package org.stuygfx.graphics;

import org.stuygfx.graphics.Pixel;
import org.stuygfx.graphics.Point;

public class Image {

    public int XRES;
    public int YRES;

    private Pixel[][] canvas;
    private int originX;
    private int originY;
    private boolean reflectOverX;

    public Image() {
        this.XRES = 512;
        this.YRES = 512;
        this.originX = 0;
        this.originY = 0;
        this.reflectOverX = false;
        this.canvas = new Pixel[YRES][XRES];
    }

    public Image(int xres, int yres) {
        this.XRES = xres;
        this.YRES = yres;
        this.originX = 0;
        this.originY = 0;
        this.reflectOverX = false;
        this.canvas = new Pixel[YRES][XRES];
    }

    public void setOrigin(Point origin) {
        this.originX = origin.x;
        this.originY = origin.y;
    }

    public void setOriginX(int x) {
        this.originX = x;
    }

    public void setOriginY(int y) {
        this.originY = y;
    }

    public void plot(Point p, Pixel color) {
        if (reflectOverX) {
            this.canvas[(this.YRES - 1) - (p.y + originY)][p.x + originX] = color;
        } else {
            this.canvas[p.y + originY][p.x + originX] = color;
        }
    }

    public void plot(int x, int y, Pixel color) {
        if (reflectOverX) {
            this.canvas[(this.YRES - 1) - (y + originY)][x + originX] = color;
        } else {
            this.canvas[y + originY][x + originX] = color;
        }
    }
}

package org.stuygfx.graphics;

import org.stuygfx.graphics.Pixel;
import org.stuygfx.graphics.Point;

public class Image {

    public int XRES;
    public int YRES;
    public Pixel[][] canvas;

    private int originX;
    private int originY;
    private boolean reflectOverX;

    public Image() {
        this.XRES = 512;
        this.YRES = 512;
        this.originX = 0;
        this.originY = 0;
        this.reflectOverX = false;
        this.canvas = new Pixel[YRES][XRES];
    }

    public Image(int xres, int yres) {
        this.XRES = xres;
        this.YRES = yres;
        this.originX = 0;
        this.originY = 0;
        this.reflectOverX = false;
        this.canvas = new Pixel[YRES][XRES];
    }

    public void setOrigin(Point origin) {
        this.originX = origin.x;
        this.originY = origin.y;
    }

    public void setOriginX(int x) {
        this.originX = x;
    }

    public void setOriginY(int y) {
        this.originY = y;
    }

    public void plot(Point p, Pixel color) {
        if (reflectOverX) {
            this.canvas[(this.YRES - 1) - (p.y + originY)][p.x + originX] = color;
        } else {
            this.canvas[p.y + originY][p.x + originX] = color;
        }
    }

    public void plot(int x, int y, Pixel color) {
        if (reflectOverX) {
            this.canvas[(this.YRES - 1) - (y + originY)][x + originX] = color;
        } else {
            this.canvas[y + originY][x + originX] = color;
        }
    }
}

Make canvas a public variable