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         subrectangles = 1
 375         rows_per_buffer = clipped.height()
 376         pixels_per_word = 32 // self._core.colorspace.depth
 377         pixels_per_buffer = clipped.size()
 378
 379         # We should have lots of memory
 380         buffer_size = clipped.size() // pixels_per_word
 381
 382         if clipped.size() > buffer_size * pixels_per_word:
 383             rows_per_buffer = buffer_size * pixels_per_word // clipped.width()
 384             if rows_per_buffer == 0:
 385                 rows_per_buffer = 1
 386             subrectangles = clipped.height() // rows_per_buffer
 387             if clipped.height() % rows_per_buffer != 0:
 388                 subrectangles += 1
 389             pixels_per_buffer = rows_per_buffer * clipped.width()
 390             buffer_size = pixels_per_buffer // pixels_per_word
 391             if pixels_per_buffer % pixels_per_word:
 392                 buffer_size += 1
 393
 394         mask_length = (pixels_per_buffer // 32) + 1  # 1 bit per pixel + 1
 395
 396         passes = 1
 397         if self._write_color_ram_command != NO_COMMAND:
 398             passes = 2
 399         for pass_index in range(passes):
 400             remaining_rows = clipped.height()
 401             if self._core.row_command != NO_COMMAND:
 402                 self._core.set_region_to_update(clipped)
 403
 404             write_command = self._write_black_ram_command
 405             if pass_index == 1:
 406                 write_command = self._write_color_ram_command
 407
 408             self._core.begin_transaction()
 409             self._core.send(DISPLAY_COMMAND, self._chip_select, bytes([write_command]))
 410             self._core.end_transaction()
 411
 412             for subrect_index in range(subrectangles):
 413                 subrectangle = Area(
 414                     x1=clipped.x1,
 415                     y1=clipped.y1 + rows_per_buffer * subrect_index,
 416                     x2=clipped.x2,
 417                     y2=clipped.y1 + rows_per_buffer * (subrect_index + 1),
 418                 )
 419                 if remaining_rows < rows_per_buffer:
 420                     subrectangle.y2 = subrectangle.y1 + remaining_rows
 421                 remaining_rows -= rows_per_buffer
 422
 423                 subrectangle_size_bytes = subrectangle.size() // (
 424                     8 // self._core.colorspace.depth
 425                 )
 426
 427                 buffer = memoryview(bytearray([0] * (buffer_size * 4))).cast("I")
 428                 mask = memoryview(bytearray([0] * (mask_length * 4))).cast("I")
 429
 430                 if not self._acep:
 431                     self._core.colorspace.grayscale = True
 432                     self._core.colorspace.grayscale_bit = 7
 433                 if pass_index == 1:
 434                     if self._grayscale:  # 4-color grayscale
 435                         self._core.colorspace.grayscale_bit = 6
 436                         self._core.fill_area(subrectangle, mask, buffer)
 437                     elif self._core.colorspace.tricolor:
 438                         self._core.colorspace.grayscale = False
 439                         self._core.fill_area(subrectangle, mask, buffer)
 440                     elif self._core.colorspace.sevencolor:
 441                         self._core.fill_area(subrectangle, mask, buffer)
 442                 else:
 443                     self._core.fill_area(subrectangle, mask, buffer)
 444
 445                 # Invert it all
 446                 if (pass_index == 1 and self._color_bits_inverted) or (
 447                     pass_index == 0 and self._black_bits_inverted
 448                 ):
 449                     for i, _ in enumerate(buffer):
 450                         buffer[i] = ~buffer[i]
 451
 452                 if not self._core.begin_transaction():
 453                     # Can't acquire display bus; skip the rest of the data. Try next display.
