def dither(self):
"""Return an Atkinson-dithered version of `bitmap`.
Each pixel in `bitmap` may take a value in [0, 255].
Based on code by Michal Migurski:
http://mike.teczno.com/notes/atkinson.html
"""
threshold = 128 * [0] + 128 * [255]
for y in xrange(self._height):
for x in xrange(self._width):
old = self.pixels[y * self._width + x]
new = threshold[old]
err = (old - new) // 8
self.pixels[y * self._width + x] = new
for nxy in [(x + 1, y), (x + 2, y), (x - 1, y + 1), (x, y + 1),
(x + 1, y + 1), (x, y + 2)]:
try:
px = nxy[1] * self._width + nxy[0]
self.pixels[px] = commons.clamp(
self.pixels[px] + err, 0, 255)
except IndexError:
pass
def render_progressbar(surface, x, y, w, h, progress):
"""Draw a progress bar widget into the given surface."""
surface.strokerect(x, y, w, h)
bar_width = int((w - 4) * commons.clamp(progress, 0, 1))
surface.fillrect(x + 2, y + 2, bar_width, h - 4)
def down_pressed(self):
self.cy += 1
self.cy = commons.clamp(self.cy, 0, len(self.stations) - 1)
self.set_needs_repaint()
