Draw a line by given 2 points

Hey everyone.
I have a question. I need to draw an arrow. The only thing that I have are two points with certain coordinates. It would not be so hard if I did not have to worry about the angle but what if the line is not horizontal? How do I draw it? Thanks!

Interesting - are you guys in the same class?
http://forum.java.sun.com/thread.jsp?forum=31&thread=409340&tstart=0&trange=100

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I am writing a program that needs to draw gradient lines according to the points that i touch on ipad. For this i am using "DrawLinearGradient" function. But the 2 colors that i am giving for drawing gradient is not dividing equally in the complete line.

Can anyone please help about the parameters that need to be passed corectly.
CGColorSpace colorSpace = CGColorSpace.CreateDeviceRGB();
CGColor[] colors = {UIColor.Red.CGColor,UIColor.Green.CGColor};
float[] locations = {0.0f,0.5f,0.5f,1.0f};
CGGradient gradient = new CGGradient(colorSpace,colors,locations);
ColorMessage.FontSize = width;
context.SetLineWidth(width);
context.SaveState();
context.Clip();
context.DrawLinearGradient(gradient,penVertices[0],penVertices[count-1],0);
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Wouldn't this be better posted in a developers forum? This forum is for Using an iPad, not writing programs for one.

Drawing Perpendicular Lines...

All,
I have a program that draws simple lines using the Line2D class. As I draw the line, I bisect it to get a point in the middle of the line. Now I have 3 points on my line.
From here I am trying to draw a short perpendicular line originating from my bisecting point.
I have been attempting to work from the slope formula m = (x1 - x2) / (y1 - y2), but my trig skills have gotten rusty and I can't figure out how to draw a line from an existing point and a known slope. So I have been trying to just manipulate the rise over run by taking the negative inverse (-run/rise), and adding those values to my known point. But to no avail.
Now that I'm frustrated, I'm wondering if I'm barking up the wrong tree. Should I be using Arcs and angles to determine my perpendicular point? Or, is there an easier way to draw lines from a known point and slope?
Thanks in advance.

Got it.
I was thinking about the triangle from the wrong perspective. I was making my line the adjacent side of the triangle. Once I looked at it as the hypotenuse, I realized I already had the point I was looking for.
Was right there all along. Doh.

How to find a second point on a line given a point and distance

Hi All,
My requirement is: Given a point on a line and distance, I have to find the second point. All geometries are in LRS.
I tried using SDO_LRS.LOCATE_PT, it is returning the second point from the start of the segment but I want to locate the point from the given start point. Kindly suggest in how to solve this.
SQL Used:
SELECT SDO_LRS.LOCATE_PT(a.shape, m.diminfo, 9, 0)
FROM lrs_access_fiber a, user_sdo_geom_metadata m
WHERE m.table_name = 'LRS_ACCESS_FIBER' AND m.column_name = 'SHAPE' AND a.unique_id = 1996;
Regards
Venkat

Hi Luc,
Thanks for the information. I have implemented this in a slightly different way like:
1. Firstly, found the distance (Distance_a of the point selected from the start point of the segment using:
SELECT SDO_LRS.GET_MEASURE(SDO_LRS.PROJECT_PT(a.shape, m.diminfo,MDSYS.SDO_GEOMETRY(2301, 8307, NULL, MDSYS.SDO_ELEM_INFO_ARRAY(1, 1, 1), MDSYS.SDO_ORDINATE_ARRAY(xa,ya, NULL)) ), m.diminfo ) into Distance_a FROM LRS_ACCESS_FIBER a, user_sdo_geom_metadata m WHERE m.table_name = 'LRS_ACCESS_FIBER' AND m.column_name = 'SHAPE' AND a.unique_id = Input_Fiber_Id;
2. Then added the given distance (b) to this computed distance (Distance_a ) to get the distance of the second point (Distance_b).
Distance_b := abs (Distance_a + b);
3. Then used SDO_LRS.LOCATE_PT with offset=0 and distance=Distance_b to get the second point.
select SDO_LRS.LOCATE_PT(a.shape, distance_pt, 0) into point_geometry from LRS_ACCESS_FIBER a where a.unique_id = input_fiber_id;
Please give your inputs and feedback.
Regards
Venkat