 454                     return False
 455                 self._core.send(
 456                     DISPLAY_DATA,
 457                     self._chip_select,
 458                     buffer.tobytes()[:subrectangle_size_bytes],
 459                 )
 460                 self._core.end_transaction()
 461         return True
 462
 463     def _send_command_sequence(
 464         self, should_wait_for_busy: bool, sequence: ReadableBuffer
 465     ) -> None:
 466         i = 0
 467         while i < len(sequence):
 468             command = sequence[i]
 469             data_size = sequence[i + 1]
 470             delay = (data_size & DELAY) != 0
 471             data_size &= ~DELAY
 472             data = sequence[i + 2 : i + 2 + data_size]
 473             if self._two_byte_sequence_length:
 474                 data_size = ((data_size & ~DELAY) << 8) + sequence[i + 2]
 475                 data = sequence[i + 3 : i + 3 + data_size]
 476
 477             self._core.begin_transaction()
 478             self._core.send(
 479                 DISPLAY_COMMAND, CHIP_SELECT_TOGGLE_EVERY_BYTE, bytes([command])
 480             )
 481             if data_size > 0:
 482                 self._core.send(
 483                     DISPLAY_DATA,
 484                     CHIP_SELECT_UNTOUCHED,
 485                     bytes(data),
 486                 )
 487             self._core.end_transaction()
 488             delay_time_ms = 0
 489             if delay:
 490                 data_size += 1
 491                 delay_time_ms = sequence[i + 1 + data_size]
 492                 if delay_time_ms == 255:
 493                     delay_time_ms = 500
 494             time.sleep(delay_time_ms / 1000)
 495             if should_wait_for_busy:
 496                 self._wait_for_busy()
 497             i += 2 + data_size
 498             if self._two_byte_sequence_length:
 499                 i += 1
 500
 501     def _start_refresh(self) -> None:
 502         # Run start sequence
 503         self._core._bus_reset()  # pylint: disable=protected-access
 504         time.sleep(self._start_up_time)
 505         self._send_command_sequence(True, self._start_sequence)
 506         self._core.start_refresh()
 507
 508     def _finish_refresh(self) -> None:
 509         # Actually refresh the display now that all pixel RAM has been updated
 510         self._send_command_sequence(False, self._refresh_sequence)
 511         self._ticks_disabled = False
 512         self._refreshing = True
 513         self._core.finish_refresh()
 514
 515     def _wait_for_busy(self) -> None:
 516         if self._busy is not None:
 517             while self._busy.value == self._busy_state:
 518                 time.sleep(0.001)
 519
 520     def _clean_area(self) -> bool:
 521         width = self._core.width
 522         height = self._core.height
 523
 524         buffer = bytearray([0x77] * (width // 2))
 525         self._core.begin_transaction()
 526         self._core.send(
 527             DISPLAY_COMMAND, self._chip_select, bytes([self._write_black_ram_command])
 528         )
 529         self._core.end_transaction()
 530         for _ in range(height):
 531             if not self._core.begin_transaction():
 532                 return False
 533             self._core.send(DISPLAY_DATA, self._chip_select, buffer)
 534             self._core.end_transaction()
 535         return True
 536
 537     @property
 538     def rotation(self) -> int:
 539         """The rotation of the display as an int in degrees"""
 540         return self._core.rotation
 541
 542     @rotation.setter
 543     def rotation(self, value: int) -> None:
 544         if value % 90 != 0:
 545             raise ValueError("Display rotation must be in 90 degree increments")
 546         transposed = self._core.rotation in (90, 270)
 547         will_transposed = value in (90, 270)
 548         if transposed != will_transposed:
 549             self._core.width, self._core.height = self._core.height, self._core.width
 550         self._core.set_rotation(value)
 551         if self._core.current_group is not None:
 552             self._core.current_group._update_transform(  # pylint: disable=protected-access
 553                 self._core.transform
 554             )
 555
 556     @property
 557     def time_to_refresh(self) -> float:
 558         """Time, in fractional seconds, until the ePaper display can be refreshed."""
 559         if self._core.last_refresh == 0:
 560             return 0
 561
 562         # Refresh at seconds per frame rate
 563         elapsed_time = time.monotonic() * 1000 - self._core.last_refresh
 564         if elapsed_time > self._milliseconds_per_frame:
 565             return 0
 566         return self._milliseconds_per_frame - elapsed_time
 567
 568     @property
 569     def busy(self) -> bool:
 570         """True when the display is refreshing. This uses the ``busy_pin`` when available or the
 571         ``refresh_time`` otherwise."""
 572         return self._refreshing
 573
 574     @property
 575     def width(self) -> int:
 576         """Display Width"""
 577         return self._core.width
 578
 579     @property
 580     def height(self) -> int:
 581         """Display Height"""
 582         return self._core.height
 583
 584     @property
 585     def bus(self) -> _DisplayBus:
 586         """Current Display Bus"""
 587         return self._core.get_bus()
 588
 589     @property
 590     def root_group(self) -> Group:
 591         """The root group on the epaper display.
 592         If the root group is set to ``None``, no output will be shown.
 593         """
 594         return self._core.root_group
 595
 596     @root_group.setter
 597     def root_group(self, new_group: Group) -> None:
 598         self._core.root_group = new_group