FILE_H
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#include "stdio.h"
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enum open_status { OPEN_OK = 0, OPEN_ERROR };
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enum close_status { CLOSE_OK = 0, CLOSE_ERROR };
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enum open_status file_open(FILE **, const char *, const char *);
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enum close_status file_close(FILE **);
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#endif

‎include/image.h

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@@ -0,0 +1,15 @@
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#ifndef IMAGE_H
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#define IMAGE_H
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#include "dimensions.h"
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#include "pixel.h"
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struct image {
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struct dimensions dims;
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struct pixel *data;
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};
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struct image image_create(struct dimensions);
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void image_destroy(struct image *);
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#endif

‎include/iostatus.h

+13
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@@ -0,0 +1,13 @@
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#ifndef IO_STATUS_H
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#define IO_STATUS_H
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enum read_status {
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READ_OK = 0,
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READ_INVALID_SIGNATURE,
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READ_INVALID_BITS,
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READ_INVALID_HEADER
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};
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enum write_status { WRITE_OK = 0, WRITE_ERROR };
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#endif

‎include/pixel.h

+8
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@@ -0,0 +1,8 @@
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#ifndef PIXEL_H
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#define PIXEL_H
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#include <stdint.h>
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struct pixel { uint8_t r, g, b; };
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#endif

‎include/transform.h

+8
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@@ -0,0 +1,8 @@
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#ifndef TRANSFORM_H
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#define TRANSFORM_H
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#include "image.h"
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struct image rotate_left(struct image);
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#endif

‎include/utils.h

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@@ -0,0 +1,6 @@
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#ifndef UTILS_H
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#define UTILS_H
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void err(const char *, ...);
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#endif

‎src/bmp.c

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@@ -0,0 +1,115 @@
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#include "bmp.h"
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#define FOR_HEADER(FOR_FIELD) \
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FOR_FIELD(uint16_t, bfType) \
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FOR_FIELD(uint32_t, bfileSize) \
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FOR_FIELD(uint32_t, bfReserved) \
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FOR_FIELD(uint32_t, bOffBits) \
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FOR_FIELD(uint32_t, biSize) \
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FOR_FIELD(uint32_t, biWidth) \
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FOR_FIELD(uint32_t, biHeight) \
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FOR_FIELD(uint16_t, biPlanes) \
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FOR_FIELD(uint16_t, biBitCount) \
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FOR_FIELD(uint32_t, biCompression) \
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FOR_FIELD(uint32_t, biSizeImage) \
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FOR_FIELD(uint32_t, biXPelsPerMeter) \
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FOR_FIELD(uint32_t, biYPelsPerMeter) \
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FOR_FIELD(uint32_t, biClrUsed) \
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FOR_FIELD(uint32_t, biClrImportant)
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#define DECLARE_FIELD(type, name) type name;
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struct __attribute__((packed)) header {
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FOR_HEADER(DECLARE_FIELD)
24+
};
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#undef FOR_HEADER
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#undef DECLARE_FIELD
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static const uint16_t SIGNATURE = 0x4d42;
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static const uint32_t HEADER_INFO_SIZE = 40;
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static const uint16_t BITS_PER_PIXEL = 24;
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static inline uint32_t get_padding(uint32_t width) { return width % 4; }
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static struct header generate_header(const struct dimensions dims) {
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const uint32_t head_size = sizeof(struct header);
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const uint32_t img_size = sizeof(struct pixel)
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* dims.height * (dims.width + get_padding(dims.width));
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const uint32_t file_size = head_size + img_size;
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return (struct header) {
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.bfType = SIGNATURE,
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.bfileSize = file_size,
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.bfReserved = 0,
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.bOffBits = head_size,
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.biSize = HEADER_INFO_SIZE,
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.biWidth = dims.width,
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.biHeight = dims.height,
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.biPlanes = 1,
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.biBitCount = BITS_PER_PIXEL,
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.biCompression = 0,
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.biSizeImage = img_size,
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.biXPelsPerMeter = 0,
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.biYPelsPerMeter = 0,
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.biClrUsed = 0,
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.biClrImportant = 0
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};
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}
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static enum read_status read_header(FILE *in, struct header *head) {
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enum read_status retval = READ_OK;
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if (fread(head, sizeof(struct header), 1, in) < 1 ||
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head->biSize != HEADER_INFO_SIZE || head->biPlanes != 1 ||
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head->biBitCount != BITS_PER_PIXEL || head->biCompression != 0)
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retval = READ_INVALID_HEADER;
65+
else if (head->bfType != SIGNATURE)
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retval = READ_INVALID_SIGNATURE;
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return retval;
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}
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static enum read_status read_image(FILE *in, struct image *img) {
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enum read_status retval = READ_OK;
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const struct dimensions dims = img->dims;
73+
for (uint32_t i = 0; i < dims.height; i++) {
74+
if (fread(&img->data[i * dims.width], sizeof(struct pixel), dims.width, in)
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< dims.width || fseek(in, get_padding(dims.width), SEEK_CUR) != 0) {
76+
retval = READ_INVALID_BITS;
77+
break;
78+
}
79+
}
80+
return retval;
81+
}
82+
83+
enum read_status from_bmp(FILE *in, struct image *img) {
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enum read_status retval = READ_OK;
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/* read the header of bitmap file */
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struct header head = {0};
87+
if ((retval = read_header(in, &head)) != 0)
88+
return retval;
89+
/* set file pointer to data section of a bitmap file */
90+
if (fseek(in, head.bOffBits, SEEK_SET) != 0)
91+
return READ_INVALID_BITS;
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/* read the image from the data section of a bitmap file */
93+
*img = image_create(dimensions_create(head.biWidth, head.biHeight));
94+
if ((retval = read_image(in, img)) != 0)
95+
image_destroy(img);
96+
return retval;
97+
}
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enum write_status to_bmp(FILE *out, struct image const *img) {
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enum write_status retval = WRITE_OK;
101+
/* write the header of bitmap file */
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const struct header head = generate_header(img->dims);
103+
if (fwrite(&head, sizeof(struct header), 1, out) < 1)
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return WRITE_ERROR;
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/* write data section */
106+
const struct dimensions dims = img->dims;
107+
for (uint32_t o = 0, i = 0; i < dims.height; i++) {
108+
if (fwrite(&img->data[i * dims.width], sizeof(struct pixel), dims.width, out)
109+
< dims.width || fwrite(&o, get_padding(dims.width), 1, out) < 1) {
110+
retval = WRITE_ERROR;
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break;
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}
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}
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return retval;
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}