It's simple... I want the Illustrator pen tool to ALWAYS make corner annchor points and NEVER smooth. Right now I have to convert every single one of them, or I have to do a work around every time I draw a line and make one of the handles disappear. Is

It's simple... I want the Illustrator pen tool to ALWAYS make corner annchor points and NEVER smooth. Right now I have to convert every single one of them, or I have to do a work around every time I draw a line and make one of the handles disappear. Is there some simple setting out there that will just "make it so?"@

The video I am watching this guy is just dragging every line to make curves. And every anchor point is a corner. He is not switching back and forth between the pen and the anchor points tool, and he is not using the convert points tool. He draws a curved line and starts another straight line only to curve it with a click and a drag. It is super efficient, and I could save a world of time if I could figure out what he is doing.

Suggestion to draw a line between two points...

I have the XYZ position of 2 points, I would like to draw a line between those points. I have tried with a cylinder and it did not work as I expect...I guess a better method exist in Java3D... Do you have any suggestions??
thanks
Pete

try the LineArray class.

How to see my code drawing a line from one point to another

hi, im wondering if you could help me.
i am working on my project which is to visualise travelling salesman heuristics.
i have managed to make my first heuristic work, but my problem is that when i clicked the run button on my GUI,
the output is already a complete tour with all the edges already drawn, but what i want is to see how it solves or draw the lines from one vertex to another just by clickin the run button once.
would be great if you could advice me of what method or technique i need to use to see my application solving the tour or drawing the edges.
below is my cofe for drawing the edges from one point to another
void drawLineNNh(Graphics g){
 Graphics2D g2 = (Graphics2D) g;
 g2.setColor(Color.blue);
 int i = 0;
 if (P == null) return;
 else
 for(i=0; i<P.getSize(); i++)
 Line2D.Double drawLine = new Line2D.Double(P.x_coor[nnH.seen]+5, P.y_coor[nnH.seen[i]]+5, P.x_coor[nnH.seen[i+1]]+5,P.y_coor[nnH.seen[i+1]]+5);
Line2D.Double drawLastEdge = new Line2D.Double(P.x_coor[nnH.seen[P.getSize()-1]]+5, P.y_coor[nnH.seen[P.getSize()-1]]+5, P.x_coor[0]+5,P.y_coor[0]+5);
g2.drawString( " Total Distance : " + nnH.totalDistance , 10, 300);
g2.draw(drawLine);
g2.draw(drawLastEdge);
public void setNNh(Points p)
nnH = new NNheuristic(p);
useNNh = true;
public void paint(Graphics g)
frame(g);
drawpoints(g);
if(useNNh)
drawLineNNh(g);
below is my code for calling the above method to draw edges, actionlistererun.addActionListener(new ActionListener()
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals("Run")) {
if (chooseHeur.getSelectedItem()=="Nearest-Neighbour")
System.out.println(chooseHeur.getSelectedItem());
//points = new Points(toInt((String)chooseNum.getSelectedItem()));
//PlotArea.set(points);
PlotArea.setNNh(points);
PlotArea.repaint();

