displayio/_epaperdisplay.py

   1 # SPDX-FileCopyrightText: 2020 Melissa LeBlanc-Williams for Adafruit Industries
   2 #
   3 # SPDX-License-Identifier: MIT
   4
   5 """
   6 `displayio.epaperdisplay`
   7 ================================================================================
   8
   9 displayio for Blinka
  10
  11 **Software and Dependencies:**
  12
  13 * Adafruit Blinka:
  14   https://github.com/adafruit/Adafruit_Blinka/releases
  15
  16 * Author(s): Melissa LeBlanc-Williams
  17
  18 """
  19
  20 import time
  21 from typing import Optional, Union
  22 import microcontroller
  23 from digitalio import DigitalInOut
  24 from circuitpython_typing import ReadableBuffer
  25 from ._displaycore import _DisplayCore
  26 from ._group import Group, circuitpython_splash
  27 from ._colorconverter import ColorConverter
  28 from ._displaybus import _DisplayBus
  29 from ._area import Area
  30 from ._constants import (
  31     CHIP_SELECT_TOGGLE_EVERY_BYTE,
  32     CHIP_SELECT_UNTOUCHED,
  33     DISPLAY_COMMAND,
  34     DISPLAY_DATA,
  35     NO_COMMAND,
  36     DELAY,
  37 )
  38
  39 __version__ = "0.0.0+auto.0"
  40 __repo__ = "https://github.com/adafruit/Adafruit_Blinka_displayio.git"
  41
  42
  43 class EPaperDisplay:
  44     # pylint: disable=too-many-instance-attributes, too-many-statements
  45     """Manage updating an epaper display over a display bus
  46
  47     This initializes an epaper display and connects it into CircuitPython. Unlike other
  48     objects in CircuitPython, EPaperDisplay objects live until
  49     displayio.release_displays() is called. This is done so that CircuitPython can use
  50     the display itself.
  51
  52     Most people should not use this class directly. Use a specific display driver instead
  53     that will contain the startup and shutdown sequences at minimum.
  54     """
  55
  56     def __init__(
  57         self,
  58         display_bus: _DisplayBus,
  59         start_sequence: ReadableBuffer,
  60         stop_sequence: ReadableBuffer,
  61         *,
  62         width: int,
  63         height: int,
  64         ram_width: int,
  65         ram_height: int,
  66         colstart: int = 0,
  67         rowstart: int = 0,
  68         rotation: int = 0,
  69         set_column_window_command: Optional[int] = None,
  70         set_row_window_command: Optional[int] = None,
  71         set_current_column_command: Optional[int] = None,
  72         set_current_row_command: Optional[int] = None,
  73         write_black_ram_command: int,
  74         black_bits_inverted: bool = False,
  75         write_color_ram_command: Optional[int] = None,
  76         color_bits_inverted: bool = False,
  77         highlight_color: int = 0x000000,
  78         refresh_display_command: Union[int, ReadableBuffer],
  79         refresh_time: float = 40,
  80         busy_pin: Optional[microcontroller.Pin] = None,
  81         busy_state: bool = True,
  82         seconds_per_frame: float = 180,
  83         always_toggle_chip_select: bool = False,
  84         grayscale: bool = False,
  85         advanced_color_epaper: bool = False,
  86         two_byte_sequence_length: bool = False,
  87         start_up_time: float = 0,
  88         address_little_endian: bool = False,
  89     ) -> None:
  90         # pylint: disable=too-many-locals
  91         """Create a EPaperDisplay object on the given display bus (`displayio.FourWire` or
  92         `paralleldisplay.ParallelBus`).
  93
  94         The ``start_sequence`` and ``stop_sequence`` are bitpacked to minimize the ram impact. Every
  95         command begins with a command byte followed by a byte to determine the parameter count and
  96         delay. When the top bit of the second byte is 1 (0x80), a delay will occur after the command
  97         parameters are sent. The remaining 7 bits are the parameter count excluding any delay
  98         byte. The bytes following are the parameters. When the delay bit is set, a single byte after
  99         the parameters specifies the delay duration in milliseconds. The value 0xff will lead to an
 100         extra long 500 ms delay instead of 255 ms. The next byte will begin a new command
 101         definition.
