fix all_pages

tested with pdf, need to test gif

TODO

@@ -7,20 +7,24 @@
 
   try with convert, get a one-band png, no alpha at all
 
-- try:
-
-	$ time vips magickload nipguide.pdf x.tif
-VipsForeignLoad: images do not match
-vips__region_start: start function failed for image nipguide.pdf
-VipsRegion: images do not match in pixel size
-
-
-- try loading one page of a PDF with the new magickload
-
 - try loading one page of a GIF with the new magickload
 
 - try loading a DICOM
 
+- add tests:
+
+	load 1 page of a pdf/gif
+	load all frames from a pdf/gif
+	svg alpha
+	density
+	png alpha
+	dicom?
+	all with file and buffer source
+
+
+
+
+
 - add more webp tests to py suite
 
 - try moving some more of the CLI tests to py

libvips/foreign/magick7load.c

@@ -563,7 +563,18 @@ vips_foreign_load_magick7_file_header( VipsForeignLoad *load )
 	vips_strncpy( magick7->image_info->filename, file->filename, 
 		MagickPathExtent );
 
-	magick7->image = PingImage( magick7->image_info, magick7->exception );
+	/* If we're reading all_frames, we can't just ping, we have to read the
+	 * whole thing, since ping does not set up the image list.
+	 *
+	 * Hopefully, all_frames is only used rarely. 
+	 */
+	if( magick7->all_frames ) 
+		magick7->image = 
+			ReadImage( magick7->image_info, magick7->exception );
+	else
+		magick7->image = 
+			PingImage( magick7->image_info, magick7->exception );
+
 	if( !magick7->image ) {
 		vips_foreign_load_magick7_error( magick7 ); 
 		return( -1 );
@@ -579,8 +590,10 @@ vips_foreign_load_magick7_file_header( VipsForeignLoad *load )
 		return( -1 );
 
 	/* No longer need the ping result, and we'll replace ->image with Read
-	 * when we do that later.
+	 * when we do that later. If we're reading all_frames, we will reuse
+	 * the read, so don't free. 
 	 */
+	if( !magick7->all_frames ) 
 		VIPS_FREEF( DestroyImageList, magick7->image );
 
 	VIPS_SETSTR( load->out->filename, file->filename );
@@ -597,12 +610,15 @@ vips_foreign_load_magick7_file_load( VipsForeignLoad *load )
 	printf( "vips_foreign_load_magick7_file_load: %p\n", load ); 
 #endif /*DEBUG*/
 
+	if( !magick7->all_frames ) {
 		g_assert( !magick7->image ); 
-	magick7->image = ReadImage( magick7->image_info, magick7->exception );
+		magick7->image = 
+			ReadImage( magick7->image_info, magick7->exception );
 		if( !magick7->image ) {
 			vips_foreign_load_magick7_error( magick7 ); 
 			return( -1 );
 		}
+	}
 
 	if( vips_foreign_load_magick7_load( magick7 ) )
 		return( -1 );
@@ -688,9 +704,18 @@ vips_foreign_load_magick7_buffer_header( VipsForeignLoad *load )
 	printf( "vips_foreign_load_magick7_buffer_header: %p\n", load ); 
 #endif /*DEBUG*/
 
+	/* See comments on file load above ^^ for notes on the all_frames
+	 * handling.
+	 */
+	if( magick7->all_frames ) 
+		magick7->image = BlobToImage( magick7->image_info, 
+			magick7_buffer->buf->data, magick7_buffer->buf->length,
+			magick7->exception );
+	else 
 		magick7->image = PingBlob( magick7->image_info, 
 			magick7_buffer->buf->data, magick7_buffer->buf->length,
 			magick7->exception );
+
 	if( !magick7->image ) {
 		vips_foreign_load_magick7_error( magick7 ); 
 		return( -1 );
@@ -708,6 +733,7 @@ vips_foreign_load_magick7_buffer_header( VipsForeignLoad *load )
 	/* No longer need the ping result, and we'll replace ->image with Read
 	 * when we do that later.
 	 */
+	if( !magick7->all_frames ) 
 		VIPS_FREEF( DestroyImageList, magick7->image );
 
 	return( 0 );
@@ -724,6 +750,9 @@ vips_foreign_load_magick7_buffer_load( VipsForeignLoad *load )
 	printf( "vips_foreign_load_magick7_buffer_load: %p\n", load ); 
 #endif /*DEBUG*/
 
+	if( !magick7->all_frames ) {
+		g_assert( !magick7->image ); 
+
 		magick7->image = BlobToImage( magick7->image_info, 
 			magick7_buffer->buf->data, magick7_buffer->buf->length,
 			magick7->exception );
@@ -731,6 +760,7 @@ vips_foreign_load_magick7_buffer_load( VipsForeignLoad *load )
 			vips_foreign_load_magick7_error( magick7 ); 
 			return( -1 );
 		}
+	}
 
 	if( vips_foreign_load_magick7_load( magick7 ) )
 		return( -1 );