modification in the animation of vertical lines with processing - animation

Question

i have modified the code for the animation of vertical lines which was given by . In the recent code I need to change the value between the two arrays of lines which are generated by the code and also make the disappearing of lines gradual. All the lines leaving or coming should have the same spacing between them. Below is the code.
//float[] linePositions = new float[10];
ArrayList<Integer> linePositions = new ArrayList<Integer>();
int lineWidth = 50;
int lineSpacing = 25;
int lineSpeed = 1;
int totalwidth;
int pixelperframe = 0;
int arraySize = 0;
void setup() {
size(640, 360);
println("Setup");
totalwidth = lineWidth+lineSpacing;
for (int i = 0; i < width; i=i +totalwidth) {
//Float value = 0 + (lineWidth+lineSpacing)*i;
linePositions.add(i);
}
arraySize = linePositions.size();
}
Boolean drawn = false;
void draw() {
println("Draw");
background(51);
//loop through the lines
//println("before Draw ka forloop"+linePositions.size());\
pixelperframe = ((lineSpeed - 10) > 1) ? (lineSpeed-10) : 1;
for (int i = 0; i < arraySize; i++) {
//println("Draw ka forloop");
rect(linePositions.get(i), 0, lineWidth, width);
int newPosition = linePositions.get(i) - pixelperframe ;
linePositions.set(i, newPosition);
//linePositions[i] -= lineSpeed;
//wrap the line
if ( linePositions.get(i) < 0) {
println("Wrapping the line");
linePositions.set(i, width);
// drawn = true;
}
}
//int temp = (width - linePositions.get(arraySize - 1)) - totalwidth;
//println(temp);
}

Answer 1

For the spacing between the lines to always be the same, you have to make sure that the total line spacing adds up to the total width of your screen. Right now each line takes up 75 pixels (50 for the line itself and 25 for the space after it), but your width is 640. That will always leave you with extra space, which will mess up your spacing after the lines start over.
So the easiest thing to do is to simply make your window a multiple of the line spacing. Let's go with 600, which is enough room for exactly 8 lines.
However, since you want your lines to slide off the screen, you actually need 9 lines, since you'll often see half of one line going off the screen while half of another line enters the screen. Draw some pictures to see exactly what I'm talking about
If I understand what you mean by making the lines "gradually" restart, you just have to restart them when their right side goes off the screen. In other words, when their x position is negative enough to be off the screen.
Putting it all together, it looks like this:
float[] linePositions = new float[9];
float lineWidth = 50;
float lineSpacing = 25;
float lineSpeed = 1;
void setup() {
size(600, 360);
for (int i = 0; i < linePositions.length; i++) {
linePositions[i] = (lineWidth+lineSpacing)*i;
}
}
void draw() {
background(51);
for (int i = 0; i < linePositions.length; i++) {
linePositions[i] -= lineSpeed;
rect(linePositions[i], 0, lineWidth, height);
if ( linePositions[i] < -(lineWidth+lineSpacing)) {
linePositions[i] = width;
}
}
}