After a request to add more axes to the previous simple variable fonts tutorial the follow up escalated a bit. Since there are several files I thought it might be better to put them on github.

Intro

This is based on an art work by Vera Molnar (a pioneer in the field of generative art).
This script will generate a pattern with randomly rotated rectangles – using two nested loops.

Code and explanation

Lets start with the default settings of DrawBot:
fill color is black, a white background and a canvas with a width and height of 1000 units.

First we define how many rows and columns we want to have in the drawing and assign this value to the variable amount

amount = 24

Next we want to define the size of each cell in the grid. We want to calculate this value and not define a fixed value so it updates automatically. To calculate the width of the cell we call the width() function which returns the width of the canvas (in our case the default value of 1000). We divide this value by the amount of cells (stored in the variable amount). Since we want to have a margin around the drawing we just add 2 to the amount.

cell_s = width() / (amount + 2)

Since we want the squares rotated by 45 degrees to touch at the corners we need to calculate the size of the rectangles.
With a rotation of 45 degrees this can be done quite easily by dividing the cell size by the square root of 2.

rect_s = cell_s / sqrt(2)

Now we should have all the numbers ready to start drawing the pattern. To apply the margin we first shift the origin of the drawing one cell size to the right and to the top. We do this by calling the translate() function with the parameters of one cell size in the x direction and the y direction

translate(cell_s, cell_s)

Now lets start to loop in the x direction as many times as defined in the amount variable

for x in range(amount):

And then for each x value do the same in the y direction. So our total amount of cells will be the square of the amount (24 * 24 = 576 cells).

    for y in range(amount):

Before we call the rotate() function lets first shift the origin with the translate() function. Since we want to revert back to the default state (with no rotation) after we have drawn a rectangle let’s call the savedState() function first:

        with savedState():

Now let’s do the shifting: Shift x times the cell size to the left and y times the cell size to the top. Since we want the rotation to be happening in the center of the cell we need to add half a cell size in each direction.

            translate( x * cell_s + cell_s/2, y * cell_s + cell_s/2 )

We only want to do the rotation on some of the cells. So we just call the random() function which returns a randomly generated value between 0 and 1. If this value is higher than 0.5 (which on average should be in half of the cases) let’s do the rotation:

            if random() > .5: 
            	rotate(45)

Finally lets draw a rectangle by calling the rect() function. The rectangle should be drawn half a cell size to the left and bottom to compensate for the extra translation from before:

            rect(-rect_s/2, -rect_s/2, rect_s, rect_s)

To save the image lets call the saveImage() function and give a path and file name:

saveImage('~/Desktop/Vera_Molnar_rotating_rects.png')

Everything put together

amount = 24
cell_s = width() / (amount + 2)

rect_s = cell_s / sqrt(2)
translate( cell_s, cell_s)

for x in range(amount):
    for y in range(amount):
        with savedState():
            translate( x * cell_s + cell_s/2, y * cell_s + cell_s/2 )
            if random() > .5: 
            	rotate(45)
            rect(-rect_s/2, -rect_s/2, rect_s, rect_s)

# saveImage('~/Desktop/Vera_Molnar_rotating_rects.png')

Image

Vera Molnar is a great computer generated arts pioneer and is still working. I could not resist to emulate and try to recode some of her artworks. Using drawbot to do so is great fun and pretty easy — one can only wonder about the struggles she had to overcome. With all due respect here is a link to github with my humble attempts.

nautil.us has a nice blogpost of optical illusions. I could not resist the attempt to build one of them in drawbot.

pw = ph = 400 # define variables to set width and height of the canvas
cols = 14 # define how many columns there should be 
rows = 4 # define how many rows there should be 
pages = 30 # define how many frames the gif should have. more pages mean slower movement

angle_diff = 2 * pi/pages # we want the loop to make one full circle. 2 times pi is 360 degrees. Divided by the amount of pages this gives us the angle difference between pages. 

gap = pw/(cols+1) # calculate the gap between the lines. 
l   = (ph - 2 * gap)/rows # calculate the length of the line. 

