OpenGl ES on android fine tuning of ray picking code - java

Ive implemented ray picking using min3d and some code I found online but when I implemented it I notice that its off a bit some times meaning that when I click on one box sometimes the wrong one is picked. Sometimes the one picked isnt even on the screen. This took quite a bit of code to get implemented in the first place but the main two methods I call are the following:
private void rayPicking(float x, float y)
{
//intersection with near plane
float[] near = new float[4];
GLU.gluUnProject(x, scene.getViewport()[3] - y, 0f, scene.getGrabber().mModelView, 0, scene.getGrabber().mProjection, 0, scene.getViewport(), 0, near, 0);
if (near[3] != 0)
{
near[0] = near[0] / near[3];
near[1] = near[1] / near[3];
near[2] = near[2] / near[3];
}
Number3d near3 = new Number3d(near[0], near[1], near[2]);
//and far plane
float[] far = new float[4];
GLU.gluUnProject(x, scene.getViewport()[3] - y, 1f, scene.getGrabber().mModelView, 0, scene.getGrabber().mProjection, 0, scene.getViewport(), 0, far, 0);
if (far[3] != 0)
{
far[0] = far[0] / far[3];
far[1] = far[1] / far[3];
far[2] = far[2] / far[3];
}
Number3d far3 = new Number3d(far[0], far[1], far[2]);
Box firstPicked = null;
Box currentModel = null;
Number3d currentCoords = null;
Number3d firstPickedCoords = new Number3d();
if (!sceneBoxes.isEmpty())
{
//here we check each model if it was tapped and if several models were tapped, we take only that which is closer to the near clipping plane
Iterator<Box> itr = sceneBoxes.iterator();
while (itr.hasNext())
{
currentModel = itr.next();
currentCoords = new Number3d(currentModel.position().x, currentModel.position().y, currentModel.position().z);
if (picked (far3, near3, currentCoords, 1.2f))
if (firstPicked==null)
{
firstPicked = currentModel;
firstPickedCoords.setAllFrom(currentCoords);
}
else if (Number3d.add(currentCoords, near3).length() < Number3d.add(firstPickedCoords, near3).length())
{
firstPicked = currentModel;
firstPickedCoords.setAllFrom(currentCoords);
}
}
}
if (firstPicked != null) // if model picked
{
String temp = firstPicked.getTitle();
String temp2 = firstPicked.getLink();
Log.w("3d touch working "+temp, "3d touch working "+temp);
Intent intent = new Intent(CurAct.this, WebViewer.class);
intent.putExtra("clkURL", temp2);
intent.putExtra("clkUID", curr_uid);
intent.putExtra("rid", curr_rid);
startActivity(intent);
firstPicked = null;
temp = null;
temp2 = null;
}
}
private boolean picked(Number3d a, Number3d b, Number3d q, float r)
{
float ab = (float) Math.sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y)+(a.z-b.z)*(a.z-b.z));
float aq = (float) Math.sqrt((a.x-q.x)*(a.x-q.x)+(a.y-q.y)*(a.y-q.y)+(a.z-q.z)*(a.z-q.z));
float bq = (float) Math.sqrt((b.x-q.x)*(b.x-q.x)+(b.y-q.y)*(b.y-q.y)+(b.z-q.z)*(b.z-q.z));
float p = (ab + aq + bq) / 2;
float hh = (float) Math.sqrt(p * (p - ab) * (p - aq) * (p - bq));
float h;
if (ab!=0) h = 2 * hh / ab; else h = 2*hh;
if (aq<h) h = aq;
if (bq<h) h = bq;
if (h<r)return true; else return false;
}
Now I have also tried implementing frustum culling but having done that it slows things way down because I didnt do much to optimize it and its not running natively. But if some one can look and maybe give me some pointers on how to make it more accurate that would be awesome. Heres where I call the picking methods.
_glSurfaceView.setOnTouchListener(
new View.OnTouchListener() {
#Override
public boolean onTouch(View arg0, MotionEvent e) {
switch (e.getAction() & MotionEvent.ACTION_MASK)
{
case MotionEvent.ACTION_DOWN:
startX = e.getX();
startY = e.getY();
trace = 0.0f;
time = System.currentTimeMillis();
touchMode = DRAG;
break;
case MotionEvent.ACTION_UP:
// we use ray picking only when the tap wasn't longer than 0.5 sec and if we almost didn't move our finger
//Log.w("this is touch y"+e.getY()+" viewport is"+scene.getViewport()[3], "this is touch x"+e.getX());
if ((System.currentTimeMillis()-time < 500) && (trace<scene.getViewport()[3]*0.075)) rayPicking(e.getX(), e.getY());
time = 0;
case MotionEvent.ACTION_POINTER_UP:
touchMode = NONE;
break;
}
return true;
}
}
);


