我編寫了一個(gè)畫線算法，在計(jì)算每個(gè)點(diǎn)時(shí)可以正確運(yùn)行，但是當(dāng)它被渲染時(shí)，程序會(huì)跳過近 20 個(gè)點(diǎn)，無法找到問題。我試圖弄亂算法，特別是 for 循環(huán)，它將點(diǎn)添加到計(jì)算線的位置列表中，因?yàn)槲以谄渌姹镜拇a中遇到了問題。我只是一輩子都找不到代碼的問題，我對(duì) Java 還很陌生，你可能會(huì)從下面混亂的代碼中看出這一點(diǎn)。它說不要發(fā)布整個(gè)文件，但我無法確定哪里出了問題。我對(duì)下面混亂的代碼感到非常抱歉，我只是不知道出了什么問題。package sample;import com.sun.jdi.ArrayReference;import javafx.application.Application;import javafx.application.Platform;import javafx.scene.Group;import javafx.scene.canvas.Canvas;import javafx.scene.canvas.GraphicsContext;import javafx.scene.paint.Color;import javafx.scene.Scene;import javafx.stage.Stage;import java.util.ArrayList;class PositionCounter { public int position; public void setPosition(int newPos){ position = newPos; }}public class Main extends Application {// public void drawRectangle(int x1, int y1, int x2, int y2, Stage primStage, GraphicsContext gc){// drawLine(x1, y2, x2, y2 , primStage, gc);// drawLine(x1, y1, x2, y2, primStage, gc);// drawLine(x1, y1, x1 , y2, primStage, gc);// drawLine(x2, y1, x2 , y2, primStage, gc);// drawLine(x1, y1, x2, y1 , primStage, gc);//// }// public void fillPosition(ArrayList<Integer[]> points, GraphicsContext gc, int positionInArray ){ gc.fillRect(points.get(positionInArray)[0], points.get(positionInArray)[1], squareWidth / 2, squareWidth / 2); //System.out.println("(" + points.get(positionInArray)[0] + ", " + points.get(positionInArray)[1]); } public void drawLine(int x1, int y1, int x2, int y2, Stage primStage, GraphicsContext gc){ ArrayList<Integer[]> points = calculateLine(x1, y1, x2, y2, gc); PositionCounter position = new PositionCounter(); Thread thread = new Thread(new Runnable() { @Override public void run() { Runnable updater = new Runnable() { @Override public void run() { fillPosition(points, gc, position.position); } };問題是計(jì)算線函數(shù)返回正確的點(diǎn)，只是沒有正確渲染它們。
1 回答
慕森卡
TA貢獻(xiàn)1806條經(jīng)驗(yàn) 獲得超8個(gè)贊
我建議您使用Timeline而不是Thread.?它可以使用 a 來完成Thread，但Timeline專為此類情況而設(shè)計(jì)。
畫線方法：
public void drawLine(int x1, int y1, int x2, int y2, Stage primStage, GraphicsContext gc)
{
? ? ArrayList<Integer[]> points = calculateLine(x1, y1, x2, y2, gc);
? ? PositionCounter position = new PositionCounter();
? ? int dy = Math.abs(y2 - y1);
? ? int dx = Math.abs(x2 - x1);
? ? int m = (dy >= dx) ? dy : dx;
? ? AtomicInteger counter = new AtomicInteger();
? ? Timeline animationTimeline = new Timeline(new KeyFrame(Duration.millis(20), (ActionEvent t) -> {
? ? ? ? position.setPosition(counter.getAndIncrement());
? ? ? ? fillPosition(points, gc, position.position);
? ? }));
? ? animationTimeline.setCycleCount(points.size());
? ? animationTimeline.play();
}
完整代碼：
import com.sun.jdi.ArrayReference;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.scene.Group;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.paint.Color;
import javafx.scene.Scene;
import javafx.stage.Stage;
import java.util.ArrayList;
import java.util.concurrent.atomic.AtomicInteger;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.util.Duration;
class PositionCounter
{
? ? public int position;
? ? public void setPosition(int newPos)
? ? {
? ? ? ? position = newPos;
? ? }
}
public class JavaFXTestingGround extends Application
{
//? ? public void drawRectangle(int x1, int y1, int x2, int y2, Stage primStage, GraphicsContext gc){
//? ? ? ? drawLine(x1, y2, x2, y2 , primStage, gc);
//? ? ? ? drawLine(x1, y1, x2, y2, primStage, gc);
//? ? ? ? drawLine(x1, y1, x1 , y2, primStage, gc);
//? ? ? ? drawLine(x2, y1, x2 , y2, primStage, gc);
