Develop Reference

How to make the bouncing ball collide with the array of rectangles on Processing?

im trying to make the bouncing ball bounce on the arrays of rectangles. I've looked at various other codes but cant seem to find a solution. Would appreciate any help!!!
Basically, i want the bouncing ball to recognise that theres the rectangles there and for it to be able to jump onto the rectangles.
PVector location; // Location of shape
PVector velocity; // Velocity of shape
PVector gravity; // Gravity acts at the shape's acceleration
PVector upwardForce;
PImage bg;
int radius = 10, directionX = 1, directionY = 0;
float x=20, y=20, speed=0.5;
int xarray[] = new int[20];
int yarray[] = new int[20];
// =========================================================
void setup() {
size(380,750);
location = new PVector(100,50);
velocity = new PVector(0.0,2.1);
upwardForce = new PVector(0.0,-10.0);
gravity = new PVector(0,0.4);
bg = loadImage("bg.png");
bg.resize(1600,1600);
background(0);
for(int i =0; i< 20;i++){
xarray[i]= i*100;
yarray[i] = 750-int(random(10))*50;
}
}
int xd =0, yd=0;
void draw() {
background(0);
noStroke();
xd--;
yd++;
// display image twice:
image(bg, y, 0);
image(bg, y+bg.height, 0);
// pos
y--;
if (y<-bg.height)
y=0;
for (int i = 0;i< 20;i++){
if (xarray[i] <100 && xarray[i]+100 >100){
fill(255,0,0);
}
else {
fill(255);
}
rect(xarray[i],yarray[i],100,1200);
fill(255);
xarray[i]=xarray[i]-4;
//yarray[i]=yarray[i]+1;
if (xarray[i] + 100 < 0){
xarray[i]+=2000;
// yarray[i]-=850;
}
}
// changing Position
x=x+speed*directionX;
y=y+speed*directionY;
// check boundaries
if ((x>width-radius) || (x<radius))
{
directionX=-directionX;
}
if ((y>height-radius) || (y<radius))
{
directionY=-directionY;
}
// draw
// if(direction==1)
// Add velocity to the location.
location.add(velocity);
// Add gravity to velocity
velocity.add(gravity);
// Bounce off edges
if ((location.x > width) || (location.x < 0)) {
velocity.x = velocity.x * -1;
}
if ((location.y > height) || (location.y < 0)){
// We're reducing velocity ever so slightly
// when it hits the bottom of the window
velocity.y = velocity.y * -0.95;
location.y = height;
}
// Display circle at location vector
stroke(255);
strokeWeight(0);
fill(255);
ellipse(location.x,location.y,30,30);
}
void keyPressed()
{
velocity.add(upwardForce);
}

The best advice we can give you is to break your problem down into smaller steps and to take those steps on one at a time.
For example, can you create a simple sketch that just shows a single hard-coded circle and a single hard-coded rectangle? Now add some code that prints a message to the console if they're colliding. You're going to have to do some research into collision detection, but here's a hint: a common technique is to treat the ball as a rectangle, so you can do rectangle-rectangle collision detection.
Get that working perfectly by itself, and then work your way forward in small steps. Can you add a second rectangle to your sketch? How about a third?
Then if you get stuck, you can post a MCVE (not your whole project, just a small example) along with a more specific question. Good luck.

Here's a few suggestions:
You're best off using a Rectangle class. That way, you don't have to store the locations in an array, and the collide function can be a method of the class. It's easier to just call the positions of the rectangles "x" and "y", but this would obviously conflict with the x and y global variables which you declared at the top of the code. Assuming that you would want to make the ball bounce if it collided, you would need to have a "ballLastx" and a "ballLasty" in order to keep track of which direction the ball came from. You would also need to store the Rectangles in an array or arrayList. It would be something like this:
PVector lastLocation;
Rectangle[] rects;
As for the rectangle class, here's how it would probably look like this:
class Rectangle {
float x, y;
Rectangle(float x_, float y_) {
x = x_;
y = y_;
}
void show() {
//Displays rectangle
if (x < 100 && x+100 > 100) fill(255,0,0);
else fill(255);
rect(x,y,100,1200);
fill(255);
x=x-4;
if (x + 100 < 0) x+=2000;
}
private boolean insideX(PVector pos) {
return (pos.x + 15 >= x && pos.x - 15 <= x+100);
}
private boolean insideY(PVector pos) {
return (pos.y + 15 >= y && pos.y - 15 <= x + 1200);
}
boolean collidedX() {
//Detects if the ball has collided along the x-axis
return ((insideX(location) && !insideX(lastLocation)) && insideY(location))
}
boolean collidedY() {
//Detects if the ball has collided along the y-axis
return ((insideY(location) && !insideY(lastLocation)) && insideX(location))
}
}
And then, in your setup function, you could declare the Rectangle classes in a for-loop:
//declare the rects array
rects = new Rectangle[20];
//declare each item of the rects array to be a Rectangle
for(int i = 0; i < rects.length; i++) {
rects[i] = new Rectangle(i*100, 750-int(random(0,10))*50;
}
In order to detect the collision and to bounce the ball, you would need to loop through all of the Rectangles and see if the ball should bounce off any of them:
boolean bouncex = false;
boolean bouncey = false;
//see if any of the rects are colliding with the ball
for(Rectangle r : rects) {
if(r.collidedX()) bouncex = true;
if(r.collidedY()) bouncey = true;
}
//if any are colliding, bounce the ball
if(bouncex) velocity.x = -velocity.x;
if(bouncey) velocity.y = -velocity.y;
Finally, don't forget to set the lastLocation PVector to the current location, just before moving the current location:
lastLocation = location.copy();
//move the ball...
Hope this was helpful!

