I have a few restrictions type of a ax+by>=c (1) and x>=z and y>=k (2). Restrictions (1) and (2) make a regions. I need to find the intersection of this regions and fill that other color. How can I do it in JavaFX? Can I use Canvas for solve this?
Sure, just fill everything with the polygon color and then for each area fill everything not in the area with the background color.
Note that this way you fill the whole Canvas except for the polygon with the background color.
public class Area {
private final double x;
private final double y;
private final double threshold;
private final int minCorner;
public Area(double x, double y, double threshold, boolean greater) {
if (x == 0 && y == 0) {
throw new IllegalArgumentException();
}
if (greater) {
x *= -1;
y *= -1;
threshold *= -1;
}
this.x = x;
this.y = y;
this.threshold = threshold;
boolean yPos = y > 0;
// find corner with minimum result for evaluate
this.minCorner = x < 0 ? (yPos ? 1 : 2) : (yPos ? 0 : 3);
}
public Area(double x, double y, double threshold) {
this(x, y, threshold, false);
}
private static final int[][] CORNER_FACTORS = {
{0, 0},
{1, 0},
{1, 1},
{0, 1}
};
public boolean contains(double x, double y) {
return evaluate(x, y) <= threshold;
}
public double hLineIntersection(double y) {
if (x == 0) {
return this.y * y == threshold ? Double.POSITIVE_INFINITY : Double.NaN;
} else {
return (threshold - this.y * y) / this.x;
}
}
public double vLineIntersection(double x) {
if (y == 0) {
return this.x * x == threshold ? Double.POSITIVE_INFINITY : Double.NaN;
} else {
return (threshold - this.x * x) / this.y;
}
}
private double evaluate(double x, double y) {
return this.x * x + this.y * y;
}
public void fillCleanArea(GraphicsContext gc, double w, double h) {
double[] xcoords = new double[5];
double[] ycoords = new double[5];
int[] factors = CORNER_FACTORS[minCorner];
boolean inside = contains(factors[0] * w, factors[1] * h);
int ptIndex = 0;
for (int i = minCorner, max = minCorner + 4; i < max; i++) {
factors = CORNER_FACTORS[i % 4];
double x = factors[0] * w;
double y = factors[1] * h;
boolean nowInside = contains(x, y);
if (inside != nowInside) {
// add intersection point with side
if ((i & 1) == 0) {
ycoords[ptIndex] = vLineIntersection(x);
xcoords[ptIndex++] = x;
} else {
xcoords[ptIndex] = hLineIntersection(y);
ycoords[ptIndex++] = y;
}
inside = nowInside;
// stop, if the end point is inside the area again
if (inside) {
break;
}
}
// add corners outside the bounds to polygon
if (!inside) {
xcoords[ptIndex] = x;
ycoords[ptIndex++] = y;
}
}
// draw polygon
if (ptIndex > 0) {
gc.fillPolygon(xcoords, ycoords, ptIndex);
}
}
}
public static void draw(Canvas canvas, Paint fill, Paint background, Area... areas) {
GraphicsContext gc = canvas.getGraphicsContext2D();
double w = canvas.getWidth();
double h = canvas.getHeight();
// fill everything with polygon color
gc.setFill(fill);
gc.fillRect(0, 0, w, h);
// fill everything outside the polygon with background color
gc.setFill(background);
for (Area area : areas) {
area.fillCleanArea(gc, w, h);
}
}
#Override
public void start(Stage primaryStage) {
Canvas canvas = new Canvas(400, 400);
draw(canvas, Color.BLUE, Color.WHITE,
new Area(1, 1, 400), new Area(1, -1, 100), new Area(1, -1, -100, true), new Area(1, 2, 250, true));
StackPane root = new StackPane(canvas);
Scene scene = new Scene(root);
primaryStage.setScene(scene);
primaryStage.show();
}
This won't give you the polygon's corner points though...
