Previous

mouseIsPressed

Η mouseIsPressed είναι μια μεταβλητή boolean που μεταβάλλεται από false σε true όταν πατηθεί το ποντίκι.

Αυτή η μεταβλητή παραμένει αληθής, όσο είναι πατημένο το ποντίκι, και όταν απελευθερωθεί, αλλάζει ξανά σε ψευδής.

Example 

Ακολουθεί ένα παράδειγμα κώδικα που σχεδιάζει έλλειψη στη θέση που δείχνει το ποντίκι, όσο πιέζεται το ποντίκι:

function setup() {
  createCanvas(800, 500);
}
function draw() {
  // set background inside draw so that the ellipse will not leave traces
  background('#D66761');
  fill(241, 213, 145);
  // if the mouse is pressed
  if (mouseIsPressed){
    // an ellipse will be drawn in the position where the mouse is pointing
    ellipse(mouseX, mouseY, 50);
  }
}

Μπορείτε να δείτε το αποτέλεσμα του παραπάνω κώδικα, click here.

Exercise

  1. Open your Visual Studio editor and the p5yourName folder.
  2. Open the file ex812.js in your editor and save it as ex914.js
  3. Open the file ex812.html in your editor and save it as ex914.html
  4. In the ex914.html file, update the link to ex914.js  from exersice812.js
  5. Go to the index.html file and create, under Module 9, a link to the ex914.html  file with the title "mouseIsPressed".

Modify the ex914.jsfile to create a drawing tool which will be drawing ellipses as long as the mouse is pressed. Also, include two other ellipses, a red and a green one. Make the drawing tool change the color of the ellipses it is drawing to red, if the user clicks inside the red ellipse and to green if the user clicks inside the green ellipse. You can see here an example.

Answer:

let mycolor = 'white';
function setup() {
  createCanvas(800, 500);
  background('#D66761');
}
function draw() {
  // this color will change every time the mouse clikcs the red or green ellipse
  fill(mycolor);
  // if the mouse is pressed
  if (mouseIsPressed){
    // an ellipse will be drawn in the position where the mouse is pointing
    ellipse(mouseX, mouseY, 20);
  }
  fill ('red');
  ellipse (600,250,50);
  fill('green');
  ellipse (600,350,50);
}
// everytime the mouse is clicked
function mouseClicked(){
  // if the mouse x and y position is inside the red ellipse
  if (mouseX >=550 && mouseX <=650 && mouseY >=200 && mouseY <=300){
    //change its color to red
    mycolor = 'red';
  }
  // if the mouse x and y position is inside the green ellipse
  if (mouseX >=550 && mouseX <=650 && mouseY >=300 && mouseY <=400){
    //change its color to green
    mycolor = 'green';
  }
}

Κάντε μια  Git commit με το μήνυμα  "mouseIsPressed".

  • Δείτε περισσότερα για τη μεταβλητή mouseIsPressed 
Previous