Algorithm to verify if a shape is inside another - javafx

I have a rectangular and circle. I need to verify whether a rectangle is inside that circle.
I tried to Shape.intersects but intersects is checked the number 1.
Does anyone know this kind of algorithm in javafx?
Just to exemplifly, in the figure only rectangles 1, 2, 3, and 4 are inside the circle.
thanks for your help.

Solution
The basic idea behind this solution is that any polygon is contained within any convex (see comments) shape iff every point within the polygon is within the shape. The intersects() method that you're attempting to use returns true if at least one point of the polygon is within the shape. You've already figured out that it'll work, but it'll also offer false positives for any partially-intersected shapes. To fix it, we define our own intersection test which looks at all points.
This can be generalized to scan any given polygon for "total intersection" with any given shape:
public boolean totalIntersects(Polygon poly, Shape testShape) {
List<Point> points = flatDoublesToPoints(poly.getPoints());
boolean inside = true; // If this is false after testing all points, the poly has at least one point outside of the shape.
for(Point point : points) {
if(!testShape.intersects(point.x, point.y, 1, 1)) { // The 3rd and 4th parameters here are "width" and "height". 1 for a point.
inside = false;
}
}
return inside;
}
where flatDoublesToPoints() and Point are defined as:
private List<Point> flatDoublesToPoints(List<Double> flatDoubles) {
List<Point> points = new ArrayList<>();
for(int i = 0; i < flatDoubles.size(); i += 2) {
points.add(new Point(flatDoubles.get(i), flatDoubles.get(i + 1)));
}
return points;
}
class Point {
public double x, y;
public Point(double x, double y) {
this.x = x;
this.y = y;
}
}
flatDoublesToPoints() is needed to split the "flat" {x1, y1, x2, y2, x3, y3...} polygon lists into a more easy-to-understand data structure. If you're doing tons of comparisons, it may be helpful to skip this step, however, and operate on the "flat list" directly for memory reasons.
Application
The following applies the other methods to a situation extremely similar to yours. (Not exact, because I didn't have your code.)
public class Main extends Application {
public static final int SIZE = 600;
#Override
public void start(Stage primaryStage) throws Exception {
Pane rootPane = new Pane();
List<Rectangle> rects = new ArrayList<>();
for (int j = 0; j < 2; j++) {
for(int i = 0; i < 5; i++) {
Rectangle r = new Rectangle(i * 100, j == 0 ? 0 : 300, 100, 200);
r.setFill(Color.BEIGE);
r.setStroke(Color.BLACK);
rects.add(r);
}
}
rootPane.getChildren().addAll(rects);
Circle circle = new Circle(350, 100, 200);
circle.setStroke(Color.BLACK);
circle.setFill(null);
rootPane.getChildren().add(circle);
List<Polygon> polys = new ArrayList<>();
for(Rectangle rect : rects) {
polys.add(rectangleToPolygon(rect));
}
List<Polygon> intersects = getTotalIntersections(polys, circle);
System.out.println(intersects);
primaryStage.setScene(new Scene(rootPane, SIZE, SIZE));
primaryStage.show();
}
public List<Polygon> getTotalIntersections(List<Polygon> polys, Shape testShape) {
List<Polygon> intersections = new ArrayList<>();
for(Polygon poly : polys) {
if(totalIntersects(poly, testShape)) {
intersections.add(poly);
}
}
return intersections;
}
public static Polygon rectangleToPolygon(Rectangle rect) {
double[] points = {rect.getX(), rect.getY(),
rect.getX() + rect.getWidth(), rect.getY(),
rect.getX() + rect.getWidth(), rect.getY() + rect.getHeight(),
rect.getX(), rect.getY() + rect.getHeight()};
return new Polygon(points);
}
public static void main(String[] args) {
Main.launch(args);
}
}
This code will print the following:
[Polygon[points=[200.0, 0.0, 300.0, 0.0, 300.0, 200.0, 200.0, 200.0], fill=0x000000ff], Polygon[points=[300.0, 0.0, 400.0, 0.0, 400.0, 200.0, 300.0, 200.0], fill=0x000000ff], Polygon[points=[400.0, 0.0, 500.0, 0.0, 500.0, 200.0, 400.0, 200.0], fill=0x000000ff]]
Which is your three polygons labeled 2, 3, and 4.

I don't think that JavaFX will have some special methods for this case.
To draw that circle you need coordinates (X_c, Y_c) of center and radius (R).
To draw rectangles you need to have coordinates ((X_1, Y_1), (X_2, Y_2) etc.) of angle points.
Then all you need is to check if all points of the rectangle is inside of the circle:
(X_1 - X_c)^2 + (Y_1 - Y_c)^2 < R^2
(X_2 - X_c)^2 + (Y_2 - Y_c)^2 < R^2
...