The bug you have sounds like you are making a mistake in you collision detection, I had a bug in the function I had for dot products and caused some really odd results. Can you post more of your collision algorithm?
I implemented ray picking here: http://android-raypick.blogspot.ca/ I did not paste the code here because there is allot of it, feel free to compare your code to this code, this code is tested and working.

Related

How do I stop the object from going outside the screen?

public class MovingBagView extends View {
private Bitmap bag[] = new Bitmap[2];
private int bagX;
private int bagY = 1000;
private int bagSpeed;
private Boolean touch = false;
private int canvasWidth, canvasHeight;
private Bitmap backgroundImage;
private Paint scorePaint = new Paint();
private Bitmap life[] = new Bitmap[2];
public MovingBagView(Context context) {
super(context);
bag[0] = BitmapFactory.decodeResource(getResources(), R.drawable.bag1);
bag[1] = BitmapFactory.decodeResource(getResources(), R.drawable.bag2);
backgroundImage = BitmapFactory.decodeResource(getResources(), R.drawable.background);
scorePaint.setColor(Color.BLACK);
scorePaint.setTextSize(40);
scorePaint.setTypeface(Typeface.DEFAULT_BOLD);
scorePaint.setAntiAlias(true);
life[0] = BitmapFactory.decodeResource(getResources(), R.drawable.heart);
life[1] = BitmapFactory.decodeResource(getResources(), R.drawable.heart_grey);
bagX = 10;
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvasWidth = canvas.getWidth();
canvasHeight = canvas.getHeight();
canvas.drawBitmap(backgroundImage, 0, 0, null);
int minBagX = bag[0].getWidth();
int maxBagX = canvasWidth - bag[0].getWidth() * 3;
bagX = bagX + bagSpeed;
if (bagX < minBagX) {
bagX = minBagX;
}
if (bagX < maxBagX) {
bagX = maxBagX;
}
bagSpeed = bagSpeed + 2;
if (touch) {
canvas.drawBitmap(bag[1], bagX, bagY, null);
}
else {
canvas.drawBitmap(bag[0], bagX, bagY, null);
}
canvas.drawText("Score : ", 20, 60, scorePaint);
canvas.drawBitmap(life[0], 500, 10, null);
canvas.drawBitmap(life[0], 570, 10, null);
canvas.drawBitmap(life[0], 640, 10, null);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
touch = true;
bagSpeed = -12;
}
return true;
}
}
I can tap on the screen to move the object to the left, and the more I tap on it, the further it should move to the left. However, the problem is that the object moves too much to the right, and goes off the screen. I want it to stop at the edge, so its still visible on the screen. Furthermore, the object is positioned in the center bottom of the screen, how do I position it to the bottom left corner? You can see how it works by looking at the GIF below.

This condition is never applied on the code you've provided. It continues to exceed the max value.
if (bagX < maxBagX) {
bagX = maxBagX;
}
It should look like this:
if (bagX >= maxBagX) {
bagX = maxBagX;
}
And the maxBagX value should be canvasWidth - bag[0].getWidth() in order to achieve the right edge of the bag itself. (Unless you're using the multiply 3 times for a different reason, this should be the solution.)

