when I receive [scan]
scan pixel

define scan pixel
colour detect script here
set [pixelcolour v] to (colour scan result)
set [contrastcolour v] to (contrastscan result)

EvilPegasus2274 wrote:

Do you mean a color detection script, as in detect a color but not its RGB values, or a color detection script to get its RGB values?

set [colour v] effect to (0)

set [some color v] to (123)
if <touching color (some color) ?> then
    ...
end

lafoudre wrote:

See project here (not my project):
http://scratch.mit.edu/projects/25078953/#editor

See definition of new blockl “get colors of image” in sprite “scanner”
Actually uses

set [some color v] to (123)
if <touching color (some color) ?> then
    ...
end

You have to try all numbers to get the color that is under your sprite. You have to draw a sprite which is just 1 dot X 1 dot

• The sprite you are using to do the scanning should be actual size. If scratch has to shrink a sprite, than that adds to the calculations it does
  
• Sending colors in the backdrop of the stage is faster than sensing colors on a sprite costume
  
• You don't have to necessarily test against all 16 million colors of the RGB spectrum. You'll often get a hit if you're close.
  
• There may be other optimizations you can make depending on what you're trying to do
  

mr-mark wrote:

I have a recent project that does a ton of color scanning, and you're right, the process can be slow. Through a lot of trial and error, I found some ways to speed it up:

• The sprite you are using to do the scanning should be actual size. If scratch has to shrink a sprite, than that adds to the calculations it does
  
• Sending colors in the backdrop of the stage is faster than sensing colors on a sprite costume
  
• You don't have to necessarily test against all 16 million colors of the RGB spectrum. You'll often get a hit if you're close.
  
• There may be other optimizations you can make depending on what you're trying to do
  

mr-mark wrote:

There is one other optimization I forgot to mention. If you can, make a list of all of the colors that you might encounter. Save that list as part of your project, and then just check against the values in that list. You can make a script to populate the list, but once the list is created, you can save it in the project, and you won't need to run it again. If you are only going to run the script once to populate the list before you share the project, then you can test all 16 million colors.

mr-mark wrote:

There is one other optimization I forgot to mention. If you can, make a list of all of the colors that you might encounter. Save that list as part of your project, and then just check against the values in that list. You can make a script to populate the list, but once the list is created, you can save it in the project, and you won't need to run it again. If you are only going to run the script once to populate the list before you share the project, then you can test all 16 million colors.

<key [<key [<key [<<<<<<<(pick random (() - (0)) to (10)) < []> < []> = []> > []> = []> < []> < []> v] pressed?> v] pressed?> v] pressed?>
when this sprite clicked
when backdrop switches to [ v]
when green flag clicked
say []
think [] for (2) secs
hide
switch costume to [ v]
show
switch costume to [ v]
switch costume to [ v]

ZoomieJr wrote:

how to delete post