Try this :
import javafx.geometry.Point2D;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Rectangle;
/*
Check if a rectangle is contained with in a circle by checking
all rectangle corners.
For the rectangle to be contained in a circle, all its corners should be
in a distance smaller or equal to the circle's radius, from the circle's center.
Note:
Requires some more testing. I tested only a few test cases.
I am not familiar with javafx. This solution does not take into
calculation rectangle's arc or other attributes I may not be aware of.
*/
public class Test{
//apply
public static void main(String[] args){
Circle circle = new Circle(0 ,0, 100);
Rectangle rec = new Rectangle(0, 0, 50 , 50);
System.out.println("Is rectungle inside the circle ? "
+ isContained(circle,rec));
}
//check if rectangle is contained within a circle
private static boolean isContained(Circle circle,Rectangle rec) {
boolean isInside = true;
//get circle center & radius
Point2D center = new Point2D(circle.getCenterX(), circle.getCenterY());
double radius= circle.getRadius();
Point2D[] corners = getRectangleCorners(rec);
for(Point2D corner : corners) {
//if any corner falls outside the circle
//the rectangle is not contained in the circle
if(distanceBetween2Points(corner, center) > radius) {
return false;
}
}
return isInside;
}
//calculate distance between two points
//(updated a per fabian's suggestion)
private static double distanceBetween2Points
(Point2D corner, Point2D center) {
return corner.distance(center);
}
private static Point2D[] getRectangleCorners(Rectangle rec) {
Point2D[] corners = new Point2D[4];
corners[0] = new Point2D(rec.getX(), rec.getY());
corners[1] = new Point2D(rec.getX()+ rec.getWidth() , rec.getY());
corners[2] = new Point2D(rec.getX()+ rec.getWidth(), rec.getY()+ rec.getHeight());
corners[3] = new Point2D(rec.getX(), rec.getY()+ rec.getHeight());
return corners;
}
}

There is a working simple solution here : https://stackoverflow.com/a/8721483/1529139
Copy-paste here:
class Boundary {
private final Point[] points; // Points making up the boundary
...
/**
* Return true if the given point is contained inside the boundary.
* See: http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html
* #param test The point to check
* #return true if the point is inside the boundary, false otherwise
*
*/
public boolean contains(Point test) {
int i;
int j;
boolean result = false;
for (i = 0, j = points.length - 1; i < points.length; j = i++) {
if ((points[i].y > test.y) != (points[j].y > test.y) &&
(test.x < (points[j].x - points[i].x) * (test.y - points[i].y) / (points[j].y-points[i].y) + points[i].x)) {
result = !result;
}
}
return result;
}
}

How to determine remaining space on a pdf page with itext [duplicate]