Create object of the layout which ever you are using linear,relative or constraint then fetch width of the screen using that object using
object.getWidth();

I did it like this //the maintainoffscreen function will maintain the path to donot move off screen, and return true ,, else if path does not collide to any side this will return false, and you can move the path by setting offset.
private boolean maintainOffScreen(Path path, float px, float py){
boolean done = true;
RectF rectF = new RectF();
path.computeBounds(rectF,true);
float l = getPathWidth(path) - rectF.right;
float r = getPathWidth(path) + rectF.left;
float t = getPathHeight(path) - rectF.bottom;
float b = getPathHeight(path)+ rectF.top;
if(l < (-1) && r < getWidth() && b < getHeight() && t< (-1)){
//if path does not collide to any side//you can move your path here as well
//by setting Path.offset(px,py)
done = false;
offScreen = OffScreen.NOOFF; //im using these as enum according to my need,
//as this is saving which side of screen collides
}
else if(l >= (-1)){
path.offset(px+(l),py);
offScreen = OffScreen.LEFT;
offscrenn_xl = 1;
done = true;
}
else if(r >= getWidth()){
float s = getWidth() - r;
path.offset(px+(s),py);
offScreen = OffScreen.RIGHT;
offscrenn_xr = s;
done = true;
}
else if(b >= getHeight()){
float s = getHeight() - b;
path.offset(px,py+s);
offScreen = OffScreen.BOTTOM;
offscrenn_yb = s;
done = true;
}
else if(t >= (-1)){
path.offset(px,py+(t));
offScreen = OffScreen.TOP;
offscrenn_yt = t;
done = true;
}
return done;
}
confuse about px,py ? this is the movement of you finger with respect to path
`
final float px = event.getX() - this.startX;
final float py = event.getY() - this.startY;
if(!maintainOffScreen(path,px,py)){path.offset(px,py); }` //you should call
//this function here ,this will move your path to finger if there is no collision.
//and donot forgot to set the startx,and starty yo new positon like this
this.startX = event.getX();
this.startY = event.getY();

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.

Move camera in respect of finger position Opengl

This is my first approach to androids opengl and I have stuck in moving my rendered object with finger.
Actually, everything works but when I try to move object really fast it loses its coordinates.
My object is hexagonal grid built by calculating coordinates for 6 vertexes. First of all I handle on touch event and check if map is grabbed:
switch(action) {
case MotionEvent.ACTION_DOWN:
mapTouched = hexMapRenderer.isMapTouched(ev);
int pointerIndex = MotionEventCompat.getActionIndex(ev);
downX = MotionEventCompat.getX(ev, pointerIndex);
downY = MotionEventCompat.getY(ev, pointerIndex);
moveX = (int)downX;
moveY = (int)downY;
break;
case MotionEvent.ACTION_MOVE:
if(!hexMapRenderer.isScaling()) {
if(mapTouched) {
hexMapRenderer.setMapMoving(true);
hexMapRenderer.moveMap((int) (moveX - ev.getX()), (int) (moveY - ev.getY()));
moveX = (int) ev.getX();
moveY = (int) ev.getY();
}
}
break;
Inside my method moveMap I calculate position of my hexagons:
public void moveMap(int shiftX, int shiftY) {
for(int i = 0; i < hexMap.length; i++) {
for (int j = 0; j < hexMap[i].length; j++) {
if(hexMap[i][j] != null && hexMap[i][j].isToDraw()) {
hexMap[i][j].setCenterPoint(new Point(hexMap[i][j].getCenterPoint().x - shiftX, hexMap[i][j].getCenterPoint().y - shiftY));
}
}
}
this.shiftX = shiftX;
this.shiftY = shiftY;
}
And inside onDrawFrame method I move map like this:
if(mapMoving) {
gl.glTranslatef(-shiftX, -shiftY, 0f);
}
As I mentioned everything works great when I move map slow and gently but when things are getting too fast it looks like that position of rendered object doesn't equals calculated position from moveMap method.
Do you have any solutions how to achieve smooth moving of object in opengl? I've tried recalculate position and redraw whole object but when map starts to move it flickers.
Thanks in advance.

My method scale isn't working, what may be the issue?

