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wasp: draw565: Add some docstrings

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This commit is contained in:
Daniel Thompson 2020-02-23 20:52:09 +00:00
parent c3d4ddafbc
commit 7fc4592383
1 changed files with 32 additions and 15 deletions
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47
wasp/draw565.py
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@ -2,7 +2,7 @@ import fonts.sans24
import micropython
@micropython.viper
def bitblit(bitbuf, pixels, bgfg: int, count: int):
def _bitblit(bitbuf, pixels, bgfg: int, count: int):
mv = ptr8(bitbuf)
px = ptr8(pixels)
@ -29,7 +29,7 @@ def bitblit(bitbuf, pixels, bgfg: int, count: int):
bitselect = 0x80
pxp += 1
def bounding_box(s, font):
def _bounding_box(s, font):
w = 0
for ch in s:
(_, h, wc) = font.get_ch(ch)
@ -37,37 +37,63 @@ def bounding_box(s, font):
return (w, h)
def draw_glyph(display, glyph, x, y, bgfg):
def _draw_glyph(display, glyph, x, y, bgfg):
(px, h, w) = glyph
buf = memoryview(display.linebuffer)[0:2*(w+1)]
bytes_per_row = (w + 7) // 8
for row in range(h):
bitblit(buf, px[row*bytes_per_row:], bgfg, w)
_bitblit(buf, px[row*bytes_per_row:], bgfg, w)
buf[2*w] = 0
buf[2*w + 1] = 0
display.rawblit(buf, x, y+row, w+1, 1)
class Draw565(object):
"""Drawing library for RGB565 displays.
A full framebufer is not required although the library will
'borrow' a line buffer from the underlying display driver.
"""
def __init__(self, display):
"""Initialise the library.
Defaults to white-on-black for monochrome drawing operations
and 24 pt Sans Serif text.
"""
self._display = display
self.set_color(0xffff)
self.set_font(fonts.sans24)
def set_color(self, color, bg=0):
"""Set the foreground (color) and background (bg) color.
The supplied color will be used for all monochrome drawing operations.
If no background color is provided then the background will be set
to black.
"""
self._bgfg = (bg << 16) + color
def set_font(self, font):
"""Set the font used for rendering text."""
self._font = font
def string(self, s, x, y, width=None):
"""Draw a string at the supplied position.
If no width is provided then the text will be left justified,
otherwise the text will be centered within the provided width and,
importantly, the remaining width will be filled with the background
color (to ensure that if we update one string with a narrower one
there is no need to "undraw" it)
"""
display = self._display
bgfg = self._bgfg
font = self._font
if width:
(w, h) = bounding_box(s, font)
(w, h) = _bounding_box(s, font)
leftpad = (width - w) // 2
rightpad = width - w - leftpad
display.fill(0, x, y, leftpad, h)
@ -75,17 +101,8 @@ class Draw565(object):
for ch in s:
glyph = font.get_ch(ch)
draw_glyph(display, glyph, x, y, bgfg)
_draw_glyph(display, glyph, x, y, bgfg)
x += glyph[2] + 1
if width:
display.fill(0, x, y, rightpad, h)
#import watch
#draw = Draw(watch.display)
#
#def test():
# watch.display.poweron()
# watch.backlight.set(2)
#
# draw.string('10-Jan-2020', 0, 24, width=240)