I have a pdf file where-in I am adding a stamp to all it's pages.
But, the problem is, the stamp is added to the upper-left corner of each page. If, the page has text in that part, the stamp appears on the text.
My question is, is there any method by which I can read each page and if there is no text in that part add the stamp else search for nearest available free space, just like what a density scanner does?
I am using IText and Java 1.7.
The free space fider class and the distance calculation function are the same that is there in the accepted answer.
Following is the edited code I am using:
// The resulting PDF file
String RESULT = "K:\\DCIN_TER\\DCIN_EPU2\\CIRCUIT FROM BRANCH\\RAINBOW ORDERS\\" + jtfSONo.getText().trim() + "\\PADR Release\\Final PADR Release 1.pdf";
// Create a reader
PdfReader reader = new PdfReader("K:\\DCIN_TER\\DCIN_EPU2\\CIRCUIT FROM BRANCH\\RAINBOW ORDERS\\" + jtfSONo.getText().trim() + "\\PADR Release\\Final PADR Release.pdf");
// Create a stamper
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(RESULT));
// Loop over the pages and add a footer to each page
int n = reader.getNumberOfPages();
for(int i = 1; i <= n; i++)
{
Collection<Rectangle2D> rectangles = find(reader, 300, 100, n, stamper); // minimum width & height of a rectangle
Iterator itr = rectangles.iterator();
while(itr.hasNext())
{
System.out.println(itr.next());
}
if(!(rectangles.isEmpty()) && (rectangles.size() != 0))
{
Rectangle2D best = null;
double bestDist = Double.MAX_VALUE;
Point2D.Double point = new Point2D.Double(200, 400);
float x = 0, y = 0;
for(Rectangle2D rectangle: rectangles)
{
double distance = distance(rectangle, point);
if(distance < bestDist)
{
best = rectangle;
bestDist = distance;
x = (float) best.getX();
y = (float) best.getY();
int left = (int) best.getMinX();
int right = (int) best.getMaxX();
int top = (int) best.getMaxY();
int bottom = (int) best.getMinY();
System.out.println("x : " + x);
System.out.println("y : " + y);
System.out.println("left : " + left);
System.out.println("right : " + right);
System.out.println("top : " + top);
System.out.println("bottom : " + bottom);
}
}
getFooterTable(i, n).writeSelectedRows(0, -1, x, y, stamper.getOverContent(i)); // 0, -1 indicates 1st row, 1st column upto last row and last column
}
else
getFooterTable(i, n).writeSelectedRows(0, -1, 94, 140, stamper.getOverContent(i)); // bottom left corner
}
// Close the stamper
stamper.close();
// Close the reader
reader.close();
public Collection<Rectangle2D> find(PdfReader reader, float minWidth, float minHeight, int page, PdfStamper stamper) throws IOException
{
Rectangle cropBox = reader.getCropBox(page);
Rectangle2D crop = new Rectangle2D.Float(cropBox.getLeft(), cropBox.getBottom(), cropBox.getWidth(), cropBox.getHeight());
FreeSpaceFinder finder = new FreeSpaceFinder(crop, minWidth, minHeight);
PdfReaderContentParser parser = new PdfReaderContentParser(reader);
parser.processContent(page, finder);
System.out.println("finder.freeSpaces : " + finder.freeSpaces);
return finder.freeSpaces;
}
// Create a table with page X of Y, #param x the page number, #param y the total number of pages, #return a table that can be used as footer
public static PdfPTable getFooterTable(int x, int y)
{
java.util.Date date = new java.util.Date();
SimpleDateFormat sdf = new SimpleDateFormat("dd MMM yyyy");
String month = sdf.format(date);
System.out.println("Month : " + month);
PdfPTable table = new PdfPTable(1);
table.setTotalWidth(120);
table.setLockedWidth(true);
table.getDefaultCell().setFixedHeight(20);
table.getDefaultCell().setBorder(Rectangle.TOP);
table.getDefaultCell().setBorder(Rectangle.LEFT);
table.getDefaultCell().setBorder(Rectangle.RIGHT);
table.getDefaultCell().setBorderColorTop(BaseColor.BLUE);
table.getDefaultCell().setBorderColorLeft(BaseColor.BLUE);
table.getDefaultCell().setBorderColorRight(BaseColor.BLUE);
table.getDefaultCell().setBorderWidthTop(1f);
table.getDefaultCell().setBorderWidthLeft(1f);
table.getDefaultCell().setBorderWidthRight(1f);
table.getDefaultCell().setHorizontalAlignment(Element.ALIGN_CENTER);
Font font1 = new Font(FontFamily.HELVETICA, 10, Font.BOLD, BaseColor.BLUE);
table.addCell(new Phrase("CONTROLLED COPY", font1));
table.getDefaultCell().setFixedHeight(20);
table.getDefaultCell().setBorder(Rectangle.LEFT);
table.getDefaultCell().setBorder(Rectangle.RIGHT);
table.getDefaultCell().setBorderColorLeft(BaseColor.BLUE);
table.getDefaultCell().setBorderColorRight(BaseColor.BLUE);
table.getDefaultCell().setBorderWidthLeft(1f);
table.getDefaultCell().setBorderWidthRight(1f);
table.getDefaultCell().setHorizontalAlignment(Element.ALIGN_CENTER);
Font font = new Font(FontFamily.HELVETICA, 10, Font.BOLD, BaseColor.RED);
table.addCell(new Phrase(month, font));
table.getDefaultCell().setFixedHeight(20);
table.getDefaultCell().setBorder(Rectangle.LEFT);
table.getDefaultCell().setBorder(Rectangle.RIGHT);
table.getDefaultCell().setBorder(Rectangle.BOTTOM);
table.getDefaultCell().setBorderColorLeft(BaseColor.BLUE);
table.getDefaultCell().setBorderColorRight(BaseColor.BLUE);
table.getDefaultCell().setBorderColorBottom(BaseColor.BLUE);
table.getDefaultCell().setBorderWidthLeft(1f);
table.getDefaultCell().setBorderWidthRight(1f);
table.getDefaultCell().setBorderWidthBottom(1f);
table.getDefaultCell().setHorizontalAlignment(Element.ALIGN_CENTER);
table.addCell(new Phrase("BLR DESIGN DEPT.", font1));
return table;
}

