Millisecond Forums » Millisecond Forums » Inquisit 5 » Changing the color of pictures?

Changing the color of pictures?

ritvov — Mon, 18 Jun 2018 11:28:23 GMT

I'm running an experiment that presents stimuli that I've created externally in Illustrator. The stimuli are novel squiggly shapes. The main task is a color memory task, so I need the color of the shape to be able to changechange. I know that you can change the color of circles, squares, etc, but can you do this with jpg/pngs, etc? The image is just white and black, and I'd like to be able to select all the white (255 255 255) values and change them to some specified color. I see there is a "transparent color" attribute for pictures where you can select a certain color and make it transparent, but can you do a similar thing to select a color and change it?

RE: Changing the color of pictures?

Dave — Mon, 18 Jun 2018 11:28:23 GMT

[quote]

[b]ritvov - Monday, June 18, 2018[/b]

[quote]

[b]Dave - Monday, June 18, 2018[/b]

[quote]

[b]ritvov - Sunday, June 17, 2018[/b]

[/quote]

There is no way to change the color of pictures or replace colors on the fly. There is however a trick which might work: You can exploit PNGs transparency: I.e. make the "squiggly shape" not a solid color like black or white, but have it be transparent. Then you can display a <shape> behind the <picture> and manipulate that <shape>'s color as needed. The result should be that it looks as if the image changes color. I.e. something like this (attached):

<picture mypicture>
/ items = ("image.png")
/ size = (50%, 30%)
</picture>

<shape myshape>
/ shape = rectangle
/ size = (32%, 30%)
</shape>

<block myblock>
/ trials = [1-6 = mytrial]
</block>

<trial mytrial>
/ ontrialbegin = [
shape.myshape.color = list.colors.nextvalue;
]
/ stimulusframes = [1=myshape, mypicture]
/ validresponse = (57)
</trial>

<list colors>
/ items = (red, green, blue, yellow, purple, orange, grey)
</list>

[/quote]

Hi Dave,

Thanks for your response, again. This leads me to some follow up questions. Essentially, on every trial I want to present a color wheel, and the participant clicks the point on the wheel that matches their memory for that item. When the cursor is over a color on the color wheel, the central image (or, with your workaround, the central square behind the transparent image) will take on that color-- otherwise the central image would be white (see attached).

So, my follow up questions are 1) Is there a way to continuously update the color of the central square within one trial, dependent on where the mouse is positioned? 2) How do I make it so it only changes color when the cursor is within the space of the color wheel? For #2, I know there is the "valid response" attribute for the trial, but I'm not sure how this would work for a space that is essentially a donut. Thank you again!

[/quote]

> 1) Is there a way to continuously update the color of the central square within one trial, dependent on where the mouse is positioned?

No. You would essentially continuously loop a trial, i.e. run multiple trials in a row, not a single one. This can, however, LOOK like a single trial that continuously updates the color to the participant.

> 2) How do I make it so it only changes color when the cursor is within the space of the color wheel?

You'd have to code some <expressions> that check where the cursor / mouse is located at the time of response (i.e. inside or outside the wheel) and then use /isvalidresponse logic in the <trial> to either accept or reject the response.

RE: Changing the color of pictures?

ritvov — Mon, 18 Jun 2018 11:09:37 GMT

[quote]

[b]Dave - Monday, June 18, 2018[/b]

[quote]

[b]ritvov - Sunday, June 17, 2018[/b]

[/quote]

RE: Changing the color of pictures?

ritvov — Mon, 18 Jun 2018 10:40:47 GMT

[quote]

[b]Dave - Monday, June 18, 2018[/b]

[quote]

[b]ritvov - Sunday, June 17, 2018[/b]

[/quote]

Thank you! This should work for me.

RE: Changing the color of pictures?

Dave — Mon, 18 Jun 2018 08:17:05 GMT

[quote]

[b]ritvov - Sunday, June 17, 2018[/b]

[/quote]