BT81x library

This module exports classes and functions to handle Bridgetek BT81x family of Embedded Video Engines.

class DisplayConf(width, height, hcycle, hoffset, hsync0, hsync1, vcycle, voffset, vsync0, vsync1, pclk, swizzle, pclkpol, cspread, dither, description)

Class to store a display configuration. List of attributes:

  • DisplayConf.width display width in pixels
  • DisplayConf.height display height in pixels
  • DisplayConf.hcycle number of total PCLK cycles per horizontal line scan
  • DisplayConf.hoffset number of PCLK cycle before pixels are scanned out
  • DisplayConf.hsync0 how many PCLK cycles for HSYNC0 during start of line
  • DisplayConf.hsync1 how many PCLK cycles for HSYNC1 during start of line
  • DisplayConf.vcycle how many lines in one frame
  • DisplayConf.voffset how many lines taken after the start of a new frame
  • DisplayConf.vsync0 how many lines of signal VSYNC0 takes at start of a new frame
  • DisplayConf.vsync1 how many lines of signal VSYNC1 takes at start of a new frame
  • DisplayConf.pclk main clock divider for PCLK, if 0 there is no PCLK output
  • DisplayConf.swizzle controls the arrangement of output RGB pins to support different LCD panels
  • DisplayConf.pclkpol 0 for PCLK polarity on the rising edge, 1 for falling edge
  • DisplayConf.cspread controls the transition of RGB signals with PCLK active clock edge
  • DisplayConf.dither 1 or 0 to respectively enable or disable dither
  • DisplayConf.description a string describing the display

display_conf module global variable is automatically set with a DisplayConf instance when importing a display module from a display vendor:

from riverdi.displays.bt81x import ctp50
from bridgetek.bt81x import bt81x
init(spi, cs, pd, int, dc=None, spi_speed=3000000)
Parameters:
  • spi – spi driver (SPI0, SPI1, ...)
  • cs – chip select pin
  • pd – pd pin
  • int – interrupt pin
  • dc – display configuration as a DisplayConf instance
  • spi_speed – spi speed in Hertz

Initializes the chip.

When dc parameter is not specified display_conf global variable is used.

class Palette(font, foreground, background)

Class to store a color palette for font, foreground and background. List of attributes:

  • font tuple of rgb values (r,g,b)
  • foreground tuple of rgb values (r,g,b)
  • background tuple of rgb values (r,g,b)
class Text(x, y, font, options, text, palette=None)

Class to store a text element configuration. List of attributes:

  • x x-coordinate top-left, in pixels
  • y y-coordinate top-left, in pixels
  • font font to use 0-31
  • options one of OPT_CENTERX, OPT_CENTERY, OPT_CENTER, OPT_RIGHTX, OPT_FORMAT, OPT_FILL
  • text text string
  • palette Palette object instance to set colors
class Button(x, y, width, height, font, options, text, palette=None)

Class to store a text element configuration. Inherits all Text attributes and adds:

  • width button width in pixels
  • height button height in pixels

Co-Processor Commands

List of available options for the options command parameter:

  • OPT_3D 3D effect
  • OPT_CENTER horizontally and vertically centered style
  • OPT_CENTERX horizontally-centered style
  • OPT_CENTERY vertically-centered style
  • OPT_FILL breaks the text at spaces into multiple lines
  • OPT_FLASH fetch the data from flash memory
  • OPT_FLAT no 3D effect
  • OPT_FORMAT flag of string formatting
  • OPT_FULLSCREEN zoom the media to fill as much of the screen as possible
  • OPT_MEDIAFIFO source data from the defined media FIFO
  • OPT_MONO decodes the source JPEG image to L8 format, i.e., monochrome
  • OPT_NOBACK no background drawn
  • OPT_NODL no display list commands generated
  • OPT_NOHANDS no hands
  • OPT_NOHM no hour and minute hands
  • OPT_NOPOINTER no pointer
  • OPT_NOSECS no second hands
  • OPT_NOTEAR sync video updates to the display blanking interval, avoiding horizontal tearing artifacts
  • OPT_NOTICKS no ticks
  • OPT_OVERLAY append the video bitmap to an existing display list
  • OPT_RGB565 decodes the source image to RGB565 format
  • OPT_RIGHTX right justified style
  • OPT_SIGNED the number is treated as a 32 bit signed integer
  • OPT_SOUND decode the audio data

Options can be combined using a bitwise OR.

dl_start()

Starts a new display list.

set_font_color(r, g, b)
Parameters:
  • r – red 0-255
  • g – green 0-255
  • b – blue 0-255

Sets current font color.

set_foreground(r, g, b)
Parameters:
  • r – red 0-255
  • g – green 0-255
  • b – blue 0-255

Sets current foreground color.

set_background(r, g, b)
Parameters:
  • r – red 0-255
  • g – green 0-255
  • b – blue 0-255

Sets current background color.

add_text(txt)
Parameters:txt – Text object instance

Adds a text element to the screen.

A call to set_font_color() is performed if the Text.palette attribute is set.

add_button(btn)
Parameters:btn – Button object instance

Adds a button element to the screen.

Calls to set_background(), set_foreground() and set_font_color() are performed if the Text.palette.font attribute is set.

add_keys(x, y, w, h, font, options, s)
Parameters:
  • x – x-coordinate top-left, in pixels
  • y – y-coordinate top-left, in pixels
  • w – width of the keys
  • h – height of the keys
  • font – font used in key label 0-31
  • options – one of OPT_3D (default), OPT_FLAT, OPT_CENTER or an ASCII code
  • s – key labels, one character per key.

Adds a row of keys to the screen. If an ASCII code is specified as option, that key is drawn as pressed (in background color with any 3D effect removed).

