HTTP API¶

Framebuffer¶

For simple integration into your projects, the fluepboard firmwares ships with a simple to use HTTP API.

Framebuffer encoding¶

Framebuffers are ASCII-encoded. The only allowed characters are <space> 0x20, X 0x58 and ``\n`` \0x0A.

A bright (set) pixel is encoded as an X.

A dark (cleared) pixel is encoded as a space character.

Each line in a framebuffer has exactly the same amount of characters, which is exactly the fluepdot’s width plus one newline character.

Each framebuffer has exactly 16 lines.

Lines are terminated by a single \n. No carriage return is used.

Framebuffer manipulations¶

GET /framebuffer¶

Params

GET: None
POST: None

Gets the current framebuffer encoded as explained above. This endpoint can be used to calculate the framebuffer dimensions, thus there is no seperate endpoint for retrieving the geometry.

POST /framebuffer¶

Params

GET: None
POST: Raw framebuffer encoded as explained above

Draw the posted framebuffer to the fluepdot.

GET /pixel¶

Params

GET: x - The x coordinate y - The y coordinate

Get the current pixel at the given coordinate encoded as above

POST /pixel¶

Params

GET

x: The x coordinate (ascii encoded decimal value)
y: The y coordinate (ascii encoded decimal value)

Sets the pixel at the given coordinate to bright.

DELETE /pixel¶

Params

GET

x: The x coordinate (ascii encoded decimal value)
y: The y coordinate (ascii encoded decimal value)

Set the pixel at the give coordinate to dark.

POST /framebuffer/text¶

Params

POST

Text to display

GET

x: The x coordinate to render text to
y: The y coordinate to render text to
font: The font’s name to use for rendering text. Retrieve a list of fonts at GET /fonts

Render a string

GET /fonts¶

Returns a list of installed fonts

For each font there are two lines: First the full_name and then short_name which is used with the POST /framebuffer/text eAPI endpoint.

Rendering options¶

Rendering mode¶

GET /rendering/mode¶

Retuns an ASCII printed integer which value is defined as follows:

enum flipdot_rendering_mode_t

Values:

FULL = 0

Always render the full framebuffer without skipping anything.

DIFFERENTIAL = 1

Redraw only those pixels that changed.

PUT /rendering/mode¶

Params

GET: None
POST: ASCII printed integer, which value is to be interpreted as stated above.

Rendering timings encoding¶

Rendering timings are ASCII-encoded. The only allowed characters are 0-9 (0x30-0x39) and \\n.

For each fluepdot column, there are exactly 3 rows:

Pre delay

How long to wait (50 microseconds steps) before rendering to the column.
Clear delay

How long to power the coils in order to clear the column (in 50 microseconds steps).
Set delay

How long to power the coils in order to set the column (in 50 microseconds steps)

Each line has exactly 5 characters and one trailing \\n. You have to pad with zeros. Each line contains the decimal value in ascii-encoded form.

Warning

Powering a coil repeatedly for a long duration might cause the coil to overheat and or fail. Decreasing the timings might result in higher framerate, but might result in not all pixels flipping.

Usually 1600uS are enough to reliably flip all pixels. This is the default.

GET /rendering/timings¶

Returns the timing configuration encoded as explained above.

POST /rendering/timings¶

Params

GET: None
POST: Timing configuration as explained above.

Set the timing configuration.