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reformat and better bmp all in one function

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klemek
2025-06-03 19:41:53 +02:00
parent 43927dadf4
commit 9a819f3a81
5 changed files with 92 additions and 122 deletions
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src/bmp.c
+74 -81
View File
@@ -1,97 +1,90 @@
#include "bmp.h"
#include <stdio.h>
#include <stdlib.h>
void write_str(char *buffer, int offset, int size, char *value, int value_offset)
{
int i;
for (i = 0; i < size; i++)
{
buffer[offset + i] = value[i];
}
#define HEADER_SIZE 54
void write_str(char *buffer, int offset, int size, char *value) {
int i;
for (i = 0; i < size; i++) {
buffer[offset + i] = value[i];
}
}
void write_num(char *buffer, int offset, int size, unsigned long value)
{
int i;
for (i = 0; i < size; i++)
{
buffer[offset + i] = (char)((value >> (8 * i)) & 0xFFu);
}
void write_num(char *buffer, int offset, int size, unsigned long value) {
int i;
for (i = 0; i < size; i++) {
buffer[offset + i] = (char)((value >> (8 * i)) & 0xFFu);
}
}
void write_nul(char *buffer, int offset, int size)
{
int i;
for (i = 0; i < size; i++)
{
buffer[offset + i] = 0;
}
void write_nul(char *buffer, int offset, int size) {
int i;
for (i = 0; i < size; i++) {
buffer[offset + i] = 0;
}
}
char *bmp_header(unsigned long width, unsigned long height, unsigned long color_depth)
{
char *output = (char *)malloc(HEADER_SIZE);
char *bmp_header(unsigned long width, unsigned long height,
unsigned int color_depth) {
char *output = (char *)malloc(HEADER_SIZE);
write_str(output, 0x00, 0x02, "BM", 0); // 0x00(2) BM
write_num(output, 0x02, 0x04, HEADER_SIZE + width * height * color_depth); // 0x02(4) file size
write_nul(output, 0x06, 0x04); // 0x06(4) application reserved
write_num(output, 0x0A, 0x04, HEADER_SIZE); // 0x0A(4) data offset
write_num(output, 0x0E, 0x04, 40); // 0x0E(4) DIB header size
write_num(output, 0x12, 0x04, width); // 0x12(4) width
write_num(output, 0x16, 0x04, height); // 0x16(4) height
write_num(output, 0x1A, 0x04, 1); // 0x1A(2) color panes
write_num(output, 0x1C, 0x02, color_depth * 8); // 0x1C(2) bits per pixel
write_nul(output, 0x1E, 0x04); // 0x1E(4) BI_RGB, no compression
write_num(output, 0x22, 0x04, width * height * color_depth); // 0x22(4) size of raw bitmap data
write_num(output, 0x26, 0x04, 2835); // 0x26(4) horizontal print resolution
write_num(output, 0x2A, 0x04, 2835); // 0x2A(4) vertical print resolution
write_nul(output, 0x2E, 0x04); // 0x2E(4) color in palette
write_nul(output, 0x32, 0x04); // 0x32(4) 0 important colors
write_str(output, 0x00, 0x02, "BM"); // 0x00(2) BM
write_num(output, 0x02, 0x04,
HEADER_SIZE + width * height * color_depth); // 0x02(4) file size
write_nul(output, 0x06, 0x04); // 0x06(4) application reserved
write_num(output, 0x0A, 0x04, HEADER_SIZE); // 0x0A(4) data offset
write_num(output, 0x0E, 0x04, 40); // 0x0E(4) DIB header size
write_num(output, 0x12, 0x04, width); // 0x12(4) width
write_num(output, 0x16, 0x04, height); // 0x16(4) height
write_num(output, 0x1A, 0x04, 1); // 0x1A(2) color panes
write_num(output, 0x1C, 0x02, color_depth * 8); // 0x1C(2) bits per pixel
write_nul(output, 0x1E, 0x04); // 0x1E(4) BI_RGB, no compression
write_num(output, 0x22, 0x04,
width * height * color_depth); // 0x22(4) size of raw bitmap data
write_num(output, 0x26, 0x04, 2835); // 0x26(4) horizontal print resolution
write_num(output, 0x2A, 0x04, 2835); // 0x2A(4) vertical print resolution
write_nul(output, 0x2E, 0x04); // 0x2E(4) color in palette
write_nul(output, 0x32, 0x04); // 0x32(4) 0 important colors
return output;
return output;
}
unsigned long bmp_data_line_length(unsigned long width, unsigned long color_depth)
{
unsigned long line_offset = (width * color_depth) % 4;
unsigned long line_padding = line_offset > 0 ? 4 - line_offset : 0;
return width * color_depth + line_padding;
unsigned long bmp_data_line_length(unsigned long width,
unsigned int color_depth) {
unsigned long line_offset = (width * color_depth) % 4;
unsigned long line_padding = line_offset > 0 ? 4 - line_offset : 0;
return width * color_depth + line_padding;
}
char *bmp_data_line(unsigned long width, unsigned long color_depth, char *data, unsigned long data_offset)