for p in range(pages): 
    newPage(pw, ph)
    translate(gap, gap)
    fill(None)
    strokeWidth(2)
    for x in range(cols):
        y_off = cos( 3 * pi * x/cols + angle_diff * p ) * gap/2 # calculate how high or low the arrowhead should be 
        for y in range(rows+1):
            stroke(1,0 ,0) if y % 2 == 0 else stroke(0, 0, 1)
            if y < rows:
                line((x*gap, y*l), (x*gap, y*l+l))
            stroke(0)
            y_off *= -1 # switch to change direction 
            line( (x*gap, y*l), (x*gap - gap/2, y*l - y_off) )
            line( (x*gap, y*l), (x*gap + gap/2, y*l - y_off) )

# saveImage('~/Desktop/opti_illu.gif')

this should generate something like this:

the script could be used to get a scarf knitted.
good idea. thanks for the tipp @frederik

rule 122 on one side which makes the other side rule 161

the mirrored drawing is probably happening outside your canvas. keep in mind that every transformation (scale, skew, rotation, etc) is always starting from the origin. so a mirroring from the default origin (left, bottom corner) will be to the left or below your canvas. see the example below with a shifted origin.

pw = 1000
ph = 400
txt = "SHADE"
newPage(pw, ph)
translate(0, 160) # shift the origin up a bit
fontSize(300)
text(txt, (pw/2, 0), align = 'center')
scale(x=1, y=-.5) # the mirroring
text(txt, (pw/2, 0), align = 'center')

@mauricemeilleur I don’t know how Crouwel defined his rules. but to me the corner-rule seems like an integral part of the design.

I had a look at my code and tried to tidy the worst bits. some of the angle calculations seem very inefficient but ¯\(ツ)/¯ here it is:

EDIT 2018-05-28 changed the code to simplify some of the horrible trigonometry and there now is the sq_cap bool to have squared linecaps.

# Draw a 'folded outline' between a set of points. 

# TO DO: There should be an error message when two dots are closer to each other and the weight.
# There should be a warning if the folding is further than the next points. 
# There should be a warning for collinear points. 

import math

# Just a bunch of points

p01 = (894, 334)
p02 = (808, 86)
p03 = (274, 792)
p04 = (481, 920)
p05 = (583, 730)
p06 = (85, 430)
p07 = (318, 100)
p08 = (870, 600)
p09 = (720, 690)

points = [p01, p02, p03, p04, p05, p06, p07, p08, p09]


def get_dist(p1, p2): return sqrt( (p2[0] - p1[0] )**2 + (p2[1] - p1[1])**2 )

def calc_angle(p1, p2): return atan2((p2[1] - p1[1]), (p2[0] - p1[0]))

def calc_delta(p1, p2, p3): 
    ''' 
    Returns the angle between three points.
    '''
    return  calc_angle(p2, p3) - calc_angle(p2, p1)
    


def calc_offset(weight, p1, p2, p3):
    '''
    Returns the x and y "offset" to be added to the points of the polygon. 
    '''
    halfWeight = weight/2

    if p1 == p2:
        alpha = calc_angle(p1, p3)
        b = -sin(alpha) * halfWeight
        a =  cos(alpha) * halfWeight
    elif p2 == p3:
        alpha = calc_angle(p1, p3)
        b =  sin(alpha) * halfWeight
        a = -cos(alpha) * halfWeight
    else:
        alpha = calc_angle(p2, p3)
        delta = calc_delta(p1, p2, p3)
        xx = halfWeight / sin((delta - pi) / 2)
        delta_f = (2 * alpha - pi - delta ) / 2

        a, b = xx * sin(delta_f), xx * cos(delta_f)
    return a, b


def wrap_line(p1, p2, p3, p4, weight):
    '''
    This draws a polygon around a line. Four points (x,y) and a weight parameter are required. 
    The polygon will be drawn around the two middle points.
    The first and last points define the angles.
    '''
    a, b = calc_offset(weight, p1, p2, p3)
    # extend first point
    x1b, y1b = p2[0] - b, p2[1] - a
    x1c, y1c = p2[0] + b, p2[1] + a
    # extend second point
    c, d = calc_offset(weight, p2, p3, p4)
    x2b, y2b = p3[0] - d, p3[1] - c
    x2c, y2c = p3[0] + d, p3[1] + c

    polygon((x1b, y1b), (x1c, y1c), (x2b, y2b), (x2c, y2c))



