[pixbuf] Enable PNG format by default

Enable IMAGE_PNG (but not IMAGE_PNM) by default, and drag in the
relevant objects only when image_pixbuf() is present in the binary.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/config/config.c

 #ifdef IMAGE_SDI
 REQUIRE_OBJECT ( sdi );
 #endif
-#ifdef IMAGE_PNM
-REQUIRE_OBJECT ( pnm );
-#endif
-#ifdef IMAGE_PNG
-REQUIRE_OBJECT ( png );
-#endif
 
 /*
  * Drag in all requested commands

src/config/config_pixbuf.c

+/*
+ * 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.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <config/general.h>
+
+/** @file
+ *
+ * Pixel buffer file format configuration
+ *
+ */
+
+PROVIDE_REQUIRING_SYMBOL();
+
+#ifdef IMAGE_PNM
+REQUIRE_OBJECT ( pnm );
+#endif
+#ifdef IMAGE_PNG
+REQUIRE_OBJECT ( png );
+#endif

src/config/general.h

 //#define	IMAGE_EFI		/* EFI image support */
 //#define	IMAGE_SDI		/* SDI image support */
 //#define	IMAGE_PNM		/* PNM image support */
-//#define	IMAGE_PNG		/* PNG image support */
+#define	IMAGE_PNG		/* PNG image support */
 #define	IMAGE_DER		/* DER image support */
 #define	IMAGE_PEM		/* PEM image support */
 

src/core/image.c

 
 	return 0;
 }
-
-/**
- * Create pixel buffer from image
- *
- * @v image		Image
- * @v pixbuf		Pixel buffer to fill in
- * @ret rc		Return status code
- */
-int image_pixbuf ( struct image *image, struct pixel_buffer **pixbuf ) {
-	int rc;
-
-	/* Check that this image can be used to create a pixel buffer */
-	if ( ! ( image->type && image->type->pixbuf ) )
-		return -ENOTSUP;
-
-	/* Try creating pixel buffer */
-	if ( ( rc = image->type->pixbuf ( image, pixbuf ) ) != 0 ) {
-		DBGC ( image, "IMAGE %s could not create pixel buffer: %s\n",
-		       image->name, strerror ( rc ) );
-		return rc;
-	}
-
-	return 0;
-}

src/core/pixbuf.c

  */
 
 #include <stdlib.h>
+#include <errno.h>
 #include <ipxe/umalloc.h>
+#include <ipxe/image.h>
 #include <ipxe/pixbuf.h>
 
 /**
  err_alloc_pixbuf:
 	return NULL;
 }
+
+/**
+ * Create pixel buffer from image
+ *
+ * @v image		Image
+ * @v pixbuf		Pixel buffer to fill in
+ * @ret rc		Return status code
+ */
+int image_pixbuf ( struct image *image, struct pixel_buffer **pixbuf ) {
+	int rc;
+
+	/* Check that this image can be used to create a pixel buffer */
+	if ( ! ( image->type && image->type->pixbuf ) )
+		return -ENOTSUP;
+
+	/* Try creating pixel buffer */
+	if ( ( rc = image->type->pixbuf ( image, pixbuf ) ) != 0 ) {
+		DBGC ( image, "IMAGE %s could not create pixel buffer: %s\n",
+		       image->name, strerror ( rc ) );
+		return rc;
+	}
+
+	return 0;
+}
+
+/* Drag in objects via image_pixbuf() */
+REQUIRING_SYMBOL ( image_pixbuf );
+
+/* Drag in pixel buffer image formats */
+REQUIRE_OBJECT ( config_pixbuf );

src/include/ipxe/errfile.h

 #define ERRFILE_ansicoldef	       ( ERRFILE_CORE | 0x001e0000 )
 #define ERRFILE_fault		       ( ERRFILE_CORE | 0x001f0000 )
 #define ERRFILE_blocktrans	       ( ERRFILE_CORE | 0x00200000 )
+#define ERRFILE_pixbuf		       ( ERRFILE_CORE | 0x00210000 )
 
 #define ERRFILE_eisa		     ( ERRFILE_DRIVER | 0x00000000 )
 #define ERRFILE_isa		     ( ERRFILE_DRIVER | 0x00010000 )