Graphic alpha value

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T_J_Arakeri

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Registered:1553465030
Posts: 10

Posted 1554591552	Reply with quote #1

Hi Jaewon, I was just wondering if it is possible to change the alpha value of a graphic created inside an adapter? For example, using mgladdcircle. Thanks, Tapas
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Jaewon

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Posts: 939

Posted 1554681494 · Edited	Reply with quote #2

I keep telling this to people. A better way to ask this kind of questions is to just explain what you want to do, not how you want to do it.
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T_J_Arakeri

Junior Member
Registered:1553465030
Posts: 10

Posted 1554745410	Reply with quote #3

Sorry Jaewon. Essentially I want to create an array of dots which are translucent, such that if they overlap, they appear darker. Here is an example:
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Jaewon

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Posts: 939

Posted 1554755606 · Edited	Reply with quote #4

Shapes drawn by MGL already have fixed alpha channel values, but you can use the ImageGraphic adapter and provide a bitmap data, including the alpha channel, as you want. In MGL, you can use a matrix of Y-by-X-by-4 to represent an ARGB bitmap or load from PNG files. See the example below. By the way, I found a typo in the ImageGraphic adapter. You need to make a change that I posted in the following link or download the new package, to run the example. http://forums.monkeylogic.org/post/nimh-monkeylogic-2-8444337?pid=1308247017 --- Beginning of example ----- radius = 1.5; % in degrees imdata = make_circle(radius*Screen.PixelsPerDegree,[1 1 1],1); % make_circle(radius_in_pixels,color,fill) imdata(:,:,1) = imdata(:,:,1) / 2; % imdata(:,:,1): alpha % imdata(:,:,2): red % imdata(:,:,3): green % imdata(:,:,4): blue crc = ImageGraphic(null_); crc.ImageList = {imdata,[-1 -0.7]; imdata,[1 -0.7]; imdata,[0 1]}; tc = TimeCounter(crc); tc.Duration = 5000; scene = create_scene(tc); run_scene(scene); idle(0); ----- End of example -----
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