‎src/dimensions.c

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@@ -0,0 +1,9 @@
1+
#include "dimensions.h"
2+
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struct dimensions dimensions_create(uint32_t width, uint32_t height) {
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return (struct dimensions) { width, height };
5+
}
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struct dimensions dimensions_reverse(struct dimensions dims) {
8+
return (struct dimensions) { dims.height, dims.width };
9+
}

‎src/file.c

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@@ -0,0 +1,18 @@
1+
#include "file.h"
2+
3+
enum open_status file_open(FILE **file, const char *pathname,
4+
const char *mode) {
5+
if ((*file = fopen(pathname, mode)) != NULL) {
6+
return OPEN_OK;
7+
} else {
8+
return OPEN_ERROR;
9+
}
10+
}
11+
12+
enum close_status file_close(FILE **file) {
13+
if (fclose(*file) != EOF) {
14+
return CLOSE_OK;
15+
} else {
16+
return CLOSE_ERROR;
17+
}
18+
}

‎src/image.c

+13
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@@ -0,0 +1,13 @@
1+
#include <malloc.h>
2+
3+
#include "image.h"
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5+
static inline size_t get_size(struct dimensions dims) {
6+
return dims.width * dims.height * sizeof(struct pixel);
7+
}
8+
9+
struct image image_create(struct dimensions dims) {
10+
return (struct image) { dims, malloc(get_size(dims)) };
11+
}
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void image_destroy(struct image *img) { free(img->data); }

‎src/main.c

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1+
#include <stdio.h>
2+
3+
#include "bmp.h"
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#include "file.h"
5+
#include "image.h"
6+
#include "transform.h"
7+
#include "utils.h"
8+
9+
#define EXECUTABLE "image-transformer"
10+
11+
static const char *r_msg[] = {
12+
[READ_INVALID_SIGNATURE] ="Invalid bitmap signature",
13+
[READ_INVALID_BITS] = "Invalid number of bits",
14+
[READ_INVALID_HEADER] = "Invalid bitmap header"
15+
};
16+
static const char *w_msg[] = {
17+
[WRITE_ERROR] = "Error while writing"
18+
};
19+
20+
void usage() {
21+
fprintf(stderr,
22+
"Usage: ./" EXECUTABLE " <source-image> <transformed-image>\n");
23+
}
24+
25+
int main(int argc, char *argv[]) {
26+
if (argc != 3) usage();
27+
if (argc < 3) err("Not enough arguments\n");
28+
if (argc > 3) err("Too many arguments\n");
29+
30+
FILE *in, *out;
31+
if (file_open(&in, argv[1], "rb") != 0) {
32+
err("Could not open the file for reading\n");
33+
}
34+
if (file_open(&out, argv[2], "wb") != 0) {
35+
file_close(&in);
36+
err("Could not create a file for writing\n");
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}
38+
39+
struct image source = {0};
40+
41+
enum read_status rstat = from_bmp(in, &source);
42+
file_close(&in);
43+
if (rstat != READ_OK) {
44+
fprintf(stderr, "%s\n", r_msg[rstat]);
45+
return rstat;
46+
}
47+
48+
struct image transformed = rotate_left(source);
49+
50+
enum write_status wstat = to_bmp(out, &transformed);
51+
file_close(&out);
52+
if (wstat != WRITE_OK) {
53+
image_destroy(&source);
54+
image_destroy(&transformed);
55+
fprintf(stderr, "%s\n", w_msg[wstat]);
56+
return wstat;
57+
}
58+
59+
image_destroy(&source);
60+
image_destroy(&transformed);
61+
62+
return 0;
63+
}

‎src/transform.c

+13
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@@ -0,0 +1,13 @@
1+
#include "transform.h"
2+
3+
struct image rotate_left(struct image const src) {
4+
struct dimensions dims = dimensions_reverse(src.dims);
5+
struct image img = image_create(dims);
6+
for (uint32_t i = 0; i < dims.width; i = i + 1) {
7+
for (uint32_t j = 0; j < dims.height; j = j + 1) {
8+
img.data[i + j * dims.width] =
9+
src.data[(dims.width - i - 1) * dims.height + j];
10+
}
11+
}
12+
return img;
13+
}

‎src/utils.c

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1+
#include <stdarg.h>
2+
#include <stdio.h>
3+
#include <stdlib.h>
4+
5+
#include "utils.h"
6+
7+
void err(const char *msg, ...) {
8+
va_list args;
9+
va_start(args, msg);
10+
// There is a bug in clang-tidy that makes it consider args as uninitialized
11+
// NOLINT helps suppress this message
12+
// See: https://bugs.llvm.org/show_bug.cgi?id=41311
13+
vfprintf(stderr, msg, args); // NOLINT
14+
va_end(args);
15+
exit(1);
16+
}

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