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M1730-Scale/web/app.py
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import base64
import pathlib
from flask import Flask, render_template, request, Response
from html import escape
app = Flask(__name__)
_FONT_PATH = pathlib.Path('/usr/local/share/fonts/г/ГОСТ_тип_А.ttf')
_FONT_B64 = base64.b64encode(_FONT_PATH.read_bytes()).decode()
_FONT_FACE = (
'<defs><style>'
'@font-face {'
'font-family:"ГОСТ тип А";'
f'src:url("data:font/truetype;base64,{_FONT_B64}") format("truetype");'
'}'
'</style></defs>'
)
# SVG absolute coordinate constants (1 user unit = 1 mm)
ZERO_X = 60.844130 # x of the zero/left tick
MAX_X = 180.251230 # x of the full-scale/right tick
BAR_Y = 107.54670 # y at the top of the scale bar (tick baseline)
SCALE_LEN = MAX_X - ZERO_X # 119.4071 mm
BIG_H = 5.0895 # major tick height
SMALL_H = 2.6683 # minor tick height
_UNIT_AREA_WIDTH = 18.445 # canvas mm available for the unit label
_UNIT_SCALE_X = 0.96486402
_UNIT_CHAR_EM = 0.65 # approximate advance-width ratio for GOST typ A
def _unit_font_size(unit: str) -> float:
n = max(1, len(unit))
return min(18.7981, _UNIT_AREA_WIDTH / (n * _UNIT_SCALE_X * _UNIT_CHAR_EM))
def _fmt(v: float) -> str:
if v == int(v):
return str(int(v))
return f"{v:.4g}"
def generate_svg(unit, min_val, max_val, range_label, big_ticks, small_ticks, label_count):
big_interval = SCALE_LEN / big_ticks
big_xs = [ZERO_X + i * big_interval for i in range(big_ticks + 1)]
label_count = max(2, min(label_count, big_ticks + 1))
label_indices = [round(k * big_ticks / (label_count - 1)) for k in range(label_count)]
parts = [
'<?xml version="1.0" encoding="UTF-8" standalone="no"?>',
'<svg width="157.18373mm" height="26.683672mm"'
' viewBox="0 0 157.18373 26.683672" version="1.1"'
' xmlns="http://www.w3.org/2000/svg">',
_FONT_FACE,
' <g transform="translate(-37.352226,-90.454928)">',
# Background rect with scale-bar cutout
' <path style="fill:#f9f9f9;stroke:#1a1a1a;stroke-width:0.184;'
'stroke-linecap:round;stroke-miterlimit:10"'
' d="M 37.444226,90.546928 V 117.0466 H 194.44395 V 90.546928 Z'
' M 58.443978,107.54692 H 183.64409 v 6.19963 H 58.443978 Z" />',
# Unit label (large letter in left panel)
f' <text style="font-size:{_unit_font_size(unit):.4f}px;font-family:\'ГОСТ тип А\',monospace;fill:#1a1a1a"'
f' x="41.455711" y="109.03796"'
f' transform="scale(0.96486402,1.0364155)">{escape(unit)}</text>',
# Range label inside the strip on the right
f' <text style="font-size:3.60539px;font-family:\'ГОСТ тип А\',monospace;fill:#1a1a1a"'
f' x="184.79707" y="113.6755">{escape(range_label)}</text>',
]
# Major ticks
for x in big_xs:
parts.append(
f' <line x1="{x:.5f}" y1="{BAR_Y}" x2="{x:.5f}" y2="{BAR_Y - BIG_H:.5f}"'
f' style="stroke:#1a1a1a;stroke-width:0.555;stroke-linecap:butt" />'
)
# Minor ticks
if small_ticks > 0:
sub = small_ticks + 1
for i in range(big_ticks):
for j in range(1, small_ticks + 1):
x = big_xs[i] + j * big_interval / sub
parts.append(
f' <line x1="{x:.5f}" y1="{BAR_Y}" x2="{x:.5f}" y2="{BAR_Y - SMALL_H:.5f}"'
f' style="stroke:#1a1a1a;stroke-width:0.302;stroke-linecap:butt" />'
)
# Numeric labels (centered on their tick, above the tick area)
for idx in label_indices:
x = big_xs[idx]
val = min_val + (max_val - min_val) * idx / big_ticks
parts.append(
f' <text style="font-size:8.89194px;font-family:\'ГОСТ тип А\',monospace;fill:#1a1a1a"'
f' text-anchor="middle" x="{x:.5f}" y="101.49598">{escape(_fmt(val))}</text>'
)
parts += [' </g>', '</svg>']
return '\n'.join(parts)
@app.route('/')
def index():
return render_template('index.html')
@app.route('/generate', methods=['POST'])
def generate():
unit = request.form.get('unit', '%')
min_val = float(request.form.get('min', 0))
max_val = float(request.form.get('max', 100))
range_label = request.form.get('range_label', '5mA')
big_ticks = max(1, min(50, int(request.form.get('big_ticks', 10))))
small_ticks = max(0, min(20, int(request.form.get('small_ticks', 4))))
label_count = max(2, int(request.form.get('label_count', 6)))
svg = generate_svg(unit, min_val, max_val, range_label, big_ticks, small_ticks, label_count)
return Response(svg, mimetype='image/svg+xml')
if __name__ == '__main__':
app.run(debug=True)