 102
 103         :param display_bus: The bus that the display is connected to
 104         :type _DisplayBus: displayio.FourWire or paralleldisplay.ParallelBus
 105         :param ~circuitpython_typing.ReadableBuffer start_sequence: Byte-packed command sequence.
 106         :param ~circuitpython_typing.ReadableBuffer stop_sequence: Byte-packed command sequence.
 107         :param int width: Width in pixels
 108         :param int height: Height in pixels
 109         :param int ram_width: RAM width in pixels
 110         :param int ram_height: RAM height in pixels
 111         :param int colstart: The index if the first visible column
 112         :param int rowstart: The index if the first visible row
 113         :param int rotation: The rotation of the display in degrees clockwise. Must be in
 114             90 degree increments (0, 90, 180, 270)
 115         :param int set_column_window_command: Command used to set the start and end columns
 116             to update
 117         :param int set_row_window_command: Command used so set the start and end rows to update
 118         :param int set_current_column_command: Command used to set the current column location
 119         :param int set_current_row_command: Command used to set the current row location
 120         :param int write_black_ram_command: Command used to write pixels values into the update
 121             region
 122         :param bool black_bits_inverted: True if 0 bits are used to show black pixels. Otherwise,
 123             1 means to show black.
 124         :param int write_color_ram_command: Command used to write pixels values into the update
 125             region
 126         :param bool color_bits_inverted: True if 0 bits are used to show the color. Otherwise, 1
 127             means to show color.
 128         :param int highlight_color: RGB888 of source color to highlight with third ePaper color.
 129         :param int refresh_display_command: Command used to start a display refresh. Single int
 130             or byte-packed command sequence
 131         :param float refresh_time: Time it takes to refresh the display before the stop_sequence
 132             should be sent. Ignored when busy_pin is provided.
 133         :param microcontroller.Pin busy_pin: Pin used to signify the display is busy
 134         :param bool busy_state: State of the busy pin when the display is busy
 135         :param float seconds_per_frame: Minimum number of seconds between screen refreshes
 136         :param bool always_toggle_chip_select: When True, chip select is toggled every byte
 137         :param bool grayscale: When true, the color ram is the low bit of 2-bit grayscale
 138         :param bool advanced_color_epaper: When true, the display is a 7-color advanced color
 139             epaper (ACeP)
 140         :param bool two_byte_sequence_length: When true, use two bytes to define sequence length
 141         :param float start_up_time: Time to wait after reset before sending commands
 142         :param bool address_little_endian: Send the least significant byte (not bit) of
 143             multi-byte addresses first. Ignored when ram is addressed with one byte
 144         """
 145
 146         if isinstance(refresh_display_command, int):
 147             refresh_sequence = bytearray([refresh_display_command, 0])
 148             if two_byte_sequence_length:
 149                 refresh_sequence += bytes([0])
 150         elif isinstance(refresh_display_command, ReadableBuffer):
 151             refresh_sequence = bytearray(refresh_display_command)
 152         else:
 153             raise ValueError("Invalid refresh_display_command")
 154
 155         if write_color_ram_command is None:
 156             write_color_ram_command = NO_COMMAND
 157
 158         if rotation % 90 != 0:
 159             raise ValueError("Display rotation must be in 90 degree increments")
 160
 161         self._refreshing = False
 162         color_depth = 1
 163         core_grayscale = True
 164
 165         if advanced_color_epaper:
 166             color_depth = 4
 167             grayscale = False
 168             core_grayscale = False
 169
 170         self._core = _DisplayCore(
 171             bus=display_bus,
 172             width=width,
