By ritvov - 6/17/2018
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?
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By Dave - 6/18/2018
+xI'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?
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>
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By ritvov - 6/18/2018
+x+xI'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? 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>
Thank you! This should work for me.
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By ritvov - 6/18/2018
+x+xI'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? 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>
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!
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