# Processing

**URL:** https://discourse.processing.org/c/processing/6.md?no_subcategories=false&page=235

[Latest](https://discourse.processing.org/latest.md) · [Categories](https://discourse.processing.org/categories.md) · [Tags](https://discourse.processing.org/tags.md)

**Page:** 236

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## [Reverse Pixel Selection OpenCV](https://discourse.processing.org/t/reverse-pixel-selection-opencv/17918)

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**Author:** [@ElwoodBlues](https://discourse.processing.org/u/ElwoodBlues)\
**Replies:** 0\
**Last updated:** [February 18, 2020, 7:19pm UTC](https://discourse.processing.org/t/reverse-pixel-selection-opencv/17918 "2020-02-18T19:19:24Z")

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Hello, I have a sketch working to pixelate faces with opencv, however I would like to reverse this, ie. pixelate the background and only have the faces showing as the normal video feed. Is there a way that I can mask out…

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## [G4P library with GUI builder - Drop down list](https://discourse.processing.org/t/g4p-library-with-gui-builder-drop-down-list/17213)

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**Author:** [@laptophead](https://discourse.processing.org/u/laptophead)\
**Replies:** 7\
**Last updated:** [February 18, 2020, 5:48pm UTC](https://discourse.processing.org/t/g4p-library-with-gui-builder-drop-down-list/17213 "2020-02-18T17:48:20Z")

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Peter I hope you read this, need some guidance please, I am using for the first time the drop down, I have a list of 10 options but all I get is dropList1 - GDropList \>\> GEvent.SELECTED @ 14368 dropList1 - GDropList \>…

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## [Colour changing! (get the values to go back)](https://discourse.processing.org/t/colour-changing-get-the-values-to-go-back/17909)

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**Author:** [@Mythikal](https://discourse.processing.org/u/Mythikal)\
**Replies:** 2\
**Last updated:** [February 18, 2020, 5:02pm UTC](https://discourse.processing.org/t/colour-changing-get-the-values-to-go-back/17909 "2020-02-18T17:02:44Z")

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I am working on a small project and I want the stoke of the lines I’m using to slowly gradient through different colours. I have an array called “col” with three integers for each RGB value. Each are set to 255 and each…

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## [Using mouse button events while developing sketches in the Eclipse IDE](https://discourse.processing.org/t/using-mouse-button-events-while-developing-sketches-in-the-eclipse-ide/17389)

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**Author:** [@spflanze](https://discourse.processing.org/u/spflanze)\
**Replies:** 8\
**Last updated:** [February 18, 2020, 2:17pm UTC](https://discourse.processing.org/t/using-mouse-button-events-while-developing-sketches-in-the-eclipse-ide/17389 "2020-02-18T14:17:47Z")

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I am developing a Processing sketch in the Eclipse IDE. I have a basic test sketch running in it. Now I need to add a menu, and in my attempt to do it I am using the information in this webpage: https://www.processing.…

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## [NullPointerExeption when using img.get()](https://discourse.processing.org/t/nullpointerexeption-when-using-img-get/17872)

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**Author:** [@Parzivalius](https://discourse.processing.org/u/Parzivalius)\
**Replies:** 9\
**Last updated:** [February 18, 2020, 8:22am UTC](https://discourse.processing.org/t/nullpointerexeption-when-using-img-get/17872 "2020-02-18T08:22:23Z")

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Hey, I am trying to get the values of a pixel in an image as well as the values of the pixels around it, however the get() function is returning a null pointer exception. Most likely something wrong in my code: void fe…

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## [Find y coordinate of point on line (given x)](https://discourse.processing.org/t/find-y-coordinate-of-point-on-line-given-x/17731)

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**Author:** [@plux](https://discourse.processing.org/u/plux)\
**Replies:** 2\
**Last updated:** [February 18, 2020, 12:19pm UTC](https://discourse.processing.org/t/find-y-coordinate-of-point-on-line-given-x/17731 "2020-02-18T12:19:36Z")

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Hi, I have this code which compiles but does not work as expected. I’ve translated it from some javascript I’ve found around and I’m trying to figure out where the issue is. Basically it should be fairly simple. There’…

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## [2d shapes on the zx plane](https://discourse.processing.org/t/2d-shapes-on-the-zx-plane/17876)

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**Author:** [@code\_X](https://discourse.processing.org/u/code_X)\
**Replies:** 9\
**Last updated:** [February 18, 2020, 10:23am UTC](https://discourse.processing.org/t/2d-shapes-on-the-zx-plane/17876 "2020-02-18T10:23:08Z")

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So the title basically explains my question, so I’m wanting to make a program that displays a circle on the x-z plane how would I do this without a rotation statement? Is it possible? I’ve done some researching and didn’…