I AM USING SWING.
HERE IS MY CODE, HOPEFULLY ENOUGH TO UNDERSTAND THE PROBLEM.
class Plot extends Panel{
 public static int num;
 NNheuristic nnH;
 Closest_insertion CI;
 Points P;
 public static boolean useNNh= false;
 boolean useCI=false;
 boolean triangleDrawn = false;
 boolean CIupdate;
 void drawpoints (Graphics g)
 Graphics2D g2 = (Graphics2D) g;
 Graphics2D g3 = (Graphics2D) g;
 int i=1;
 g2.setColor(Color.red);
 if (P==null) return;
 else
 while (i<P.getSize())
 Ellipse2D.Double vertices = new Ellipse2D.Double(P.x_coor,P.y_coor[i],10,10);
g2.fill(vertices);
i++;
g3.setColor(Color.MAGENTA);
Ellipse2D.Double initial = new Ellipse2D.Double(P.x_coor[0],P.y_coor[0],10,10);
g3.fill(initial);
System.out.println("No. of Vertices: " + P.getSize());
for(int k = 0; k < P.getSize(); k++)
System.out.println("x coordinate: " + P.x_coor[k] + ", " + "y coordinate :" + P.y_coor[k] );
// System.out.println("next:"+ P.x_coor[k+1]);
triangleDrawn = false;
void drawLineNNh(Graphics g){
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.blue);
int i = 0;
if (P == null) return;
else
for(i=0; i<P.getSize(); i++)
Line2D.Double drawLine = new Line2D.Double(P.x_coor[nnH.seen[i]]+5, P.y_coor[nnH.seen[i]]+5, P.x_coor[nnH.seen[i+1]]+5,P.y_coor[nnH.seen[i+1]]+5);
Line2D.Double drawLastEdge = new Line2D.Double(P.x_coor[nnH.seen[P.getSize()-1]]+5, P.y_coor[nnH.seen[P.getSize()-1]]+5, P.x_coor[0]+5,P.y_coor[0]+5);
g2.drawString( " Total Distance : " + nnH.totalDistance , 10, 300);
g2.draw(drawLine);
g2.draw(drawLastEdge);
public void set (Points p)
P=p;
useNNh = false;
useCI = false;
public void setNNh(Points p)
nnH = new NNheuristic(p);
useNNh = true;
void frame (Graphics g)
g.setColor(Color.white);
 g.fillRect(0,0,size().width,size().height);
 g.setColor(Color.green);
 g.drawRect(0,0,579,280);
public void paint(Graphics g)
frame(g);
drawpoints(g);
if(useNNh)
drawLineNNh(g);
else if(useCI)
if(!CIupdate)
drawTriCI(g);
else
drawRestCI(g);
// drawLineNNh(g);
public void clear ()
 // remove the points and the graph.
P=null;
triangleDrawn = false;
code of my GUIpublic class TSP extends JFrame{
JButton run;
...................codes...........
TSP() {
...............................codes...........
run = new JButton ("Run");
run.setPreferredSize(new Dimension(113,30));
run.addActionListener(new ActionListener()
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals("Run")) {
if (chooseHeur.getSelectedItem()=="Nearest-Neighbour")
System.out.println(chooseHeur.getSelectedItem());
//points = new Points(toInt((String)chooseNum.getSelectedItem()));
//PlotArea.set(points);
PlotArea.setNNh(points);
PlotArea.repaint();
else if(chooseHeur.getSelectedItem()=="Closest-Insertion")
PlotArea.setC_I(points);
PlotArea.repaint();
pane2.add(run);

Custom Control Help: Draw a line and output start and end points

I'm looking to find or make a custom control (or simple subVI) that will appear as a 100x100 unit grid and allow me to draw a line from one point to another on that grid. It will then output the (x,y) of the starting and end point of that line on the grid. Any help or ideas?
Thanks,
Steve
LabVIEW 2009 SP1
Solved!
Go to Solution.

