It’s quite easy to make fake 3D anaglyph images in Photoshop, the kinds of images you view with red-blue 3D glasses. Here’s a guide for example, and here’s an image I made years ago with text in Photoshop:
But can you do this with GIMP? Well, I think it’s quite hard but can be done. I’m not a big fan of GIMP, but it is free and it’s very cross-platform. And free is my favourite price.
I started with this image of my dog Ellie, and thought I’d have a go at making her stand out from the background:
I opened it in GIMP and then went to Colours > Components > Channel mixer.
I then isolated the red channel by picking each channel and turning green and blue down to 0% and leaving red at 100%. You seem to have to do this 3 times, once for every output channel.
I then exported this as a new image, ‘ellie red.png’
Then I did the same to create a cyan image, by having red at 0% in each channel, just green at 100% in the green channel, and just blue at 100% in the blue channel, and exported this as ‘ellie cyan.png’
I then went File > Open as layers and opened the red and cyan images:
If you then have the red layer on top and you change the mode of the red, top layer to difference, you should then see a full colour image made from your red and cyan layers:
Now if you move the red layer left and right, you can experiment with creating a 3D effect.
Moving layers is annoying in GIMP – you select the move tool, fair enough – but then you have to ensure you have the layer button selected (highlighted with red oval below):
Don your 3D specs! If you move the red layer left you should see the whole image move backwards behind your computer screen! We want our dog to stand out, so I moved the red layer right instead, and got something like this:
When your happy with the 3D effect go to Layer > Merge down in the menu.
Now we have a 3D image that should stand out from your computer screen, but I want the dog alone to stand out. The way I did this was to open the original full-colour image as a new layer and move it to the bottom. The mode of the top layer should be normal.
Then, using the eraser tool, I turned off visibility for the bottom, full-colour layer and roughly erased all the background parts of the anaglyph-coloured shifted image layer:
Then when you turn the visibility of the full-colour layer back on, you should see something like this:
The background should remain unshifted and Ellie the dog should be standing out.
If there’s a simpler way of shifting colour channels in GIMP, please let me know!
I’ve written before about how badly I got on with NaNoWriMo – National Novel Writing Month. Each November loads of people sign up to a challenge to write a 50,000 word novel in a month. I wonder what proportion succeed. I’m guessing it’s a pretty low number.
Anyway, while social media is awash with New Year’s Resolutions, which I hate almost as much as New Year’s Eve, I had an idea: I have loads of ideas and unfinished novels, so what about trying to write a novel not in a month, but in a YEAR.
It works out to 137 words a day. Much more realistic than NaNoWriMo’s 1613 words a day. And this is a leap year, so you can take a whole day off. Call that New Year’s Day and you can start tonight.
With NaNoWriYo you write 600 fewer words in a week than NaNoWriMo would have you write in a day.
Sure, a year sounds like a long time, but it’s about 7 years since I actually completed any proper fiction writing, so what’s another year?
Inspired by http://www.sniff.org.uk/2015/12/hacking-pimoroni-flotillla.html I plugged Flotilla into my Mac. I browsed my /dev/ folder and took a guess that the Flotilla dock was ‘tty.usbmodem1421′ – which proved correct. Then I typed screen /dev/tty.usbmodem1421 9600 at the Terminal prompt, and wiggled a few controls.
This is what I saw >
Straight away you can see values from named devices as I turned the dial and moved the slider. The 4 numbers on ‘touch’ seem to register 1 or 0 for each of the 4 buttons pressed, and the ‘colour’ values (judging from what I placed the colour sensor on) seem to be red, green, blue and overall brightness.
As per the Sniff article, I managed to get my LED strip to light red by typing s 7 255,0,0
with the LEDs plugged into socket 1 on the dock – odd indeed that the port numbering is reversed.
I also managed to list all the devices that came with my Large Starter Kit by typing ‘d’ for debug:
You can see some weather data there too – I thought this was pressure then temperature, but reading the Sniff article again I suppose it’s more likely to be 19.65 degrees C and 1018 millibars of air pressure.
Next step is to play with some proper OS X terminal software rather than using screen, and try to work out what parameters need passing to the LED matrix display – but looks promising that Flotilla can be made to work with other operating systems and computers aside from the Raspberry Pi.
