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I am using Point Cloud. I have 3D points with me .
Let's say : Point P(x,y,z), Point Q(x,y,z), Point R(x,y,z) assuming this points as Triangle PQR we proceed further .
Triangle Like this :
.
How can it be possible to fill the area inside this points plotted , so that the triangle will be filled with colour.
Like this :
.
My study that might have helped :
Convex hull
Java how to draw and fill a Polygon which has holes
Edit :
Some way to success :
public void make_polygon(float[] points_x,float[] points_y,float[] points_z)
{
Material mSphereMaterial_z = new Material();
//mSphereMaterial_z.setColor(Color.BLUE);
Bitmap p_z_bitty = getTriangleBitmap(BitmapFactory.decodeResource(mContext.getResources(),R.drawable.label_bg_sm),5,points_x,points_y,points_z);
Texture t = new Texture("text",p_z_bitty);
try {
mSphereMaterial_z.addTexture(t);
}
catch(Exception e)
{
e.printStackTrace();
}
Object3D p_z = new Plane();
p_z.setPosition(points_x[0],points_y[1],points_z[2]);
p_z.setMaterial(mSphereMaterial_z);
p_z.setDoubleSided(true);
getCurrentScene().addChild(p_z);
}
public static Bitmap getTriangleBitmap(Bitmap bitmap, int radius,float[] a,float[] b,float[] c) {
Bitmap finalBitmap;
if (bitmap.getWidth() != radius || bitmap.getHeight() != radius)
finalBitmap = Bitmap.createScaledBitmap(bitmap, radius, radius,
false);
else
finalBitmap = bitmap;
Bitmap output = Bitmap.createBitmap(finalBitmap.getWidth(),
finalBitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(output);
Paint paint = new Paint();
final Rect rect = new Rect(0, 0, finalBitmap.getWidth(),
finalBitmap.getHeight());
// Point point1_draw = new Point(75, 0);
// Point point2_draw = new Point(0, 180);
// Point point3_draw = new Point(180, 180);
PointF point1_draw = new PointF(a[0],a[1]);
PointF point2_draw = new PointF(b[0], b[1]);
PointF point3_draw = new PointF(c[0],c[1] );
Path path = new Path();
path.moveTo(point1_draw.x, point1_draw.y);
path.lineTo(point2_draw.x, point2_draw.y);
path.lineTo(point3_draw.x, point3_draw.y);
path.lineTo(point1_draw.x, point1_draw.y);
path.close();
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(Color.parseColor("#BAB399"));
canvas.drawPath(path, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(finalBitmap, rect, rect, paint);
return output;
}
Now result is :
Can some one guide me or suggest some article about it for Android java ?
If any more information / code needed , it shall be provided.
You should be able to do this by simply passing the vertices from the triangle to Rajawali in order to draw the triangle as a primitive. That way you can avoid using Canvas or drawing a bitmap and simplify the rendering.
// p, q, and r are triangle vertices and are of the form {x, y, z}.
public void make_triangle(float[] p, float[] q, float[] r)
{
Object3D triangle = new Object3D();
// Copy three points into a flat array as our vertices.
float[] vertices = new float[3 * 3];
for (int i = 0; i < 3; i++) {
vertices[i] = p[i];
vertices[3 + i] = q[i];
vertices[6 + i] = r[i];
}
// Set up index buffer to point at our three vertices and thus draw one triangle.
int[] indices = new int[3];
for (int i = 0; i < 3; i++) {
indices[i] = i;
}
// Set up the rendering data.
triangle.setData(vertices, null, null, null, indices, true);
// Render the triangle double sided.
triangle.setDoubleSided(true);
// Use a blue material.
Material material = new Material();
material.setColor(Color.BLUE);
triangle.setMaterial(material);
// Add the triangle to the current scene.
getCurrentScene().addChild(triangle);
}
There are balls in my app that just fly through display. They draws as I want. But now I want to draw the trail behind them.
All I could make is just drawing by canvas.drawPath something like following picture:
But it is not what I want. It should have pointed tail and gradient color like this:
I have no idea how to make it. Tried BitmapShader - couldn't make something right. Help, please.
Code:
First of all, there is Point class for position on display:
class Point {
float x, y;
...
