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/*
* Visual arts with Processing
* Chapter 0, The Beginning
* Otso Sorvettula, Mehackit (CC BY-SA 4.0)
*
* This program takes an image and transforms it into a binary image. You can draw on the by image using the mouse.
*
* Set the image by setting the url for linkToImage variable
*
* Change the threshold by pressing '+' and '-'.
* Toggle webcam feed on and off with 't'.
* Save image with 's'
*
*/
// Create global variables for the whole program to use
// linkToImage can be a link on internet or link to an image in the same folder
String linkToImage = "https://processing.org/img/processing3-logo.png"; //link on internet
// String linkToImage = "image.jpg" //link to an image in the same folder
PImage originalImage;
PImage newImage;
int threshold = 100;
/*
* The setup-function is executed once when the program starts
*
* Load image and check that the image exists
*/
void setup() {
size(640, 480);
originalImage = loadImage(linkToImage);
newImage = loadImage(linkToImage);
if (originalImage == null || newImage == null) {
println("No image found, exiting");
exit();
} else {
originalImage.loadPixels();
newImage.loadPixels();
drawLinkedImage();
}
}
/*
* The draw-function is looped again and again as long as the program runs.
*
* Draw mouse actions. The image isn't drawn here. The image is only drawn again when the threshold is changed.
*/
void draw() {
// drawLinkedImage is not called in the draw loop. The image is drawn only when '+' or '-' keys are pressed
// Draw something on top of the image if the mouse is pressed. You can try to change, comment or uncomment some of these lines.
if (mousePressed) {
stroke(0, 20); // set stroke to almost transparent black
// noStroke(); // turn stroke (outlines) off
// fill(random(100, 255), random(100, 255), random(200, 255), 5); // generate and set almost random fill color
// float r = random(0, 50); // Generate a random value and save it to a variable
// ellipse(mouseX, mouseY, r, r); // Draw a circle to the mouse location with the random diameter
line(mouseX, mouseY, mouseX + random(-50, 50), mouseY + random(-50, 50)); // Draw a line from the mouse location to a point in 50 pixel radius
}
}
/*
* Manipulate and draw the linked image
*
* The pixels of the original image are loaded into an array. The array is iterated over with for loops.
* The brightness on each pixel is checked against a threshold.
* If the brightness is lower than the threshold the pixel on newImage is set black, otherwise white.
* In the end newImage is drawn at the center of the canvas.
*/
void drawLinkedImage() {
for (int x = 0; x < originalImage.width; x++) {
for (int y = 0; y < originalImage.height; y++) {
int coordinate = x + y * originalImage.width;
float pixelBrightness = brightness(originalImage.pixels[coordinate]); // Calculate the brightness of the given pixel in the original image.
if (pixelBrightness < threshold) { // If the pixel is darker than the threshold...
newImage.pixels[coordinate] = color(0); // ...set the color of the corresponding pixel in newImage to this.
} else { // If the pixel is lighter than the threshold...
newImage.pixels[coordinate] = color(255); // ...set the color of the corresponding pixel in newImage to this.
}
}
}
newImage.updatePixels();
image(newImage, width/2 - newImage.width/2, height/2 - newImage.height/2);
}
/*
* Listen to key presses and match keys to actions.
*/
void keyPressed() {
if (key == '+') {
threshold++;
threshold = min(threshold, 255);
println("Threshold set to " + threshold); // Print information to the console.
drawLinkedImage();
} else if (key == '-') {
threshold--;
threshold = max(threshold, 0);
println("Threshold set to " + threshold);
drawLinkedImage(); // If useWebcam is false, draw the linked image.
} else if (key == 's' || key == 'S') { // If the key matches 's' or 'S'
saveFrame("Processing-portrait-###.png"); // Save the screen as a png image to the same folder where this sketch is saved.
println("Image saved"); // Guess what this does :)
}
}
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