如何解决为什么我的图表点不显示? Java图形问题
到目前为止,我是 Java 新手,只有一门课。 这是我正在开发的一个娱乐程序,如果您想象一个窗口,其中每个 x 和 y 坐标对应于时间表中的基本整数,并且每个乘积都是一个像素,那么每个像素都有一个对应的值,这些值来自乘以它们的坐标。因此 (4,9) 处的像素值为 36。 我希望程序做的是使用一个数组将坐标 (x * y) 的乘积与素数列表 (P) 进行比较,如果乘积小于素数,则绘制一个点。我的代码如下:
import java.awt.Canvas;
import java.awt.Graphics;
import javax.swing.JFrame;
import java.awt.Color;
public class PrimeAdjacents extends Canvas {
static int screenSize = 500;
int[] integersX = new int[screenSize];//all integers along the X axis
int[] integersY = new int[screenSize];//all integers along the Y axis
//this list of prime numbers came from GitHub,all primes up to 1500
int[] prime = {2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,269,271,277,281,283,293,307,311,313,317,331,337,347,349,353,359,367,373,379,383,389,397,401,409,419,421,431,433,439,443,449,457,461,463,467,479,487,491,499,503,509,521,523,541,547,557,563,569,571,577,587,593,599,601,607,613,617,619,631,641,643,647,653,659,661,673,677,683,691,701,709,719,727,733,739,743,751,757,761,769,773,787,797,809,811,821,823,827,829,839,853,857,859,863,877,881,883,887,907,911,919,929,937,941,947,953,967,971,977,983,991,997,1009,1013,1019,1021,1031,1033,1039,1049,1051,1061,1063,1069,1087,1091,1093,1097,1103,1109,1117,1123,1129,1151,1153,1163,1171,1181,1187,1193,1201,1213,1217,1223,1229,1231,1237,1249,1259,1277,1279,1283,1289,1291,1297,1301,1303,1307,1319,1321,1327,1361,1367,1373,1381,1399,1409,1423,1427,1429,1433,1439,1447,1451,1453,1459,1471,1481,1483,1487,1489,1493,1499};
public static void main(String[] args) {
//Creates the screen
JFrame frame = new JFrame("PrimeAdjacents"); //give screen a name
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
PrimeAdjacents canvas = new PrimeAdjacents();
// Sets the size of the screen
// See https://docs.oracle.com/javase/9/docs/api/javafx/scene/canvas/Canvas.html
canvas.setSize(screenSize,screenSize);
// Sets the background color
// See https://docs.oracle.com/javase/7/docs/api/java/awt/Color.html
canvas.setBackground(Color.GRAY);
frame.add(canvas);
frame.pack();
frame.setVisible(true);
frame.setResizable(false);
}
/*if the product of any x coord and any y coord is equal to any prime-1
then draw a red dot at that coordinate,if the product is not adjacent to a prime then draw a blue dot
*/
public void paint(Graphics g) {
for (int i = 0; i < integersX.length; i++) {
int ex = integersX[i];
for (int j = 0; j < integersY.length; j++) {
int wy = integersY[i];
for (int k = 0; k < prime.length; k++) {
int P = prime[k];
g.setColor(Color.GREEN);
g.fillOval(P,P,5);//draw dots at each prime-squared
if (ex * wy == P - 1) {
g.setColor(Color.RED);
g.fillOval(ex,wy,5);
}
}
}
}
}
}
您可以看到我提供了一个最多 1500 的素数列表以进行比较。比较发生在paint方法中,我让它在P-squared处绘制点只是为了表明图形正在工作,但是P-1处的点要么没有被绘制,要么只有第一个被绘制。如果这很重要,我正在使用 IntelliJ。 谁能告诉我需要或需要更改什么才能获得我正在寻找的积分?
解决方法
您使用 i
和 j
迭代画布的坐标,但是除了从第一次实例化时用零填充的两个数组中提取零之外,您从未将这些值用于任何其他用途他们。因此,ex * wy
将始终为零并且不会绘制任何内容,因为 1
不在您的素数数组中。
您不需要 integersX
和 integersY
数组,因为您可以直接使用 i
和 j
作为坐标。
public void paint(Graphics g) {
for (int i = 0; i < screenSize; i++) {
for (int j = 0; j < screenSize; j++) {
for (int k = 0; k < prime.length; k++) {
int P = prime[k];
if (i * j == P - 1) {
g.setColor(Color.RED);
g.fillOval(i,j,5,5);
}
}
}
}
}
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