Related
So I'm working on a paint program in school and now I have to double buffer it. After a week of searching and using tutorials online I am still unable to double buffer my program properly... I have written a double buffer function but then you can't paint anything... When i disable the double buffer you can paint fine but the screen flickers. Please help
(Yes I am aware that some of my code is deprecated and I should fix that)
Code:
import java.applet.*;
import java.awt.*;
public class PaintRun extends Applet
{
static int posx = 0;
static int posy = 0;
static int posxOld = 0;
static int posyOld = 0;
static int size = 20;
static int toolNum = 0;
static boolean ready = false;
static Color col = new Color(120,120,120);
static Button clear = new Button(0,0,20,'C');
static Button sizeInc = new Button(20,0,20,'+');
static Button sizeDec = new Button(40,0,20,'-');
static Tools tool = new Tools(posx,posy);
public void paint(Graphics g)
{
drawButtons(g);
detectButtons(g);
}
private static void detectButtons(Graphics g)
{
if (clear.detect(posx,posy) == true)
{
g.setColor(Color.WHITE);
g.fillRect(0, 0, 800000, 800000);
drawButtons(g);
}
else if (sizeInc.detect(posx, posy))
{
size+=2;
drawButtons(g);
}
else if (sizeDec.detect(posx, posy))
{
size-=2;
if (size <= 2)
size = 2;
drawButtons(g);
}
else
{
if (ready == true)
{
g.setColor(Color.BLACK);
g.drawLine(posxOld, posyOld, posx, posy);
drawButtons(g);
}
}
}
private static void drawButtons(Graphics g)
{
clear.setColor(col, Color.BLACK);
sizeInc.setColor(col, Color.BLACK);
sizeDec.setColor(col, Color.BLACK);
clear.drawButton(g);
sizeInc.drawButton(g);
sizeDec.drawButton(g);
}
public boolean mouseDown(Event e, int x, int y)
{
posx = x;
posy = y;
posxOld = x;
posyOld = y;
ready = true;
repaint();
return true;
}
public boolean mouseDrag(Event e, int x, int y)
{
posxOld = posx;
posyOld = posy;
posx = x;
posy = y;
repaint();
return true;
}
// Normal Update function
public void update(Graphics g)
{
paint(g);
}
// Double buffered Update function
/*public void update(Graphics g)
{
Graphics offgc;
Image offscreen = null;
Dimension d = size();
offscreen = createImage(d.width, d.height);
offgc = offscreen.getGraphics();
offgc.setColor(getBackground());
offgc.fillRect(0, 0, d.width, d.height);
offgc.setColor(getForeground());
paint(offgc);
g.drawImage(offscreen, 0, 0, this);
}
*/
}
class Button extends Applet
{
int minX; // X coord where the button is drawn
int minY; // Y coord where the button is drawn
int maxX; // X size
int maxY; // Y size
char letter;
Color back;
Color line;
// Constructor block
public Button(char desc)
{
minX = 0;
minY = 0;
maxX = 40;
maxY = 40;
back = new Color(255,255,255);
line = new Color(0,0,0);
letter = desc;
}
public Button(int x, int y, char desc)
{
minX = x;
minY = y;
maxX = 40;
maxY = 40;
back = new Color(255,255,255);
line = new Color(0,0,0);
letter = desc;
}
public Button(int x, int y, int size, char desc)
{
minX = x;
minY = y;
maxX = size;
maxY = size;
back = new Color(255,255,255);
line = new Color(0,0,0);
letter = desc;
}
public Button(int x, int y, int sizeX, int sizeY, char desc)
{
minX = x;
minY = y;
maxX = sizeX;
maxY = sizeY;
back = new Color(255,255,255);
line = new Color(0,0,0);
letter = desc;
}
// Draws the button
public void drawButton(Graphics g)
{
g.setColor(back);
g.fillRect(minX, minY, maxX, maxY);
g.setColor(line);
g.drawRect(minX, minY, maxX, maxY);
g.drawString(Character.toString(letter), (minX+maxX/2)-4, (minY+maxY/2)+4);
}
// Sets the button colors
public void setColor(Color b, Color l)
{
back = b;
line = l;
}
// Detects if those coordinates are in the button location or not
public boolean detect(int x, int y)
{
boolean flag = false;
if (x > minX && x < (minX + maxX) && y > minY && y < (minY + maxY))
flag = true;
else
flag = false;
return flag;
}
}
I am writing a ray tracer.I am currently working on reflections.But the seem not to be reflecting correctly.I keep on getting StackOverflowError.I increased the memory and it runs now but the reflections are not like I thought the would be this.
(source: ageofarmour.com)
I thought it would Reflect the reflections!But it just ends up like this.
Note:This is after moved the normal off the object and changed the color calculations!Check the Cal_Reflection for new color calculation!
Here is my code for my tracer!
public class Tracer {
public boolean Tracing;
public Camera Cam;
public int Width, Height;
public BufferedImage Image;
public Color BackGroundColor;
public int StartX, StartY, EndX, EndY, RowCount, ColCount;
public double AmbientLight;
public double DiffuseLight;
public int MaxReflectionCount;
public ArrayList<GeometricObject> GeoObjects;
public ArrayList<LightObject> LightObjects;
