diff --git a/doc/binding.xml b/doc/binding.xml
index 1215134f..68419e52 100644
--- a/doc/binding.xml
+++ b/doc/binding.xml
@@ -16,7 +16,7 @@
This chapter runs through the four main styles that have been found to work well. If you want to write a new binding, one of these should be close to what you need.
-
+
Don’t bind the top-level C API
The libvips C API (vips_add() and so on) is very inconvenient and dangerous to use from other languages due to its heavy use of varargs.
@@ -79,7 +79,7 @@ main( int argc, char **argv )
/* Call the operation. This will look up the operation+args in the vips
* operation cache and either return a previous operation, or build
- * this one. In either case, we have a new ref we mst release.
+ * this one. In either case, we have a new ref we must release.
*/
if( !(new_op = vips_cache_operation_build( op )) ) {
g_object_unref( op );
@@ -112,13 +112,13 @@ main( int argc, char **argv )
}
- libvips has a couple of extra things to let you examine the arguments and types of an operator at runtime. Use vips_lib.vips_argument_map() to loop over all the arguments of an operator, and vips_object_get_argument() to fetch the type and flags of a specific argument.
+ libvips has a couple of extra things to let you examine the arguments and types of an operator at runtime. Use vips_argument_map() to loop over all the arguments of an operator, and vips_object_get_argument() to fetch the type and flags of a specific argument.
Use vips_operation_get_flags() to get general information about an operator.
-
-
+
+
Compiled language which can call C
The C++ binding uses this lower layer to define a function called VImage::call() which can call any libvips operator with a not-varargs set of variable arguments.
@@ -144,23 +144,23 @@ VImage VImage::invert( VOption *options )
The VImage class also adds automatic reference counting, constant expansion, operator overloads, and various other useful features.
-
-
+
+
Dynamic language with FFI
- Languages like Ruby, Python, JavaScript and Lua can’t call C directly, but they do support FFI. The bindings for these languages work rather like C++, but use FFI to call into libvips and run operations.
+ Languages like Ruby, Python, JavaScript and LuaJIT can’t call C directly, but they do support FFI. The bindings for these languages work rather like C++, but use FFI to call into libvips and run operations.
Since these languages are dynamic, they can add another trick: they intercept the method-missing hook and attempt to run any method calls not implemented by the Image class as libvips operators. This makes these bindings self-writing: they only contain a small amount of code and just expose everything they find in the libvips class hierarchy.
-
-
+
+
Dynamic langauge without FFI
PHP does not have FFI, unfortunately, so for this language a small native module implements the general vips_call() function for PHP language types, and a larger pure PHP layer makes it convenient to use.
-
-
+
+
gobject-introspection
The C source code to libvips has been marked up with special comments describing the interface in a standard way. These comments are read by the gobject-introspection package when libvips is compiled and used to generate a typelib, a description of how to call the library. Many languages have gobject-introspection packages: all you need to do to call libvips from your favorite language is to start g-o-i, load the libvips typelib, and you should have the whole library available. For example, from Python it’s as simple as:
@@ -177,8 +177,8 @@ from gi.repository import Vips
If you have a choice, I would recommend simply using FFI.
-
-
+
+
Documentation
You can generate searchable docs from a .gir (the thing that is built from scanning libvips and which in turn turn the typelib is made from) with g-ir-doc-tool, for example:
@@ -202,7 +202,7 @@ $ yelp-build html .
To make HTML docs. This is an easy way to see what you can call in the library.
-
+