}
And trail is stored as queue of Point:
private ConcurrentLinkedQueue<Point> trail;
It doesn't matter how it fills, just know it has size limit:
trail.add(position);
if(trail.size() > TRAIL_MAX_COUNT) {
trail.remove();
}
And drawing happened in DrawTrail method:
private void DrawTrail(Canvas canvas) {
trailPath.reset();
boolean isFirst = true;
for(Point p : trail) {
if(isFirst) {
trailPath.moveTo(p.x, p.y);
isFirst = false;
} else {
trailPath.lineTo(p.x, p.y);
}
}
canvas.drawPath(trailPath, trailPaint);
}
By the way, trailPaint is just really fat paint :)
trailPaint = new Paint();
trailPaint.setStyle(Paint.Style.STROKE);
trailPaint.setColor(color);
trailPaint.setStrokeWidth(radius * 2);
trailPaint.setAlpha(150);
I see you want to see a gradient on the ball path, you could use something like this
int x1 = 0, y1 = 0, x2 = 0, y2 = 40;
Shader shader = new LinearGradient(0, 0, 0, 40, Color.WHITE, Color.BLACK, TileMode.CLAMP);
trailPaint = new Paint();
trailPaint.setShader(shader);
This is what you should change your trailPaint to and see if it works.
provided from here.
I found solution. But still think it is not the best one.
First of all there are my class fields used for that task.
static final int TRAIL_MAX_COUNT = 50; //maximum trail array size
static final int TRAIL_DRAW_POINT = 30; //number of points to split the trail for draw
private ConcurrentLinkedQueue<Point> trail;
private Paint[] trailPaints;
private float[][] trailPoss, trailTans;
private Path trailPath;
Additionally to trailPath object I used PathMeasure object to split path to multiple equal parts.
After filling trail array object added call of trail calculating function.
lastTrailAdd = now;
trail.add(pos.Copy());
if (trail.size() > TRAIL_MAX_COUNT) {
trail.remove();
}
FillTrail();
Then my FillTrail function.
private void FillTrail() {
trailPath.reset();
boolean isFirst = true;
for(Point p : trail) {
if(isFirst) {
trailPath.moveTo(p.x, p.y);
trailPoss[0][0] = p.x;
trailPoss[0][1] = p.y;
isFirst = false;
} else {
trailPath.lineTo(p.x, p.y);
}
}
PathMeasure path = new PathMeasure(trailPath, false);
float step = path.getLength() / TRAIL_DRAW_POINT;
for(int i=0; i<TRAIL_DRAW_POINT; i++) {
path.getPosTan(step * i, trailPoss[i], trailTans[i]);
}
}
It separated from drawing thread. Next code is drawing function.
private void DrawTrail(Canvas canvas) {
if(trail.size() > 1) {
float prevWidthHalfX = 0f, prevWidthHalfY = 0f, prevX = 0f, prevY = 0f;
Path trailStepRect = new Path();
boolean isFirst = true;
for (int i = 0; i < TRAIL_DRAW_POINT; i++) {
float currWidthHalf = (float) (radius) * i / TRAIL_DRAW_POINT / 2f,
currWidthHalfX = currWidthHalf * trailTans[i][1],
currWidthHalfY = currWidthHalf * trailTans[i][0],
currX = trailPoss[i][0], currY = trailPoss[i][1];
if (!isFirst) {
trailStepRect.reset();
trailStepRect.moveTo(prevX - prevWidthHalfX, prevY + prevWidthHalfY);
trailStepRect.lineTo(prevX + prevWidthHalfX, prevY - prevWidthHalfY);
trailStepRect.lineTo(currX + currWidthHalfX, currY - currWidthHalfY);
trailStepRect.lineTo(currX - currWidthHalfX, currY + currWidthHalfY);
canvas.drawPath(trailStepRect, trailPaints[i]);
} else {
isFirst = false;
}
prevX = currX;
prevY = currY;
prevWidthHalfX = currWidthHalfX;
prevWidthHalfY = currWidthHalfY;
}
}
}
Main point of this is drawing trail by parts with different paints. Closer to ball - wider the trail. I think I will optimise it, but it is allready work.
If you want to watch how it looks just install my app from google play.
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.
