diff --git a/doc/How-it-opens-files.md b/doc/How-it-opens-files.md
index cdc68440..59104f20 100644
--- a/doc/How-it-opens-files.md
+++ b/doc/How-it-opens-files.md
@@ -70,7 +70,7 @@ image decompress happens on the first pixel access.
You can control this process with environment variables, command-line
flags and API calls as you choose, see
-`vips_image_new_from_file()`.
+vips_image_new_from_file().
They let you set the threshold at which libvips switches between memory
and disc and where on disc the temporary files are held.
@@ -115,28 +115,6 @@ this hint set, libvips will hook up the pipeline of operations directly
to the read-a-line interface provided by the image library, and add a
small cache of the most recent 100 or so lines.
-There's an extra unbuffered sequential mode where vips does not keep a
-cache of recent lines. This gives a useful memory saving for operations
-like copy which do not need any non-local access.
-
-# Debugging
-
-There are a few flags you can use to find out what libvips is doing.
-
-`--vips-leak` This makes libvips test for leaks on program exit. It checks
-for images which haven't been closed and also (usefully) shows the memory
-high-water mark. It counts all memory allocated in libvips for pixel buffers.
-
-`--vips-progress` This makes libvips show a crude progress bar for every major
-image loop, with destination and elapsed time. You can see whether images
-are going to disc or to memory and how long the decompression is taking.
-
-`--vips-cache-trace This shows a line for every vips operation that executes,
-with arguments. It's part of vips8, so it doesn't display vips7 operations,
-sadly.
-
-# Summary
-
-libvips tries hard to do the quickest thing in every case, but will
-sometimes fail. You can prod it in the right direction with a mixture of
-hints and flags to the load system.
+This is done automatically in command-line operation. In programs, you need to
+set `access` to #VIPS_ACCESS_SEQUENTIAL in calls to functions like
+vips_image_new_from_file().
diff --git a/doc/How-it-opens-files.xml b/doc/How-it-opens-files.xml
index 6c3b6698..fd03df88 100644
--- a/doc/How-it-opens-files.xml
+++ b/doc/How-it-opens-files.xml
@@ -49,7 +49,7 @@
For small images (less than 100mb when decompressed), libvips allocates a large area of memory and decompresses the entire image to that. It then uses that memory buffer of decompressed pixels to feed the pipeline. For large images, libvips decompresses to a temporary file on disc, then loads that temporary file in direct access mode (see above). Note that on open libvips just reads the image header and is quick: the image decompress happens on the first pixel access.
- You can control this process with environment variables, command-line flags and API calls as you choose, see vips_image_new_from_file(). They let you set the threshold at which libvips switches between memory and disc and where on disc the temporary files are held.
+ You can control this process with environment variables, command-line flags and API calls as you choose, see vips_image_new_from_file(). They let you set the threshold at which libvips switches between memory and disc and where on disc the temporary files are held.
This is the slowest and most memory-hungry way to read files, but it’s unavoidable for many file formats. Unless you can use the next one!
@@ -88,7 +88,7 @@ $ vips shrink fred.png jim.png 10 10
To help in this case, libvips has a hint you can give to loaders to say I will only need pixels from this image in top-to-bottom order
. With this hint set, libvips will hook up the pipeline of operations directly to the read-a-line interface provided by the image library, and add a small cache of the most recent 100 or so lines.
- There’s an extra unbuffered sequential mode where vips does not keep a cache of recent lines. This gives a useful memory saving for operations like copy which do not need any non-local access.
+ This is done automatically in command-line operation. In programs, you need to set access to #VIPS_ACCESS_SEQUENTIAL in calls to functions like vips_image_new_from_file().