run methods on a layer created by PGraphics

Programming Questions

yshuky

run methods on a layer created by PGraphics

in Programming Questions • 3 years ago

Hi,

I'm trying to run a method in a different class "on" a layer created by PGraphics and createGraphics.

I have just started to use Class and cannot sort out by myself now, so could anyone give some help?

What I'm trying now is.....

------------------------------------------------------------------------------------------------------------------

myClass myInstance;

PGraphics topLayer;

void setup()

{

myInstance= new myClass();

topLayer= createGraphics(width,height,g.getClass(),getName());

}

void draw()

{

topLayer.beginDraw();

topLayer.myInstance.myMethod(); // <- this line is the problem...

topLayer.endDraw();

image( topLayer, 0, 0 );

}

------------------------------------------------------------------------------------------------------------------

I know it means I need "myInstance.myMethod()" under "topLayer". But PGraphics class is something I cannot reach easily.

Is there any way I can run "myInstance.myMethod()" on the "topLayer"?

Thanks in advance,

P.S.

I refered this topic:

http://processing.org/discourse/yabb2/YaBB.pl?num=1197673835

Replies(9)

PhiLho

Re: run methods on a layer created by PGraphics

3 years ago

Is there any way I can run "myInstance.myMethod()" on the "topLayer"?

No. Unless you sub-class PGraphics, perhaps. It is simpler to write:

topLayer.beginDraw();
myInstance.myMethod(topLayer);
topLayer.endDraw();
image( topLayer, 0, 0 );

Less elegant, but much easier to implement...

yshuky

Re: run methods on a layer created by PGraphics

3 years ago

Thanks a lot phi.lho!

Simpler and easier is more elegant actually, so it seems perfect.

Probably my question was a basic grammar question for you guys...

But can I ask just one more for how I can write if I want to send the data for the methods?

For example, if I want to run....

myMethod(x,y);

I tried

topLayer.beginDraw();
myInstance.myMethod(x,y)(topLayer);
topLayer.endDraw();
image( topLayer, 0, 0 );

but obviously it didn't work...

Could you tell me how I can write? It's more exact what I want to do actually.

Thanks again

adamcsmit..

Re: run methods on a layer created by PGraphics

3 years ago

Ah, I see what you're missing. I think PhiLho's example gave you the impression that there's an "automatic" way to have drawing commands go to some PGraphics object instead of the main surface; there isn't. In his example, he was assuming that you re-wrote the methods of your class to take a PGraphics object as an argument. For example:

class Foo {
// ...
void drawACircle(PGraphics pg, float x, float y, float r) {
pg.ellipse(x, y, r, r);
}
// ...
}

Then in your program, you'd do something like:

PGraphics topLayer = createGraphics( // ... whatever
Foo myFoo = new Foo();
myFoo.drawACircle(topLayer, 10, 10, 5);

... which then causes myFoo to draw a circle on the topLayer object. Basically, there's no "magical" way to change what surface you're drawing on; if you want to draw an object on different surfaces then you have to set it up that way yourself.

Oh, and because this will probably be your next question: the PGraphics object used as the main drawing surface for a sketch is called g. So, if you wanted your Foo object to draw a circle on the main sketch display, you'd do:

myFoo.drawACircle(g, 10, 10, 5);

yshuky

Re: run methods on a layer created by PGraphics

3 years ago

Thanks a lot adamcsmitty!

I was misunderstanding but now have got crystal clear idea! The code I was trying is now working fine!

Then, I hope it's my final question... is it possible I can get fadeout effect on PGraphics?

It should work normally by overwriting rectangle with alpha but in this case I don't want to give any colour to the background of PGraphics. I just want to fade my drawing on the toplayer.

I'm now trying to capture the screen every frames and load it as PImage with tint. I guess it's going to be ridiculous heavy...

Thanks many times

PhiLho

Re: run methods on a layer created by PGraphics

3 years ago

It should work normally by overwriting rectangle with alpha but in this case I don't want to give any colour to the background of PGraphics

Just use black or some gray grey.

yshuky

Re: run methods on a layer created by PGraphics

3 years ago

mmm...I've been trying with using black as fill colour for the rectangle but still not sorting out.

It makes the background black/grey although I want to keep background as transparent.

I tried

topLayer.beginDraw();
topLayer.noStroke();
topLayer.fill(0,50);
topLayer.rect(0,0,width,height);
myInstance.myMethod(x,y,topLayer);
topLayer.endDraw();
image( topLayer, 0, 0 );

or...

topLayer.beginDraw();
myInstance.myMethod(x,y,topLayer);
topLayer.endDraw();
image( topLayer, 0, 0 );
topLayer.beginDraw();
topLayer.noStroke();
topLayer.fill(0,50);
topLayer.rect(0,0,width,height);
topLayer.endDraw();
image(topLayer,0,0);

mmm.. could I have any advice?

adamcsmit..

Re: Re: run methods on a layer created by PGraphics

3 years ago

I think topLayer.background(0, 50) will make your background black with an alpha of 50 (out of 255);

ericsoco

Re: run methods on a layer created by PGraphics

3 years ago

don't think you can fade out a PGraphics, as it only supports binary (on/off) transparency. from PGraphics doc page:

" Note that transparency levels are binary: pixels are either complete opaque or transparent."

PhiLho

Re: Re: run methods on a layer created by PGraphics

3 years ago

The doc. is outdated with regard to this... At least for the JAVA2D PGraphics.

Top Reply