Support built-in variables

[gaocegege]

There are some built-in variables such as height, width and frameCount, some works and others don't work, now.

Screen

• height
• width
• pixelHeight
• pixelWidth

Time

• frameCount
• frameRate
• looping

Geometry

• HALF_PI
• PI
• QUARTER_PI
• TWO_PI
• TAU

Interaction

• focused
• key
• keyCode
• mouseX
• mouseY
• pmouseX
• pmouseY
• keyPressed
• mousePressed

[jeremydouglass]

You mentioned that some variables work -- can you give an example of one that works? In my last round of tests none of them were working, but I might not be calling them correctly.

I would say this may be higher than p3 because the majority of all demo Processing sketches use the width and height variables.

[gaocegege]

For example:

yPos <- 0

draw <- function() {
    background(as.integer(204))
    yPos <- yPos - 1
    if (yPos < 0) {
        yPos <- height
    }
    line(0, yPos, width, yPos)
}

I set it to p3 because width and height works well. Do you meet any error when using these two variables?

[jeremydouglass]

Got it. I see that you've now added width and height, so I'm catching up.

I've updated the checklist above for checking off specific things as they are resolved.

If it makes sense then break parts of the list off into other issues -- for example, if the interaction constants won't be implemented.

Note also the related:

• frameCount issue: Refactor the logic about frameCount #81
• constants issue: Support Constants (math) from Processing #49

[jeremydouglass]

For new contributors, it looks like exposing the keyPressed and mousePressed booleans are only things left in this issue.

• https://processing.org/reference/keyPressed.html
• https://processing.org/reference/mousePressed.html

Currently frameCount is exposed in RLAngPApplet.java handleDraw():

https://github.com/gaocegege/Processing.R/blob/master/src/rprocessing/RLangPApplet.java#L332

while focused is exposed in wrapProcessingVariables():

https://github.com/gaocegege/Processing.R/blob/master/src/rprocessing/RLangPApplet.java#L387

[gaocegege]

Closed since it has been solved.