public Tracer(Camera cam, int width, int height, BufferedImage image, Color backGroundColor, int startX, int startY, int endX, int endY, int rowCount, int colCount, double ambientLight, double diffuseLight, int maxReflectionCount, ArrayList<GeometricObject> geoObjects, ArrayList<LightObject> lightObjects) {
super();
Cam = cam;
Width = width;
Height = height;
Image = image;
BackGroundColor = backGroundColor;
StartX = startX;
StartY = startY;
EndX = endX;
EndY = endY;
RowCount = rowCount;
ColCount = colCount;
AmbientLight = ambientLight;
DiffuseLight = diffuseLight;
MaxReflectionCount = maxReflectionCount;
GeoObjects = geoObjects;
LightObjects = lightObjects;
}
public void TracePixelFast(int x, int y) {
Color color = new Color(BackGroundColor.r, BackGroundColor.g, BackGroundColor.b);
for (int o = 0; o < GeoObjects.size(); o++) {
GeometricObject GO = GeoObjects.get(o);
Ray r = new Ray(Cam.GetRayPos(Width, Height, x, y, 1, 1, RowCount, ColCount), Cam.GetRayDir(Width, Height, x, y, 1, 1, RowCount, ColCount));
double hit = GO.hit(r);
if (hit != 0.0) {
color = Cal_Pixel(x, y);
Image.setRGB(x, y, color.toInt());
break;
}
}
}
public void TracePixelSmooth(int x, int y) {
Image.setRGB(x, y, Cal_Pixel(x, y).toInt());
}
public Color Cal_Pixel(int x, int y) {
Color color = new Color(BackGroundColor);
Color colorh = new Color(BackGroundColor);
Color bgc = new Color(BackGroundColor);
int HIT = 0;
int MISS = 0;
for (int row = 0; row < RowCount; row++) {
for (int col = 0; col < ColCount; col++) {
double min = Double.MAX_VALUE;
Ray r = new Ray(Cam.GetRayPos(Width, Height, x, y, row, col, RowCount, ColCount), Cam.GetRayDir(Width, Height, x, y, row, col, RowCount, ColCount));
for (int o = 0; o < GeoObjects.size(); o++) {
GeometricObject GO = GeoObjects.get(o);
double hit = GO.hit(r);
if (hit != 0.0 && hit < min) {
min = hit;
colorh = ShadePixel(0, GO, r, hit);
HIT++;
} else {
double min2 = Double.MAX_VALUE;
for (int o2 = 0; o2 < GeoObjects.size(); o2++) {
if (o != o2) {
GeometricObject GO2 = GeoObjects.get(o2);
double hit2 = GO2.hit(r);
if (hit2 != 0.0 && hit2 < min2) {
min2 = hit2;
bgc = ShadePixel(0, GO2, r, hit2);
}
}
}
MISS++;
}
}
}
}
for (int h = 0; h < HIT; h++) {
color.Add(colorh);
}
for (int m = 0; m < MISS; m++) {
color.Add(bgc);
}
color.Divide(RowCount * ColCount);
return color;
}
public Color ShadePixel(int ReflectionDepthCount, GeometricObject GO, Ray ray, double t) {
Normal normal = GO.Cal_Normal(ray, t);
if (GO.Reflectivity > 0) {
Color GoColor = new Color(Cal_Reflection(GO, ReflectionDepthCount, ray, normal));
Color finalcolor = new Color(Cal_Light(GoColor, normal));
return finalcolor;
} else {
;
Color finalcolor = new Color(Cal_Light(GO.Color, normal));
return finalcolor;
}
}
public Color Cal_Light(Color color, Normal normal) {
ArrayList<Color> PixelShade = new ArrayList<Color>();
Color Final = new Color();
for (int l = 0; l < LightObjects.size(); l++) {
LightObject light = LightObjects.get(l);
Vector3D r_Dir = light.Pos.Sub(normal.Origin);
r_Dir.normalize();
Ray raytolight = new Ray(normal.Origin, r_Dir);
int WAS_HIT = 0;
for (int o = 0; o < GeoObjects.size(); o++) {
GeometricObject NGO = GeoObjects.get(o);
double hit = NGO.hit(raytolight);
if (hit != 0.0) {
WAS_HIT = 1;
}
}
PixelShade.add(light.ShadePixel(WAS_HIT, normal, r_Dir, color, AmbientLight, DiffuseLight));
}
for (int s = 0; s < PixelShade.size(); s++) {
Final.Add(PixelShade.get(s));
}
Final.Divide(PixelShade.size());
return Final;
}
public Color Cal_Reflection(GeometricObject OriginalObject, int ReflectionDepthCount, Ray InRay, Normal normal) {
if (ReflectionDepthCount <= MaxReflectionCount) {
GeometricObject LastGO = null;
Ray LastRay = null;
double LastT = 0.0;
double min = Double.MAX_VALUE;
Vector3D Origin = normal.Origin.Add(normal.Direction.Mul(1E-100));
Vector3D Direction = normal.Direction;
Direction.normalize();
Ray r = new Ray(Origin, Direction);
for (int o = 0; o < GeoObjects.size(); o++) {
GeometricObject GO = GeoObjects.get(o);
double hit = GO.hit(r);
if (hit != 0.0 && hit < min) {
min = hit;
LastGO = GO;
LastRay = r;
LastT = hit;
}
}
if (LastGO != null) {
System.out.println(ReflectionDepthCount);
Color Reflected = new Color(ShadePixel(ReflectionDepthCount++, LastGO, LastRay, LastT));
Color HitColor = new Color(LastGO.Color);
Color FinalColor = new Color(OriginalObject.Color);
Reflected.Mul(OriginalObject.Reflectivity);
HitColor.Mul(OriginalObject.Reflectivity);
FinalColor.Add(HitColor);
FinalColor.Add(Reflected);
FinalColor.Divide(2);
return FinalColor;
}
} else {
return BackGroundColor;
}
return OriginalObject.Color;
}
public void TraceArea(boolean SmoothTracing) {
Tracing = true;
if (SmoothTracing) {
for (int x = StartX; x < EndX; x++) {
for (int y = StartY; y < EndY; y++) {
TracePixelSmooth(x, y);
}
}
} else {
for (int x = StartX; x < EndX; x++) {
for (int y = StartY; y < EndY; y++) {
TracePixelFast(x, y);
}
}
}
}}
Here is my code for my sphere!