What you basically want is a loop with an event structure where you process Mouse Down, Move and Up events for your controls. There are any number of ways of implementing something like this, but this one will probably be the simplest:
Use a multicolumn listbox or a table for your grid. Hide the scrollbars and headers.
You can use the ActiveCell property with -2,-2 to select all cells. You can then use the cell size property to set the exact size of the cell.
Next, you put a picture control on top of the table and color its background transparent so that the table shows through. You use property node to make sure the two are aligned to exactly the same spot and size.
You use the mouse events on the picture control to detect the clicks and moves.
You use the table's Point to Row Column method to translate the event's position data to a cell.
You use the picture control VIs to draw the line on the picture based on that data.
You can even color the selected cells in the table using the table properties.
If you want to simplify things somewhat, you can also use the timeout event instead of the Mouse Move event to draw the line, but then you'll need to keep the timeout value in a shift register and reset it to -1 (no timeout) when the Mouse Up event happens.
I would also suggest processing Mouse Enter and Leave events to change the cursor and cancel if the user leaves in the middle of dragging.
Try to take over the world!

Draw a Line

I want to draw a line for a given co-ordinate values (x, y). i developed one program for that line. But if i give small numbers the line is appearing verry small. But i want the line for small and big numbers.
please help me.

I have a related question here: http://www.javadesktop.org/forums/thread.jspa?threadID=22940&tstart=0
If I can get my question answered, I think it will answer yours as well.
What I want to do is to be able to pick a point on a sphere and have a thin cylinder be projected from the user's point of view into it.
Note that you might look at my code there to get started.

How to draw horizontal line in smartform after end of the all line items

Hi Friends,
I am working on the smartform. I have created TABLE node in Main window.
i want to draw a horizontal line after end of the main window table node. i mean after printing all the line items of the table, I need to print one horizontal line.
Could you please help me how to resolve this issue.
FYI: I tried with the below two options. But no use.
1. desinged footer area in the table node of the main window.
2. tried with uline and system symbols.
please correct me if i am wrong. please explain in detail how to draw horizontal line after end of the main window table.
this is very urgent.
Thanks in advance
Regards
Raghu

Hello Valter Oliveira,
Thanks for your answer. But I need some more detail about blank line text. i.e thrid point.
Could you please tell me how to insert blank line text.
1 - in your table, create a line type with only one column, with the same width of the table
2 - in table painter, create a line under the line type
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Here are my last 3 duke dollars. Can someone please help me draw a line?

I have been BEATING my head on this for well over a week now. I'm new to Java2D and I cannot find even one example of this simple little thing that I am trying to do. Not one.
All I want to do is draw an image, zoom that image, then draw some lines on that image, and then zoom it and have those lines show up where they should.
For example, we have an image which has been zoomed. No lines are yet drawn on it.
A line is added.
The image is then zoomed in or out one more time.
How do we get the line to remap to the newly zoomed image?
What I am doing is:
0) Load up an image from a file.
1) Create a zoomed image by using the Image.getScaledInstance() method.
2) Create a BufferedImage with the width and height of the image AFTER the zoom has taken place.
3) Create a Graphics2D object by the createGraphics from this BufferedImage.
4) Place the image into the BufferedImage by doing a BufferedImage.drawImage
5) Select two points to be the start and end of the line.
6) Draw the line using Graphics2D.drawLine(start.x, start.y, end.x, end.y).
7) Zoom the image again (using the Image.getScaledInstance() method.
8) Create a new ImageIcon using the image from above and override its paintIcon method like this:
ImageIcon newIcon = new ImageIcon(newImage) {
public void paintIcon(Component c, Graphics g, int x, int y)
super.paintIcon(c, g, x, y);
zoom(); //<---- ZOOM call
Now in the zoom routine, what do I need to do to get the lines to draw at the proper location and size?
Remember, the points of the lines (stored in a list as home grown line objects) are in screen coordinates, not image coordinates since they are just click points
Note that when I use these points to draw a line, all is well (the line gets drawn where it should), but I have problems when I zoom the image.
Thanks!