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## [Completing this problem too?](https://discourse.processing.org/t/completing-this-problem-too/17907)

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**Author:** [@kandrews](https://discourse.processing.org/u/kandrews)\
**Replies:** 1\
**Last updated:** [February 18, 2020, 4:06am UTC](https://discourse.processing.org/t/completing-this-problem-too/17907 "2020-02-18T04:06:06Z")

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here is a second problem I don’t know how to solve, any solutions? Complete the following method. Given an array of ints, return an array with all the same elements but in reverse order. public int\[\] reverse(int\[\] nums…

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## [Live programming](https://discourse.processing.org/t/live-programming/17217)

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**Author:** [@code\_X](https://discourse.processing.org/u/code_X)\
**Replies:** 4\
**Last updated:** [February 18, 2020, 9:42am UTC](https://discourse.processing.org/t/live-programming/17217 "2020-02-18T09:42:03Z")

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so, I’m the kind of person who likes to test their program and edit it while doing so and i was wondering if Processing has a live programming option, where it will run the program and you can change the code and when th…

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## [Completing this problem?](https://discourse.processing.org/t/completing-this-problem/17905)

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**Author:** [@kandrews](https://discourse.processing.org/u/kandrews)\
**Replies:** 4\
**Last updated:** [February 18, 2020, 4:03am UTC](https://discourse.processing.org/t/completing-this-problem/17905 "2020-02-18T04:03:22Z")

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can someone solve this? Complete the longestRun method as described. Given an array of ints, determine the length of the longest “run” of values contained therein. A “run” is a group of identical values that are adjace…

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## [How to create a diagonal line](https://discourse.processing.org/t/how-to-create-a-diagonal-line/17869)

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**Author:** [@anon94203042](https://discourse.processing.org/u/anon94203042)\
**Replies:** 9\
**Last updated:** [February 18, 2020, 2:27am UTC](https://discourse.processing.org/t/how-to-create-a-diagonal-line/17869 "2020-02-18T02:27:36Z")

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So I have this relatively simple code that creates a white line moving left to right across the screen. It’s similar to a “shinny” effect. However, How would I do the same effect, but have the line move diagonally from t…

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## [How does one transfer the data in a String over the network to anther instance of the program](https://discourse.processing.org/t/how-does-one-transfer-the-data-in-a-string-over-the-network-to-anther-instance-of-the-program/17894)

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**Author:** [@TechMaster04](https://discourse.processing.org/u/TechMaster04)\
**Replies:** 4\
**Last updated:** [February 17, 2020, 11:14pm UTC](https://discourse.processing.org/t/how-does-one-transfer-the-data-in-a-string-over-the-network-to-anther-instance-of-the-program/17894 "2020-02-17T23:14:16Z")

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Hello I’m writing a queue manager for a school project, and thought it would be cool if the names in the queue show up for everyone who’s running the program. I’ve tried a UDP server, but I couldn’t get that to work ove…

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## [I2C Connection not working with MAX517](https://discourse.processing.org/t/i2c-connection-not-working-with-max517/17399)

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**Author:** [@Samsanit](https://discourse.processing.org/u/Samsanit)\
**Replies:** 1\
**Last updated:** [February 17, 2020, 8:50pm UTC](https://discourse.processing.org/t/i2c-connection-not-working-with-max517/17399 "2020-02-17T20:50:17Z")

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Hi all, I’m working on a project using a MAX517 Digital to Analog converter, however I’m having some trouble getting the I2C connection to work properly. I’m able to pick up that there is an I2C device using the println…

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## [Format Specifiers](https://discourse.processing.org/t/format-specifiers/17760)

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**Author:** [@spflanze](https://discourse.processing.org/u/spflanze)\
**Replies:** 2\
**Last updated:** [February 17, 2020, 6:32pm UTC](https://discourse.processing.org/t/format-specifiers/17760 "2020-02-17T18:32:44Z")

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I set up my output data stream with this code. It works without any errors indicated: try { println( "Path: " + selection.getCanonicalPath() ); println( "ext: \\""+ getFileExtension(selection.getCanonicalPath() ) + …

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## [How to change colors between circles when overlapping?](https://discourse.processing.org/t/how-to-change-colors-between-circles-when-overlapping/17716)

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**Author:** [@kandrews](https://discourse.processing.org/u/kandrews)\
**Replies:** 3\
**Last updated:** [February 17, 2020, 4:15pm UTC](https://discourse.processing.org/t/how-to-change-colors-between-circles-when-overlapping/17716 "2020-02-17T16:15:51Z")

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Circle \[\] circles = new Circle \[10\]; class Circle { float x; float y; float speed; float diam; color c; boolean valid; final int MAX\_COLOR = 255; final int MIN\_X = 50, MAX\_X = 750; final int MIN\_Y = …