{
unsigned long line_offset = (width * color_depth) % 4;
unsigned long line_padding = line_offset > 0 ? 4 - line_offset : 0;
unsigned long line_length = width * color_depth + line_padding;
char *output = (char *)malloc(line_length);
write_str(output, 0, width * color_depth, data, data_offset);
if (line_padding > 0)
{
write_nul(output, width * color_depth, line_padding);
}
return output;
char *bmp_data_line(unsigned long width, unsigned int color_depth, char *data) {
unsigned long line_offset = (width * color_depth) % 4;
unsigned long line_padding = line_offset > 0 ? 4 - line_offset : 0;
unsigned long line_length = width * color_depth + line_padding;
char *output = (char *)malloc(line_length);
write_str(output, 0, width * color_depth, data);
if (line_padding > 0) {
write_nul(output, width * color_depth, line_padding);
}
return output;
}
unsigned long bmp_data_length(unsigned long width, unsigned long height, unsigned long color_depth)
{
return bmp_data_line_length(width, color_depth) * height;
}
char *bmp_data(unsigned long width, unsigned long height, unsigned long color_depth, char *data)
{
unsigned long line_offset = (width * color_depth) % 4;
unsigned long line_padding = line_offset > 0 ? 4 - line_offset : 0;
unsigned long line_length = width * color_depth + line_padding;
char *output = (char *)malloc(height * line_length);
int y, offset, offset_data;
for (y = 0; y < height; y++)
{
offset = y * line_length;
offset_data = (height - y - 1) * color_depth * width;
write_str(output, offset, width * color_depth, data, offset_data);
if (line_padding > 0)
{
write_nul(output, offset + width * color_depth, line_padding);
}
}
return output;
void bmp_generate(unsigned long width, unsigned long height,
unsigned int color_depth, char *file_path,
void generate_line(unsigned long y, char *data_buffer)) {
FILE *fptr;
fptr = fopen(file_path, "w");
char *header = bmp_header(width, height, color_depth);
fwrite(header, HEADER_SIZE, 1, fptr);
free(header);
int y;
char *data_buffer = malloc(width * color_depth);
char *line_buffer = NULL;
for (y = 0; y < height; y++) {
generate_line(height - y - 1, data_buffer);
line_buffer = bmp_data_line(width, color_depth, data_buffer);
fwrite(line_buffer, bmp_data_line_length(width, color_depth), 1, fptr);
free(line_buffer);
}
free(data_buffer);
fclose(fptr);
}
src/bmp.h
+3 -9
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@@ -1,9 +1,3 @@
#include <stdlib.h>
#define HEADER_SIZE 54
char *bmp_header(unsigned long width, unsigned long height, unsigned long color_depth);
unsigned long bmp_data_line_length(unsigned long width, unsigned long color_depth);
char *bmp_data_line(unsigned long width, unsigned long color_depth, char *data, unsigned long data_offset);
unsigned long bmp_data_length(unsigned long width, unsigned long height, unsigned long color_depth);
char *bmp_data(unsigned long width, unsigned long height, unsigned long color_depth, char *data);
void bmp_generate(unsigned long width, unsigned long height,
unsigned int color_depth, char *file_path,
void generate_line(unsigned long y, char *data_buffer));
src/main.c
+14 -21
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@@ -1,23 +1,16 @@
#include "main.h"
#include <string.h>
int main()
{
FILE *fptr;
fptr = fopen("test.bmp", "w");
char *header = bmp_header(WIDTH, HEIGHT, COLOR_DEPTH);
fwrite(header, HEADER_SIZE, 1, fptr);
free(header);
int y;
char *data = malloc(WIDTH * COLOR_DEPTH);
char *data_line = NULL;
for (y = 0; y < HEIGHT; y++)
{
memset(data, HEIGHT - y - 1, WIDTH * COLOR_DEPTH);
data_line = bmp_data_line(WIDTH, COLOR_DEPTH, data, 0);
fwrite(data_line, bmp_data_line_length(WIDTH, COLOR_DEPTH), 1, fptr);
free(data_line);
}
free(data);
fclose(fptr);
return 0;
#include "bmp.h"
#define WIDTH 256
#define HEIGHT 256
#define COLOR_DEPTH 3
void generate_line(unsigned long y, char *data_buffer) {
memset(data_buffer, y, WIDTH * COLOR_DEPTH);
}
int main() {
bmp_generate(WIDTH, HEIGHT, COLOR_DEPTH, "test.bmp", generate_line);
return 0;
}
src/main.h
-8
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@@ -1,8 +0,0 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "bmp.h"
#define WIDTH 256
#define HEIGHT 256
#define COLOR_DEPTH 3