public class Sphere extends GeometricObject{
public Vector3D Center;
public double Radius;
public Sphere(Vector3D Center,Color Color,double Radius,double Reflectivity){
this.Center = Center;
this.Radius = Radius;
this.Color = Color;
this.Reflectivity = Reflectivity;
}
public double hit(Ray ray) {
double a = ray.Direction.Dot(ray.Direction);
double b = 2 * ray.Origin.Sub(Center).Dot(ray.Direction);
double c = ray.Origin.Sub(Center).Dot(ray.Origin.Sub(Center))-Radius*Radius;
double discreminant = b*b-4*a*c;
if(discreminant < 0.0f){
return 0.0;
}else{
double t = (-b - Math.sqrt(discreminant))/(2*a);
if(t > 10E-9){
return t;
}else{
return 0.0;
}
}
}
public Normal Cal_Normal(Ray ray,double t) {
Vector3D NPos = new Vector3D(ray.Origin.x + ray.Direction.x*t,ray.Origin.y + ray.Direction.y*t,ray.Origin.z + ray.Direction.z*t);
Vector3D NDir = NPos.Sub(Center).Div(Radius);
NDir.normalize();
return new Normal(NPos,NDir);
}}
And here is my launcher that controls the scene and tracer!
public class Launcher {
public static int Width = 600;
public static int Height = 600;
public static void main(String[] args) {
Scene scene = new Scene(Width, Height, 8, 8, new Color(0, 0, 0), new Camera(new Vector3D(0, 0, 30), new Vector3D(0.3, 0, -1), 1, true, Width, Height, 40), 0.1, 0.2, 2);
// scene.AddObject(new Sphere(new Vector3D(0,0,0),new
// Color(0,255,0),5,1));
// scene.AddObject(new Sphere(new Vector3D(-30,0,0),new
// Color(0,0,255),10,0.5));
// scene.AddObject(new Sphere(new Vector3D(30,0,0),new
// Color(255,0,0),10,0.5));
scene.AddObject(new Sphere(new Vector3D(15, 0, 0), new Color(255, 0, 0), 15, 1));
scene.AddObject(new Sphere(new Vector3D(-15, 0, 0), new Color(0, 0, 255), 15, 1));
scene.AddLight(new NonColoredLight(new Vector3D(0, 0, 20), 0.1));
long Start = System.currentTimeMillis();
BufferedImage Image = scene.Trace(false, 2);
long End = System.currentTimeMillis();
System.out.println("Milli Seconds To Render " + (End - Start));
File ImageFile = new File("TracedImage.png");
try {
ImageIO.write(Image, "PNG", ImageFile);
} catch (IOException e) {
e.printStackTrace();
}
}}
And here is the scene code!
public Scene(int width, int height, int row, int col, Color backGroundColor, Camera cam, double ambientLight, double diffuseLight, int maxReflectionCount) {
super();
Width = width;
Height = height;
Row = row;
Col = col;
BackGroundColor = backGroundColor;
Cam = cam;
AmbientLight = ambientLight;
DiffuseLight = diffuseLight;
MaxReflectionCount = maxReflectionCount;
GeoObjects = new ArrayList<GeometricObject>();
LightObjects = new ArrayList<LightObject>();
if (ambientLight > 1) {
AmbientLight = 1;
} else if (ambientLight < 0) {
AmbientLight = 0;
} else {
AmbientLight = ambientLight;
}
if (diffuseLight > 1) {
DiffuseLight = 1;
} else if (diffuseLight < 0) {
DiffuseLight = 0;
} else {
DiffuseLight = ambientLight;
}
}
public void AddObject(GeometricObject GO) {
GeoObjects.add(GO);
}
public void AddLight(LightObject Light) {
LightObjects.add(Light);
}
public BufferedImage Trace(boolean SmoothTracing, int ThreadCount) {
Image = new BufferedImage(Width, Height, BufferedImage.TYPE_INT_RGB);
Tracer tracer = new Tracer(Cam, Width, Height, Image, BackGroundColor, 0, 0, Width, Height, Row, Col, AmbientLight, DiffuseLight, MaxReflectionCount, GeoObjects, LightObjects);
tracer.TraceArea(SmoothTracing);
return Image;
}}
If you need me to post any more of my code just let me know!
Thanks in advance!
Variables for first reflection!
AmbientLight 0.1
BackGroundColor Color (id=39)
b 0.0
g 0.0
r 0.0
Cam Camera (id=41)
Direction Vector3D (id=104)
x 0.3
y 0.0
z -1.0
Distance 357.526077778263
FOV 40.0
Height 600
Perspective true
PixelSize 1.0
Pos Vector3D (id=115)
x 0.0
y 0.0
z 30.0
u Vector3D (id=116)
x -0.9578262852211514
y 0.0
z -0.28734788556634544
v Vector3D (id=117)
x 0.0
y 1.0
z 0.0
w Vector3D (id=118)
x 0.2873478855663454
y 0.0
z -0.9578262852211513
Width 600
ColCount 8
DiffuseLight 0.1
EndX 600
EndY 600
GeoObjects ArrayList<E> (id=43)
[0] Sphere (id=26)
[1] Sphere (id=34)
Height 600
Image BufferedImage (id=50)
accelerationPriority 0.5
colorModel DirectColorModel (id=120)
imageType 1
osis null
properties null
raster IntegerInterleavedRaster (id=124)
surfaceManager null
LightObjects ArrayList<E> (id=59)
[0] NonColoredLight (id=88)
MaxReflectionCount 2
RowCount 8
StartX 0
StartY 0
Tracing true
Width 600
OriginalObject Sphere (id=26)
Center Vector3D (id=60)
Color Color (id=61)
Radius 15.0
Reflectivity 1.0
ReflectionDepthCount 0
InRay Ray (id=29)
Direction Vector3D (id=62)
Origin Vector3D (id=63)
normal Normal (id=31)
Direction Vector3D (id=38)
Origin Vector3D (id=36)
LastGO Sphere (id=34)
Center Vector3D (id=64)
Color Color (id=65)
Radius 15.0
Reflectivity 1.0
LastRay Ray (id=35)
Direction Vector3D (id=38)
Origin Vector3D (id=36)
LastT 4.2468950498166125
min 4.2468950498166125
Origin Vector3D (id=36)
x 0.5809721247344103
y -0.023188722729640822
z 0.8135930637731328
Direction Vector3D (id=38)
x -0.32494278056317
y -0.02694400302823308
z 0.9453497818589108
r Ray (id=35)
Direction Vector3D (id=38)
Origin Vector3D (id=36)
Project Zip File
You are reflecting your ray exactly on the surface of the object. When checking intersections with the reflected ray, you hit on the same object again. You assume that checking if the distance is equal to 0.0 is enough to avoid this, but FP numbers are trickier than you think...