I am writing a program in Processing to make a 3-D scatterplot that one can rotate around in space using PeasyCam. Data is read in from a text file to an ArrayList of PVectors. The entire code is shown below. What I don't understand is that importTextfile() needs to be called (repeatedly) within draw() and this significantly slows things down. Why can't I get away with calling it once within setup()? With "println(pointsList)" within draw() I can see that pointList changes if it's not preceded by importTextFile(). Can anyone explain why?
(Update: From trying to construct a minimum working example I see now that the problem is when I make a PVector V and then write over it to map it to the display window. I would still appreciate feedback on a good work around that involves calling importTextFile() just during setup(). What do I use instead of .get() so I get a copy of what's in the Arraylist and not a pointer to the actually value in the ArrayList?)
Here is the code:
import peasy.*;
PeasyCam cam;
ArrayList <PVector>pointList;
int maxX = 0;
int maxY = 0;
int maxZ = 0;
int minX = 10000;
int minY = 10000;
int minZ = 10000;
int range = 0;
void setup() {
size(500, 500, P3D);
cam = new PeasyCam(this, width/2, width/2, width/2, 800);
cam.setMinimumDistance(100);
cam.setMaximumDistance(2000);
pointList = new ArrayList();
importTextFile();
println(pointList);
//Determine min and max along each axis
for (int i=0; i < pointList.size(); i++) {
PVector R = pointList.get(i);
if (R.x > maxX) {
maxX = (int)R.x;
}
if (R.x < minX) {
minX = (int)R.x;
}
if (R.y > maxY) {
maxY = (int)R.y;
}
if (R.y < minY) {
minY = (int)R.y;
}
if (R.z > maxZ) {
maxZ = (int)R.z;
}
if (R.z < minZ) {
minZ = (int)R.z;
}
}
if (maxX - minX > range) {
range = maxX - minX;
}
if (maxY - minY > range) {
range = maxY - minY;
}
if (maxZ - minZ > range) {
range = maxZ - minZ;
}
println(pointList);
}
void draw() {
//importTextFile(); Uncomment to make run properly
println(pointList);
background(255);
stroke(0);
strokeWeight(2);
line(0, 0, 0, width, 0, 0);
line(0, 0, 0, 0, width, 0);
line(0, 0, 0, 0, 0, width);
stroke(150);
strokeWeight(1);
for (int i=1; i<6; i++) {
line(i*width/5, 0, 0, i*width/5, width, 0);
line(0, i*width/5, 0, width, i*width/5, 0);
}
lights();
noStroke();
fill(255, 0, 0);
sphereDetail(10);
//**The problem is here**
for (int i=0; i < pointList.size(); i++) {
PVector V = pointList.get(i);
V.x = map(V.x, minX-50, minX+range+50, 0, width);
V.y = map(V.y, minY-50, minY+range+50, 0, width);
V.z = map(V.z, minZ-50, minZ+range+50, 0, width);
pushMatrix();
translate(V.x, V.y, V.z);
sphere(4);
popMatrix();
}
}
void importTextFile() {
String[] strLines = loadStrings("positions.txt");
for (int i = 0; i < strLines.length; ++i) {
String[] arrTokens = split(strLines[i], ',');
float xx = float(arrTokens[2]);
float yy = float(arrTokens[1]);
float zz = float(arrTokens[0]);
pointList.add( new PVector(xx,zz,yy) );
}
}
You could continue to refactor, I don't know why they show this way of iterating through ArrayLists in the Processing documentation but here is a go at refactoring it:
float calcV (float n) {
return map (n, minX-50, minX+range+50, 0, width);
}
for (PVector V: pointList) {
pushMatrix();
translate(calcV(V.x), calcV(V.y), calcV(V.z));
sphere(4);
popMatrix();
}
You might consider creating a new Class with a PVector as a field or extending PVector. Daniel Shiffman uses this pattern a lot. Create a Class with a PVector for position, another for velocity, a method to calc the new position per frame and another to draw it out to screen. That gives you a lot of flexibility without having to write a ton of loops, other than one to calc and display the objects in your ArrayList.
As PVector is an object, when you do PVector V = pointList.get(i) you pass the reference for that specific element in pointList, to V. It's address in memory. So now V and pointList.get(number) share the same memory address. Any change in either one will change both, as they are two different pointers to same place.