is there any method by which I can read each page and if there is no text in that part add the stamp else search for nearest available free space, just like what a density scanner does?
iText does not offer that functionality out of the box. Depending of what kind of content you want to evade, though, you might consider either rendering the page to an image and looking for white spots in the image or doing text extraction with a strategy that tries to find locations without text.
The first alternative, analyzing a rendered version of the page, would be the focus of a separate question as an image processing library would have to be chosen first.
There are a number of situations, though, in which that first alternative is not the best way to go. E.g. if you only want to evade text but not necessarily graphics (like watermarks), or if you also want to evade invisible text (which usually can be marked in a PDF viewer and, therefore, interfere with your addition).
The second alternative (using text and image extraction abilities of iText) can be the more appropriate approach in such situations.
Here a sample RenderListener for such a task:
public class FreeSpaceFinder implements RenderListener
{
//
// constructors
//
public FreeSpaceFinder(Rectangle2D initialBox, float minWidth, float minHeight)
{
this(Collections.singleton(initialBox), minWidth, minHeight);
}
public FreeSpaceFinder(Collection<Rectangle2D> initialBoxes, float minWidth, float minHeight)
{
this.minWidth = minWidth;
this.minHeight = minHeight;
freeSpaces = initialBoxes;
}
//
// RenderListener implementation
//
#Override
public void renderText(TextRenderInfo renderInfo)
{
Rectangle2D usedSpace = renderInfo.getAscentLine().getBoundingRectange();
usedSpace.add(renderInfo.getDescentLine().getBoundingRectange());
remove(usedSpace);
}
#Override
public void renderImage(ImageRenderInfo renderInfo)
{
Matrix imageMatrix = renderInfo.getImageCTM();
Vector image00 = rect00.cross(imageMatrix);
Vector image01 = rect01.cross(imageMatrix);
Vector image10 = rect10.cross(imageMatrix);
Vector image11 = rect11.cross(imageMatrix);
Rectangle2D usedSpace = new Rectangle2D.Float(image00.get(Vector.I1), image00.get(Vector.I2), 0, 0);
usedSpace.add(image01.get(Vector.I1), image01.get(Vector.I2));
usedSpace.add(image10.get(Vector.I1), image10.get(Vector.I2));
usedSpace.add(image11.get(Vector.I1), image11.get(Vector.I2));
remove(usedSpace);
}
#Override
public void beginTextBlock() { }
#Override
public void endTextBlock() { }
//
// helpers
//
void remove(Rectangle2D usedSpace)
{
final double minX = usedSpace.getMinX();
final double maxX = usedSpace.getMaxX();
final double minY = usedSpace.getMinY();
final double maxY = usedSpace.getMaxY();
final Collection<Rectangle2D> newFreeSpaces = new ArrayList<Rectangle2D>();
for (Rectangle2D freeSpace: freeSpaces)
{
final Collection<Rectangle2D> newFragments = new ArrayList<Rectangle2D>();
if (freeSpace.intersectsLine(minX, minY, maxX, minY))
newFragments.add(new Rectangle2D.Double(freeSpace.getMinX(), freeSpace.getMinY(), freeSpace.getWidth(), minY-freeSpace.getMinY()));
if (freeSpace.intersectsLine(minX, maxY, maxX, maxY))
newFragments.add(new Rectangle2D.Double(freeSpace.getMinX(), maxY, freeSpace.getWidth(), freeSpace.getMaxY() - maxY));
if (freeSpace.intersectsLine(minX, minY, minX, maxY))
newFragments.add(new Rectangle2D.Double(freeSpace.getMinX(), freeSpace.getMinY(), minX - freeSpace.getMinX(), freeSpace.getHeight()));
if (freeSpace.intersectsLine(maxX, minY, maxX, maxY))
newFragments.add(new Rectangle2D.Double(maxX, freeSpace.getMinY(), freeSpace.getMaxX() - maxX, freeSpace.getHeight()));
if (newFragments.isEmpty())
{
add(newFreeSpaces, freeSpace);
}
else
{
for (Rectangle2D fragment: newFragments)
{
if (fragment.getHeight() >= minHeight && fragment.getWidth() >= minWidth)
{
add(newFreeSpaces, fragment);
}
}
}
}
freeSpaces = newFreeSpaces;
}
void add(Collection<Rectangle2D> rectangles, Rectangle2D addition)
{
final Collection<Rectangle2D> toRemove = new ArrayList<Rectangle2D>();
boolean isContained = false;
for (Rectangle2D rectangle: rectangles)
{
if (rectangle.contains(addition))
{
isContained = true;
break;
}
if (addition.contains(rectangle))
toRemove.add(rectangle);
}
rectangles.removeAll(toRemove);
if (!isContained)
rectangles.add(addition);
}
//
// members
//
public Collection<Rectangle2D> freeSpaces = null;
final float minWidth;
final float minHeight;
final static Vector rect00 = new Vector(0, 0, 1);
final static Vector rect01 = new Vector(0, 1, 1);
final static Vector rect10 = new Vector(1, 0, 1);
final static Vector rect11 = new Vector(1, 1, 1);
}
Using this FreeSpaceFinder you can find empty areas with given minimum dimensions in a method like this:
public Collection<Rectangle2D> find(PdfReader reader, float minWidth, float minHeight, int page) throws IOException
{
Rectangle cropBox = reader.getCropBox(page);