Below is the documentation and method signature of
Graphics.drawImage(Image img, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, ImageObserver observer);The important thing to note is that it does scaling on the fly if the size dictated by the source co-ordinates is defferent than the size dictated by the destination co-ordinates. The source image is always left un-touched.
So basically your visual data is located in an offscreen image. You can draw a line on that. Then create a new image, get it's graphics and call drawImage(original_image, co-ordinates that cause it to scale how you like).
Then you can draw lines on the 2nd image, create a 3rd, ...etc
 * Draws as much of the specified area of the specified image as is
 * currently available, scaling it on the fly to fit inside the
 * specified area of the destination drawable surface. Transparent pixels
 * do not affect whatever pixels are already there.
 * 
 * This method returns immediately in all cases, even if the
 * image area to be drawn has not yet been scaled, dithered, and converted
 * for the current output device.
 * If the current output representation is not yet complete then
 * <code>drawImage</code> returns <code>false</code>. As more of
 * the image becomes available, the process that draws the image notifies
 * the specified image observer.
 * 
 * This method always uses the unscaled version of the image
 * to render the scaled rectangle and performs the required
 * scaling on the fly. It does not use a cached, scaled version
 * of the image for this operation. Scaling of the image from source
 * to destination is performed such that the first coordinate
 * of the source rectangle is mapped to the first coordinate of
 * the destination rectangle, and the second source coordinate is
 * mapped to the second destination coordinate. The subimage is
 * scaled and flipped as needed to preserve those mappings.
 * @param img the specified image to be drawn
 * @param dx1 the x coordinate of the first corner of the
 * destination rectangle.
 * @param dy1 the y coordinate of the first corner of the
 * destination rectangle.
 * @param dx2 the x coordinate of the second corner of the
 * destination rectangle.
 * @param dy2 the y coordinate of the second corner of the
 * destination rectangle.
 * @param sx1 the x coordinate of the first corner of the
 * source rectangle.
 * @param sy1 the y coordinate of the first corner of the
 * source rectangle.
 * @param sx2 the x coordinate of the second corner of the
 * source rectangle.
 * @param sy2 the y coordinate of the second corner of the
 * source rectangle.
 * @param observer object to be notified as more of the image is
 * scaled and converted.
 * @return <code>true</code> if the current output representation
 * is complete; <code>false</code> otherwise.
 * @see java.awt.Image
 * @see java.awt.image.ImageObserver
 * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int)
 * @since JDK1.1
 public abstract boolean drawImage(Image img,
 int dx1, int dy1, int dx2, int dy2,
 int sx1, int sy1, int sx2, int sy2,
 ImageObserver observer);

Is there a way to make keynote "draw" a line over a period of time. In some cases I can "fake" it using a wipe but if the line double backs on itself, it is not what I would like. Suggestions? Enhancement request?

I can fake what I need if the path is something like:
But if the path doubles back on itself, such as:
The wipe does not have the desired effect. I would think the appropriate name for what I want would be "Draw". I want the line to be drawn from one end to the other in a specified amount of time.

create 2 draw shapes showing as a single coloured line;
one that shows the line from the starting point at the left to the furthest point it extends to the right
the second line starts from the end point of line 1 to the furthest point it extends to the left
add a wipe to line 1, wiping from left to right
add a wipe to line 2, wiping from right to left, which automatically builds after build 1, with no delay
when played back it will look like a single wipe

Is it possible to quickly straighten lines or remove multiple points of a line

Hi, sorry not too sure how to word the question.
I am studying for an MSc in Geology and am doing seismic mapping. To tidy up my maps I exported them to ArcGIS so I could join various ones together and also contour the maps. Then I exported the GIS maps into illustrator so I could attempt to smooth some of the contours as they are extremely jaggedy due to the nature of the data.
Is there a way to quickly smooth lines or mass delete points that make up the lines?
I am asking because I have 30+ maps and each map has maybe 50lines with each line being made up of currently about 1000 points each...
If I can't find a solution I will probably end up drawing over the contours with the pen tool and just smoothing it that way, as it should be a lot faster then deleting so many points.
Any help greatly appreciated.
I am currently using Illustrator CS5 and have access to CS4.
Thanks

And if you get good using the smooth tool, it is on the pencil flyout, you might be able to use it to refine the contours as well.
it they are actually angled segments then you can select the paths and use the make
Smooth tool can be set to your specification but you have ti experiment wih it to see how it works.
Give it a little more work and you get this

How to draw a line on ADF page between two nodes for mapping.