So I am trying to create a tool that can convert a .svg file type to a Java Shape or Some kind of class that will allow me to do .contains(x, y) or .contains(Rectangle2D). However I have been unable to find any methods of doing such. I found this post SVG to Java's Path2d parser this seems to give the answer but doesn’t explicitly describe how. I took a look at the classes and don't see how I would load a file then convert it to a shape. I was originally doing this with any kind of image but it turned out to be impractical and really slow. Code for that:
public static Area toArea(URL url, Color color, int tolerance) {
return toArea(toBufferedImage(url), color, tolerance);
}
public static Area toArea(Image image, Color color, int tolerance) {
return toArea(toBufferedImage(image), color, tolerance);
}
/**
* Creates an Area with PixelPerfect precision
*
* #param image
* #param color The color that is draws the Custom Shape
* #param tolerance The color tolerance
* #return Area
*/
public static Area toArea(BufferedImage image, Color color, int tolerance) {
if (image == null) {
return null;
}
Area area = new Area();
for (int x = 0; x < image.getWidth(); x++) {
for (int y = 0; y < image.getHeight(); y++) {
Color pixel = new Color(image.getRGB(x, y));
if (isIncluded(color, pixel, tolerance)) {
Rectangle r = new Rectangle(x, y, 1, 1);
area.add(new Area(r));
}
}
}
return area;
}
public static Area toArea(URL url) {
return toArea(toBufferedImage(url));
}
public static Area toArea(Image image) {
return toArea(toBufferedImage(image));
}
public static Area toArea(BufferedImage image) {
//Assumes Black as Shape Color
if (image == null) {
return null;
}
Area area = new Area();
Rectangle r;
int y1, y2;
for (int x = 0; x < image.getWidth(); x++) {
y1 = 99;
y2 = -1;
for (int y = 0; y < image.getHeight(); y++) {
Color pixel = new Color(image.getRGB(x, y));
//-16777216 entspricht RGB(0,0,0)
if (pixel.getRGB() == -16777216) {
if (y1 == 99) {
y1 = y;
y2 = y;
}
if (y > (y2 + 1)) {
r = new Rectangle(x, y1, 1, y2 - y1);
area.add(new Area(r));
y1 = y;
y2 = y;
}
y2 = y;
}
}
if ((y2 - y1) >= 0) {
r = new Rectangle(x, y1, 1, y2 - y1);
area.add(new Area(r));
}
}
return area;
}
private static boolean isIncluded(Color target, Color pixel, int tolerance) {
int rT = target.getRed();
int gT = target.getGreen();
int bT = target.getBlue();
int rP = pixel.getRed();
int gP = pixel.getGreen();
int bP = pixel.getBlue();
return ((rP - tolerance <= rT) && (rT <= rP + tolerance)
&& (gP - tolerance <= gT) && (gT <= gP + tolerance)
&& (bP - tolerance <= bT) && (bT <= bP + tolerance));
}
public static BufferedImage toBufferedImage(Image image) {
BufferedImage buffer = new BufferedImage(image.getHeight(null), image.getHeight(null), BufferedImage.TYPE_INT_RGB);
buffer.createGraphics().drawImage(image, null, null);
return buffer;
}
public static BufferedImage toBufferedImage(URL url) {
try {
return toBufferedImage(ImageIO.read(url));
} catch (IOException ex) {
return null;
}
}
private ImageShaper() {
}
Basically I am trying to write a function that can load a file that stores an irregular shape like a batman logo and then have it able to run a contains function to see if something hit it.
I have an assignment that requires us to paint a tree of Pythagoras using recursion. The tree is started with the square ABCD and the points A and B are defined by mouse clicks. Everything seems to work until I get to the recursion where I can get either the left or right part of the tree to paint, but not both. I placed a comment where I believe I am running into problems.
