Documentation: Better file formats documentation

Base/usr/share/man/man5/af.md

@@ -1,6 +1,6 @@
 ## Name
 
-af - Application File format
+af - Application File format (.af)
 
 ## Synopsis
 
@@ -8,11 +8,40 @@ The Application Files define System Menu entries and launcher file types / proto
 
 ## Description
 
-.af files are human-readable and are a subset of the INI-format, have no easily detectable filemagic. These files define System Menu entries and launcher file types / protocols.
+Application files are a subset of the INI format.
+They have no easily detectable filemagic and contain application information (App group):
 
-They are stored in [`/res/apps`](../../../../res/apps).
+| Key           | Description                      |
+|---------------|----------------------------------|
+| Name          | name                             |
+| Executable    | executable path                  |
+| Category      | category (optional)              |
+| Description   | description (optional)           |
+| IconPath      | application icon path (optional) |
+| RunInTerminal | run in terminal flag (optional)  |
 
-## See Also
+and launcher information (Launcher group, optional):
 
+| Key       | Description                           |
+|-----------|---------------------------------------|
+| FileTypes | supported file types separated by ',' |
+| Protocols | protocols separated by ','            |
+
+All application files are stored in [`/res/apps`](../../../../res/apps).
+
+## Examples
+
+[`/res/apps/Calendar.af`](../../../../res/apps/Calendar.af)
+
+```ini
+[App]
+Name=Calendar
+Executable=/bin/Calendar
+Category=Utilities
+```
+
+## See also
+
+- [ini(5)](help://man/5/ini)
 - [`Userland/Services/Taskbar/main.cpp`](../../../../../Userland/Services/Taskbar/main.cpp)
-- `Launcher::load_handlers` in [`Userland/Services/LaunchServer/Launcher.cpp`](../../../../../Userland/Services/LaunchServer/Launcher.cpp).
+- `Launcher::load_handlers` in [`Userland/Services/LaunchServer/Launcher.cpp`](../../../../../Userland/Services/LaunchServer/Launcher.cpp)

Base/usr/share/man/man5/font.md

@@ -1,17 +1,39 @@
 ## Name
 
-font - Bitmap Font File format
+font - Bitmap Font File format (.font)
 
 ## Synopsis
 
-The .font file format stores bitmap fonts in SerenityOS's own binary format.
+Font files contain bitmap definitions of fonts (`Gfx::BitmapFont`).
 
 ## Description
 
-These files contain bitmap definitions of fonts, either varying-width or fixed-width.
+Bitmap fonts can be either varying-width or fixed-width.
+The first four bytes of font files contain the filemagic: `!Fnt` (0x21466e74).
 
-The first four bytes contain the filemagic: `!Fnt` (0x21466e74).
+In addition, `Gfx::BitmapFont` supports reading from and writing to font files (as well as reading directly from memory)
+and the question mark '?' used as a fallback for unknown glyphs or emojis.
+
+## Structure
+
+The order is big-endian.
+
+| Size       | Member name         |
+|------------|---------------------|
+| 4 bytes    | Filemagic           |
+| 1 byte     | Glyph width         |
+| 1 byte     | Glyph height        |
+| 2 bytes    | Range mask size     |
+| 1 byte     | Variable width flag |
+| 1 byte     | Glyph spacing       |
+| 1 byte     | Baseline            |
+| 1 byte     | Mean line           |
+| 1 byte     | Presentation size   |
+| 2 bytes    | Weight              |
+| 1 byte     | Slope               |
+| 32 bytes   | Name                |
+| 32 bytes   | Family              |
 
 ## See also
 
-- Format header definition in `Gfx::FontFileHeader` in [`Userland/Libraries/LibGfx/Font/BitmapFont.cpp`](../../../../../Userland/Libraries/LibGfx/Font/BitmapFont.cpp).
+- Format header definition in `Gfx::FontFileHeader` in [`Userland/Libraries/LibGfx/Font/BitmapFont.cpp`](../../../../../Userland/Libraries/LibGfx/Font/BitmapFont.cpp)

Base/usr/share/man/man5/ini.md

@@ -0,0 +1,21 @@
+## Name
+
+INI - generic config file format (.ini)
+
+## Description
+
+INI files serve as human-readable configuration files.
+
+They consist of key-value pairs separated by '=', optionally located under a unique group in square brackets.
+
+Additionally, [`Userland/Libraries/LibCore/ConfigFile.cpp`](../../../../../Userland/Libraries/LibCore/ConfigFile.cpp)
+supports comments: the characters '#' and ';' skip the entire line only if they appear at the beginning of the line.
+
+## Examples
+
+[`/etc/Keyboard.ini`](../../../../etc/Keyboard.ini)
+
+```ini
+[Mapping]
+Keymaps=en-us
+```