Here’s a very simple ‘paint’ project for the RaspberryPi SenseHAT. I was trying to draw icons for a graphical weather project, and I felt the need of some kind of paint program that would allow me to draw on the computer screen and light pixels on the SenseHAT.
Here’s my attempt. I almost hesitate to post it, as it’s coded with brute force and ignorance. There may already be a better paint program for the SenseHAT. There may be a way of doing it in 5 lines of code. But here’s my (ham-fisted) attempt.
To use it, you pick a colour by pressing a keyboard letter – b is black, w is white, r red, g green, y yellow and, confusingly, L is blue. You could easily add more colours. The selected colour is shown on the right. You then click in the squares to light the pixels your chosen colour. You then have 2 other buttons – ‘clear’ clears the screen, and the beautifully-named ‘dump’ dumps the pixel values into the console, so you can copy and paste them and use them in another project. My next step is probably to allow you to save the images to a file – and possibly load images as well, not in PNG format but as a list of tuples (threeples?)
It uses PyGame, so you’ll need to use Python 2 not 3 – just open it in IDLE for Python 2 on your Raspberry Pi. I did look at Tkinter, but decided I didn’t have time to learn enough of it. PyGame is much easier to get going with. I probably should have used sprites, but instead I just draw coloured rectangles and then check to see if each mouse click falls in the area for that square, and then light the appropriate light. Very inefficient coding, but it seems to work.
You can see it in action in this exciting video:
This is what the image in the video looked like on the SenseHAT:
Here’s the rotten code. Read it and weep! You can also download it here.
# SenseHAT paint by Giles Booth / @blogmywiki
# www.suppertime.co.uk/blogmywiki
# This work is licensed under a Creative Commons
# Attribution-NonCommercial 4.0 International License.
from sense_hat import SenseHat
import pygame, sys
from pygame.locals import *
sense = SenseHat()
b = [0, 0, 0]
green = [0, 255, 0]
red = [255, 0, 0]
white = [255, 255, 255]
yellow = [255, 255, 0]
blue = [0, 0, 255]
def clearscreen():
sense.clear()
global pixels
pixels = [
b,b,b,b,b,b,b,b,
b,b,b,b,b,b,b,b,
b,b,b,b,b,b,b,b,
b,b,b,b,b,b,b,b,
b,b,b,b,b,b,b,b,
b,b,b,b,b,b,b,b,
b,b,b,b,b,b,b,b,
b,b,b,b,b,b,b,b,
]
clearscreen()
sense.set_pixels(pixels)
pygame.init()
screen = pygame.display.set_mode((300,170))
pygame.display.set_caption('SenseHAT paint')
font = pygame.font.Font(None,16)
screen.fill((200,200,200))
inklabel = font.render("Colour", 1, (0,0,0))
screen.blit(inklabel, (160,20))
keylabel = font.render("Keys: b", 1, (0,0,0))
screen.blit(keylabel, (160,36))
keylabel = font.render("w", 1, white)
screen.blit(keylabel, (205,36))
keylabel = font.render("r", 1, red)
screen.blit(keylabel, (220,36))
keylabel = font.render("g", 1, green)
screen.blit(keylabel, (235,36))
keylabel = font.render("l", 1, blue)
screen.blit(keylabel, (250,36))
keylabel = font.render("y", 1, yellow)
screen.blit(keylabel, (265,36))
pygame.draw.rect(screen, b, (160,55,45,15))
keylabel = font.render("Clear", 1, white)
screen.blit(keylabel, (163,55))
pygame.draw.rect(screen, b, (220,55,45,15))
keylabel = font.render("Dump", 1, white)
screen.blit(keylabel, (223,55))
def drawink():
pygame.draw.rect(screen, ink, (200,20,15,15))
pygame.display.update()
def drawgrid():
z = 0
xpos = 0
ypos = 20
for colours in pixels:
z = z + 1
if z == 9:
xpos = 0
ypos = ypos + 16
if z == 17:
xpos = 0
ypos = ypos + 16
if z == 25:
xpos = 0
ypos = ypos + 16
if z == 33:
xpos = 0
ypos = ypos + 16
if z == 41:
xpos = 0
ypos = ypos + 16
if z == 49:
xpos = 0
ypos = ypos + 16
if z == 57:
xpos = 0
ypos = ypos + 16
xpos = xpos + 16
pygame.draw.rect(screen, colours, (xpos,ypos,15,15))
pygame.display.update()
#pygame.draw.rect(windowObj, r, (10,10,20,20))
ink = white
drawgrid()
drawink()
while True:
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_w:
ink = white
elif event.key == pygame.K_b:
ink = b
elif event.key == pygame.K_y:
ink = yellow
elif event.key == pygame.K_r:
ink = red
elif event.key == pygame.K_g:
ink = green
elif event.key == pygame.K_l:
ink = blue
drawink()
## elif event.type == pygame.MOUSEMOTION:
## print (pygame.mouse.get_pos())
elif event.type == pygame.MOUSEBUTTONDOWN:
x, y = event.pos
# 1st row
if (x>15 and x<30) and (y>20 and y<35):
pixels[0] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>31 and x<46) and (y>20 and y<35):
pixels[1] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>47 and x<62) and (y>20 and y<35):