 173             height=height,
 174             ram_width=ram_width,
 175             ram_height=ram_height,
 176             colstart=colstart,
 177             rowstart=rowstart,
 178             rotation=rotation,
 179             color_depth=color_depth,
 180             grayscale=core_grayscale,
 181             pixels_in_byte_share_row=True,
 182             bytes_per_cell=1,
 183             reverse_pixels_in_byte=True,
 184             reverse_bytes_in_word=True,
 185             column_command=set_column_window_command,
 186             row_command=set_row_window_command,
 187             set_current_column_command=set_current_column_command,
 188             set_current_row_command=set_current_row_command,
 189             data_as_commands=False,
 190             always_toggle_chip_select=always_toggle_chip_select,
 191             sh1107_addressing=False,
 192             address_little_endian=address_little_endian,
 193         )
 194
 195         if highlight_color != 0x000000:
 196             self._core.colorspace.tricolor = True
 197             self._core.colorspace.tricolor_hue = ColorConverter._compute_hue(
 198                 highlight_color
 199             )
 200             self._core.colorspace.tricolor_luma = ColorConverter._compute_luma(
 201                 highlight_color
 202             )
 203         else:
 204             self._core.colorspace.tricolor = False
 205
 206         self._acep = advanced_color_epaper
 207         self._core.colorspace.sevencolor = advanced_color_epaper
 208         self._write_black_ram_command = write_black_ram_command
 209         self._black_bits_inverted = black_bits_inverted
 210         self._write_color_ram_command = write_color_ram_command
 211         self._color_bits_inverted = color_bits_inverted
 212         self._refresh_time_ms = refresh_time * 1000
 213         self._busy_state = busy_state
 214         self._milliseconds_per_frame = seconds_per_frame * 1000
 215         self._chip_select = (
 216             CHIP_SELECT_TOGGLE_EVERY_BYTE
 217             if always_toggle_chip_select
 218             else CHIP_SELECT_UNTOUCHED
 219         )
 220         self._grayscale = grayscale
 221
 222         self._start_sequence = start_sequence
 223         self._start_up_time = start_up_time
 224         self._stop_sequence = stop_sequence
 225         self._refresh_sequence = refresh_sequence
 226         self._busy = None
 227         self._two_byte_sequence_length = two_byte_sequence_length
 228         if busy_pin is not None:
 229             self._busy = DigitalInOut(busy_pin)
 230             self._busy.switch_to_input()
 231
 232         self._ticks_disabled = False
 233
 234         # Clear the color memory if it isn't in use
 235         if highlight_color == 0x00 and write_color_ram_command != NO_COMMAND:
 236             """TODO: Clear"""
 237
 238         self.show(circuitpython_splash)
 239
 240     def __new__(cls, *args, **kwargs):
 241         from . import (  # pylint: disable=import-outside-toplevel, cyclic-import
 242             allocate_display,
 243         )
 244
 245         display_instance = super().__new__(cls)
 246         allocate_display(display_instance)
 247         return display_instance
 248
 249     def show(self, group: Group) -> None:
 250         # pylint: disable=unnecessary-pass
 251         """Switches to displaying the given group of layers. When group is None, the default
 252         CircuitPython terminal will be shown (eventually).
 253         """
 254         if group is None:
 255             group = circuitpython_splash
 256         self._core.set_root_group(group)
 257
 258     def update_refresh_mode(
 259         self, start_sequence: ReadableBuffer, seconds_per_frame: float
 260     ) -> None:
 261         """Updates the ``start_sequence`` and ``seconds_per_frame`` parameters to enable
 262         varying the refresh mode of the display."""
 263         self._start_sequence = bytearray(start_sequence)
 264         self._milliseconds_per_frame = seconds_per_frame * 1000
 265
 266     def refresh(self) -> None:
 267         """Refreshes the display immediately or raises an exception if too soon. Use
 268         ``time.sleep(display.time_to_refresh)`` to sleep until a refresh can occur.