I have been trying to scale a Shape in java, but I'm having some problems. When i try it the Shape simple dissapears... This method receives 2 points, toScale is the point that i want the shape to extend to, and p1 is the point that I clicked in the rectangle that is around the shape to select (there's a rectangle(boundingBox) surrounding the shape wheter is a polygone or a rectangle or just polylines)
Here's the scale method code:
public void scale(Point toScale, Point p1) {
Graphics g = parent.getGraphics();
int distanceToClicked = 0;
int distanceToBoundingBox = 0;
int scaleFactor = 0;
Vector<Point> pointsAux = new Vector<Point>();
Iterator<Point> it = points.iterator();
while (it.hasNext()){
Point p = it.next();
distanceToClicked = (int) Math.sqrt(Math.pow(getCentroid().getX()-p1.getX(), 2)+Math.pow(getCentroid().getY()-p1.getY(),2));
distanceToBoundingBox = (int) Math.sqrt(Math.pow(getCentroid().getX()-toScale.getX(),2)+Math.pow(getCentroid().getY()-toScale.getY(),2));
scaleFactor = distanceToClicked/distanceToBoundingBox;
p = new Point((int)p.getX()*scaleFactor,(int) p.getY()*scaleFactor);
pointsAux.add(p);
}
points.clear();
points.addAll(pointsAux);
}
public Point getCentroid(){
int sumx = 0;
int sumy = 0;
for(int i = 0; i<points.size();i++){
sumx+=points.get(i).getX();
sumy+=points.get(i).getY();
}
Point centroid = new Point(sumx/points.size(), sumy/points.size());
return centroid;
}
Any help would be appreciated
Thanks in advance, and eventually I'm sorry for the misunderstanding code

Something like that would do the trick:
public Collection<Point> scaleShape(float scale, Collection<Point> shape) {
Point centroid = getCentroid();
Collection<Point> scaledShape = new ArrayList<>(shape.size());
for (Point point : shape) {
Point diff = new Point(point.x() - centroid.x(), point.y() - centroid.y());
Point scaledPoint = new Point(
(int) (centroid.x() + scale * diff.x()),
(int) (centroid.y() + scale * diff.y()));
scaledShape.add(scaledPoint);
}
return scaledShape;
}
Basically, every points make a linear function with the centroid. Centroid's relative x = 0, while the current computed point is at relative x = 1. You want to find the point if it were at relative x = scale.

How to check if VERTEX ARRAY is clockwise?

Solved, used this code:
if ( !isClockwise(TempVectArray) ) { Collections.reverse(TempVectArray); }
...
private boolean isClockwise(ArrayList<Vec2> arl){
Iterator<Vec2> it = arl.iterator();
Vec2 pt1 = (Vec2)it.next();
Vec2 firstPt = pt1;
Vec2 lastPt = null;
double area = 0.0;
while(it.hasNext()){
Vec2 pt2 = (Vec2) it.next();
area += (((pt2.x - pt1.x) * (pt2.y + pt1.y)) / 2);
pt1 = pt2;
lastPt = pt1;
}
area += (((firstPt.x - lastPt.x) * (firstPt.y + lastPt.y)) / 2);
return area < 0;
}
Suppose I get a vertex array from the user tapping on the screen, but need it to be clockwise.
Maybe you know of some standard methods to check if it is clockwise and if it's not, then make it clockwise?
Thanks!

One way to do it is to first calculate the average point, and then sort everything around it by angle. Should be something like this:
public static void sortPointsClockwise(ArrayList<PointF> points) {
float averageX = 0;
float averageY = 0;
for (PointF point : points) {
averageX += point.x;
averageY += point.y;
}
final float finalAverageX = averageX / points.size();
final float finalAverageY = averageY / points.size();
Comparator<PointF> comparator = new Comparator<PointF>() {
public int compare(PointF lhs, PointF rhs) {
double lhsAngle = Math.atan2(lhs.y - finalAverageY, lhs.x - finalAverageX);
double rhsAngle = Math.atan2(rhs.y - finalAverageY, rhs.x - finalAverageX);
// Depending on the coordinate system, you might need to reverse these two conditions
if (lhsAngle < rhsAngle) return -1;
if (lhsAngle > rhsAngle) return 1;
return 0;
}
};
Collections.sort(points, comparator);
}
public static void sortPointsCounterClockwise(ArrayList<PointF> points) {
sortPointsClockwise(points);
Collections.reverse(points);
}

You have the sequence numbers and positions of the nodes. Get the movements which hold x and y changes in the move. All left to do is define a control structure such as:
if(movement_before is "up")
movement should-be "up" or "up-right"
if(movement_before is "up-left")
movement should-be "up" or "up-left" or "up-right"
etc..

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