Rectangle2D crop = new Rectangle2D.Float(cropBox.getLeft(), cropBox.getBottom(), cropBox.getWidth(), cropBox.getHeight());
FreeSpaceFinder finder = new FreeSpaceFinder(crop, minWidth, minHeight);
PdfReaderContentParser parser = new PdfReaderContentParser(reader);
parser.processContent(page, finder);
return finder.freeSpaces;
}
For your task you now have to choose from the returned rectangles the one which suits you best.
Beware, this code still may have to be tuned to your requirements:
It ignores clip paths, rendering modes, colors, and covering objects. Thus, it considers all text and all bitmap images, whether they are actually visible or not.
It does not consider vector graphics (because the iText parser package does not consider them).
It is not very optimized.
Applied to this PDF page:
with minimum width 200 and height 50, you get these rectangles:
x y w h
000,000 000,000 595,000 056,423
000,000 074,423 595,000 168,681
000,000 267,304 314,508 088,751
000,000 503,933 351,932 068,665
164,296 583,598 430,704 082,800
220,803 583,598 374,197 096,474
220,803 583,598 234,197 107,825
000,000 700,423 455,000 102,396
000,000 700,423 267,632 141,577
361,348 782,372 233,652 059,628
or, more visually, here as rectangles on the page:
The paper plane is a vector graphic and, therefore, ignored.
Of course you could also change the PDF rendering code to not draw stuff you want to ignore and to visibly draw originally invisible stuff which you want to ignore, and then use bitmap image analysis nonetheless...
EDIT
In his comments the OP asked how to find the rectangle in the rectangle collection returned by find which is nearest to a given point.
First of all there not necessarily is the nearest rectangle, there may be multiple.
That been said, one can choose a nearest rectangle as follows:
First one needs to calculate a distance between point and rectangle, e.g.:
double distance(Rectangle2D rectangle, Point2D point)
{
double x = point.getX();
double y = point.getY();
double left = rectangle.getMinX();
double right = rectangle.getMaxX();
double top = rectangle.getMaxY();
double bottom = rectangle.getMinY();
if (x < left) // point left of rect
{
if (y < bottom) // and below
return Point2D.distance(x, y, left, bottom);
if (y > top) // and top
return Point2D.distance(x, y, left, top);
return left - x;
}
if (x > right) // point right of rect
{
if (y < bottom) // and below
return Point2D.distance(x, y, right, bottom);
if (y > top) // and top
return Point2D.distance(x, y, right, top);
return x - right;
}
if (y < bottom) // and below
return bottom - y;
if (y > top) // and top
return y - top;
return 0;
}
Using this distance measurement one can select a nearest rectangle using code like this for a Collection<Rectangle2D> rectangles and a Point2D point:
Rectangle2D best = null;
double bestDist = Double.MAX_VALUE;
for (Rectangle2D rectangle: rectangles)
{
double distance = distance(rectangle, point);
if (distance < bestDist)
{
best = rectangle;
bestDist = distance;
}
}
After this best contains a best rectangle.
For the sample document used above, this method returns the colored rectangles for the page corners and left and right centers:
EDIT TWO
Since iText 5.5.6, the RenderListener interface has been extended as ExtRenderListener to also be signaled about Path construction and path drawing operations. Thus, the FreeSpaceFinder above could also be extended to handle paths:
//
// Additional ExtRenderListener methods
//
#Override
public void modifyPath(PathConstructionRenderInfo renderInfo)
{
List<Vector> points = new ArrayList<Vector>();
if (renderInfo.getOperation() == PathConstructionRenderInfo.RECT)
{
float x = renderInfo.getSegmentData().get(0);
float y = renderInfo.getSegmentData().get(1);
float w = renderInfo.getSegmentData().get(2);
float h = renderInfo.getSegmentData().get(3);
points.add(new Vector(x, y, 1));
points.add(new Vector(x+w, y, 1));
points.add(new Vector(x, y+h, 1));
points.add(new Vector(x+w, y+h, 1));
}
else if (renderInfo.getSegmentData() != null)
{
for (int i = 0; i < renderInfo.getSegmentData().size()-1; i+=2)
{
points.add(new Vector(renderInfo.getSegmentData().get(i), renderInfo.getSegmentData().get(i+1), 1));
}
}
for (Vector point: points)
{
point = point.cross(renderInfo.getCtm());
Rectangle2D.Float pointRectangle = new Rectangle2D.Float(point.get(Vector.I1), point.get(Vector.I2), 0, 0);
if (currentPathRectangle == null)
currentPathRectangle = pointRectangle;
else
currentPathRectangle.add(pointRectangle);
}
}
#Override
public Path renderPath(PathPaintingRenderInfo renderInfo)
{
if (renderInfo.getOperation() != PathPaintingRenderInfo.NO_OP)
remove(currentPathRectangle);
currentPathRectangle = null;
return null;
}
#Override
public void clipPath(int rule)
{
// TODO Auto-generated method stub
}
Rectangle2D.Float currentPathRectangle = null;
(FreeSpaceFinderExt.java)
Using this class the result above is improved to
As you see the paper plane and the table background colorations now also are taken into account.