Base/usr/share/man/man5/ipc.md

@@ -1,6 +1,6 @@
 ## Name
 
-ipc - Inter Process Communication endpoint definition format
+IPC - Inter-Process Communication endpoint definition format (.ipc)
 
 ## Synopsis
 
@@ -8,10 +8,77 @@ The IPC format of SerenityOS is a domain-specific language (DSL) used to define
 
 ## Description
 
-These files are human-readable, have no easily detectable filemagic, and define IPC interfaces.
+Informally, IPC files - with the help of the IPC compiler - are used to generate message classes that will wrap messages
-The format is loosely inspired by C++ headers.
+for interprocess communication in the system. IPC syntax is loosely inspired by C++ headers. Generated IPC message
+classes support encode and decode functions to pass messages between the processes.
 
-## See Also
+Every IPC pair in the system has a client endpoint and a server endpoint that are described in the IPC files.
+Each IPC endpoint should have a unique hashable name that will uniquely identify endpoints in the system.
 
-- [`Meta/Lagom/Tools/CodeGenerators/IPCCompiler/`](../../../../../Meta/Lagom/Tools/CodeGenerators/IPCCompiler/).
+There are 2 types of APIs that are supported by the IPC files: synchronous and asynchronous.
-- [ipc(4)](help://man/4/ipc) (IPC Unix socket documentation)
+Synchronous function calls always wait for a response from the other side, while the asynchronous counterparts do not.
+In other words, in case of the synchronous calls, the IPC library will not return until it has a response for a caller.
+
+Ideally, all APIs for the server endpoint should be asynchronous.
+
+## Examples
+
+To create a new connection, you first need to generate client and server endpoints.
+These endpoints should implement the communication logic using the IPC compiler-generated API messages.
+
+Start from defining an endpoint in the IPC file in `MyServer.ipc`.
+
+```
+endpoint MyServer
+{
+    SyncAPI(String text) => (i32 status)
+    AsyncAPI(i32 mode) =|
+}
+```
+
+Part of the generated C++ messages:
+
+```cpp
+class SyncAPI final : public IPC::Message {
+public:
+    using ResponseType = SyncAPIResponse;
+    SyncAPI(const String& text) : m_text(text) {}
+    virtual ~SyncAPI() override {}
+    static OwnPtr<SyncAPI> decode(...);
+    virtual IPC::MessageBuffer encode(...) const override;
+};
+```
+
+Then, you need to inherit your connection class from `IPC::ConnectionFromClient` with created server and client
+endpoints as template parameters if it is a server connection. Otherwise, your class need to be inherited
+from `IPC::ConnectionToServer` with created server and client endpoints as template parameters and from the client
+endpoint class.
+
+Part of the connection implementations:
+
+```cpp
+// Server side.
+namespace MyServer {
+
+class ConnectionFromClient final
+    : public IPC::ConnectionFromClient<MyClientEndpoint, MyServerEndpoint> {};
+
+}
+
+// Client side.
+namespace MyClient {
+    
+    class Client final
+        : public IPC::ConnectionToServer<MyClientEndpoint, MyServerEndpoint>
+        , public MyClientEndpoint {};
+    
+}
+```
+
+Note, there are two types of functions for sending the messages: synchronous and asynchronous. The generated
+asynchronous functions are prefixed with `async_` and the names of the synchronous functions are not changed.
+
+## See also
+
+- [`Meta/Lagom/Tools/CodeGenerators/IPCCompiler/main.cpp`](../../../../../Meta/Lagom/Tools/CodeGenerators/IPCCompiler/main.cpp)
+- [ipc(4)](help://man/4/ipc) (IPC Unix socket documentation) 

Base/usr/share/man/man5/pp.md

@@ -0,0 +1,29 @@
+## Name
+
+PP - Pixel Paint application file format (.pp)
+
+## Description
+
+Pixel Paint files store the drawing data produced by the Pixel Paint application.
+
+This is a rough overview of the contents of the files:
+
+- width
+- height
+- layers (optional)
+    - width
+    - height
+    - name
+    - locationx
+    - locationy
+    - opacity_percent
+    - visible
+    - selected
+    - bitmap
+- guides (optional)
+    - offset
+    - orientation
+
+## See also
+
+- [`Userland/Applications/PixelPaint/Image.cpp`](../../../../../Userland/Applications/PixelPaint/Image.cpp)