146 lines
3.4 KiB
C
146 lines
3.4 KiB
C
#include "bmp.h"
|
|
#include "ff.h"
|
|
|
|
typedef struct
|
|
{
|
|
uint8_t b;
|
|
uint8_t m;
|
|
uint32_t bitmap_file_size;
|
|
uint32_t reserved;
|
|
uint32_t bitmap_data_offset;
|
|
} __attribute__((packed)) BMP_FileHeader_t;
|
|
|
|
typedef struct
|
|
{
|
|
uint32_t header_size;
|
|
uint16_t bitmap_width;
|
|
uint16_t bitmap_height;
|
|
uint16_t colour_planes;
|
|
uint16_t bits_per_pixel;
|
|
} __attribute((packed)) BMP_CoreHeader_t;
|
|
|
|
const char* BMP_FilenamePrefix = "TCIM-";
|
|
|
|
int BMP_PickFileNumber(void)
|
|
{
|
|
int maximum = -1;
|
|
DIR dp;
|
|
|
|
if(f_opendir(&dp, "/") != FR_OK)
|
|
return -1;
|
|
|
|
FILINFO finfo;
|
|
for(;;)
|
|
{
|
|
FRESULT rc = f_readdir(&dp, &finfo);
|
|
if(rc != FR_OK || finfo.fname[0] == 0)
|
|
break;
|
|
|
|
// Check if the item is a directory
|
|
if(finfo.fattrib & AM_DIR)
|
|
continue;
|
|
|
|
if(strncmp(finfo.fname, BMP_FilenamePrefix, strlen(BMP_FilenamePrefix))
|
|
== 0)
|
|
{
|
|
int number = atoi(finfo.fname + strlen(BMP_FilenamePrefix));
|
|
if(number > maximum)
|
|
maximum = number;
|
|
}
|
|
}
|
|
|
|
return maximum + 1;
|
|
}
|
|
|
|
void BMP_ConstructFilename(int number, char *buffer, unsigned int size)
|
|
{
|
|
unsigned int prefix_length = strlen(BMP_FilenamePrefix);
|
|
memcpy(buffer, BMP_FilenamePrefix, prefix_length);
|
|
for(unsigned int i = size - 6; i >= prefix_length; i--)
|
|
{
|
|
buffer[i] = '0' + (number % 10);
|
|
number /= 10;
|
|
}
|
|
memcpy(buffer + size - 5, ".BMP", 5);
|
|
}
|
|
|
|
int BMP_Save(uint8_t *data, int width, int height)
|
|
{
|
|
FATFS fs;
|
|
FIL fp;
|
|
FRESULT rc;
|
|
unsigned int bw;
|
|
|
|
rc = f_mount(&fs, "", 0);
|
|
if(rc)
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
int file_number = BMP_PickFileNumber();
|
|
if(file_number == -1)
|
|
return -2;
|
|
char filename[13];
|
|
BMP_ConstructFilename(file_number, filename, sizeof(filename));
|
|
|
|
rc = f_open(&fp, filename, FA_WRITE | FA_CREATE_NEW);
|
|
if(rc)
|
|
{
|
|
return -3;
|
|
}
|
|
|
|
// Rows must be padded to a multiple of 4 bytes
|
|
int row_size = width / 8;
|
|
int padding_length = (4 - (row_size % 4)) % 4;
|
|
uint8_t padding_bytes[4] = {0};
|
|
row_size += padding_length;
|
|
|
|
BMP_FileHeader_t file_header =
|
|
{
|
|
.b = 'B',
|
|
.m = 'M',
|
|
.bitmap_file_size = 14 + 12 + 6 + row_size * height,
|
|
.bitmap_data_offset = 14 + 12 + 6
|
|
};
|
|
|
|
// Use the simplest possible header
|
|
BMP_CoreHeader_t core_header =
|
|
{
|
|
.header_size = 12,
|
|
.bitmap_width = width,
|
|
.bitmap_height = height,
|
|
.colour_planes = 1,
|
|
.bits_per_pixel = 1
|
|
};
|
|
|
|
// At one bit per pixel, we need a colour table
|
|
uint8_t colour_table[6] =
|
|
{
|
|
0xff, 0xff, 0xff,
|
|
0x00, 0x00, 0x00
|
|
};
|
|
|
|
if(f_write(&fp, &file_header, sizeof(file_header), &bw) != FR_OK)
|
|
return -4;
|
|
if(f_write(&fp, &core_header, sizeof(core_header), &bw) != FR_OK)
|
|
return -4;
|
|
if(f_write(&fp, &colour_table, sizeof(colour_table), &bw) != FR_OK)
|
|
return -4;
|
|
|
|
// BMPs are stored with their rows from the bottom upwards
|
|
for(int y = height - 1; y >= 0; y--)
|
|
{
|
|
uint8_t *row = data + y * (width / 8);
|
|
if(f_write(&fp, row, width / 8, &bw) != FR_OK)
|
|
return -4;
|
|
if(padding_length != 0)
|
|
{
|
|
if(f_write(&fp, padding_bytes, padding_length, &bw) != FR_OK)
|
|
return -4;
|
|
}
|
|
}
|
|
|
|
f_close(&fp);
|
|
|
|
return file_number;
|
|
}
|