Swing/AWT/SWT :: Drawing A Semicircle Using Formula For The Equation Of A Circle
Sep 19, 2014
So Ive got to make a turtle on an image draw a semicircle that starts at the top of a circle and goes down and to the left, changing colors halfway through. I've got everything down, I can draw the turtles and make them do straight lines. My problem is more math related. I need to use the equation of a circle, give it points, and figure out how to write that code in java.
We use the equation for a circle: (x - a)^2 + (y - b)^2 = r^2
i want to draw a circle inside a circle in java. so far i'm using this piece of code
private Ellipse2D.Float drawEllipse(int x1, int y1, int x2, int y2) { int x = Math.min(x1, x2); int y = Math.min(y1, y2); int width = Math.abs(x1 - x2); int height = Math.abs(y1 - y2); return new Ellipse2D.Float(x, y, width, height); }
public void paintComponent (Graphics g) { g.setColor(Color.white); g.fillRect(0,0,this.getWidth(), this.getHeight()); g.setColor(Color.green); g.fillOval(x, y, 40, 40); }
I had done all the previous code (in my own style) and found that the background rectangle was either being redrawn on its own, or there was something else removing the old circles from the screen. I then typed in the code from the previous page exactly as it was, to see if I had some change in syntax that would cause this, and it did the same thing.
Here's my code:
import javax.swing.*; import java.awt.*; public class SimpleAnimation { int x, y; private static final int HEIGHT = 600; private static final int WIDTH = 600;
[Code] .....
Is this because I'm using JRE7? I can't find any documentation that indicates the repaint() method has changed since Java 5.
I have a question about the execution of code to draw images relative to code that comes after that. I don't normally do this sort of thinghere's the problematic code:
Where glb1 is a final reference to an object that holds common data for the game.while its x and y values say they are for text, they are also used for image placement (at least during this testing phase.)
gc1 is the "graphics context" of the canvas that the images are being drawn on.
The person who wrote this said, "When the attached code is run, the calls to TimeKeeper.pause(500), which in turn call Thread.sleep(500), are all executed in row, and then the results of drawing the image 10 times is displayed. (I know because some of the previous image pastes left some visual data behind.)"
I recall from reading about drawing graphics (a long time ago) that drawImage() could take time, but I don't know why the thread does not indeed sleep between calls to drawImage().
how to phrase the question. I created a small applet in java.. it allows me to move a toon around a blank applet window. I am using four gif files that have a walking animation in them. The issue i am having is after moving around the gif just flashes in and out really quickly.. when i start the program, moving up and down seems to be working perfectly fine, but the moment i move left or right it starts messing up for all directions. here is my code.
import javax.swing.*; import java.awt.*; import java.awt.event.*; public class CharactorMove extends JApplet implements KeyListener
I have to do an assigment using Swing, where I have to make a Board(extends JPanel) and add multiple instances of moving elements to it, with following requirements:
By adding a new object to the Board, the others must not slow down. Also the user interface must not be blocked by the moving objects. So, the movement of the objects must be handled in a separate thread.
and
The application must support adding lots of objects, so it is not okay if every object has its own thread, as this would take too many resources. Design the application in such a way that it uses a constant number of threads, meaning that the number of threads does not grow when adding more objects.
The question is:
How to do this thing with constant number of threads?
I am buildning a paint application in java, where the user can choose from a combobox wheather he/she wants to draw a rectangle or by free hand. The objects are stored in an arrayList. The user can also choose in the menubar to go back one step, which means to remove the last drawn item from the arrayList and then loop through the arraylist to draw the remaining objects.
It works fine with rectangles. When I create a rectangle it creates only one rectangle, which I add to the arrayList. My problem is with the free hand. When I draw by free hand (using mousePressed and mouseDragged) I add every "dot" of the line as an object. Which means that when I remove the last item in the arrayList it only removes one dot of the line, not the whole line.
I need to add the dots together as one line, but how can I do that?
if (e.getSource().equals(comboBox)) { JComboBox cb = (JComboBox)e.getSource(); if (cb.getSelectedItem().equals("Rectangle")) { this.addMouseListener(new MouseAdapter() {
I'm trying to make a simple program that will feature some graphics. It will have a JCombobox that the user selects to draw various shapes. I can't get the repaint function to work however.
I am struggling to make a double border which has rounded corners. The border should be 2 parallel lines.
I made something which looks almost good, but if you look closer there are a few wrong things.To achieve this, I made 2 paths, then painted them in 2 different colours.
The main problem is painting with AA, because the colours overlap and are affected.
I think it would be smoother to paint a single path using 2 colours.
For the first problem, I think some kind of a stroke would be enough. But, if I build a stroke, it's almost same thing like drawing the path twice, like I did before. Anyway i think that would fix AA problem. But still, maybe I can achieve a smoother effect for the corners.
Question:Maybe something with a 2x1 Texture ? It's possible to achieve this ? I know I tried this before and when a curve was encountered the direction of the texture was wrong and looked messy.
PS: Ignore the blueish thing, it's a dragged component to activate the highlight border.