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## [Render high-res images using Hype Framework](https://discourse.processing.org/t/render-high-res-images-using-hype-framework/17815)

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**Author:** [@mrclstrtr](https://discourse.processing.org/u/mrclstrtr)\
**Replies:** 4\
**Last updated:** [February 17, 2020, 3:11pm UTC](https://discourse.processing.org/t/render-high-res-images-using-hype-framework/17815 "2020-02-17T15:11:44Z")

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Hi everybody, I recently started working with Processing in combination with Joshuas’ Hype Framework. I’m able to save single frames from an animation but only in the same resolution as the sketch e.g. 800x500. Is there…

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## [Changing Colours after X iterations](https://discourse.processing.org/t/changing-colours-after-x-iterations/17881)

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**Author:** [@ChrisHaz3ll](https://discourse.processing.org/u/ChrisHaz3ll)\
**Replies:** 1\
**Last updated:** [February 17, 2020, 2:48pm UTC](https://discourse.processing.org/t/changing-colours-after-x-iterations/17881 "2020-02-17T14:48:41Z")

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Hi guys, So essentially I’m trying to figure out how to cycle through colours assigned within an array. I would like for every 50 frames/iterations, for the colour to change to the next one in the array (ie, 0-50 = yel…

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## [How to draw PGraphics out of an array](https://discourse.processing.org/t/how-to-draw-pgraphics-out-of-an-array/17852)

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**Author:** [@fmS3lect](https://discourse.processing.org/u/fmS3lect)\
**Replies:** 5\
**Last updated:** [February 17, 2020, 9:46am UTC](https://discourse.processing.org/t/how-to-draw-pgraphics-out-of-an-array/17852 "2020-02-17T09:46:53Z")

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Hi all, i am trying to code an Poster wich takes the color out of the webcam and draws shaps on the canvas. This works finde, but now i want to it to only draw a certain amount of shapes on the canvas, like 50 or so and…

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## [HUD delay when is following the object](https://discourse.processing.org/t/hud-delay-when-is-following-the-object/17811)

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**Author:** [@kisdfnfn](https://discourse.processing.org/u/kisdfnfn)\
**Replies:** 1\
**Last updated:** [February 17, 2020, 12:57am UTC](https://discourse.processing.org/t/hud-delay-when-is-following-the-object/17811 "2020-02-17T00:57:35Z")

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“I’m brazilian then, i’m sorry, my english is very poop” I have a problem, because i’m trying to create a MMORPG with Processing, but my HUD have delay. Look: https://imgur.com/ZkFE451 draw function void draw() { b…

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## [Save .txt file to desktop Mac](https://discourse.processing.org/t/save-txt-file-to-desktop-mac/17750)

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**Author:** [@sdotjo](https://discourse.processing.org/u/sdotjo)\
**Replies:** 1\
**Last updated:** [February 17, 2020, 12:50am UTC](https://discourse.processing.org/t/save-txt-file-to-desktop-mac/17750 "2020-02-17T00:50:46Z")

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Hi all, I want to save the .txt file my processing sketch outputs directly to a mac desktop. Can you suggest how I’d do that? I assume it’s within createWriter(), but I don’t know how to signify a path on mac. Here’s my…

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## [Motion Detection Changing an Aspect Ration](https://discourse.processing.org/t/motion-detection-changing-an-aspect-ration/17826)

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**Author:** [@tiasocci](https://discourse.processing.org/u/tiasocci)\
**Replies:** 1\
**Last updated:** [February 17, 2020, 12:22am UTC](https://discourse.processing.org/t/motion-detection-changing-an-aspect-ration/17826 "2020-02-17T00:22:29Z")

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I have a code of a vibrating rectangle with a video captured by the webcam. As you play with the mouse, the aspect ratio changes. I was wondering how to do it so when there is motion or a change in position detected by t…

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## [Three faces coin flip](https://discourse.processing.org/t/three-faces-coin-flip/17518)

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**Author:** [@BrokenCode](https://discourse.processing.org/u/BrokenCode)\
**Replies:** 6\
**Last updated:** [February 16, 2020, 11:46pm UTC](https://discourse.processing.org/t/three-faces-coin-flip/17518 "2020-02-16T23:46:08Z")

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Hello everybody, I need to simulate a coin flip, but with three possible outcomes, method1(), method2() and method3(). But if method1() is completed, then go to method2(), but if method2() is completed then go to method…

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## [Thick strokes overlap with stray pixels](https://discourse.processing.org/t/thick-strokes-overlap-with-stray-pixels/17865)

