To properly display the text you will need to choose a font that is loaded on your system or device or use the two web font downloaded with the page (Noto Serif Thai). The font list indicates which fonts are standard for Mac (Snow Leopard/Lion) and Windows7, as well as which are the web fonts. Note that the fonts aren't guarranteed to work on every system/device, because the font often relies on rendering algorithms provided by the operating system. See more information about standard OS fonts in Mac and Windows.
You can also add codepoints and escapes via the "Add codepoint" field (hit return to add to the output field). You can also paste text into the output field to get information about it. Use the yellow boxes to set preferences or search. Regular expressions are allowed when searching – for example, to find characters with the word KA in their name, enter \bka\b, or the short form :ka:.
When working on an iPad or similar device, you should turn off more controls/Autofocus. This prevents the keyboard popping up after you input every character. You may also need to select a character twice to add it to the output field.
There are three buttons that allow you to convert from Thai text to Latin transcriptions. If you highlight part of the text, only that part will be transcribed.
The toISO-1 button produces an ISO 11940-1 transliteration, that basically latinises the Thai characters and without changing their order. The result doesn't normally tell you how to pronounce the Thai text, but it can be converted back to Thai as each Thai character is represented by a unique sequence in Latin. This transcription should produce fully conformant output. There is no need to identify syllables boundaries first.
The toISO-2 and toIPA buttons produce an output that is intended to approximately reflect actual pronunciation. It will work fine most of the time, but there are occasional ambiguities and idiosynchrasies in Thai which will cause the converter to render certain, less common syllables incorrectly. It also doesn't automatically add accent marks to the phonetic version (though that may be added later). So the output of these buttons should be treated as something that gets you 90% of the way. NOTE: Before using these two buttons you need to add spaces or hyphens between each syllable of the Thai text. Syllable boundaries are important for correct interpretation of the text, and they are not detected automatically.
The condense button removes the spaces from the highlighted range (or the whole output area, if nothing is highlighted).
Note: For the toISO-2 transcription I use a macron over long vowels. This is non-standard.
About the chart
Includes almost the characters in the Unicode Thai block as of Unicode 7.0.
All Thai text is output in Unicode normalisation form NFC by default. You can change to NFD or no normalisation by clicking on 'more controls' and using the switch in the yellow area. Note that normalization only takes place when you add a character by clicking on the table – text pasted into the box won't be normalised until you click on another character below, or change the control in the yellow area.
The following alternative views are available by clicking on the vertical grey bar to the left of the selection area.
Table This view is likely to be most useful to people who are somewhat familiar with the alphabet and characters of Thai. Characters are arranged based on the use of the script in order to speed up picking.
Vowel signs that appear to the left of a syllable appear to the left of the table. To their right are the Thai consonants, arranged so that phonetically similar characters are grouped together. This helps when creating a Thai sequence from a transcription. Further to the right are vowels and tone marks; below them are characters that frequently occur at the end of a syllable; and below them are punctuaion marks. Digits appear to the far right.
Open the expanding link for more cantillation signs, symbols, astrological signs, religious signs, vocalic modification and transliteration head letters, and other marks and signs. Another expanding link for obsoleted consonants and other less commonly used characters.
Hinted table This changes the behaviour of the table view so that, when you mouse over a character, characters that are similar in appearance, and may be easily confused, are automatically highlighted. This can be particularly useful for people who are not familiar with the script, to avoid confusing similar characters, or to find the right character when two or more look similar. To turn this feature off, simply return to the default Table view.
Shape lookup This adds a row of orange pictures that represent basic shapes associated with the Thai characters. When you click on a picture, characters that incorporate that shape are highlighted. This is particularly helpful for those who don't know the script at all and want to pick characters based on their shape, or for those times when you just can't find the character you want and need a hint.
Font grid Shows characters in Unicode order, using whatever font is specified in the Font list or Custom font input fields. This allows comparison of fonts (especially useful in IE, which shows if a glyph is missing from a font).
Notes on controls
Controls at the bottom of the page allow you to modify fonts used, the font size, and the height of the output box.
Searching by character name or codepoint. If you are searching for a particular character and know (at least part of) the name or the codepoint, type that in the search box and hit return. All characters with matching text in the name or codepoint number will be highlighted. The highlighting is only removed when you click on the X next to the search input field. You can also use regular expression syntax to improve your search results. For example, to find the letter 'ha', but not 'gha' etc, you can use '\bha\b' (or the shortcut, ':b:').