My other answer focuses on the original question, i.e. how to find free space with given minimum dimensions on a page.
Since that answer had been written, the OP provided code trying to make use of that original answer.
This answer deals with that code.
The code has a number of shortcoming.
The choice of free space on a page depends on the number of pages in the document.
The reason for this is to be found at the start of the loop over the pages:
for(int i = 1; i <= n; i++)
{
Collection<Rectangle2D> rectangles = find(reader, 300, 100, n, stamper);
...
The OP surely meant i, not n there. The code as is always looks for free space on the last document page.
The rectangles are lower than they should be.
The reason for this is to be found in the retrieval and use of the rectangle coordinates:
x = (float) best.getX();
y = (float) best.getY();
...
getFooterTable(i, n).writeSelectedRows(0, -1, x, y, stamper.getOverContent(i));
The Rectangle2D methods getX and getY return the coordinates of the lower left rectangle corner; the PdfPTable methods writeSelectedRows, on the other hand, require the upper left rectangle corner. Thus, getMaxY should be used instead of getY.

Dragging png files in processing

I am trying to design something in processing for a university experiment. I need people to be able to drag images and place them on a map.
I was able to create the layout of my program and can load in the png files in a specific place within the window and I have place the map where I want in the window to.
I found some approach to dragging images and it was ok but it broke and was not efficient.
I came across the "dragging objects in processing" question on this website(found here: dragging objects in processing). Mike 'Pomax' Kamermans' code is really efficient and I was able to incorporate my current code with his so that I almost have what I want. The issue is that I am dragging stings. I have tried to adapt the code so that I can load in and drag images instead but it is beyond my level of knowledge. I do think that his approach to redrawing is the way to go. I also tried to find a method of replacing each string with an images but failed.
// adapted from Mike 'Pomax' Kamermans' code https://stackoverflow.com/questions/15305722/dragging-objects-in-processing
PImage wheel;
LineCollection lines;
float textSize;
void setup(){
size(displayWidth, displayHeight);
wheel = loadImage("wheel.png");
// fix the text size, reference a real font
textSize = 32;
textFont(createFont("Times New Roman", textSize));
// parse strings, construct Lines container
String[] textValues = new String[]{"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10",
"11", "12", "13", "14", "15", "16", "17", "18", "19"};
lines = new LineCollection(textValues);
// Do not loop! only update when events warrant,
// based on redraw() calls
noLoop();
}
// fall through drawing
void draw() {
background(255);
image(wheel, ((displayWidth/2) - ((displayWidth * 0.4167)/2)), 0, (displayWidth * 0.4167), (displayWidth * 0.4167));
stroke(0, 0, 0, 0);
fill(210, 210, 210);
rect(0, (displayHeight*0.75), displayWidth, displayHeight);
lines.draw();
}
// fall through event handling
void mouseMoved() { lines.mouseMoved(mouseX,mouseY); redraw(); }
void mousePressed() { lines.mousePressed(mouseX,mouseY); redraw(); }
void mouseDragged() { lines.mouseDragged(mouseX,mouseY); redraw(); }
void mouseReleased() { lines.mouseReleased(mouseX,mouseY); redraw(); }
/**
* A collection of lines. This is *only* a collecton,
* it is simply responsible for passing along events.
*/
class LineCollection {
Line[] lines;
int boundaryOverlap = 20;
// construct
LineCollection(String[] strings){
lines = new Line[strings.length];
int x, y;
for(int i=0, last=strings.length; i<last; i++) {
x = (int) (((displayWidth/20) * i) + 10);
y = (int) ((displayHeight*0.85)-10);
lines[i] = new Line(strings[i], x, y);
}
}
// fall through drawing
void draw() {
// since we don't care about counting elements
// in our "lines" container, we use the "foreach"
// version of the for loop. This is identical to
// "for(int i=0; i<lines.size(); i++) {
// Line l = lines[i];
// [... use l here ...]
// }"
// except we don't have to unpack our list manually.
for(Line l: lines) { l.draw(); }
}
// fall through event handling
void mouseMoved(int mx, int my) { for(Line l: lines) { l.mouseMoved(mx,my); }}
void mousePressed(int mx, int my) { for(Line l: lines) { l.mousePressed(mx,my); }}
void mouseDragged(int mx, int my) { for(Line l: lines) { l.mouseDragged(mx,my); }}
void mouseReleased(int mx, int my) { for(Line l: lines) { l.mouseReleased(mx,my); }}
}
/**
* Individual lines
*/
class Line {
String s;
float x, y, w, h;
boolean active;
color fillColor = 0;
int cx, cy, ox=0, oy=0;
public Line(String _s, int _x, int _y) {
s = _s;
x = _x;
y = _y;
w = textWidth(s);
h = textSize;
}
void draw() {
fill(fillColor);
text(s,ox+x,oy+y+h);
}
boolean over(int mx, int my) {
return (x <= mx && mx <= x+w && y <= my && my <= y+h);
}
// Mouse moved: is the cursor over this line?
// if so, change the fill color
void mouseMoved(int mx, int my) {
active = over(mx,my);
fillColor = (active ? color(155,155,0) : 0);
}
// Mouse pressed: are we active? then
// mark where we started clicking, so
// we can do offset computation on
// mouse dragging.
void mousePressed(int mx, int my) {
if(active) {
cx = mx;
cy = my;
ox = 0;
oy = 0;
}
}
// Mouse click-dragged: if we're active,
// change the draw offset, based on the
// distance between where we initially
// clicked, and where the mouse is now.
void mouseDragged(int mx, int my) {
if(active) {
ox = mx-cx;
oy = my-cy;
}
}
// Mouse released: if we're active,
// commit the offset to this line's
// position. Also, regardless of
// whether we're active, now we're not.
void mouseReleased(int mx, int my) {
if(active) {
x += mx-cx;
y += my-cy;
ox = 0;
oy = 0;
}
active = false;
}
}
Any help would be greatly appreciated.

The best advice I can give you is to stop trying to hamfist code you find on the internet into doing what you want. Even if the code is great, you need to understand what it's doing before you use it.
Take a step back and ask yourself how you would accomplish this yourself.
If all you want to do is drag a rectangular area (like an image), then you simply need to determine when the mouse is inside that area, then use the pmouseX and pmouseY variables to figure out how much to move that area. Something like this:
float squareX = 200;
float squareY = 200;
float squareWidth = 50;
float squareHeight = 50;
//keep track of when the mouse is inside the square
boolean mouseInSquare = false;
void setup() {
size(500, 500);
}
//check if the mouse is in the square
void mousePressed() {
if (mouseX > squareX && mouseX < squareX + squareWidth && mouseY > squareY && mouseY < squareY + squareHeight) {
mouseInSquare = true;
}
}
//if the mouse is in the square, then move it when the mouse is dragged
void mouseDragged() {
if (mouseInSquare) {
float deltaX = mouseX - pmouseX;
float deltaY = mouseY - pmouseY;
squareX += deltaX;
squareY += deltaY;
}
}
//when we let go of the mouse, stop dragging the square
void mouseReleased() {
mouseInSquare = false;
}
//draw the square
void draw() {
background(0);
rect(squareX, squareY, squareWidth, squareHeight);
}