 269         """
 270         if not self._refresh():
 271             raise RuntimeError("Refresh too soon")
 272
 273     def _refresh(self) -> bool:
 274         if self._refreshing and self._busy is not None:
 275             if self._busy.value != self._busy_state:
 276                 self._ticks_disabled = True
 277                 self._refreshing = False
 278                 self._send_command_sequence(False, self._stop_sequence)
 279             else:
 280                 return False
 281         if self._core.current_group is None:
 282             return True
 283         # Refresh at seconds per frame rate
 284         if self.time_to_refresh > 0:
 285             return False
 286
 287         if not self._core.bus_free():
 288             # Can't acquire display bus; skip updating this display. Try next display
 289             return False
 290
 291         areas_to_refresh = self._get_refresh_areas()
 292         if not areas_to_refresh:
 293             return True
 294
 295         if self._acep:
 296             self._start_refresh()
 297             self._clean_area()
 298             self._finish_refresh()
 299             while self._refreshing:
 300                 # TODO: Add something here that can change self._refreshing
 301                 pass
 302
 303         self._start_refresh()
 304         for area in areas_to_refresh:
 305             self._refresh_area(area)
 306         self._finish_refresh()
 307
 308         return True
 309
 310     def _release(self) -> None:
 311         """Release the display and free its resources"""
 312         if self._refreshing:
 313             self._wait_for_busy()
 314             self._ticks_disabled = True
 315             self._refreshing = False
 316             # Run stop sequence but don't wait for busy because busy is set when sleeping
 317             self._send_command_sequence(False, self._stop_sequence)
 318         self._core.release_display_core()
 319         if self._busy is not None:
 320             self._busy.deinit()
 321
 322     def _background(self) -> None:
 323         """Run background refresh tasks."""
 324
 325         # Wait until initialized
 326         if not hasattr(self, "_core"):
 327             return
 328
 329         if self._ticks_disabled:
 330             return
 331
 332         if self._refreshing:
 333             refresh_done = False
 334             if self._busy is not None:
 335                 busy = self._busy.value
 336                 refresh_done = busy == self._busy_state
 337             else:
 338                 refresh_done = (
 339                     time.monotonic() * 1000 - self._core.last_refresh
 340                     > self._refresh_time
 341                 )
 342
 343             if refresh_done:
 344                 self._ticks_disabled = True
 345                 self._refreshing = False
 346                 # Run stop sequence but don't wait for busy because busy is set when sleeping
 347                 self._send_command_sequence(False, self._stop_sequence)
 348
 349     def _get_refresh_areas(self) -> list[Area]:
 350         """Get a list of areas to be refreshed"""
 351         areas = []
 352         if self._core.full_refresh:
 353             areas.append(self._core.area)
 354             return areas
 355         first_area = None
 356         if self._core.current_group is not None:
 357             self._core.current_group._get_refresh_areas(  # pylint: disable=protected-access
 358                 areas
 359             )
 360             first_area = areas[0]
 361         if first_area is not None and self._core.row_command == NO_COMMAND:
 362             # Do a full refresh if the display doesn't support partial updates
 363             areas = [self._core.area]
 364         return areas
 365
 366     def _refresh_area(self, area: Area) -> bool:
 367         """Redraw the area."""
 368         # pylint: disable=too-many-locals, too-many-branches
 369         clipped = Area()
 370         # Clip the area to the display by overlapping the areas.
 371         # If there is no overlap then we're done.
