Generating a stencil border

stencil.py

# -*- coding: utf-8 -*-

from decimal import Decimal
from copy import copy

from django.shortcuts import render
from django.contrib import messages
from django.contrib.auth.decorators import login_required

from .forms import StencilBorderForm

from groups import group_required

unit_conversions = {
    'cm': Decimal(10),
    'mm': Decimal(1),
    'in': Decimal(25.4),
    'mil': Decimal(25.4)/1000,
}

def convert_to_mm(length, unit):
    
    return Decimal(length) * unit_conversions[unit]

def convert_from_mm(length, unit):
    
    return Decimal(length) / unit_conversions[unit]

# TODO: Handle up is +ve/-ve
# TODO: Generate a gerber file
# TODO: Do the translation in the gerber file

@login_required
@group_required('backend')
def stencil_border(request):
    # GET: Show "stencil param" form
    # POST: Accept and validate stencil info, then create it.
    data = {}
    if request.method == 'POST':
        # print "order_change: in POST"
        form = StencilBorderForm(request.POST)
        if form.is_valid():
            print "stencil_border: form is valid"
            print "form.cleaned_data=", form.cleaned_data
            # error = False
            board_size_x = convert_to_mm(form.cleaned_data['board_size_x'], form.cleaned_data['board_size_units'])
            board_size_y = convert_to_mm(form.cleaned_data['board_size_y'], form.cleaned_data['board_size_units'])
            board_tl_x = convert_to_mm(form.cleaned_data['board_tl_x'], form.cleaned_data['board_tl_units'])
            board_tl_y = convert_to_mm(form.cleaned_data['board_tl_y'], form.cleaned_data['board_tl_units'])
            stencil_size_x = convert_to_mm(form.cleaned_data['stencil_size_x'], form.cleaned_data['stencil_size_units'])
            stencil_size_y = convert_to_mm(form.cleaned_data['stencil_size_y'], form.cleaned_data['stencil_size_units'])

            # print "pre:  ssx=", stencil_size_x, "ssy=", stencil_size_y
            if form.cleaned_data['stencil_size_x'].startswith('+'):
                stencil_size_x = (stencil_size_x * 2) + board_size_x
            if form.cleaned_data['stencil_size_y'].startswith('+'):
                stencil_size_y = (stencil_size_y * 2) + board_size_y
            # print "post: ssx=", stencil_size_x, "ssy=", stencil_size_y

            board_middle_x = board_tl_x + (board_size_x / 2)
            board_middle_y = board_tl_y - (board_size_y / 2)
            
            stencil_middle_x = stencil_size_x / 2
            stencil_middle_y = -stencil_size_y / 2

            stencil_translation_x = board_middle_x - stencil_middle_x
            stencil_translation_y = stencil_middle_y - board_middle_y
            
            radius = 5
            
            # Top left, top right, bottom left, bottom right
            tl = {'x': stencil_translation_x, 'y': stencil_translation_y}
            tr = {'x': stencil_translation_x + stencil_size_x, 'y': stencil_translation_y}
            bl = {'x': stencil_translation_x, 'y': stencil_translation_y + stencil_size_y}
            br = {'x': stencil_translation_x + stencil_size_x, 'y': stencil_translation_y + stencil_size_y}

            # tle=top left then east, brw=bottom right then west
            tle = copy(tl); tle['x'] += radius
            tls = copy(tl); tls['y'] += radius
            trw = copy(tr); trw['x'] -= radius
            trs = copy(tr); trs['y'] += radius
            ble = copy(bl); ble['x'] += radius
            bln = copy(bl); bln['y'] -= radius
            brw = copy(br); brw['x'] -= radius
            brn = copy(br); brn['y'] -= radius
            
            data = {
                'form': form,
                'board_middle_x': convert_from_mm(board_middle_x, form.cleaned_data['board_middle_units']),
                'board_middle_y': convert_from_mm(board_middle_y, form.cleaned_data['board_middle_units']),
                'stencil_middle_x': convert_from_mm(stencil_middle_x, form.cleaned_data['stencil_middle_units']),
                'stencil_middle_y': convert_from_mm(stencil_middle_y, form.cleaned_data['stencil_middle_units']),
                'stencil_size_x': convert_from_mm(stencil_size_x, form.cleaned_data['stencil_translation_units']),
                'stencil_size_y': convert_from_mm(stencil_size_y, form.cleaned_data['stencil_translation_units']),
                'tl': tl,
                'bl': bl,
                'tle': tle,
                'tls': tls,
                'trw': trw,
                'trs': trs,
                'ble': ble,
                'bln': bln,
                'brw': brw,
                'brn': brn,
            }

            # No point redirecting, as we haven't changed anything.
            # return HttpResponseRedirect(reverse('backend.views.order', args={order.hash}))
            
        else:
            messages.error(request, 'Invalid data')
    else:
        data['form'] = StencilBorderForm()
    
    return render(request, 'backend/stencil-border.html', data)