diff options
Diffstat (limited to 'bmp.c')
| -rw-r--r-- | bmp.c | 72 |
1 files changed, 64 insertions, 8 deletions
@@ -13,27 +13,33 @@ #define OFFSET_biHeight 22 #define HEADERSIZE 54 +static size_t +bmp_calc_padding(int32_t width) { + return (4 - (width % 4)) % 4; +} + static const char* header_template = "BM \0\0\0\0\x36\0\0\0\x28\0\0\0 \x01\0\x18\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; -int -bmp_write_header(FILE* fh, int32_t width, int32_t height) { +static int +bmp_write_header(bmp_write_handle_t* bmph) { char* header; uint32_t filesize; + int32_t height; if(!(header = malloc(HEADERSIZE))) { fputs("Could not allocate memory for BMP header.\n", stderr); return 0; } - filesize = HEADERSIZE + (width * height * BYTES_PER_PIXEL); - height *= -1; + filesize = HEADERSIZE + (bmph->width * BYTES_PER_PIXEL + bmph->line_padding) * bmph->height; + height = -(bmph->height); memcpy(header, header_template, HEADERSIZE); memcpy(header + OFFSET_bfSize, &filesize, 4); - memcpy(header + OFFSET_biWidth, &width, 4); + memcpy(header + OFFSET_biWidth, &(bmph->width), 4); memcpy(header + OFFSET_biHeight, &height, 4); - if(fwrite(header, HEADERSIZE, 1, fh) != 1) { + if(fwrite(header, HEADERSIZE, 1, bmph->fh) != 1) { fprintf(stderr, "Could not write BMP header: %s\n", strerror(errno)); free(header); return 0; @@ -43,12 +49,62 @@ bmp_write_header(FILE* fh, int32_t width, int32_t height) { return 1; } +bmp_write_handle_t* +bmp_create(const char* fn, int32_t width, int32_t height) { + FILE* fh = NULL; + bmp_write_handle_t* rv; + + if(!(fh = fopen(fn, "wb"))) { + return NULL; + } + + if(!(rv = malloc(sizeof(bmp_write_handle_t)))) { + fclose(fh); + return NULL; + } + + rv->fh = fh; + rv->width = width; + rv->height = height; + rv->line_left = width; + rv->line_padding = bmp_calc_padding(width); + + if(!bmp_write_header(rv)) { + fclose(fh); + free(rv); + return NULL; + } + + return rv; +} + +static const char* padding = "\0\0\0\0"; + int -bmp_write_pixel(FILE* fh, color_t col) { +bmp_write_pixel(bmp_write_handle_t* bmph, color_t col) { uint8_t pixel[3]; pixel[0] = col.b; pixel[1] = col.g; pixel[2] = col.r; - return (fwrite(pixel, 3, 1, fh) == 1); + if(fwrite(pixel, 3, 1, bmph->fh) != 1) { + return 0; + } + + if(--(bmph->line_left) == 0) { + bmph->line_left = bmph->width; + + return (fwrite(padding, bmph->line_padding, 1, bmph->fh) == 1); + } + + return 1; +} + +void +bmp_destroy(bmp_write_handle_t* bmph) { + if(bmph->fh) { + fclose(bmph->fh); + } + + free(bmph); } |