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base repository: whitequark/glasgow
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head repository: whitequark/glasgow
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compare: 44f9b182e953
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  • 2 commits
  • 1 file changed
  • 1 contributor

Commits on Mar 4, 2019

  1. applet.display.pdi: add --checkerboard option.

    @whitequark
    whitequark committed Mar 4, 2019
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    ab19c43 View commit details

  2. applet.display.pdi: experiment with staging.

    @whitequark
    whitequark committed Mar 4, 2019
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    44f9b18 View commit details
Showing with 39 additions and 17 deletions.
  1. +39 −17 software/glasgow/applet/display/pdi/__init__.py
56 changes: 39 additions & 17 deletions software/glasgow/applet/display/pdi/__init__.py
View file
Original file line number Diff line number Diff line change
@@ -43,6 +43,14 @@
# the odd lines and then even lines leads to ghosting. It appears that the display has some
# logic dependent on scan order, in spite of the scan bytes seemingly implying that the drivers
# can be scanned in any desired order.
#
# * The staging differs from that described in the datasheet in two aspects. First, there is no
# Compensate stage, since the applet can't know what the old image was. Second, the datasheet
# suggests White→Inverse→Normal staging. My experimentation shows that a different staging,
# Black→White→Normal→Normal (with two Normal frames, not one Normal frame that's twice as
# long!), produces significantly higher contrast, and an even longer staging, Black→White→
# Black→White→Normal→Normal has higher contrast and reduced ghosting. I'm guessing these
# would be more unpleasant on something like a ebook reader.

import math
import re
@@ -390,28 +398,42 @@ async def run(self, device, args):

@classmethod
def add_interact_arguments(cls, parser):
parser.add_argument(
"image_file", metavar="IMAGE-FILE", type=argparse.FileType("rb"),
g_pattern = parser.add_mutually_exclusive_group(required=True)
g_pattern.add_argument(
"--checkerboard", default=False, action="store_true",
help="display a checkerboard pattern")
g_pattern.add_argument(
"image_file", metavar="IMAGE-FILE", type=argparse.FileType("rb"), nargs="?",
help="image file to display (format: pbm)")

async def interact(self, device, args, pdi_iface):
image_header = args.image_file.readline()
if image_header != b"P4\n":
raise GlasgowAppletError("image file is not a raw PBM file")
image_comment = args.image_file.readline()
image_size = re.match(rb"^(\d+) (\d+)$", args.image_file.readline())
if not image_size:
raise GlasgowAppletError("image file is corrupt")
image_width, image_height = int(image_size[1]), int(image_size[2])
if image_width != pdi_iface.width or image_height != pdi_iface.height:
raise GlasgowAppletError("image size does not match display size")
image = bitarray()
image.frombytes(args.image_file.read())
if args.checkerboard:
image = bitarray(([0,0,1,1] * (pdi_iface.width // 2) +
[1,1,0,0] * (pdi_iface.width // 2))
* (pdi_iface.height // 4))

if args.image_file:
image_header = args.image_file.readline()
if image_header != b"P4\n":
raise GlasgowAppletError("image file is not a raw PBM file")
image_comment = args.image_file.readline()
image_size = re.match(rb"^(\d+) (\d+)$", args.image_file.readline())
if not image_size:
raise GlasgowAppletError("image file is corrupt")
image_width, image_height = int(image_size[1]), int(image_size[2])
if image_width != pdi_iface.width or image_height != pdi_iface.height:
raise GlasgowAppletError("image size does not match display size")
image = bitarray()
image.frombytes(args.image_file.read())

stage_ms = 300

await pdi_iface.power_on()
await pdi_iface.display_frame(mode="black", time_ms=100)
await pdi_iface.display_frame(mode="white", time_ms=100)
await pdi_iface.display_frame(mode="white", time_ms=100, image=image)
for _ in range(2):
await pdi_iface.display_frame(mode="black", time_ms=stage_ms)
await pdi_iface.display_frame(mode="white", time_ms=stage_ms)
await pdi_iface.display_frame(mode="white", time_ms=stage_ms, image=image)
await pdi_iface.display_frame(mode="white", time_ms=stage_ms, image=image)
await pdi_iface.power_off()

# -------------------------------------------------------------------------------------------------