1 files changed, 54 insertions, 0 deletions
diff --git a/bmp.c b/bmp.c
new file mode 100644
index 0000000..9537704
--- /dev/null
+++ b/bmp.c
@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+
+#include "color.h"
+#include "bmp.h"
+
+#define BYTES_PER_PIXEL 3
+#define OFFSET_bfSize   2
+#define OFFSET_biWidth  18
+#define OFFSET_biHeight 22
+#define HEADERSIZE      54
+
+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) {
+	char* header;
+	uint32_t filesize;
+	
+	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;
+	
+	memcpy(header, header_template, HEADERSIZE);
+	memcpy(header + OFFSET_bfSize, &filesize, 4);
+	memcpy(header + OFFSET_biWidth, &width, 4);
+	memcpy(header + OFFSET_biHeight, &height, 4);
+	
+	if(fwrite(header, HEADERSIZE, 1, fh) != 1) {
+		fprintf(stderr, "Could not write BMP header: %s\n", strerror(errno));
+		free(header);
+		return 0;
+	}
+	
+	free(header);
+	return 1;
+}
+
+int
+bmp_write_pixel(FILE* fh, 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);
+}