# --------------------------------------------------------------------
# The actual drawing

fill(0, .4)

weight = 180
sq_cap = True

if len(points) == 1:
    rect(points[0][0] - weight/2, points[0][1] - weight/2, weight, weight)    

for i, point in enumerate(points[:-1]):
    # print (get_dist(point, points[i+1]))

    if len(points) == 2:
        wrap_line(points[i], points[i], points[i+1], points[i+1], weight)
    else:
        if i == 0:
            aaa = calc_angle(points[i], points[i+1])
            if sq_cap:
                point = point[0] - weight/2 * cos(aaa), point[1] - weight/2 * sin(aaa)
            wrap_line(point, point, points[i+1], points[i+2], weight)

        elif i == len(points)-2:
            next_p = points[i+1]
            aaa = calc_angle(points[i], next_p)
            if sq_cap:
                next_p = next_p[0] + weight/2 * cos(aaa), next_p[1] + weight/2 * sin(aaa)
            wrap_line(points[i-1], points[i], next_p, next_p, weight)
        else:
            # print ( calc_delta(points[i-1], points[i], points[i+1]) )
            wrap_line(points[i-1], points[i], points[i+1], points[i+2], weight)

hi there
I will try to give you a basic start with a very simple linear interpolation.

–––

Let’s animate some variable fonts.

we are on mac os so lets first see if there are any variable fonts installed on the system

To do this lets iterate through all installed fonts and ask if they do have any font variation axes. the function listFontVariations() will return this information as an OrderedDict if you supply a font name. Let’s print the name of the font if it returns any variable axes. And then let’s iterate through this information (short code and information on the values that could be set) for every axis and print this as well.

for fontName in installedFonts():
    variations = listFontVariations(fontName)
    if variations: 
        print(fontName)
        for axis_name, dimensions in variations.items():
            print (axis_name, dimensions)
        print ()

Depending on your os version you should get a few fonts.
Let’s assume one of the fonts is 'Skia-Regular' and it did print the following information:

Skia-Regular
wght {'name': 'Weight', 'minValue': 0.4799, 'maxValue': 3.1999, 'defaultValue': 1.0}
wdth {'name': 'Width', 'minValue': 0.6199, 'maxValue': 1.2999, 'defaultValue': 1.0}

This information can now be used to set some typographic parameters. Let’s use the weight axis (wght) and animate from the minimum to the maximum. To do so we assign these two values to variables.

min_val = listFontVariations('Skia-Regular')['wght']['minValue']
max_val = listFontVariations('Skia-Regular')['wght']['maxValue']

Let’s also assign the amount of steps for the interpolation to a variable and the text we want to render.

steps = 10
txt = 'var fonts are fun'

The last variable we are going to need is a calculation of the stepsize.
So let’s get the range by subtracting the minimum from the maximum and divide this value by the amount of steps minus one step.

step_size = (max_val - min_val) / (steps-1)

We should now be ready to loop through the amount of steps.
For every step we make a new page and set the font and font size. We calculate the value for the respective step by multiplying the step_size by the step and add it to the minimum value. The result of this calculation is then used in the fontVariations() function to set the variable font values.

for i in range(steps):

    newPage(1100, 200)
    font("Skia-Regular")
    fontSize(120)
    curr_value = min_val + i * step_size
    fontVariations(wght= curr_value )
    text(txt, (70, 70))

Everything put together

for fontName in installedFonts():
    variations = listFontVariations(fontName)
    if variations: 
        print(fontName)
        for axis_name, dimensions in variations.items():
            print (axis_name, dimensions)
        print ()


min_val = listFontVariations('Skia-Regular')['wght']['minValue']
max_val = listFontVariations('Skia-Regular')['wght']['maxValue']


steps = 10
txt = 'var fonts are fun'

step_size = (max_val - min_val) / (steps-1)

for i in range(steps):

    newPage(1100, 200)
    font("Skia-Regular")
    fontSize(120)
    curr_value = min_val + i * step_size
    fontVariations(wght= curr_value )
    text(txt, (70, 70))

    fontSize(20)
    fontVariations(wght= 1 )

    text('Weight axis: %f' % curr_value, (10, 10))

saveImage('~/Desktop/var_fonts_interpol.gif')

Final gif

With 20 interpolation steps and with a smaller canvas size.

Any questions or corrections please let me know!

Here is some code to draw a Lissajous table.
Change the func_x and/or func_y (sin or cos) and/or add some value to the delta to get other curves.
Well, actually the curves are just polygons.