pixels[2] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>63 and x<78) and (y>20 and y<35):
pixels[3] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>79 and x<94) and (y>20 and y<35):
pixels[4] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>95 and x<110) and (y>20 and y<35):
pixels[5] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>111 and x<126) and (y>20 and y<35):
pixels[6] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>127 and x<142) and (y>20 and y<35):
pixels[7] = ink
sense.set_pixels(pixels)
drawgrid()
# 2nd row
if (x>15 and x<30) and (y>36 and y<51):
pixels[8] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>31 and x<46) and (y>36 and y<51):
pixels[9] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>47 and x<62) and (y>36 and y<51):
pixels[10] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>63 and x<78) and (y>36 and y<51):
pixels[11] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>79 and x<94) and (y>36 and y<51):
pixels[12] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>95 and x<110) and (y>36 and y<51):
pixels[13] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>111 and x<126) and (y>36 and y<51):
pixels[14] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>127 and x<142) and (y>36 and y<51):
pixels[15] = ink
sense.set_pixels(pixels)
drawgrid()
# 3rd row
if (x>15 and x<30) and (y>52 and y<67):
pixels[16] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>31 and x<46) and (y>52 and y<67):
pixels[17] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>47 and x<62) and (y>52 and y<67):
pixels[18] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>63 and x<78) and (y>52 and y<67):
pixels[19] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>79 and x<94) and (y>52 and y<67):
pixels[20] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>95 and x<110) and (y>52 and y<67):
pixels[21] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>111 and x<126) and (y>52 and y<67):
pixels[22] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>127 and x<142) and (y>52 and y<67):
pixels[23] = ink
sense.set_pixels(pixels)
drawgrid()
# 4th row
if (x>15 and x<30) and (y>68 and y<83):
pixels[24] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>31 and x<46) and (y>68 and y<83):
pixels[25] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>47 and x<62) and (y>68 and y<83):
pixels[26] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>63 and x<78) and (y>68 and y<83):
pixels[27] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>79 and x<94) and (y>68 and y<83):
pixels[28] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>95 and x<110) and (y>68 and y<83):
pixels[29] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>111 and x<126) and (y>68 and y<83):
pixels[30] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>127 and x<142) and (y>68 and y<83):
pixels[31] = ink
sense.set_pixels(pixels)
drawgrid()
# 5th row
if (x>15 and x<30) and (y>84 and y<99):
pixels[32] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>31 and x<46) and (y>84 and y<99):
pixels[33] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>47 and x<62) and (y>84 and y<99):
pixels[34] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>63 and x<78) and (y>84 and y<99):
pixels[35] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>79 and x<94) and (y>84 and y<99):
pixels[36] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>95 and x<110) and (y>84 and y<99):
pixels[37] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>111 and x<126) and (y>84 and y<99):
pixels[38] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>127 and x<142) and (y>84 and y<99):
pixels[39] = ink
sense.set_pixels(pixels)
drawgrid()
# 6th row
if (x>15 and x<30) and (y>100 and y<115):
pixels[40] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>31 and x<46) and (y>100 and y<115):
pixels[41] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>47 and x<62) and (y>100 and y<115):
pixels[42] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>63 and x<78) and (y>100 and y<115):
pixels[43] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>79 and x<94) and (y>100 and y<115):
pixels[44] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>95 and x<110) and (y>100 and y<115):
pixels[45] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>111 and x<126) and (y>100 and y<115):
pixels[46] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>127 and x<142) and (y>100 and y<115):
pixels[47] = ink
sense.set_pixels(pixels)
drawgrid()
# 7th row
if (x>15 and x<30) and (y>116 and y<131):