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**Author:** [@sgt\_slaughtermelon](https://discourse.processing.org/u/sgt_slaughtermelon)\
**Replies:** 1\
**Last updated:** [February 16, 2020, 7:06pm UTC](https://discourse.processing.org/t/thick-strokes-overlap-with-stray-pixels/17865 "2020-02-16T19:06:53Z")

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Okay, so I have some code that is meant to draw a series of thick strokes of random color that overlay eachother. The problem is that when they draw, they should theoretically overlap perfectly, but instead there are con…

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## [How to use PrivateProfileString()](https://discourse.processing.org/t/how-to-use-privateprofilestring/17631)

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**Author:** [@spflanze](https://discourse.processing.org/u/spflanze)\
**Replies:** 3\
**Last updated:** [February 16, 2020, 5:08pm UTC](https://discourse.processing.org/t/how-to-use-privateprofilestring/17631 "2020-02-16T17:08:34Z")

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I am attempting to follow the example at: to store user settings between sketch invocations. I am using the Eclipse IDE to develop it. In this code snippet: /\*\* default starting directory where browsing for…

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## [Problem with making Window loading](https://discourse.processing.org/t/problem-with-making-window-loading/17843)

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**Author:** [@NumericPrime](https://discourse.processing.org/u/NumericPrime)\
**Replies:** 4\
**Last updated:** [February 16, 2020, 2:02pm UTC](https://discourse.processing.org/t/problem-with-making-window-loading/17843 "2020-02-16T14:02:36Z")

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As I was using the javax.swing library I made a Window, that should paint something if the correct button is pressed. The problem is that it is only painted if I close the window I made. How can I Prevent the program fro…

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## [Class and background image](https://discourse.processing.org/t/class-and-background-image/17846)

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**Author:** [@Taby](https://discourse.processing.org/u/Taby)\
**Replies:** 2\
**Last updated:** [February 16, 2020, 11:08am UTC](https://discourse.processing.org/t/class-and-background-image/17846 "2020-02-16T11:08:33Z")

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Hello. I wrote a code using functions and had a background image written like that: PImage bg; Void setup() { size (600,400); bg = loadimage(“floral.jpg”); } Void draw() { background(bg); stroke(0); } How…

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## [Camera recognizing parts](https://discourse.processing.org/t/camera-recognizing-parts/17817)

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**Author:** [@Ladan](https://discourse.processing.org/u/Ladan)\
**Replies:** 1\
**Last updated:** [February 15, 2020, 7:41pm UTC](https://discourse.processing.org/t/camera-recognizing-parts/17817 "2020-02-15T19:41:43Z")

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Hello, I want to code and buy a camera, that can recognize parts of a mini car (https://www.youtube.com/watch?v=qs2jdXHgGLQ) if you hold them under it. Can somebody recommend me a camera, a programming enviroment and…

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## [Perhaps another way to shuffle lerped colors in an array?](https://discourse.processing.org/t/perhaps-another-way-to-shuffle-lerped-colors-in-an-array/17597)

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**Author:** [@debxyz](https://discourse.processing.org/u/debxyz)\
**Replies:** 38\
**Last updated:** [February 15, 2020, 11:40am UTC](https://discourse.processing.org/t/perhaps-another-way-to-shuffle-lerped-colors-in-an-array/17597 "2020-02-15T11:40:59Z")

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Watching a D Shiffman tutorial on probability prompted me to try this. I want to shuffle a colorList array of lerped colors. Search turned up to use IntList and shuffle. But in setup for loop I thought to replace k++; …

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## [macOS processing unable to start "we're off on the wrong foot"-Solved](https://discourse.processing.org/t/macos-processing-unable-to-start-were-off-on-the-wrong-foot-solved/16464)

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**Author:** [@niuuin](https://discourse.processing.org/u/niuuin)\
**Replies:** 5\
**Last updated:** [February 15, 2020, 5:49am UTC](https://discourse.processing.org/t/macos-processing-unable-to-start-were-off-on-the-wrong-foot-solved/16464 "2020-02-15T05:49:09Z")

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I have been using it normally before, but suddenly something went wrong yesterday. I checked a lot of previous topics, but still can’t solve this problem.I don’t understand deeper principles, but I haven’t found a soluti…

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## [oscP5 - vectors and length of message](https://discourse.processing.org/t/oscp5-vectors-and-length-of-message/17791)

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**Author:** [@AndreasRef](https://discourse.processing.org/u/AndreasRef)\
**Replies:** 1\
**Last updated:** [February 15, 2020, 5:46am UTC](https://discourse.processing.org/t/oscp5-vectors-and-length-of-message/17791 "2020-02-15T05:46:02Z")

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Hi Two quick questions about the oscP5 library: Am I correct that you cannot send PVectors via OSC? When receiving an array of ints of a varying length via OSC, how do I parse it correctly, in situations where I d…

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