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class PythagorasTree extends JFrame
{
public static void main(String[] args)
{
new PythagorasTree();
}
PythagorasTree()
{
super("Pythagoras Tree");
setSize(800,800);
add("Center", new DrawingPanel());
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
class DrawingPanel extends JPanel
{
Random random = new Random();
int centerX;
int centerY;
int clickCount = 0;
float pixelSize;
float rWidth = 10.0F;
float rHeight = 7.5F;
float red, green, blue;
Point a = new Point();
Point b = new Point();
Point c = new Point();
Point d = new Point();
Point e = new Point();
Point u = new Point();
DrawingPanel()
{
addMouseListener(new MouseAdapter()
{
public void mousePressed(MouseEvent click)
{
clickCount++;
if (clickCount == 1)
{
a.x = fx(click.getX());
a.y = fy(click.getY());
repaint();
}
if (clickCount == 2)
{
b.x = fx(click.getX());
b.y = fy(click.getY());
repaint();
}
}
});
}
void initgr()
{
Dimension d = getSize();
int maxX = d.width - 1;
int maxY = d.height - 1;
pixelSize = Math.max(rWidth/maxX, rHeight/maxY);
centerX = maxX/2;
centerY = maxY/2;
}
int iX(float x){return Math.round(centerX + x/pixelSize);}
int iY(float y){return Math.round(centerY - y/pixelSize);}
float fx(int x){return (x - centerX) * pixelSize;}
float fy(int y){return (centerY - y) * pixelSize;}
public void paintComponent(Graphics g)
{
initgr();
super.paintComponent(g);
setBackground(Color.white);
g.setColor(Color.red);
if (clickCount == 1)
g.drawLine(iX(a.x), iY(a.y), iX(a.x), iY(a.y));
if (clickCount > 1)
drawTree(g,a,b);
}
public void drawTree(Graphics g, Point first, Point second)
{
float xSquared = (float) Math.pow((second.x-first.x),2);
float ySquared = (float) Math.pow((second.y-first.y),2);
float length = (float) Math.sqrt(xSquared + ySquared);
if ( length > .001)
{
u.x = second.x - first.x;
u.y = second.y - first.y;
a.x = first.x;
a.y = first.y;
b.x = second.x;
b.y = second.y;
d.x = first.x + (u.y * -1);
d.y = first.y + u.x;
c.x = d.x + u.x;
c.y = d.y + u.y;
e.x = d.x + .5F * (u.x + (u.y*-1));
e.y = d.y + .5F * (u.y + u.x);
Polygon square = new Polygon();
Polygon triangle = new Polygon();
square.addPoint(iX(a.x), iY(a.y));
square.addPoint(iX(b.x), iY(b.y));
square.addPoint(iX(c.x), iY(c.y));
square.addPoint(iX(d.x), iY(d.y));
red = random.nextFloat();
green = random.nextFloat();
blue = random.nextFloat();
g.setColor(new Color(red, green, blue));
g.fillPolygon(square);
triangle.addPoint(iX(c.x), iY(c.y));
triangle.addPoint(iX(d.x), iY(d.y));
triangle.addPoint(iX(e.x), iY(e.y));
red = random.nextFloat();
green = random.nextFloat();
blue = random.nextFloat();
g.setColor(new Color(red, green, blue));
g.fillPolygon(triangle);
/* Problem code is here, tree will draw Left or Right depending on which recursive call
* is first in the code, but will never reach the 2nd call.
*/
drawTree(g,d,e); //Draw tree left
drawTree(g,e,c); //Draw tree right
}
}
}
class Point
{
public float x;
public float y;
public Point()
{
}
}
It's time this question had an answer. The problem is with these member variable declarations:
Point c = new Point();
Point e = new Point();
And this code in drawTree():
drawTree(g,d,e); //Draw tree left
drawTree(g,e,c); //Draw tree right
Since c and e are a member variables, not local, they get modified by the first recursive call to drawTree(g, d, e) so by the time we make the second call to drawTree(g, e, c), it's no longer the same c and e we thought we had. The following rework of the code makes these local (clearly not as efficient GC-wise, but also not as buggy) as well as several other small modifications:
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
class Point
{
public float x;
public float y;
public Point(float x, float y) {
this.x = x;
this.y = y;
}
public Point() {
}
}
class DrawingPanel extends JPanel
{
Random random = new Random();
int clickCount = 0;
float pixelSize;
float rWidth = 10.0F;
float rHeight = 7.5F;
float red, green, blue;
Point a = new Point();
Point b = new Point();
Point center = new Point();
DrawingPanel()
{
addMouseListener(new MouseAdapter()
{
public void mousePressed(MouseEvent click)
{
clickCount++;
if (clickCount == 1)
{
a.x = fx(click.getX());
a.y = fy(click.getY());
repaint();
}
else if (clickCount == 2)
{
b.x = fx(click.getX());
b.y = fy(click.getY());
repaint();
}
}
});
}
void initgr()
{
Dimension d = getSize();
int maxX = d.width - 1;
int maxY = d.height - 1;
pixelSize = Math.max(rWidth / maxX, rHeight / maxY);
center.x = maxX / 2;
center.y = maxY / 2;
}
int iX(float x){ return Math.round(center.x + x / pixelSize); }
int iY(float y){ return Math.round(center.y - y / pixelSize); }
float fx(int x){ return (x - center.x) * pixelSize; }
float fy(int y){ return (center.y - y) * pixelSize; }
public void paintComponent(Graphics g)
{
super.paintComponent(g);
initgr();
setBackground(Color.white);
if (clickCount == 1)
{
g.setColor(Color.red);
g.drawLine(iX(a.x), iY(a.y), iX(a.x), iY(a.y));
}
else if (clickCount > 1) {
drawTree(g, a, b);
}
}
