micropython-font-to-py/writer/writer_minimal.py

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Python

# writer_minimal.py Implements the Writer class.
# Minimal version for SSD1306
# V0.22 Peter Hinch 3rd Jan 2018: Supports new SSD1306 driver.
# The MIT License (MIT)
#
# Copyright (c) 2016 Peter Hinch
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
# A Writer supports rendering text to a Display instance in a given font.
# Multiple Writer instances may be created, each rendering a font to the
# same Display object.
import framebuf
class Writer():
text_row = 0 # attributes common to all Writer instances
text_col = 0
row_clip = False # Clip or scroll when screen full
col_clip = False # Clip or new line when row is full
@classmethod
def set_textpos(cls, row, col):
cls.text_row = row
cls.text_col = col
@classmethod
def set_clip(cls, row_clip, col_clip):
cls.row_clip = row_clip
cls.col_clip = col_clip
def __init__(self, device, font, verbose=True):
self.device = device
self.font = font
# Allow to work with any font mapping
if font.hmap():
self.map = framebuf.MONO_HMSB if font.reverse() else framebuf.MONO_HLSB
else:
raise ValueError('Font must be horizontally mapped.')
if verbose:
print('Orientation: {} Reversal: {}'.format('horiz' if font.hmap() else 'vert', font.reverse()))
self.screenwidth = device.width # In pixels
self.screenheight = device.height
def _newline(self):
height = self.font.height()
Writer.text_row += height
Writer.text_col = 0
margin = self.screenheight - (Writer.text_row + height)
if margin < 0:
if not Writer.row_clip:
self.device.scroll(0, margin)
Writer.text_row += margin
def printstring(self, string):
for char in string:
self._printchar(char)
# Method using blitting. Efficient rendering for monochrome displays.
# Tested on SSD1306. Invert is for black-on-white rendering.
def _printchar(self, char, invert=False):
if char == '\n':
self._newline()
return
glyph, char_height, char_width = self.font.get_ch(char)
if Writer.text_row + char_height > self.screenheight:
if Writer.row_clip:
return
self._newline()
if Writer.text_col + char_width > self.screenwidth:
if Writer.col_clip:
return
else:
self._newline()
buf = bytearray(glyph)
if invert:
for i, v in enumerate(buf):
buf[i] = 0xFF & ~ v
fbc = framebuf.FrameBuffer(buf, char_width, char_height, self.map)
self.device.blit(fbc, Writer.text_col, Writer.text_row)
Writer.text_col += char_width