I've been working my way through a tutorial to build a simple 2D tile-based engine that also allows the code to manipulate the colour of pixels on the screen based on a monochrome map read from a file. I've got the code right line for line, but I seem to have a bug when it comes to draw to the screen! At regular intervals, despite what is held in the pixel array of ints (which I have confirmed to be correct when debugging), I get the same row of pixels being draw twice in a row. I figured there was some loop issue somewhere, but after attempting to debug this for some time, I haven't come up with the answer.
I am trying to read Point objects from .drw file which contains endpoints of line segments, and draw lines making a square on panel when I run the program. This is what I have got so far. how to get the points using array for drawing ?
// inside the method to read points objects from .drw file try { fos = new FileInputStream("square.drw"); oos = new ObjectInputStream(fos); // creating an object of Point class endPoints = new Point[sampleSize];
Allow the user to specify the number of terms (5 terms are shown) to use in the computation. Each time around the loop only one extra term should be added to the estimate for PI.
Alter your solution from part one so that the user is allowed to specify the precision required between 1 and 8 digits (i.e. the number of digits which are correct; e.g. to 5 digits PI is 3.14159), rather than the number of terms. The condition on the loop should be altered so that it continues until the required precision is obtained. Note that you need only submit this second version of the program (assuming you have it working).
My output for part 1 is :
Enter number of wanted terms for value of PI 100 PI = 3.1666666666666665 Number of Term = 2 PI = 3.1333333333333333 Number of Term = 3 PI = 3.145238095238095 Number of Term = 4 PI = 3.1396825396825396 Number of Term = 5 PI = 3.1427128427128426 Number of Term = 6 PI = 3.1408813408813407 Number of Term = 7 PI = 3.142071817071817 Number of Term = 8 PI = 3.1412548236077646 Number of Term = 9 PI = 3.141839618929402 Number of Term = 10 ................ and so on
I know you have to compare value of current Pi to the previous one but I'm stuck.
Here is my full program, you can find these lines of code on lines 64 and 70.
Java Code:
import java.util.Scanner; public class StockTransaction { public static void main(String[] args) { // TODO Auto-generated method stub //Variable Declaration Section
I am working on this new project where we are using the great distance formula but every time I run my ending result is NaN. I was researching, and people say its because you divide by 0. I think I have my formula correct.
Java Code:
public class testingFormula { public static void main(String[] args) { double lat = 34.01858902; double lon = -118.2817688; double lat2 =33.94530869; double lon2 = -118.3994904;
I want make a math equation game. usually math game use equation for the question and we answer that equation. ex : what is the result of 2*5 / 2+2/ 2^2 etc. and we answering that. but i want to make it different so i want to make the equation answer as the question and the equation as the answer of the game. Ex : the question is 54 so we can answer it with 9*6 or 24+30. and this is my java code
package coba; import java.util.Scanner; public class Coba {
public static void main(String[] args) { double angka = Math.random()*70;
[Code] ....
but when i run it the error code show like this : Quote
The question states: Design a class named LinearEquation
for a 2 x 2 system of linear equations:
ax + by = e
cx + dy = f
Where
x =
ed − bf/ad − bc
y =
af − ec/ad − bc
The class contains:
- Private data fields a, b, c, d, e, and f. - A constructor with the arguments for a, b, c, d, e, and f. - Six get methods for a, b, c, d, e, and f. - A method named isSolvable() that returns true if ad−bc is not 0. - Methods getX() and getY() that return the solution for the equation.
Write a test program that prompts the user to enter a, b, c, d, e, and f and displays the result. If ad − bc is 0, report that "The equation has no solution."
I believe that my program is correct because I am able to compile it and get no errors, however I have no clue how to display the information for x and y or display this equation has no solution if ad-bc=0.
Java Code:
import java.util.Scanner; public class Exer911 { public static void main(String[] args){ // Create a scanner system to hold the numbers for each variable Scanner input = new Scanner(System.in); // Prompt the user to enter a number for each of the variables
I just created a program to calculate the roots for a 2. degree equation, When I first created my program, I defined the r1 and r2 as double, but got an error saying they needed to be defined as String, why is that?When should I be using string? I am new to java and I have mostly only used int, double and Boolean so far.
import java.util.Scanner; import java.text.DecimalFormat; public class c3e1 { public static void main(String[]args){
It's suppose to generate a table with the month, and the new amount of the CD. Right now, the program generates a continuous table for months, but it doesn't update the value of the CD.
import java.util.*; public class Excercise04_31 { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in);
i am trying to calculate the number of months it takes to pay off a set amount of credit card debt given the following information: principle amount, annual interest rate, and monthly payment. How to import the formula necessary to system.out.print the answer (number of months it takes to pay off debt) ???
I have just started to learn programming in the book I am teaching myself from it said how would you write the following arithmetic expression with it being the quadratic formula but only the plus part of it in the plus or minus..
package javalearning; import java.util.Scanner; public class QuadraticFormula { public static void main(String[] args){ Scanner input = new Scanner(System.in); System.out.print("Enter value for B: "); double B = input.nextDouble(); System.out.print("Enter value for A: "); double A = input.nextDouble(); System.out.print("Enter value for C: "); double C = input.nextDouble(); double negativeOfB = -B;
