createGraphics, Processing 2 and backward compatibility with Processing 1.x

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Jo Wood

createGraphics, Processing 2 and backward compatibility with Processing 1.x

in General Discussion • Other • 11 months ago

I need to be able to create an off-screen buffer using createGraphics() as part of a library that should be usable in both Processing 2.x and Processing 1.x.

In Processing 2.x, you can use the two-parameter createGraphics(w,h) which will use the same renderer as that created in the main sketch through the size() command. However, Processing 1.x requires a three-parameter version createGraphics(w,h,iRenderer) where iRenderer is an explicit string such as P2D, P3D etc, that indicates the renderer to use.

My question is, what is the best way to use createGraphics() that works with both Processing 1.x and 2.x? As far as I can see, there is nothing exposed in PApplet that allows programmatic detection of the renderer type. If there was, I could simply set the createGraphics renderer type to that of the main sketch. Since this is for a library, I have no control over the renderer that a user of the library may have selected with size(), so I need to be able to set the appropriate createGraphics renderer at runtime.

Any thoughts?

Replies(3)

PhiLho

Re: createGraphics, Processing 2 and backward compatibility with Processing 1.x

11 months ago

g instanceof PGraphicsJava2D
g instanceof PGraphics2D
g instanceof PGraphics3D
g instanceof PGraphicsPDF

In standard Processing, one of the 4 above should be true.
Now, it can be an instance of another PGraphics, like P8gGraphicsSVG, although this one is also an instance of PGraphicsJava2D.
Note that PGraphicsPDF is also an instance of PGraphicsJava2D...

Jo Wood

Re: createGraphics, Processing 2 and backward compatibility with Processing 1.x

11 months ago

Thanks PhiLho. I'd forgotten that this would all be stored in g. This seems to work well, but I always feel a little uncomfortable using g like this as it feels a bit 'hacky' and I worry that it might break with future versions of Processing.

PhiLho

Re: createGraphics, Processing 2 and backward compatibility with Processing 1.x

11 months ago

Anything can break in future versions of Processing... At least they can break on the next major version.
But since g is a public field, it is supposed to be usable for any purpose.
Looking at the code, the renderer parameter of createGraphics() (used in size() too) isn't stored anywhere, just used to pick up the right class to create g (or other instances).

Note that PGraphics defines also a number of query functions: isDisplayable() (PDF isn't), is2D(), is3D(), isGL()... This is more future proof, in theory.

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