Breaking bricks with chain reaction

I am developing a game in java just for fun. It is a ball brick breaking game of some sort.
Here is a level, when the ball hits one of the Orange bricks I would like to create a chain reaction to explode all other bricks that are NOT gray(unbreakable) and are within reach of the brick being exploded.
So it would clear out everything in this level without the gray bricks.
I am thinking I should ask the brick that is being exploded for other bricks to the LEFT, RIGHT, UP, and DOWN of that brick then start the same process with those cells.
//NOTE TO SELF: read up on Enums and List
When a explosive cell is hit with the ball it calls the explodeMyAdjecentCells();
//This is in the Cell class
public void explodeMyAdjecentCells() {
exploded = true;
ballGame.breakCell(x, y, imageURL[thickness - 1][0]);
cellBlocks.explodeCell(getX() - getWidth(),getY());
cellBlocks.explodeCell(getX() + getWidth(),getY());
cellBlocks.explodeCell(getX(),getY() - getHeight());
cellBlocks.explodeCell(getX(),getY() + getHeight());
remove();
ballGame.playSound("src\\ballgame\\Sound\\cellBrakes.wav", 100.0f, 0.0f, false, 0.0d);
}
//This is the CellHandler->(CellBlocks)
public void explodeCell(int _X, int _Y) {
for(int c = 0; c < cells.length; c++){
if(cells[c] != null && !cells[c].hasExploded()) {
if(cells[c].getX() == _X && cells[c].getY() == _Y) {
int type = cells[c].getThickness();
if(type != 7 && type != 6 && type != 2) {
cells[c].explodeMyAdjecentCells();
}
}
}
}
}
It successfully removes my all adjacent cells,
But in the explodeMyAdjecentCells() method, I have this line of code
ballGame.breakCell(x, y, imageURL[thickness - 1][0]);
//
This line tells the ParticleHandler to create 25 small images(particles) of the exploded cell.
Tough all my cells are removed the particleHandler do not create particles for all the removed cells.
The problem was solved youst now, its really stupid.
I had set particleHandler to create max 1500 particles. My god how did i not see that!
private int particleCellsMax = 1500;
private int particleCellsMax = 2500;
thx for all the help people, I will upload the source for creating the particles youst for fun if anyone needs it.
The source code for splitting image into parts was taken from:
Kalani's Tech Blog
//Particle Handler
public void breakCell(int _X, int _Y, String URL) {
File file = new File(URL);
try {
FileInputStream fis = new FileInputStream(file);
BufferedImage image = ImageIO.read(fis);
int rows = 5;
int colums = 5;
int parts = rows * colums;
int partWidth = image.getWidth() / colums;
int partHeight = image.getHeight() / rows;
int count = 0;
BufferedImage imgs[] = new BufferedImage[parts];
for(int x = 0; x < colums; x++) {
for(int y = 0; y < rows; y++) {
imgs[count] = new BufferedImage(partWidth, partHeight, image.getType());
Graphics2D g = imgs[count++].createGraphics();
g.drawImage(image, 0, 0, partWidth, partHeight, partWidth * y, partHeight * x, partWidth * y + partWidth, partHeight * x + partHeight, null);
g.dispose();
}
}
int numParts = imgs.length;
int c = 0;
for(int iy = 0; iy < rows; iy ++) {
for(int ix = 0; ix < colums; ix++) {
if(c < numParts) {
Image imagePart = Toolkit.getDefaultToolkit().createImage(imgs[c].getSource());
createCellPart(_X + ((image.getWidth() / colums) * ix), _Y + ((image.getHeight() / rows) * iy), c, imagePart);
c++;
} else {
break;
}
}
}
} catch(IOException io) {}
}

You could consider looking at this in a more OO way, and using 'tell don't ask'. So you would look at having a Brick class, which would know what its colour was, and its adjacent blocks. Then you would tell the first Block to explode, it would then know that if it was Orange (and maybe consider using Enums for this - not just numbers), then it would tell its adjacent Blocks to 'chain react' (or something like that), these blocks would then decide what to do (either explode in the case of an orange block - and call their adjacent blocks, or not in the case of a grey Block.
I know its quite different from what your doing currently, but will give you a better structured program hopefully.

I would imagine a method that would recursively get all touching cells of a similar color.
Then you can operate on that list (of all touching blocks) pretty easily and break all the ones are haven't been broken.
Also note that your getAdjentCell() method has side effects (it does the breaking) which isn't very intuitive based on the name.
// I agree with Matt that color (or type) should probably be an enum,
// or at least a class. int isn't very descriptive
public enum CellType { GRAY, RED, ORANGE }
public class Cell{
....
public final CellType type;
/**
* Recursively find all adjacent cells that have the same type as this one.
*/
public List<Cell> getTouchingSimilarCells() {
List<Cell> result = new ArrayList<Cell>();
result.add(this);
for (Cell c : getAdjecentCells()) {
if (c != null && c.type == this.type) {
result.addAll(c.getTouchingSimilarCells());
}
}
return result;
}
/**
* Get the 4 adjacent cells (above, below, left and right).<br/>
* NOTE: a cell may be null in the list if it does not exist.
*/
public List<Cell> getAdjecentCells() {
List<Cell> result = new ArrayList<Cell>();
result.add(cellBlock(this.getX() + 1, this.getY()));
result.add(cellBlock(this.getX() - 1, this.getY()));
result.add(cellBlock(this.getX(), this.getY() + 1));
result.add(cellBlock(this.getX(), this.getY() - 1));
return result;
}
}