[README] Add basic Megane and Tablegen docs

README.md

@@ -60,3 +60,75 @@ AnimateFile("084b8.svg", "084b8-out.svg", AnimationSettings {
     .DelayBetweenStrokes = 50ms,
 });
 ```
+
+## Megane
+
+A tiny library that loads the `kvg-index.json` into a dictionary to translate the UTF-8
+representation of kanji characters into the ID that kanjivg uses to refer to the characters.
+
+Example usage:
+```cpp
+auto lookup = Megane::Megane("/path/to/kvg-index.json");
+auto id = lookup.GetCode("日"); // id should contain "065e5.svg"
+```
+
+## Tablegen
+
+This library generates a table of kanji images from a specified list with various configurable
+values. It's made up of the following interface:
+
+```cpp
+std::string GeneratePage(const Settings& settings = Settings::Default());
+
+void GeneratePage(const std::string& path, const Settings& settings = Settings::Default());
+
+#ifdef TABLEGEN_EXPOSE_XML
+void GenerateAsChild(pugi::xml_node& node, const Settings& settings = Settings::Default());
+
+pugi::xml_document GenerateDocument(const Settings& settings = Settings::Default());
+#endif
+```
+
+The first function returns a serialized HTML document in a string
+(can return just the table by changing the `FullDocument` value in the settings).
+The second function dumps the same document inside a file at the specified path.
+The final two functions are hidden behing the `TABLEGEN_EXPOSE_XML` preprocessor flag, because they
+expose the library that Tablegen uses internally to generate the document. They let the user
+modify the XML tree before it gets serialized into the final document. The first of these functions
+takes in a reference to the node that will act as the parent of the generated table.
+The second function returns a whole XML document.
+
+Some caveats:
+- `GenerateDocument` returns a `pugi::xml_document`, which cannot be assigned as a child
+  of anothe node. You don't want to use this function if you plan to generate a full document
+  with the table as a child (the `FullDocument` option isn't applicable in all cases either).
+- The default serialisation options do not generate a valid document, some specific options
+  need to be set for the document to be valid (currently `pugi::format_no_escapes`,
+  and `pugi::format_no_declaration`, but this is an implementation detail of the pugixml library).
+
+The default settings generate a table with no characters (and horrible styling), you will need to
+specify custom settings like this for actual use:
+```cpp
+auto doc = GeneratePage({
+    .FullDocument = Flag::Enable,
+    .OverrideIndentLevel = Flag::Disable,
+    .IndentLevel = 0,
+    .TableWidth = 90,
+    .TableMargin = 5,
+    .TableItemWidth = 30,
+    .TableItemPadding = 2,
+    .TableItemColour = RGB::FromHex("#666666"),
+    .LabelFontSize = 1.75,
+    .LabelFontUnits = FontSizeUnits::Em,
+    .ButtonColour = RGB::FromHex("#FF6347"),
+    .ButtonHoverColour = RGB::FromHex("#FFA500"),
+    .ButtonAnimationLength = 0.5,
+    .CharactersPerRow = 3,
+    .ImageFormat = "http://the.url/where/you/have/images/{}.svg",
+    .AnimationFormat = "http://the.url/where/you/have/animations/{}.svg",
+    .Characters = {
+        /* The actual characters you want in the table, example: */
+        { .Label = "Day", .ImagePath = "%E6%97%A5", .AnimationPath = "%E6%97%A5", },
+    },
+});
+```