# ----------------------
#  lissajous table 
# ----------------------
#  settings 

cols = 12 
rows = 8
cell_s = 80
r_factor = .8 # fraction of the cell size to have a gap between them

func_x = cos  # should be `sin` or `cos` 
func_y = sin  # should be `sin` or `cos` 
delta = 0 #pi/3  # some angle in radians 

density = 360 # amount of points per cell – higher values make nicer curve approximations 

# ----------------------
#  calculated settings 

radius = (cell_s * r_factor) / 2
step = (2 * pi) / density

pw = cell_s * (cols + 1)
ph = cell_s * (rows + 1)

x_coords = { (col, d) : func_x(step * (col + 1) * d  + pi/2 + delta) * radius for col in range(cols) for d in range(density) }
y_coords = { (row, d) : func_y(step * (row + 1) * d  + pi/2) * radius for row in range(rows) for d in range(density) }


# ----------------------
#  function(s)

def draw_cell(pos, col, row):
    cx, cy = pos
    points = [(cx + x_coords[(col, f)], cy + y_coords[(row, f)]) for f in range(density)]
    polygon(*points)


# ----------------------
#  drawings 

newPage(pw, ph)
rect(0, 0, pw, ph)
fontSize(12)
translate(0, ph)
fill(1)
text('δ\n{0:.2f}°'.format(degrees(delta)), (cell_s * (1 - r_factor)/2, -20))

for col in range(1, cols+1):
    cx = col * cell_s + cell_s * (1 - r_factor)/2
    text('{0}\n{1}'.format(func_x.__name__, col), (cx, -20))

for row in range(1, rows + 1):
    cy = row * cell_s + cell_s * (1 - r_factor)
    text('{0}\n{1}'.format(func_y.__name__, row), (cell_s * (1 - r_factor)/2, -cy))
    
fill(None)
stroke(.5)
strokeWidth(1)

for col in range(cols):
    for row in range(rows):
        draw_cell((cell_s * col + cell_s * 1.5, - cell_s * row -cell_s * 1.5), col, row)

You cannot draw a circle with Beziers.

When I first read this some time ago I was a bit confused.
Why is this not a circle. It sure looks like one.

After learning a bit more about curve descriptions and calculations I kind of agree but the quote should better say:

You cannot draw a perfect circle with Beziers.

Getting the best tangent values.

We have a formula to calculate points on a Bezier Curve.

x = (1-t)**3*p1[0] + 3*(1-t)**2*t*t1[0] + 3*(1-t)*t**2*t2[0] + t**3*p2[0]
y = (1-t)**3*p1[1] + 3*(1-t)**2*t*t1[1] + 3*(1-t)*t**2*t2[1] + t**3*p2[1]

p1 and p2 are the two endpoints and t1 and t2 the two tangent points. t is the factor (0-1) at which we want the point on the curve.

On a bezier curve with the following coördinates:

p1 = (1, 0)
p2 = (0, 1)
t1 = (1, tangent_val)
t2 = (tangent_val, 1)

we can calculate the tangent_val if we assume that the point at t=0.5 (halfway the curve) is exactly on the circle. Halfway of a quartercircle is 45 degrees so x and y are both at 1/sqrt(2). If we plug these numbers into the formula we can calculate the tangent value:

1/sqrt(2) = (1-.5)**3*1 + 3*(1-.5)**2*.5*1 + 3*(1-.5)*.5**2*tangent_val + .5**3*0
...
tangent_val = 4*(sqrt(2)-1)/3 ≈ 0.5522847493

With this tangent_val we can calculate other points on the bezier curve. Of which we can calculate the angle in respect to the center point at (0, 0). And with this angle we can use sine and cosine to get the point that would be on a circle.

We can also calculate the distance of the bezier point and see where the offset is the biggest. As we can see the difference is really tiny. With a radius of 1 the biggest off value is 1.0002725295591013 (not even one permille). The difference is hardly visible so I added only the top part of a really long bar chart to make it show.
See the image below:

Code

# -------------------
#  settings 

pw, ph = 595, 842 #A4
margin = 70

tang = 4*(sqrt(2)-1)/3
r = pw - 2 * margin

density = 90 # amount of points 
dia_ = 1 # diameter to draw the points 

r_plot = 100000 # this is a magnifying factor to make the tiny difference visible. 

r_plot_y = margin - r_plot   #radius plotting 
c_plot_y = ph - 3 * margin - r  # circle plotting 