//? ? ? ? drawLine(x1, y1, x2, y1 , primStage, gc);
//
//? ? }
//
? ? public void fillPosition(ArrayList<Integer[]> points, GraphicsContext gc, int positionInArray)
? ? {
? ? ? ? gc.fillRect(points.get(positionInArray)[0], points.get(positionInArray)[1], squareWidth / 2, squareWidth / 2);
? ? ? ? //System.out.println("(" + points.get(positionInArray)[0] + ", " + points.get(positionInArray)[1]);
? ? }
? ? public void drawLine(int x1, int y1, int x2, int y2, Stage primStage, GraphicsContext gc)
? ? {
? ? ? ? ArrayList<Integer[]> points = calculateLine(x1, y1, x2, y2, gc);
? ? ? ? PositionCounter position = new PositionCounter();
? ? ? ? int dy = Math.abs(y2 - y1);
? ? ? ? int dx = Math.abs(x2 - x1);
? ? ? ? int m = (dy >= dx) ? dy : dx;
? ? ? ? AtomicInteger counter = new AtomicInteger();
? ? ? ? Timeline animationTimeline = new Timeline(new KeyFrame(Duration.millis(20), (ActionEvent t) -> {
? ? ? ? ? ? position.setPosition(counter.getAndIncrement());
? ? ? ? ? ? fillPosition(points, gc, position.position);
? ? ? ? }));
? ? ? ? animationTimeline.setCycleCount(points.size());
? ? ? ? animationTimeline.play();
? ? }
? ? @Override
? ? public void start(Stage primaryStage) throws Exception
? ? {
? ? ? ? //STUFF
? ? ? ? Group root = new Group();
? ? ? ? Scene scene = new Scene(root, 400, 400);
? ? ? ? scene.setFill(Color.GOLD);
? ? ? ? Canvas canvas = new Canvas(400, 400);
? ? ? ? GraphicsContext gc = canvas.getGraphicsContext2D();
? ? ? ? root.getChildren().add(canvas);
? ? ? ? //////////
? ? ? ? gc.fillRect(0, 200, 400, 1);
? ? ? ? gc.fillRect(0, 100, 400, 1);
? ? ? ? gc.fillRect(0, 300, 400, 1);
? ? ? ? gc.fillRect(200, 0, 1, 400);
? ? ? ? gc.fillRect(100, 0, 1, 400);
? ? ? ? gc.fillRect(300, 0, 1, 400);
? ? ? ? // drawRectangle(50, 50, 350, 250, primaryStage, gc);
? ? ? ? //drawLine(50, 250, 350, 250 , primaryStage, gc);
? ? ? ? //drawLine(50, 50, 350, 250, primaryStage, gc);
? ? ? ? //drawLine(50, 50, 50 , 250, primaryStage, gc);
? ? ? ? //drawLine(350, 50, 350 , 250, primaryStage, gc);
? ? ? ? drawLine(50, 50, 350, 50, primaryStage, gc);
? ? ? ? //////////
? ? ? ? primaryStage.setScene(scene);
? ? ? ? primaryStage.show();
? ? ? ? /////////
? ? }
? ? int squareWidth = 2;
? ? public ArrayList<Integer[]> calculateLine(int x1, int y1, int x2, int y2, GraphicsContext gc)
? ? {
? ? ? ? ArrayList<Integer[]> points = new ArrayList<Integer[]>();
? ? ? ? int dy = Math.abs(y2 - y1);
? ? ? ? int dx = Math.abs(x2 - x1);
? ? ? ? int sx = (x1 < x2) ? 1 : -1;
? ? ? ? int sy = (y1 < y2) ? 1 : -1;
? ? ? ? int err = dx - dy;
? ? ? ? int x = x1;
? ? ? ? int y = y1;
? ? ? ? int e2 = 0;
? ? ? ? Integer[] pos = new Integer[2];
? ? ? ? pos[0] = x;
? ? ? ? pos[1] = y;
? ? ? ? points.add(pos);
? ? ? ? int m = (dy >= dx) ? dy : dx;
? ? ? ? for (int i = 0; i <= m; i++) {
? ? ? ? ? ? e2 = 2 * err;
? ? ? ? ? ? if (e2 > -dy) {
? ? ? ? ? ? ? ? err = err - dy;
? ? ? ? ? ? ? ? x = x + sx;
? ? ? ? ? ? ? ? Integer[] position = new Integer[2];
? ? ? ? ? ? ? ? position[0] = x;
? ? ? ? ? ? ? ? position[1] = y;
? ? ? ? ? ? ? ? points.add(position);
? ? ? ? ? ? }
? ? ? ? ? ? if (e2 < dx) {
? ? ? ? ? ? ? ? err = err + dx;
? ? ? ? ? ? ? ? y = y + sy;
? ? ? ? ? ? ? ? Integer[] position = new Integer[2];
? ? ? ? ? ? ? ? position[0] = x;
? ? ? ? ? ? ? ? position[1] = y;
? ? ? ? ? ? ? ? points.add(position);
? ? ? ? ? ? }
? ? ? ? }
? ? ? ? return points;
? ? }
? ? public static void main(String[] args)
? ? {
? ? ? ? launch(args);
? ? }
}
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