BindBC-Fontconfig

This project provides a set of both static and dynamic bindings to Fontconfig. They are compatible with @nogc and nothrow, and can be compiled with BetterC compatibility.

Table of Contents
License
Fontconfig documentation
Quickstart guide
Configurations
Library versions

License

BindBC-Fontconfig—as well as every other binding in the BindBC project—is licensed under the Boost Software License.

Bear in mind that you still need to abide by Fontconfig's license if you use it through these bindings.

Fontconfig documentation

This readme describes how to use BindBC-Fontconfig, not Fontconfig itself.

Quickstart guide

To use BindBC-Fontconfig in your dub project, add it to the list of dependencies in your dub configuration file. The easiest way is by running dub add bindbc-fontconfig in your project folder. The result should look something like this:

Example dub.json

"dependencies": {
	"bindbc-fontconfig": "~>1.0",
},

Example dub.sdl

dependency "bindbc-fontconfig" version="~>1.0"

If you want to use Fontconfig's FreeType 2 support, you'll have to add the submodule :freetype as a dependency as well:

Example dub.json

"dependencies": {
	"bindbc-fontconfig": "~>1.0",
	"bindbc-fontconfig:freetype": "~>1.0",
},

Example dub.sdl

dependency "bindbc-fontconfig" version="~>1.0"
dependency "bindbc-fontconfig:freetype" version="~>1.0"

By default, BindBC-Fontconfig is configured to compile as a dynamic binding that is not BetterC-compatible. If you prefer static bindings or need BetterC compatibility, they can be enabled via subConfigurations in your dub configuration file. For configuration naming & more details, see Configurations.

Example dub.json

"subConfigurations": {
	"bindbc-fontconfig": "staticBC",
},

Example dub.sdl

subConfiguration "bindbc-fontconfig" "staticBC"

If you need to use versions of Fontconfig newer than 1.15.0, then you will have to add the appropriate version identifier to versions in your dub configuration. For a list of library version identifiers, see Library versions.

If you're using static bindings, then you will also need to add the name of the Fontconfig library to libs.

Example dub.json

"versions": [
	"Fc_1_16_0",
],
"libs": [
	"fontconfig",
],

Example dub.sdl

versions "Fc_`1_16_0"
libs "fontconfig"

If you're using static bindings: import bindbc.fontconfig in your code, and then you can use all of Fontconfig just like you would in C. That's it!

import bindbc.fontconfig;

void main(){
	FcConfig* config = FcConfigCreate();
	
	//etc.
	
	FcConfigDestroy(config);
}

If you're using dynamic bindings: you need to load each library you need with the appropriate load function. loadFontconfig for Fontconfig, or loadFontconfigFreeType for Fontconfig FreeType.

For most use cases, it's best to use BindBC-Loader's error handling API to see if there were any errors while loading the library. This information can be written to a log file before aborting the program.

The load function will also return a member of the LoadMsg enum, which can be used for debugging:

• noLibrary means the library couldn't be found.
• badLibrary means there was an error while loading the library.
• success means that the library was loaded without any errors.

Here's a simple example using only the load function's return value:

import bindbc.fontconfig;
import bindbc.loader;

/*
This code attempts to load the Fontconfig shared library using
well-known variations of the library name for the host system.
*/
LoadMsg ret = loadFontconfig();
if(ret != LoadMsg.success){
	/*
	Error handling. For most use cases, it's best to use the error handling API in
	BindBC-Loader to retrieve error messages for logging and then abort.
	If necessary, it's possible to determine the root cause via the return value:
	*/
	if(ret == LoadMsg.noLibrary){
		//The Fontconfig shared library failed to load
	}else if(ret == LoadMsg.badLibrary){
		//One or more symbols failed to load.
	}
}

/*
This code attempts to load Fontconfig using a user-supplied file name.
Usually, the name and/or path used will be platform specific, as in this
example which attempts to load `fontconfig.dll` from the `libs` subdirectory,
relative to the executable, only on Windows.
*/
version(Windows) loadFontconfig("libs/fontconfig.dll");

The error handling API in BindBC-Loader can be used to log error messages:

import bindbc.fontconfig;

/*
Import the sharedlib module for error handling. Assigning an alias ensures that the
function names do not conflict with other public APIs. This isn't strictly necessary,
but the API names are common enough that they could appear in other packages.
*/
import loader = bindbc.loader.sharedlib;

bool loadLib(){
	LoadMsg ret = loadFontconfig();
	if(ret != LoadMsg.success){
		//Log the error info
		foreach(info; loader.errors){
			/*
			A hypothetical logging function. Note that `info.error` and
			`info.message` are `const(char)*`, not `string`.
			*/
			logError(info.error, info.message);
		}
		
		//Optionally construct a user-friendly error message for the user
		string msg;
		if(ret == LoadMsg.noLibrary){
			msg = "This application requires the Fontconfig library.";
		}else{
			const(char)* version_ = FcGetVersion();
			msg = "Your Fontconfig version is too low: "~
				itoa(version_ / 10_000)~"."~
				itoa(version_ / 100 % 100)~"."~
				itoa(version_       % 100)~
				". Please upgrade to 1.16.0+.";
		}
		//A hypothetical message box function
		showMessageBox(msg);
		return false;
	}
	return true;
}

Configurations

BindBC-Fontconfig has the following configurations:

┌	DRuntime	BetterC
Dynamic	dynamic	dynamicBC
Static	static	staticBC

For projects that don't use dub, if BindBC-Fontconfig is compiled for static bindings then the version identifier BindFc_Static must be passed to your compiler when building your project.

Note

The version identifier BindBC_Static can be used to configure all of the official BindBC packages used in your program. (i.e. those maintained in the BindBC GitHub organisation) Some third-party BindBC packages may support it as well.

Dynamic bindings

The dynamic bindings have no link-time dependency on Fontconfig, so the Fontconfig shared library must be manually loaded at runtime from the shared library search path of the user's system. On Windows, this is typically handled by distributing the Fontconfig DLLs with your program. On other systems, it usually means installing the Fontconfig shared library through a package manager.

The function isFontconfigLoaded returns true if any version of the shared library has been loaded and false if not. unloadFontconfig can be used to unload a successfully loaded shared library.

Static bindings

Static bindings do not require static linking. The static bindings have a link-time dependency on either the shared or static Fontconfig library. On Windows, you can link with the static library or, to use the DLLs, the import library. On other systems, you can link with either the static library or directly with the shared library.

When linking with the shared (or import) library, there is a runtime dependency on the shared library just as there is when using the dynamic bindings. The difference is that the shared library are no longer loaded manually—loading is handled automatically by the system when the program is launched. Attempting to call loadFontconfig with the static bindings enabled will result in a compilation error.

Static linking requires Fontconfig's development packages be installed on your system. The Fontconfig releases provide the library's source code. You can also install them via your system's package manager. For example, on Debian-based Linux distributions sudo apt install libfontconfig-dev will install both the development and runtime packages for the Fontconfig library.

When linking with the static library, there is no runtime dependency on Fontconfig.

Library Versions

Version	Version identifier
1.15.0	(none; default)