The TAG value is set to the ASCII value of each key, so that key presses can be detected with a callback on that value.

add_clock(x, y, r, options, h, m, s, ms)
Parameters:
  • x – x-coordinate top-left, in pixels
  • y – y-coordinate top-left, in pixels
  • r – clock radius
  • options – one of OPT_3D (default), OPT_FLAT, OPT_NOBACK, OPT_NOTICKS, OPT_NOSECS, OPT_NOHANDS, OPT_NOHM
  • h – hours
  • m – minutes
  • s – seconds
  • ms – milliseconds

Adds a clock to the screen.

clear(color, stencil, tag)
Parameters:
  • color – clear color 0-1
  • stencil – clear stencil 0-1
  • tag – clear tag 0-1

Clears buffers to default values.

clear_color(rgb=None, a=None)
Parameters:
  • rgb – tuple for red, green and blue values (0-255, 0-255, 0-255)
  • a – alpha 0-255

Sets the default color when colors are cleared. The initial value is ((0, 0, 0), 0).

clear_tag(default_tag)
Parameters:default_tag – default tag

Sets the default tag when tag buffer is cleared. The initial value is 0.

spinner(x, y, style, scale)
Parameters:
  • x – x-coordinate top-left, in pixels
  • y – y-coordinate top-left, in pixels
  • style – spinner style, one of SPINNER_CIRCLE, SPINNER_LINE, SPINNER_CLOCK, SPINNER_ORBITING

Draws a spinner with a chosen style.

calibrate()

Starts the calibration procedure (needed by Resistive Displays).

inflate(ram_ptr, resource)
Parameters:
  • ram_ptr – address in RAM_G to inflate the resource to
  • resource – name of the resource to inflate

Inflates a Zerynth resource to RAM_G (General purpose graphics RAM, bt81x main memory) for later use. The resource should be a valid bt81x image (zlib-compressed)

Raises:
  • PeripheralError – if an error occurs while inflating
  • TimeoutError – if the process takes longer than set timeout (set_timeout())
load_image(ram_ptr, options, resource)
Parameters:
  • ram_ptr – address in RAM_G to load the resource to
  • options – load options
  • resource – name of the resource to inflate

Inflates a Zerynth resource consisting of a PNG image to RAM_G (General purpose graphics RAM, bt81x main memory) for later use.

Raises:
  • PeripheralError – if an error occurs while loading
  • TimeoutError – if the process takes longer than set timeout (set_timeout())
vertex_format(fmt)
Parameters:fmt – format frac value, one of 0, 1, 2, 3, 4

Selects a vertex format for subsequent draw operations.

Vertex format are useful to specify pixel coordinates beyond the 0-511 range.

class Bitmap(handle, source, layout, size)
Parameters:
  • handle – a user-defined handle to refer to the bitmap
  • source – bitmap source in RAM_G
  • layout – a tuple of (bitmap_format, linestride)
  • size – a tuple of (filtering_mode, x_wrap_mode, y_wrap_mode, bitmap_width, bitmap_height)

Class to store a bitmap element and to allow subsequent bitmap draw operations.

linestride value represents the amount of memory used for each line of bitmap pixels. It depends on selected format and can be usually calculated with the following formula:

linestride = width * byte/pixel

Allowed values for bitmap_format and number of bits/pixel for that format:

  • L1 1
  • L2 2
  • L4 4
  • L8 8
  • ARGB2 8
  • RGB332 8
  • ARGB4 16
  • ARGB1555 16
  • RGB565 16
  • PALETTED8 8
  • PALETTED4444 8
  • PALETTED565 8
  • BARGRAPH
  • TEXT8X8

Allowed values for filtering_mode are:

  • NEAREST
  • BILINEAR

Allowed values for x_wrap_mode and y_wrap_mode are:

  • BORDER
  • REPEAT
prepare_draw()

To be called before draw().

draw(vertex, vertex_fmt=None)

Draws prepared image on screen. Can be called multiple times after a single prepare_draw().

If vertex tuple has 2 elements the vertex format is set according to vertex_fmt parameter (vertex_format()) and vertex elements are assumed to be the image x and y top-left coordinates.

If vertex tuple has 4 elements vertex_fmt parameter is ignored and vertex elements are assumed to be the image x and y top-left coordinates, image handle and cell.

end()

Ends drawing a graphics primitive.

display()

Ends a display list.

swap_and_empty()

Swaps current display list and waits until all commands are executed.

Raises:
  • PeripheralError – if an error occurs while executing commands
  • TimeoutError – if the process takes longer than set timeout (set_timeout())
set_timeout(timeout_millis)
Parameters:timeout_millis – timeout in milliseconds

Sets a timeout for Co-Processor commands. Default timeout value is 4000.

tag(n)
Parameters:n – tag value 1-255

Attaches the tag value to all the following graphics objects drawn on the screen, unless tag_mask() is used to disable it. When the graphics objects attached with the tag value are touched, if calls to track() and touch_loop() have been previously issued, a callback function is called.

The initial tag value is specified by function clear_tag() and takes effect calling function clear().

tag_mask(mask)
Parameters:mask – mask value 0-1

If called with value 0 the default value of the tag buffer is used for current display list.

tag_mask(mask)
Parameters:mask – mask value 0-1

If called with value 0 the default value of the tag buffer is used for current display list.

touch_loop(cbks)
Parameters:
  • cbks – tuple of tuples of callback and tag value for the callback to be activated on ((tag_value1, cbk1), (tag_value2, cbk2), ...)
  • touch_points – number of multiple touch points (to be supported by used display)

Starts the touch loop to call set callbacks when touches are detected. Each callback function is called passing tag value, tracked value and touch point.

If a tag value of -1 is specified for a certain callback, that callback is called for every detected tag value.