Hi everyone,
Does anyone have a solution that how can I wiring two points by drawing a line on ADF pages.
My scenario is user want to do a mapping between two xml files. We will build an ADF faces page. This page have two parts, left part contains one tree(base on the source xml), right part is the destination tree(target xml). User can drag an node from left and drop to right. Meantime, a line will be created to connect two node, it would be perfect that when user scroll down the page, or extend the tree node, the line between source and target will be remain connection two node.
Does anyone have a solution for this, thanks in advance.
Hongfu.

so you want to do something like. xsl mapper in soa
http://www.haertfelder.com/images/pSoaBPEL3.png
i can think of using javascript.. not sure... neeed extra programming..

Drawing a Line in JAVA

Well Ive got my program to draw a line, but when I drag the mouse across the screen I'd like it to show its actual progress. Ill try to explain this better, if I click my mouse on one point on the screen and drag it to the enxt the line doesnt show up untill I reach my final spot when i release my mouse. What Id like for it to do is to be able to start the line and then have it show the lines progress while Im dragging it. I dont want it to hide the line or whatever. Can anyone give me some help with this? Heres both my java and HTML code.
Java:
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class Lab11 extends Applet implements MouseListener {
 int x0, y0, x1, y1;
 public void init() {
 addMouseListener(this);
 public void mouseClicked(MouseEvent e) { }
 public void mouseEntered(MouseEvent e) { }
 public void mouseExited (MouseEvent e) { }
 public void mousePressed(MouseEvent e) {
 x0 = e.getX();
 y0 = e.getY();
 System.out.println("Mouse pressed at: (" +
 x0 + ", " + y0 + ")" );
 public void mouseReleased(MouseEvent e) {
 x1 = e.getX();
 y1 = e.getY();
 System.out.println("Mouse released at: (" +
 x1 + ", " + y1 + ")" );
 this.repaint();
 public void paint(Graphics g) {
 g.drawLine(x0, y0, x1, y1);
}HTML:
<html>
<head>
 <title>Lab 11 Applets</title>
</head>
<body bgcolor=white>
 <applet code="Lab11.class" width=300 height=300>
 </applet>
</body>
</html>Thanks guys!

You forgot to add this to your paint() code ...
g.setColor(Color.BLACK)
You'll never see anything drawn unless you set a color different thatn background.
This works, I added code so you can run it in a frame too because I don't want to be bothered with dealing with applets and html files;
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Lab11 extends Applet implements MouseListener, MouseMotionListener {
 int x0, y0, x1, y1;
 //public void init() {
 public Lab11() {
 addMouseListener(this);
 addMouseMotionListener(this);
 public void mouseDragged(MouseEvent e)
 x1 = e.getX();
 y1 = e.getY();
 repaint();
 public void mouseMoved(MouseEvent e) { }
 public void mouseClicked(MouseEvent e) { }
 public void mouseEntered(MouseEvent e) { }
 public void mouseExited (MouseEvent e) { }
 public void mousePressed(MouseEvent e) {
 x0 = e.getX();
 y0 = e.getY();
 System.out.println("Mouse pressed at: (" +
 x0 + ", " + y0 + ")" );
 public void mouseReleased(MouseEvent e) {
 x1 = e.getX();
 y1 = e.getY();
 System.out.println("Mouse released at: (" +
 x1 + ", " + y1 + ")" );
 this.repaint();
 public void paint(Graphics g) {
 g.setColor(Color.BLACK);
 g.drawLine(x0, y0, x1, y1);
 public static void main(String[] argv)
 JFrame f = new JFrame("Test");
 f.getContentPane().add(new Lab11());
 f.setVisible(true);
 f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

Draw a line by given 2 points

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