# -------------------
#  functions  

def get_bezier_p(p1, t1, t2, p2, t):
    ''' get the point on a bezier curve at t (should be between 0 and 1) '''
    x = (1 - t)**3 * p1[0] + 3*(1 - t)**2 * t * t1[0] + 3*(1 - t)* t**2 * t2[0] + t**3 * p2[0]
    y = (1 - t)**3 * p1[1] + 3*(1 - t)**2 * t * t1[1] + 3*(1 - t)* t**2 * t2[1] + t**3 * p2[1]
    return x, y

def get_dist(p1, p2): 
    ''' returns the distance between two points (x, y)'''
    return sqrt((p2[0]-p1[0])**2 + (p2[1]-p1[1])**2)

# -------------------
#  drawings  

newPage(pw, ph)
fill(1)
rect(0, 0, pw, ph)
translate(margin, margin)

# draw the tangent points 
rect(r - dia_, c_plot_y + tang*r - dia_, dia_*2, dia_*2)
rect(tang*r -dia_, c_plot_y + r - dia_, dia_*2, dia_*2)

max_off = 1

for i in range(density+1):

    # -------
    #  bezier 

    # calculate the factor f 
    f = i/density
    fill(0)
    if i == 0 or i == (density): dia = dia_ * 4
    else: dia = dia_
    # get the coordinates for the point at factor f 
    x_b, y_b = get_bezier_p( (1, 0), (1, tang), (tang, 1), (0, 1), f )
    # get the distance of the point from the center at (0, 0)
    r_b = get_dist((0, 0), (x_b, y_b))
    max_off = max(max_off, r_b)
    # get the angle of the point 
    angle = atan2(y_b, x_b)
    # draw the point and a rect for the bar chart     
    oval(x_b * r - dia/2, c_plot_y + y_b * r - dia/2, dia, dia)
    rect((angle/(pi/2)) * r - dia_/2, r_plot_y, dia_, r_plot * r_b)

    # -------
    #  circle

    fill(1, 0, 0)

    # get the point on a circle 
    x_c, y_c = cos(angle), sin(angle)
    # draw the point and a rect for the bar chart     
    oval(x_c * r - dia/2, c_plot_y + y_c * r - dia/2, dia, dia)
    rect((angle/(pi/2)) * r - dia_/2, r_plot_y, dia_, r_plot)
        
    fill(.3)
    if i % 10 == 0:
        x_p, y_p = r * f, margin #* 1.5
        rect(x_p - .25, y_p, .5, 30)
        text('%d°' % (f * 90), (x_p-2, y_p * 1.5))

print (max_off)
text('%.6f' % max_off, (-50, max_off * r_plot - r_plot + margin - 2))
text('%.6f' % 1, (-50, margin - 2))
    

The maybe more interesting peculiarity of bezier curves is the difference between time and distance. We can compare the bezier distance at factor f (0-1) to the circle if we use the same factor to get the appropriate fraction of 90 degrees.

Code

# -------------------
#  settings 

pw, ph = 595, 842 #A4
margin = 70

tang = 4*(sqrt(2)-1)/3
r = pw - 2 * margin

density = 90 # amount of points 
dia_ = 1 # diameter to draw the points 

r_plot = 100000 # this is a magnifying factor to make the tiny difference visible. 

r_plot_y = margin - r_plot   #radius plotting 
c_plot_y = ph - 3 * margin - r  # circle plotting 

# -------------------
#  functions  

def get_bezier_p(p1, t1, t2, p2, t):
    ''' get the point on a bezier curve at t (should be between 0 and 1) '''
    x = (1 - t)**3 * p1[0] + 3*(1 - t)**2 * t * t1[0] + 3*(1 - t)* t**2 * t2[0] + t**3 * p2[0]
    y = (1 - t)**3 * p1[1] + 3*(1 - t)**2 * t * t1[1] + 3*(1 - t)* t**2 * t2[1] + t**3 * p2[1]
    return x, y

def get_dist(p1, p2): 
    ''' returns the distance between two points (x, y)'''
    return sqrt((p2[0]-p1[0])**2 + (p2[1]-p1[1])**2)

# -------------------
#  drawings  

newPage(pw, ph)
fill(1)
rect(0, 0, pw, ph)
translate(margin, margin)

# draw the tangent points 
rect(r - dia_, c_plot_y + tang*r - dia_, dia_*2, dia_*2)
rect(tang*r -dia_, c_plot_y + r - dia_, dia_*2, dia_*2)


for i in range(density+1):