 372         if not self._core.clip_area(area, clipped):
 373             return True
 374
 375         subrectangles = 1
 376         rows_per_buffer = clipped.height()
 377         pixels_per_word = 32 // self._core.colorspace.depth
 378         pixels_per_buffer = clipped.size()
 379
 380         # We should have lots of memory
 381         buffer_size = clipped.size() // pixels_per_word
 382
 383         if clipped.size() > buffer_size * pixels_per_word:
 384             rows_per_buffer = buffer_size * pixels_per_word // clipped.width()
 385             if rows_per_buffer == 0:
 386                 rows_per_buffer = 1
 387             subrectangles = clipped.height() // rows_per_buffer
 388             if clipped.height() % rows_per_buffer != 0:
 389                 subrectangles += 1
 390             pixels_per_buffer = rows_per_buffer * clipped.width()
 391             buffer_size = pixels_per_buffer // pixels_per_word
 392             if pixels_per_buffer % pixels_per_word:
 393                 buffer_size += 1
 394
 395         mask_length = (pixels_per_buffer // 8) + 1  # 1 bit per pixel + 1
 396
 397         passes = 1
 398         if self._write_color_ram_command != NO_COMMAND:
 399             passes = 2
 400         for pass_index in range(passes):
 401             remaining_rows = clipped.height()
 402             if self._core.row_command != NO_COMMAND:
 403                 self._core.set_region_to_update(clipped)
 404
 405             write_command = self._write_black_ram_command
 406             if pass_index == 1:
 407                 write_command = self._write_color_ram_command
 408
 409             self._core.begin_transaction()
 410             self._core.send(DISPLAY_COMMAND, self._chip_select, bytes([write_command]))
 411             self._core.end_transaction()
 412
 413             for subrect_index in range(subrectangles):
 414                 subrectangle = Area(
 415                     clipped.x1,
 416                     clipped.y1 + rows_per_buffer * subrect_index,
 417                     clipped.x2,
 418                     clipped.y1 + rows_per_buffer * (subrect_index + 1),
 419                 )
 420                 if remaining_rows < rows_per_buffer:
 421                     subrectangle.y2 = subrectangle.y1 + remaining_rows
 422                 remaining_rows -= rows_per_buffer
 423
 424                 subrectangle_size_bytes = subrectangle.size() // (
 425                     8 // self._core.colorspace.depth
 426                 )
 427
 428                 buffer = memoryview(bytearray([0] * (buffer_size * 4)))
 429                 mask = memoryview(bytearray([0] * mask_length))
 430
 431                 if not self._acep:
 432                     self._core.colorspace.grayscale = True
 433                     self._core.colorspace.grayscale_bit = 7
 434                 if pass_index == 1:
 435                     if self._grayscale:  # 4-color grayscale
 436                         self._core.colorspace.grayscale_bit = 6
 437                         self._core.fill_area(subrectangle, mask, buffer)
 438                     elif self._core.colorspace.tricolor:
 439                         self._core.colorspace.grayscale = False
 440                         self._core.fill_area(subrectangle, mask, buffer)
 441                     elif self._core.colorspace.sevencolor:
 442                         self._core.fill_area(subrectangle, mask, buffer)
 443                 else:
 444                     self._core.fill_area(subrectangle, mask, buffer)
 445
 446                 # Invert it all
 447                 if (pass_index == 1 and self._color_bits_inverted) or (
 448                     pass_index == 0 and self._black_bits_inverted
 449                 ):
 450                     for i, _ in enumerate(buffer):
 451                         buffer[i] = ~buffer[i]
 452
 453                 if not self._core.begin_transaction():
 454                     # Can't acquire display bus; skip the rest of the data. Try next display.
