So I have a lot of code so I guess I'll just post the couple classes that seem to be giving me problems and where the problem is occuring.
// line class to store lines from .ps file
class line {
// for outcodes
private int RIGHT = 2;
private int TOP = 8;
private int LEFT = 1;
private int BOTTOM = 4;
// two points signify each line
private point point0;
private point point1;
public line(point _point1, point _point2) {
point0 = _point1;
point1 = _point2;
}
public void setPoint1(point _new) {
point0 = _new;
}
public void setPoint2 (point _another) {
point1 = _another;
}
public point getPoint1() {
return point0;
}
public point getPoint2() {
return point1;
}
public float getSlope() {
int rise = point0.getY() - point1.getY();
int run = point0.getX() - point1.getX();
float slope = rise/run;
return slope;
}
// only for drawing
// AFTER clipping
public void DDA(xpm _file) {
int x1 = this.getPoint1().getX();
int y1 = this.getPoint1().getY();
int x2 = this.getPoint2().getX();
int y2 = this.getPoint2().getY();
double m = (double)(y2-y1)/(x2-x1);
double y = (double)y1;
int iy;
for (int x = x1 ; x <= x2 ; x++) {
iy = (int)Math.round(y);
setPixel(x, iy, _file);
y += m;
}
}
// actually setting the correct pixel in .XPM
private void setPixel(int x, int iy, xpm _file) {
_file.pixels[x][iy].setValue("b");
}
// getting the codes for the inputted lines
// find out where to clip them
public int ComputeOutCode (int x, int y, int xmin, int ymin, int xmax, int ymax)
{
int code = 0;
if (y > ymax)
code |= TOP;
else if (y < ymin)
code |= BOTTOM;
if (x > xmax)
code |= RIGHT;
else if (x < xmin)
code |= LEFT;
return code;
}
// clip the lines right before drawing them
public void cohenSutherland( int x1, int y1, int x2, int y2, int xmin, int ymin, int xmax, int ymax)
{
//Outcodes for P0, P1, and whatever point lies outside the clip rectangle
int outcode0, outcode1, outcodeOut, hhh = 0;
boolean accept = false, done = false;
//compute outcodes
outcode0 = ComputeOutCode (x1, y1, xmin, ymin, xmax, ymax);
outcode1 = ComputeOutCode (x2, y2, xmin, ymin, xmax, ymax);
//System.out.println( outcode0 + " " + outcode1 );
do{
if ((outcode0 | outcode1) == 0 )
{
accept = true;
done = true;
}
else if ( (outcode0 & outcode1) > 0 )
{
done = true;
}
else
{
//failed both tests, so calculate the line segment to clip
//from an outside point to an intersection with clip edge
int x = 0, y = 0;
//At least one endpoint is outside the clip rectangle; pick it.
outcodeOut = outcode0 != 0 ? outcode0: outcode1;
//Now find the intersection point;
//use formulas y = y0 + slope * (x - x0), x = x0 + (1/slope)* (y - y0)
if ( (outcodeOut & TOP) > 0 )
{
x = x1 + (x2 - x1) * (ymax - y1)/(y2 - y1);
y = ymax;
}
else if ((outcodeOut & BOTTOM) > 0 )
{
x = x1 + (x2 - x1) * (ymin - y1)/(y2 - y1);
y = ymin;
}
else if ((outcodeOut & RIGHT)> 0)
{
y = y1 + (y2 - y1) * (xmax - x1)/(x2 - x1);
x = xmax;
}
else if ((outcodeOut & LEFT) > 0)
{
y = y1 + (y2 - y1) * (xmin - x1)/(x2 - x1);
x = xmin;
}
//Now we move outside point to intersection point to clip
//and get ready for next pass.
if (outcodeOut == outcode0)
{
x1 = x;
y1 = y;
outcode0 = ComputeOutCode (x1, y1, xmin, ymin, xmax, ymax);
}
else
{
x2 = x;
y2 = y;
outcode1 = ComputeOutCode (x2, y2, xmin, ymin, xmax, ymax);
}
}
hhh ++;
}
while (done != true && hhh < 5000);
if(accept)
{
set( x1, y1, x2, y2);
}
}
private void set(int x1, int y1, int x2, int y2) {
point newPoint1 = new point(x1,y1);
point newPoint2 = new point(x2,y2);
this.setPoint1(newPoint1);
this.setPoint2(newPoint2);
}
}The null pointer exception occurs in line 63 when it goes to setPixel in the array. Here is my xpm class, which might help.
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
// xpm class
// aka frame buffer
public class xpm {
public pixel[][] pixels;
private String header = "/* XPM */";
private String array = "static char *sco100[] = { ";
private String header2 = " /* width height num_colors chars_per_pixel */ ";
private String dimensions = " \"500 500 2 1\", ";
private String header3 = " /* colors */ ";
private String white = " \"- c #ffffff\", ";
private String black = " \"b c #000000\", ";
private String header4 = " /* pixels */ ";
private String pixelsString = "";
private String end = "};";
public xpm() {
pixels = new pixel[500][500];
}
public void makePixelsString() {
String thisLine = "";
for (int i = 0; i < pixels.length; i++) {
thisLine += "\"";
for (int j = 0; j < pixels[i].length; j++) {
thisLine += pixels[i][j].getValue();
}
if (i == pixels.length - 1) {
thisLine += "\"\n";
}
else {
thisLine += "\",\n";
}
}
pixelsString = thisLine;
}
public pixel getArraySpot(int x, int y) {
return pixels[x][y];
}
public void makeXPM() throws IOException {
String text = header + array + header2 + dimensions + header3 + white + black + header4
+ pixelsString + end;
// add pixels..
File file = new File("out.xpm");
BufferedWriter output = new BufferedWriter(new FileWriter(file));
output.write(text);
output.close();
}
}Also if you have any other pointers or need to see more code I can provide it for you.
This thing is due by tonight at midnight, it's 8:17pm here right now :(
