started bitmap support

1 files changed, 111 insertions, 0 deletions

diff --git a/src/bmp.c b/src/bmp.c
new file mode 100644
index 0000000..9f79a9f
--- /dev/null
+++ b/src/bmp.c
@@ -0,0 +1,111 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "meh.h"
+
+unsigned short getshort(FILE *f){
+	unsigned short ret;
+	ret = getc(f);
+	ret = ret | (getc(f) << 8);
+	return ret;
+}
+
+unsigned long getlong(FILE *f){
+	unsigned short ret;
+	ret = getc(f);
+	ret = ret | (getc(f) << 8);
+	ret = ret | (getc(f) << 16);
+	ret = ret | (getc(f) << 24);
+	return ret;
+}
+
+struct rgb_t{
+	unsigned char r, g, b;
+};
+
+struct bmp_t{
+	struct image img;
+	unsigned long bitmapoffset;
+	int bpp;
+	int ncolors;
+	struct rgb_t *colours;
+};
+
+struct image *bmp_open(FILE *f){
+	struct bmp_t *b;
+	unsigned long headerend;
+	
+	rewind(f);
+	if(getc(f) != 'B' || getc(f) != 'M')
+		return NULL;
+
+	b = malloc(sizeof(struct bmp_t));
+	b->img.f = f;
+
+	fseek(f, 10, SEEK_SET);
+	b->bitmapoffset = getlong(f);
+
+	fseek(f, 18, SEEK_SET);
+	b->img.width = getlong(f);
+	b->img.height = getlong(f);
+
+	fseek(f, 14, SEEK_SET);
+	headerend = 14 + getlong(f);
+
+	fseek(f, 28, SEEK_SET);
+	b->bpp = getshort(f);
+
+	if(b->bpp == 24){
+		b->ncolors = 0;
+	}else{
+		int i;
+		fseek(f, 46, SEEK_SET);
+		if(!(b->ncolors = getlong(f))){
+			b->ncolors = 1 << b->bpp;
+		}
+		
+		b->colours = malloc(b->ncolors * sizeof(struct rgb_t));
+		fseek(f, headerend, SEEK_SET);
+		for(i = 0; i < b->ncolors; i++){
+			b->colours[i].b = getc(f);
+			b->colours[i].g = getc(f);
+			b->colours[i].r = getc(f);
+		}
+	}
+
+	return (struct image *)b;
+}
+
+int bmp_read(struct image *img){
+	struct bmp_t *b = (struct bmp_t *)img;
+	FILE *f = img->f;
+
+	fseek(f, b->bitmapoffset, SEEK_SET);
+	if(b->bpp == 24){
+		int i, x, y;
+		int row = img->width * 3;
+		i = img->height * row;
+		for(y = img->height; y; y--){
+			i -= row;
+			for(x = 0; x < img->width * 3; x+=3){
+				img->buf[i + x + 2] = getc(f);
+				img->buf[i + x + 1] = getc(f);
+				img->buf[i + x + 0] = getc(f);
+			}
+			if(x & 3){
+				fseek(f, 4 - (x & 3), SEEK_CUR);
+			}
+		}
+	}else{
+		//TODO
+	}
+
+	return 0;
+}
+
+struct imageformat gif = {
+	bmp_open,
+	bmp_read
+};
+