fix binary ppm read for some width

configure.ac

@@ -1322,8 +1322,9 @@ VIPS_CFLAGS="$VIPS_DEBUG_FLAGS $VIPS_CFLAGS"
 VIPS_INCLUDES="$ZLIB_INCLUDES $PNG_INCLUDES $TIFF_INCLUDES $JPEG_INCLUDES $NIFTI_INCLUDES" 
 VIPS_LIBS="$ZLIB_LIBS $HEIF_LIBS $MAGICK_LIBS $SPNG_LIBS $PNG_LIBS $IMAGEQUANT_LIBS $TIFF_LIBS $JPEG_LIBS $GTHREAD_LIBS $GIO_LIBS $REQUIRED_LIBS $EXPAT_LIBS $PANGOFT2_LIBS $GSF_LIBS $FFTW_LIBS $ORC_LIBS $LCMS_LIBS $GIFLIB_LIBS $RSVG_LIBS $NIFTI_LIBS $PDFIUM_LIBS $POPPLER_LIBS $OPENEXR_LIBS $OPENSLIDE_LIBS $CFITSIO_LIBS $LIBWEBP_LIBS $LIBWEBPMUX_LIBS $MATIO_LIBS $EXIF_LIBS -lm"
 
-# autoconf hates multi-line AC_SUBST
+# autoconf hates multi-line AC_SUBST so we have to have another copy of this
-VIPS_CONFIG="native win32: $vips_os_win32, native OS X: $vips_os_darwin, open files in binary mode: $vips_binary_open, enable debug: $enable_debug, enable deprecated library components: $enable_deprecated, enable docs with gtkdoc: $enable_gtk_doc, gobject introspection: $found_introspection, enable radiance support: $with_radiance, enable analyze support: $with_analyze, enable PPM support: $with_ppm, use fftw3 for FFT: $with_fftw, Magick package: $with_magickpackage, Magick API version: $magick_version, load with libMagick: $enable_magickload, save with libMagick: $enable_magicksave, accelerate loops with orc: $with_orc, ICC profile support with lcms: $with_lcms, file import with niftiio: $with_nifti, file import with libheif: $with_heif, file import with OpenEXR: $with_OpenEXR, file import with OpenSlide: $with_openslide, file import with matio: $with_matio, PDF import with PDFium: $with_pdfium, PDF import with poppler-glib: $with_poppler, SVG import with librsvg-2.0: $with_rsvg, zlib: $with_zlib, file import with cfitsio: $with_cfitsio, file import/export with libwebp: $with_libwebp, text rendering with pangoft2: $with_pangoft2, file import/export with libpng: $with_png, support 8bpp PNG quantisation: $with_imagequant, file import/export with libtiff: $with_tiff, file import/export with giflib: $with_giflib, file import/export with libjpeg: $with_jpeg, image pyramid export: $with_gsf, use libexif to load/save JPEG metadata: $with_libexif"
+# thing
+VIPS_CONFIG="native win32: $vips_os_win32, native OS X: $vips_os_darwin, open files in binary mode: $vips_binary_open, enable debug: $enable_debug, enable deprecated library components: $enable_deprecated, enable docs with gtkdoc: $enable_gtk_doc, gobject introspection: $found_introspection, enable radiance support: $with_radiance, enable analyze support: $with_analyze, enable PPM support: $with_ppm, use fftw3 for FFT: $with_fftw, Magick package: $with_magickpackage, Magick API version: $magick_version, load with libMagick: $enable_magickload, save with libMagick: $enable_magicksave, accelerate loops with orc: $with_orc, ICC profile support with lcms: $with_lcms, file import with niftiio: $with_nifti, file import with libheif: $with_heif, file import with OpenEXR: $with_OpenEXR, file import with OpenSlide: $with_openslide, file import with matio: $with_matio, PDF import with PDFium: $with_pdfium, PDF import with poppler-glib: $with_poppler, SVG import with librsvg-2.0: $with_rsvg, zlib: $with_zlib, file import with cfitsio: $with_cfitsio, file import/export with libwebp: $with_libwebp, text rendering with pangoft2: $with_pangoft2, file import/export with libpng: $with_png, support 8bpp PNG quantisation: $with_imagequant, file import/export with libtiff: $with_tiff, file import/export with giflib: $with_giflib, file import/export with libjpeg: $with_jpeg, image pyramid export: $with_gsf, use libexif to load/save JPEG metadata: $with_libexif, file import/export with libspng: $with_libspng"
 
 AC_SUBST(VIPS_LIBDIR)
 
@@ -1382,6 +1383,7 @@ AC_OUTPUT([
 	fuzz/Makefile
 ])
 
+# also add any new items to VIPS_CONFIG above
 AC_MSG_RESULT([dnl
 * build options
 native win32:				$vips_os_win32

libvips/foreign/ppmload.c

@@ -492,23 +492,22 @@ vips_foreign_load_ppm_generate_1bit_binary( VipsRegion *or,
 	VipsImage *image = or->im;
 
 	int x, y;
-	int bits;
 
-	bits = VIPS_SBUF_GETC( ppm->sbuf );
 	for( y = 0; y < r->height; y++ ) {
 		VipsPel *q = VIPS_REGION_ADDR( or, 0, r->top + y );
 
+		int bits;
+
+		/* Not needed, but stop a compiler warning.
+		 */
+		bits = 0;
+
 		for( x = 0; x < image->Xsize; x++ ) {
+			if( (x & 7) == 0 )
+				bits = VIPS_SBUF_GETC( ppm->sbuf );
 			q[x] = (bits & 128) ? 0 : 255;
 			bits = VIPS_LSHIFT_INT( bits, 1 );
-			if( (x & 7) == 7 )
-				bits = VIPS_SBUF_GETC( ppm->sbuf );
 		}
-
-		/* Skip any unaligned bits at end of line.
-		 */
-		if( (x & 7) != 0 )
-			bits = VIPS_SBUF_GETC( ppm->sbuf );
 	}
 
 	return( 0 );

libvips/foreign/ppmsave.c

@@ -161,7 +161,7 @@ vips_foreign_save_ppm_line_binary_squash( VipsForeignSavePpm *ppm,
 	for( x = 0; x < image->Xsize; x++ ) {
 		bits = VIPS_LSHIFT_INT( bits, 1 );
 		n_bits += 1;
-		bits |= p[x] ? 0 : 1;
+		bits |= p[x] > 128 ? 0 : 1;
 
 		if( n_bits == 8 ) {
 			if( VIPS_TARGET_PUTC( ppm->target, bits ) )