# Workshop This workshop is designed to go over the **most commonly used functions** with [Ronin](https://github.com/hundredrabbits/Ronin). The list of all available functions and their usage is located [here](https://github.com/hundredrabbits/Ronin/#library). You can also follow along our [video tutorial](https://youtu.be/SgAWGh1s9zg). - **Part 1**: [Images](#Images) `(import)`, `(crop)`, `(export)` - **Part 2**: [Draw](#Draw) `(stroke)`, `(fill)`, `(gradient)`, `(clear)` - **Part 3**: [Filters](#Filters) `(pixels)`, `(saturation)`, `(convolve)`, `(sharpen)` - **Part 4**: [Events](#Events) `(echo)`, `(on "mouse-down")`, `(on "animate")`, `(on "/a")` ## Images This section will teach the basics of opening, cropping and saving an image file. You can use the `$path` helper to quickly get an image's path into Ronin, by writing `$path` and dragging a file onto the Ronin window. ### Import To import an image onto the current canvas, type the following text, drag an image file onto the Ronin window, trace a shape in the canvas and press `cmd+r`: ```lisp (import $path (guide $rect)) ``` The previous code will import an image, and preserve its ratio. Alternatively, you could use a `$line` to stretch the image, or a `$pos` to simply draw the image at its original size. ```lisp (import $path (guide $line)) ``` ### Crop To crop the canvas, type the following text, drag an image file onto the Ronin window press `cmd+r`: ```lisp (import $path (pos 0 0)) (crop (rect 50 50 300 300)) ``` ### Export To export the resulting image, type the following text, drag an image file onto the Ronin window, then drag a folder and add the new file's name, and press `cmd+r`: ```lisp (import $path) (export $path) ``` For example, a version of that same code with file paths, might look something like the following: ```lisp (import "~/Desktop/photo.jpg") (export "~/Desktop/export.png") ``` You could also **generate the export path from the import path**. To import `~/Desktop/photo.jpg`, and automatically generate the export path `~/Desktop/photo-export.jpg`, use this: ```lisp (def import-path $path) (def export-path (concat (dirpath import-path) "/" (filename import-path) "-export.jpg")) (import import-path) (export export-path) ``` ## Draw This section will teach you how to draw some basic shapes and colorize them. ### Stroke In Ronin, a shape is either a `(rect)`, a `(line)`, a `(circle)` or a `(pos)`. To draw the outline of any shape, wrap the shape inside of a `(stroke shape width color)` function, like: ```lisp (stroke (rect 100 100 300 200) "red" 10) ``` Or, if you would like to trace the shape with your mouse: ```lisp (stroke $rect "red" 10) ``` ### Fill To fill the inside of any shape, wrap it inside of a `(fill shape color)` function, like: ```lisp (fill (rect 100 100 300 200) "orange") ``` ### Gradient To colorize a stroke or a fill, with a gradient, use the `(gradient line colors)` where the colors is a list of colors like `("blue" "red" "yellow")`: ```lisp (clear) (fill (circle 300 300 200) (gradient (line 0 0 500 500) ("white" "black"))) ``` To better understand how the `(line)` affects the coloring of the circle, wrap the `$line` inside a `(guide)`, as follows to preserve the guide interface: ```lisp (clear) (fill (circle 300 300 200) (gradient (guide $line) ("white" "black"))) ``` ### Clear In the previous example, we used the `(clear)` function, which clears the canvas, but it can also be used to clear only a part of the canvas: ```lisp (clear) (fill frame "red") (clear (rect 100 100 300 300)) ``` ## Filters This section will cover how to manipulate the pixels of an image. ### Pixels First let's open an image, ideally one in color, and change every pixel of a selected area at `(rect 100 100 200 200)`: ```lisp (import $path) (pixels saturation 10 (rect 100 100 200 200)) ``` The `(pixels)` function expects a function that returns 4 values(r,g,b,a), and so you can define a custom filter like: ``` (defn invert (pixel) ( (sub 255 pixel:0) (sub 255 pixel:1) (sub 255 pixel:2) pixel:3)) (pixels invert) ``` ### saturation In the previous example, we increased the saturation of a region of the image, to desaturate an entire image, you can simply omit the `(rect)` which will select the entire canvas, and set the pixel filter to `saturation` and the value to `0.5`(50% saturation): ```lisp (import $path) (pixels saturation 0.5) ``` ### convolve Effects which use the surrounding pixels, or convolution matrix, are used with the `(convolve)` function, you can learn more about this family of filters [here](https://en.wikipedia.org/wiki/Kernel_(image_processing)). ### sharpen ```lisp (import $path) (convolve (sharpen) $rect) ``` Custom convolve kernels can also be created like this: ```lisp (import $path) (def (blur) ( (-1 -1 -1) (-1 5 -1) (-1 -1 -1))) (convolve (blur)) ``` ## Events This section will demonstrate how to use events in Ronin to create interactive scripts. ### Echo You can print some content to the screen in Ronin, by using the `(echo)` function, for example, the following script will write the word `hello` at the bottom left of the interface: ```lisp (echo "hello") ``` ### MouseDown Let's use the `(debug)` function to display the position of the mouse cursor in the interface. ```lisp (on "mouse-down" echo) ``` We can define a function that triggers when the `mouse-down` event is detected, or when you click on the canvas: ```lisp ; define the function (defn draw-rect (e) (fill e:circle "red")) ; use the function (on "mouse-move" draw-rect) ``` For more examples of functions, see the [examples](https://github.com/hundredrabbits/Ronin/tree/master/examples). You can find a more elaborate version of this example [here](https://github.com/hundredrabbits/Ronin/blob/master/examples/events/on-mouse.lisp). ### Animate The `animate` event fires around 30 times per second, and is a perfect tool to create animations. Following the previous example, and the pattern of creating a function and binding it to the event, let's make a function that will use the `(time)` to animate a box: ```lisp ; define the function (defn wob-rect () ( (clear) (def rect-x 300) (def rect-y (add (mul (sin (time 0.005)) 50) 300)) (fill (rect rect-x rect-y 100 100) "red"))) ; use the function (on "animate" wob-rect) ``` You can find a more elaborate version of this example [here](https://github.com/hundredrabbits/Ronin/blob/master/examples/events/on-animate.lisp). ### OSC Other programs can communicate with Ronin via OSC with the previous pattern. For example, if you send OSC data to the port `49162`, at the path `/a`, the event can be used in Ronin to trigger a function: ```lisp (on "/a" echo) ``` You can find a more elaborate version of this example [here](https://github.com/hundredrabbits/Ronin/blob/master/examples/events/on-osc.lisp). I hope this workshop has been enlightening, if you have questions or suggestions, please visit the [community](https://hundredrabbits.itch.io/ronin/community). Enjoy!