pixels[48] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>31 and x<46) and (y>116 and y<131):
pixels[49] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>47 and x<62) and (y>116 and y<131):
pixels[50] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>63 and x<78) and (y>116 and y<131):
pixels[51] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>79 and x<94) and (y>116 and y<131):
pixels[52] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>95 and x<110) and (y>116 and y<131):
pixels[53] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>111 and x<126) and (y>116 and y<131):
pixels[54] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>127 and x<142) and (y>116 and y<131):
pixels[55] = ink
sense.set_pixels(pixels)
drawgrid()
# 8th row
if (x>15 and x<30) and (y>132 and y<147):
pixels[56] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>31 and x<46) and (y>132 and y<147):
pixels[57] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>47 and x<62) and (y>132 and y<147):
pixels[58] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>63 and x<78) and (y>132 and y<147):
pixels[59] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>79 and x<94) and (y>132 and y<147):
pixels[60] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>95 and x<110) and (y>132 and y<147):
pixels[61] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>111 and x<126) and (y>132 and y<147):
pixels[62] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>127 and x<142) and (y>132 and y<147):
pixels[63] = ink
sense.set_pixels(pixels)
drawgrid()
elif (x>160 and x<205) and (y>55 and y<70):
clearscreen()
drawgrid()
elif (x>220 and x<265) and (y>55 and y<70):
print
print pixels
pygame.quit()
Hot on the heels of my official Raspberry Pi SenseHAT, Mr Postman brought me the Pimoroni Flotilla. I got this early because I backed it on Kickstarter, ooh quite a long time ago now, and I’d almost forgotten about it. A very welcome early Christmas present from the crew at Sheffield’s Pimoroni.
Flotilla is billed as ‘friendly electronics’ – modular sensors and LED output devices you plug into your Raspberry Pi, with no soldering required. As such, you might think there’s an overlap with the SenseHAT, but they are very different. The SenseHAT is self-contained, it plugs directly onto the pins on your Pi and you program it in Python. Flotilla, on the other hand, is anything but self-contained:
The heart of it is the ‘dock’ – a round device that plugs into the Pi’s USB port. It has 8 sockets to plug in ‘tentacles’ which you attach input and output devices to. The attention to detail on these is amazing – the blue leads have little anchors embossed on the plugs, and as is the way with Pimoroni, the graphics are beautiful in a very Sheffield-ish kind of way:
Once a studio manager, always a studio manager – so rather than reading any instructions I just plugged it all in and played with it to try to figure out what it would do. You program it using a web interface called ‘Rockpool’:
You click on inputs, which can be physical devices or patterns like a sine wave or saw-tooth wave, do stuff in the middle, and then pipe things to output devices on the right.
I can see Flotilla appealing very much to younger children, and I will save the diorama cut-out cards supplied for my KS2 computer club next term, to see what they make of it – I think my own children are probably too old for this.
Here’s a very simple project I knocked up in a couple of minutes, using the colour sensor to detect and mimic colours on my patchwork Elmer tablecloth. I piped the red input to the red output on the led strip, green to green and blue to blue:
And here’s the result:
I’ve only scratched the surface with Flotilla – it’s clearly got lots of potential and I like the way you can get a simple project running in seconds with the scope to build much more complex and sophisticated projects later on.
My ‘large starter kit’ came with an RGB LED colour strip and an 8×8 text/numerical LED matrix display as output devices, and lots of input devices: a 4 button touch pad, a rotary dial, a linear fader, a thermometer/baromoter, a motion sensor, and a colour sensor – plus blue leads, or ‘rope’, to attach them all to the dock. Installation of the software was quick and easy and included a nice touch in the command line:
I look forward to many adventures aboard my Flotilla, and seeing what projects other folk (especially kids) come up with. Children always have the best ideas when you give them creative toys like this (and I don’t use the word ‘toys’ in a negative way at all – play is good!).
