Fix: BLOAD was silently misreading bitfields for BMPs with the undocumented BITMAPV3HEADER format (56-byte) headers.

It was treating them the same as the older 24-byte header, which placed the bitfield values after the header (where the colour table is), so was looking for them after the header.

Author: countingpine

changelog.txt

@@ -54,6 +54,7 @@ Version 1.01.0
 - DRAW was not unsetting the B/N qualifiers after 0-length directional commands, e.g. "R0", resulting in them being applied to the following command, e.g. DRAW "B U0D0L0R0 R10" would not draw "R10"
 - Bad code was generated when initializing integer variables with a wstring-indexing expressions
 - #723: LINE clipping now doesn't affect which (unclipped) pixels are plotted, eliminating rounding differences and correctly preserving the position of the style bits
+- BLOAD was silently misreading bitfields for BMPs with BITMAPV3HEADER format (56-byte) headers
 
 
 Version 1.00.0 (former 0.91.0):

src/gfxlib2/gfx_bload.c

@@ -227,8 +227,8 @@ static int load_bmp(FB_GFXCTX *ctx, FILE *f, void *dest, void *pal, int usenewhe
 					return FB_RTERROR_FILEIO;
 				}
 
-				if (biSize >= 108) {
-					/* Windows V4 (BITMAPV4HEADER) or later */
+				if (biSize >= 56) {
+					/* Windows V3 (BITMAPV3HEADER) or later */
 					if ((fseek(f, 4*4, SEEK_CUR)) ||
 					    (!fread_32_le(&rgba[0], f)) ||
 					    (!fread_32_le(&rgba[1], f)) ||
@@ -329,7 +329,7 @@ static int load_bmp(FB_GFXCTX *ctx, FILE *f, void *dest, void *pal, int usenewhe
 
 	expand = (biBitCount < 8) ? biBitCount : 0;
 	if (biCompression == BI_BITFIELDS) {
-		if (biSize < 108) {
+		if (biSize < 56) {
 			if (!fread(rgba, 12, 1, f))
 				return FB_RTERROR_FILEIO;
 		}