public void drawTree(Graphics g, Point first, Point second)
{
double xSquared = Math.pow(second.x - first.x, 2);
double ySquared = Math.pow(second.y - first.y, 2);
if (Math.sqrt(xSquared + ySquared) < 0.01) {
return;
}
Point u = new Point(second.x - first.x, second.y - first.y);
Point d = new Point(first.x - u.y, first.y + u.x);
Point c = new Point(d.x + u.x, d.y + u.y);
Point e = new Point(d.x + 0.5F * (u.x - u.y), d.y + 0.5F * (u.y + u.x));
Polygon square = new Polygon();
square.addPoint(iX(first.x), iY(first.y));
square.addPoint(iX(second.x), iY(second.y));
square.addPoint(iX(c.x), iY(c.y));
square.addPoint(iX(d.x), iY(d.y));
red = random.nextFloat();
green = random.nextFloat();
blue = random.nextFloat();
g.setColor(new Color(red, green, blue));
g.fillPolygon(square);
Polygon triangle = new Polygon();
triangle.addPoint(iX(c.x), iY(c.y));
triangle.addPoint(iX(d.x), iY(d.y));
triangle.addPoint(iX(e.x), iY(e.y));
red = random.nextFloat();
green = random.nextFloat();
blue = random.nextFloat();
g.setColor(new Color(red, green, blue));
g.fillPolygon(triangle);
drawTree(g, d, e); // Draw tree left
drawTree(g, e, c); // Draw tree right
}
}
public class PythagorasTree extends JFrame
{
PythagorasTree()
{
super("Pythagoras Tree");
setSize(800, 800);
add("Center", new DrawingPanel());
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args)
{
new PythagorasTree();
}
}
OUTPUT
I absolutely love maths (or 'math' as most of you would say!) but I haven't done it to a level where I know the answer to this problem. I have a main circle which could have a centre point at any x and y on a display. Other circles will move around the display at will but at any given call to a render method I want to render not only those circles that intersect the main circle, but also only render the segment of that circle that is visible inside the main circle. An analogy would be a shadow cast on a real life object, and I only want to draw the part of that object that is 'illuminated'.
I want to do this preferably in Java, but if you have a raw formula that would be appreciated. I wonder how one might draw the shape and fill it in Java, I'm sure there must be some variation on a polyline with arcs or something?
Many thanks
Let A and B be the 2 intersection points (you can ignore it when there is no, or 1 intercetion point).
Then calculate the length of the circular line segment between A and B.
With this information, you should be able to draw the arc using Graphics' drawArc(...) method (if I'm not mistaken...).
EDIT
Well, you don't even need the length of the circular line segment. I had the line-intersection code laying around, so I built a small GUI around it how you could paint/view the ARC of such intersecting circles (there are a bit of comments in the code):
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Arc2D;
/**
* #author: Bart Kiers
*/
public class GUI extends JFrame {
private GUI() {
super("Circle Intersection Demo");
initGUI();
}
private void initGUI() {
super.setSize(600, 640);
super.setDefaultCloseOperation(EXIT_ON_CLOSE);
super.setLayout(new BorderLayout(5, 5));
final Grid grid = new Grid();
grid.addMouseMotionListener(new MouseMotionAdapter() {
#Override
public void mouseDragged(MouseEvent e) {
Point p = new Point(e.getX(), e.getY()).toCartesianPoint(grid.getWidth(), grid.getHeight());
grid.showDraggedCircle(p);
}
});
grid.addMouseListener(new MouseAdapter() {
#Override
public void mouseReleased(MouseEvent e) {
Point p = new Point(e.getX(), e.getY()).toCartesianPoint(grid.getWidth(), grid.getHeight());
grid.released(p);
}
#Override
public void mousePressed(MouseEvent e) {
Point p = new Point(e.getX(), e.getY()).toCartesianPoint(grid.getWidth(), grid.getHeight());
grid.pressed(p);
}
});
super.add(grid, BorderLayout.CENTER);
super.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new GUI();
}
});
}
private static class Grid extends JPanel {
private Circle c1 = null;
private Circle c2 = null;
private Point screenClick = null;
private Point currentPosition = null;
public void released(Point p) {
if (c1 == null || c2 != null) {
c1 = new Circle(screenClick, screenClick.distance(p));
c2 = null;
} else {
c2 = new Circle(screenClick, screenClick.distance(p));
}
screenClick = null;
repaint();
}
public void pressed(Point p) {
if(c1 != null && c2 != null) {
c1 = null;
c2 = null;
}
screenClick = p;
repaint();
}
#Override
public void paintComponent(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setColor(Color.WHITE);
g2d.fillRect(0, 0, super.getWidth(), super.getHeight());
final int W = super.getWidth();
final int H = super.getHeight();
g2d.setColor(Color.LIGHT_GRAY);
g2d.drawLine(0, H / 2, W, H / 2); // x-axis
g2d.drawLine(W / 2, 0, W / 2, H); // y-axis
if (c1 != null) {
g2d.setColor(Color.RED);
c1.drawOn(g2d, W, H);
}
if (c2 != null) {
g2d.setColor(Color.ORANGE);
c2.drawOn(g2d, W, H);
}
if (screenClick != null && currentPosition != null) {
g2d.setColor(Color.DARK_GRAY);
g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f));