    # -------
    #  bezier 

    # calculate the factor f 
    f = i/density
    fill(0)
    if i == 0 or i == (density): dia = dia_ * 4
    else: dia = dia_
    # get the coordinates for the point at factor f 
    x_b, y_b = get_bezier_p( (1, 0), (1, tang), (tang, 1), (0, 1), f )
    # get the distance of the point from the center at (0, 0)
    r_b = get_dist((0, 0), (x_b, y_b))
    # get the angle of the point 
    angle = atan2(y_b, x_b)
    # draw the point and a rect for the bar chart     
    oval(x_b * r - dia/2, c_plot_y + y_b * r - dia/2, dia, dia)
    rect((angle/(pi/2)) * r - dia_/2, r_plot_y, dia_, r_plot)

    # -------
    #  circle

    fill(1, 0, 0)

    # get the point on a circle 
    x_c, y_c = cos( pi/2*f ), sin( pi/2*f )
    # draw the point and a rect for the bar chart     
    oval(x_c * r - dia/2, c_plot_y + y_c * r - dia/2, dia, dia)
    rect(f * r - dia_/2, r_plot_y, dia_, r_plot)
        
    fill(.3)
    if i % 10 == 0:
        x_p, y_p = r * f, margin #* 1.5
        rect(x_p - .25, y_p, .5, 30)
        text('%d°' % (f * 90), (x_p-2, y_p * 1.5))

oké
I had some small hope but thanks for testing and clarifying!

not very elegant but kind of working:

txt = 'Some Text\nwith new lines\rIs a return\na new line\ror a new paragraph?'

paras = [[l + '\n' for l in p.split('\n')] for p in txt.split('\r')]

newPage(150, 150)

fstr = FormattedString()
for para in paras:
    for l in para:
        extra_space = 5 if l == para[-1] else 0
        fstr.append(l, paragraphBottomSpacing = extra_space)
text(fstr, (20, 110))

I tried to use paragraphBottomSpacing and was hoping that drawbot would interpret \n as still the same paragraph and only apply the extra white space once I use a \r.

So there should only be extra white space after the line 'with new lines' but not after the other newlines.

txt = 'Some Text\nwith new lines\rIs a return\na new line\ror a new paragraph?'
fstr = FormattedString(txt, paragraphBottomSpacing=3)
newPage(150, 150)
text(fstr, (20, 110))

hope that makes sense, thanks

you instantiate the BezierPath outside the loop and then draw the text in every round of the loop. just put the bp = BezierPath() inside the loop.

hi, I think the BezierPath text does not accept variable font settings. You can first draw the text into a FormattedString() and then add that to the BezierPath.

bp = BezierPath()
fstr = FormattedString("JUICY", font='Skia-Regular', fontSize=80, fontVariations = {'wght' : curr_value})
bp.text(fstr, (10, 10))

hope that helps!

reload is python 2
afaik in python 3.4 and newer you are supposed to use:

import importlib
importlib.reload(module)

good luck!

this should work already.

when you select the bool (True or False) and then press the Cmd + arrow keys the value should change.

you will need to use a loop to iterate over your list of characters and append them to a formattedString.

first initiate the formattedString:

f_str = FormattedString(font = myFont, fontSize = pointSize)

then iterate over your list:

for ch in wordText:

select a random color inside the loop and append the character to the formattedString

    ch_col = random.choice(colors)
    f_str.append(ch, fill = ch_col)

finally draw your textBox with the formattedString

textBox(f_str, box, align="left")

so the last four lines of your code should be:

f_str = FormattedString(font = myFont, fontSize = pointSize)

for ch in wordText:
    ch_col = random.choice(colors)
    f_str.append(ch, fill = ch_col)

textBox(f_str, box, align="left")

good luck!

@monomonnik
yes and no.
in the chessboard examples it does not really matter if you go by columns or by rows.
but yes the first returned value is the quotient i//n or int(i/n) and the second returned value is the remainder (modulo) i % n.

@monomonnik
perfect place to use divmod.
this:

x = i % 8
y = int(i/8)

could be written like:

x, y = divmod(i, 8)

it will return the quotient (x) and the remainder (y).

I am not quite sure what exactly you are asking but the get a random integer value inside a range you could use randint(min_value, max_value). This works for integers. To get a random value between 100 and 900 you would use randint(100, 900).
If you have a smaller range and want fractions as well you could use min_value + random() * (max_value - min_value) eg 100 + (900-100) * random()
I hope that helps, good luck!