blend file thumbnailing

- uses same thumbnail system as image browser
- blend files show thumbnails in ubuntu/gnome (freedesktop spec)
- 128x128 images are embedded into the blend file header, a simple loader avoids reading the entire blend file to extract it when generating thumbnails in the file selector.
  When the image browser reads a directory it loads images and creates thumbnails, blend files embedded images are treated just like loading an image.
- the thumbnail is created from the camera view in solid mode. (no camera == no thumbnal).
- readfile/writefile.c: had to use the 'TEST' code name to save thumbnails, anything else would segfault older blender versions on load. (its not used elsewhere).

2 files changed, 139 insertions, 8 deletions

diff --git a/source/blender/imbuf/intern/thumbs.c b/source/blender/imbuf/intern/thumbs.c
index 45fbf49dbbd..8c75f5ab1ab 100644
--- a/source/blender/imbuf/intern/thumbs.c
+++ b/source/blender/imbuf/intern/thumbs.c
@@ -241,9 +241,8 @@ void IMB_thumb_makedirs()
 }
 
 /* create thumbnail for file and returns new imbuf for thumbnail */
-ImBuf* IMB_thumb_create(const char* path, ThumbSize size, ThumbSource source)
+ImBuf* IMB_thumb_create(const char* path, ThumbSize size, ThumbSource source, ImBuf *img)
 {
-	ImBuf *img = 0;
 	char uri[URI_MAX];
 	char desc[URI_MAX+22];
 	char tpath[FILE_MAX];
@@ -285,8 +284,18 @@ ImBuf* IMB_thumb_create(const char* path, ThumbSize size, ThumbSource source)
 			img = IMB_allocImBuf(0,0,32, IB_rect | IB_metadata, 0);
 			if (!img) return 0;
 		} else {
-			if (THB_SOURCE_IMAGE == source) {
-				img = IMB_loadiffname(path, IB_rect | IB_metadata);
+			if (THB_SOURCE_IMAGE == source || THB_SOURCE_BLEND == source) {
+				
+				/* only load if we didnt give an image */
+				if(img==NULL) {
+					if(THB_SOURCE_BLEND == source) {
+						img = IMB_loadblend_thumb(path);
+					}
+					else {
+						img = IMB_loadiffname(path, IB_rect | IB_metadata);
+					}
+				}
+
 				if (img != NULL) {
 					stat(path, &info);
 					sprintf(mtime, "%ld", info.st_mtime);
@@ -425,10 +434,10 @@ ImBuf* IMB_thumb_manage(const char* path, ThumbSize size, ThumbSource source)
 						IMB_thumb_delete(path, THB_NORMAL);
 						IMB_thumb_delete(path, THB_LARGE);
 						IMB_thumb_delete(path, THB_FAIL);
-						img = IMB_thumb_create(path, size, source);
+						img = IMB_thumb_create(path, size, source, NULL);
 						if(!img){
 							/* thumb creation failed, write fail thumb */
-							img = IMB_thumb_create(path, THB_FAIL, source);
+							img = IMB_thumb_create(path, THB_FAIL, source, NULL);
 							if (img) {
 								/* we don't need failed thumb anymore */
 								IMB_freeImBuf(img);
@@ -438,10 +447,10 @@ ImBuf* IMB_thumb_manage(const char* path, ThumbSize size, ThumbSource source)
 					}
 				}
 			} else {
-				img = IMB_thumb_create(path, size, source);
+				img = IMB_thumb_create(path, size, source, NULL);
 				if(!img){
 					/* thumb creation failed, write fail thumb */
-					img = IMB_thumb_create(path, THB_FAIL, source);
+					img = IMB_thumb_create(path, THB_FAIL, source, NULL);
 					if (img) {
 						/* we don't need failed thumb anymore */
 						IMB_freeImBuf(img);
diff --git a/source/blender/imbuf/intern/thumbs_blend.c b/source/blender/imbuf/intern/thumbs_blend.c
new file mode 100644
index 00000000000..f38975f1da1
--- /dev/null
+++ b/source/blender/imbuf/intern/thumbs_blend.c
@@ -0,0 +1,122 @@
+/**
+ * $Id:
+ *
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version. 
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Contributor(s): Campbell Barton.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#include <string.h>
+
+#include "zlib.h"
+
+#include "BKE_utildefines.h"
+#include "BKE_global.h"
+
+#include "IMB_imbuf_types.h"
+#include "IMB_imbuf.h"
+#include "IMB_thumbs.h"
+
+#include "MEM_guardedalloc.h"
+
+ImBuf *IMB_loadblend_thumb(const char *path)
+{
+	char buf[8];
+	int code= 0;
+	char endian, pointer_size;
+	char endian_switch;
+	int len, im_len, x, y;
+	int *rect= NULL;
+
+	gzFile gzfile;
+	
+	ImBuf *img;
+	
+	/* not necessarily a gzip */
+	gzfile = gzopen(path, "rb");
+
+	if (NULL == gzfile ) {
+		return NULL;
+	}
+	
+	/* read the blend file header */
+	if(gzread(gzfile, buf, 8) < 8)		goto thumb_error;
+	if(strncmp(buf, "BLENDER", 7))		goto thumb_error;
+	
+	if(buf[7]=='-')						pointer_size= 8;
+	else if(buf[7]=='_')				pointer_size= 4;
+	else								goto thumb_error;
+	
+	/* read the next 4 bytes, only need the first char, ignore the version */
+	/* endian and vertsion (ignored) */
+	if(gzread(gzfile, buf, 4) < 4)		goto thumb_error;
+	
+	if(buf[0]=='V')						endian= B_ENDIAN; /* big: PPC */
+	else if(buf[0]=='v')				endian= L_ENDIAN; /* little: x86 */
+	else								goto thumb_error;
+
+	while(gzread(gzfile, &code, 4) == 4) {
+		endian_switch = ((ENDIAN_ORDER != endian)) ? 1 : 0;
+		
+		if(gzread(gzfile, buf, 4) < 4)		goto thumb_error;
+		len = *( (int *)((void *)buf) );
+		if(endian_switch) SWITCH_INT(len);
+		
+		/* finally read the rest of the bhead struct, pointer and 2 ints */
+		if(gzread(gzfile, buf, pointer_size) < pointer_size)	goto thumb_error;
+		if(gzread(gzfile, buf, 8) < 8)	goto thumb_error;
+		/* we dont actually care whats in the bhead */
+		
+		if (code==REND) {
+			gzseek(gzfile, len, SEEK_CUR); /* skip to the next */
+		}
+		else {
+			break;
+		}
+	}
+	
+	/* using 'TEST' since new names segfault when loading in old blenders */
+	if(code != TEST)					goto thumb_error;
+	
+	/* finally malloc and read the data */
+	rect= MEM_mallocN(len, "imb_loadblend_thumb");
+
+	if(gzread(gzfile, rect, len) < len)	goto thumb_error;
+
+	/* read ok! */
+	gzclose(gzfile);
+	
+	x= rect[0];	y= rect[1];
+	if(endian_switch) { SWITCH_INT(x); SWITCH_INT(y); }
+
+	im_len = x * y * sizeof(int);
+
+	img = IMB_allocImBuf(x, y, 32, IB_rect | IB_metadata, 0);
+
+	memcpy(img->rect, rect + 2, im_len);
+
+	MEM_freeN(rect);
+	
+	return img;	
+
+thumb_error:
+	gzclose(gzfile);
+	if(rect) MEM_freeN(rect);
+	return NULL;
+}