Circle temp = new Circle(screenClick, screenClick.distance(currentPosition));
temp.drawOn(g2d, W, H);
currentPosition = null;
}
if (c1 != null && c2 != null) {
g2d.setColor(Color.BLUE);
g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.4f));
Point[] ips = c1.intersections(c2);
for (Point ip : ips) {
ip.drawOn(g, W, H);
}
g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.2f));
if (ips.length == 2) {
g2d.setStroke(new BasicStroke(10.0f));
c1.highlightArc(g2d, ips[0], ips[1], W, H);
}
}
g2d.dispose();
}
public void showDraggedCircle(Point p) {
currentPosition = p;
repaint();
}
}
private static class Circle {
public final Point center;
public final double radius;
public Circle(Point center, double radius) {
this.center = center;
this.radius = radius;
}
public void drawOn(Graphics g, int width, int height) {
// translate Cartesian(x,y) to Screen(x,y)
Point screenP = center.toScreenPoint(width, height);
int r = (int) Math.rint(radius);
g.drawOval((int) screenP.x - r, (int) screenP.y - r, r + r, r + r);
// draw the center
Point screenCenter = center.toScreenPoint(width, height);
r = 4;
g.drawOval((int) screenCenter.x - r, (int) screenCenter.y - r, r + r, r + r);
}
public void highlightArc(Graphics2D g2d, Point p1, Point p2, int width, int height) {
double a = center.degrees(p1);
double b = center.degrees(p2);
// translate Cartesian(x,y) to Screen(x,y)
Point screenP = center.toScreenPoint(width, height);
int r = (int) Math.rint(radius);
// find the point to start drawing our arc
double start = Math.abs(a - b) < 180 ? Math.min(a, b) : Math.max(a, b);
// find the minimum angle to go from `start`-angle to the other angle
double extent = Math.abs(a - b) < 180 ? Math.abs(a - b) : 360 - Math.abs(a - b);
// draw the arc
g2d.draw(new Arc2D.Double((int) screenP.x - r, (int) screenP.y - r, r + r, r + r, start, extent, Arc2D.OPEN));
}
public Point[] intersections(Circle that) {
// see: http://mathworld.wolfram.com/Circle-CircleIntersection.html
double d = this.center.distance(that.center);
double d1 = ((this.radius * this.radius) - (that.radius * that.radius) + (d * d)) / (2 * d);
double h = Math.sqrt((this.radius * this.radius) - (d1 * d1));
double x3 = this.center.x + (d1 * (that.center.x - this.center.x)) / d;
double y3 = this.center.y + (d1 * (that.center.y - this.center.y)) / d;
double x4_i = x3 + (h * (that.center.y - this.center.y)) / d;
double y4_i = y3 - (h * (that.center.x - this.center.x)) / d;
double x4_ii = x3 - (h * (that.center.y - this.center.y)) / d;
double y4_ii = y3 + (h * (that.center.x - this.center.x)) / d;
if (Double.isNaN(x4_i)) {
// no intersections
return new Point[0];
}
// create the intersection points
Point i1 = new Point(x4_i, y4_i);
Point i2 = new Point(x4_ii, y4_ii);
if (i1.distance(i2) < 0.0000000001) {
// i1 and i2 are (more or less) the same: a single intersection
return new Point[]{i1};
}
// two unique intersections
return new Point[]{i1, i2};
}
#Override
public String toString() {
return String.format("{center=%s, radius=%.2f}", center, radius);
}
}
private static class Point {
public final double x;
public final double y;
public Point(double x, double y) {
this.x = x;
this.y = y;
}
public double degrees(Point that) {
double deg = Math.toDegrees(Math.atan2(that.y - this.y, that.x - this.x));
return deg < 0.0 ? deg + 360 : deg;
}
public double distance(Point that) {
double dX = this.x - that.x;
double dY = this.y - that.y;
return Math.sqrt(dX * dX + dY * dY);
}
public void drawOn(Graphics g, int width, int height) {
// translate Cartesian(x,y) to Screen(x,y)
Point screenP = toScreenPoint(width, height);
int r = 7;
g.fillOval((int) screenP.x - r, (int) screenP.y - r, r + r, r + r);
}
public Point toCartesianPoint(int width, int height) {
double xCart = x - (width / 2);
double yCart = -(y - (height / 2));
return new Point(xCart, yCart);
}
public Point toScreenPoint(int width, int height) {
double screenX = x + (width / 2);
double screenY = -(y - (height / 2));
return new Point(screenX, screenY);
}
#Override
public String toString() {
return String.format("(%.2f,%.2f)", x, y);
}
}
}
If you start the GUI above and then type 100 0 130 -80 55 180 in the text box and hit return, you'll see the following: ...
Changed the code so that circles can be drawn by pressing- and dragging the mouse. Screenshot:
Assuming you know the center point and the radius of the two circles:
Calculate the points where the circles intersect. This can easily be done with trigonometry. There may be no intersection (distance between the center points is longer than the sum of the radiuses, ignorable in your case), one point (distance between center points is equal to the sum of the radiuses, ignorable), or two. Special cases: the circles are identical, or the moving circle ist smaller and completely inside the main circle.
If there are two intersection points: take the center point from the moving circle and draw an arc between those points.
(I have no code for you, but since you love maths... ;-)