 455                     return False
 456                 self._core.send(
 457                     DISPLAY_DATA, self._chip_select, buffer[:subrectangle_size_bytes]
 458                 )
 459                 self._core.end_transaction()
 460         return True
 461
 462     def _send_command_sequence(
 463         self, should_wait_for_busy: bool, sequence: ReadableBuffer
 464     ) -> None:
 465         i = 0
 466         while i < len(sequence):
 467             command = sequence[i]
 468             data_size = sequence[i + 1]
 469             delay = (data_size & DELAY) != 0
 470             data_size &= ~DELAY
 471             data = sequence[i + 2 : i + 2 + data_size]
 472             if self._two_byte_sequence_length:
 473                 data_size = ((data_size & ~DELAY) << 8) + sequence[i + 2]
 474                 data = sequence[i + 3 : i + 3 + data_size]
 475
 476             self._core.begin_transaction()
 477             self._core.send(
 478                 DISPLAY_COMMAND, CHIP_SELECT_TOGGLE_EVERY_BYTE, bytes([command])
 479             )
 480             if data_size > 0:
 481                 self._core.send(
 482                     DISPLAY_DATA,
 483                     CHIP_SELECT_UNTOUCHED,
 484                     bytes(data),
 485                 )
 486             self._core.end_transaction()
 487             delay_time_ms = 0
 488             if delay:
 489                 data_size += 1
 490                 delay_time_ms = sequence[i + 1 + data_size]
 491                 if delay_time_ms == 255:
 492                     delay_time_ms = 500
 493             time.sleep(delay_time_ms / 1000)
 494             if should_wait_for_busy:
 495                 self._wait_for_busy()
 496             i += 2 + data_size
 497             if self._two_byte_sequence_length:
 498                 i += 1
 499
 500     def _start_refresh(self) -> None:
 501         # Run start sequence
 502         self._core._bus_reset()  # pylint: disable=protected-access
 503         time.sleep(self._start_up_time)
 504         self._send_command_sequence(True, self._start_sequence)
 505         self._core.start_refresh()
 506
 507     def _finish_refresh(self) -> None:
 508         # Actually refresh the display now that all pixel RAM has been updated
 509         self._send_command_sequence(False, self._refresh_sequence)
 510         self._ticks_disabled = False
 511         self._refreshing = True
 512         self._core.finish_refresh()
 513
 514     def _wait_for_busy(self) -> None:
 515         if self._busy is not None:
 516             while self._busy.value == self._busy_state:
 517                 time.sleep(0.001)
 518
 519     def _clean_area(self) -> bool:
 520         width = self._core.width
 521         height = self._core.height
 522
 523         buffer = bytearray([0x77] * (width // 2))
 524         self._core.begin_transaction()
 525         self._core.send(
 526             DISPLAY_COMMAND, self._chip_select, bytes([self._write_black_ram_command])
 527         )
 528         self._core.end_transaction()
 529         for _ in range(height):
 530             if not self._core.begin_transaction():
 531                 return False
 532             self._core.send(DISPLAY_DATA, self._chip_select, buffer)
 533             self._core.end_transaction()
 534         return True
 535
 536     @property
 537     def rotation(self) -> int:
 538         """The rotation of the display as an int in degrees"""
 539         return self._core.rotation
 540
 541     @rotation.setter
 542     def rotation(self, value: int) -> None:
 543         if value % 90 != 0:
 544             raise ValueError("Display rotation must be in 90 degree increments")
 545         transposed = self._core.rotation in (90, 270)
 546         will_transposed = value in (90, 270)
 547         if transposed != will_transposed:
 548             self._core.width, self._core.height = self._core.height, self._core.width
 549         self._core.set_rotation(value)
 550
 551     @property
 552     def time_to_refresh(self) -> float:
 553         """Time, in fractional seconds, until the ePaper display can be refreshed."""
 554         if self._core.last_refresh == 0:
 555             return 0
 556
 557         # Refresh at seconds per frame rate
 558         elapsed_time = time.monotonic() * 1000 - self._core.last_refresh
 559         if elapsed_time > self._milliseconds_per_frame:
 560             return 0
 561         return self._milliseconds_per_frame - elapsed_time
 562
 563     @property
 564     def busy(self) -> bool:
 565         """True when the display is refreshing. This uses the ``busy_pin`` when available or the
 566         ``refresh_time`` otherwise."""
 567         return self._refreshing
 568
 569     @property
 570     def width(self) -> int:
 571         """Display Width"""
 572         return self._core.width
 573
 574     @property
 575     def height(self) -> int:
 576         """Display Height"""
 577         return self._core.height
 578
 579     @property
 580     def bus(self) -> _DisplayBus:
 581         """Current Display Bus"""
 582         return self._core.get_bus()
 583
 584     @property
 585     def root_group(self) -> Group:
 586         """The root group on the epaper display.
 587         If the root group is set to ``None``, no output will be shown.
 588         """
 589         return self._core.root_group
 590
 591     @root_group.setter
 592     def root_group(self, new_group: Group) -> None:
 593         self._core.root_group = new_group