But, if you do:
PVector V = new PVector(pointList.get(i).x, pointList.get(i).y, pointList.get(i).z);
V will be a new object and things will work as you want, cause now V has it's own memory address. And poinList will remain untouched. Same thing goes for other objects, arrays for instance, try this to see:
int[] one = new int[3];
int[] two = new int[3];
void setup(){
one[0] = 0;
one[1] = 1;
one[2] = 2;
print("one firstPrint -> \n");
println(one);
two = one;
print("two firstPrint -> \n");
println(two);
two[2] = 4;
// we didn't mean to change one, but...
print("one secondPrint -> \n");
println(one);
}
I fixed things with the code below but am still interested in other ways.
for (int i=0; i < pointList.size(); i++) {
PVector V = pointList.get(i);
PVector W = new PVector(0.0, 0.0, 0.0);
W.x = map(V.x, minX-50, minX+range+50, 0, width);
W.y = map(V.y, minY-50, minY+range+50, 0, width);
W.z = map(V.z, minZ-50, minZ+range+50, 0, width);
pushMatrix();
translate(W.x, W.y, W.z);
sphere(4);
popMatrix();
}
I'm making my first game using Java on Android. I need to draw a lot of pixels which together should create a line. My first approach was to make a large array of booleans, create a loop, and draw a pixel when the associated boolean was true.
It wasn't a good idea of course (the array is about 200x300). Now I remember only the position of the first pixel of the line, and every next pixel has to remember his follower. It works pretty well, but when the line gets longer (but still not very long), the efficiency is bad (<20 fps after 4000 frames).
This is the function that I use to draw a line (only one for now). Can anybody help me improve its efficiency?
public void drawLine(Canvas canvas, int beginx, int beginy) {
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.RED);
paint.setStrokeWidth(3);
int x = beginx;
int y = beginy;
while(C.mGrid[x][y].nx != -1) {
//canvas.drawLine(x, y, C.mGrid[x][y].nx, C.mGrid[x][y].ny, paint);
canvas.drawPoint(x, y, paint);
Grid temp = C.mGrid[x][y];
if ((C.mGrid[x][y].nx == x) && (C.mGrid[x][y].ny == y)) break;
x = temp.nx;
y = temp.ny;
}
}
and Grid.java:
package com.qwak.achtung;
public float x = 0,y = 0;
public int px = -1, py = -1, nx = -1, ny = -1;
public Grid(float x, float y) {
this.x = x;
this.y = y;
}
public void set(int px, int py, int nx, int ny) {
this.px = px;
this.py = py;
this.nx = nx;
this.ny = ny;
}
public void setp(int px, int py) {
this.px = px;
this.py = py;
}
public void setn(int nx, int ny) {
this.nx = nx;
this.ny = ny;
}
PS: It looks like this http://c.wrzuta.pl/wi10559/11f7d10b00110e504e25ebd3/0/andek 14 is fps (on my phone (samsung Spica) it run better - 40 but after a while it decreases to 20 and even less) and 983 is number of frames at all.
There is a drawLine method in the canvas object.
Use the example here: How to draw a line in android
canvas.drawLine(0, 0, 20, 20, paint);
If you want to draw a curve. Find the function of the curve. A Parabola for example is x=y^2. You can get points from the curve: 1 = 1, 2 = 4, 3 = 9, 4 = 16... etc.. If your drawing pixel by pixel you can plug in your x and get your y and draw it.
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.RED);
paint.setStrokeWidth(3);
for(int i = beginx; i < CanvasWidth; i++)
{
int x = i;
int y = i * i; //x=y^2
canvas.drawPoint(x, y, paint);
}
To keep a record of points that were visited you could do the following:
class Point
{
int x;
int y;
}
List<Point> points = new List<Point>();
onMove(int newX, int newY)
{
Point p = new Point();
p.x = newX;
p.y = newY;
points.add(p);
}
onDraw()
{
for(Point p : points)
{
canvas.drawPoint(p.x, p.y, paint);
}
}
You want to look into the bresenham algorithm. A bresenham algorithm is a method to draw or rasterize a line. It's a bit different from the subdivision of a grid in a certain angle for example a morton-curve. It's a bit like compute the scalar product for every angle like recall here Traversing a 2D array in an angle.