java - 如何将绘图上的 x 和 y 坐标转换为 GUI 上的像素

Question

我正在为显示在网格上的凸包 GUI 创建一个程序。以下代码是 GUI。

public class Plot extends JPanel{
    private int width = 1025;
    private int height = 500;
    private int padding = 50;
    private int labelPadding = 50;
    private Color lineColor = new Color(44, 102, 230, 180);
    private Color pointColor = new Color(100, 100, 100, 180);
    private Color gridColor = new Color(200, 200, 200, 200);
    private static final Stroke GRAPH_STROKE = new BasicStroke(2f);
    private int pointWidth = 4;
    private int numberYDivisions = 10;
    private Vector<Point> convexHull;
    private static DecimalFormat df = new DecimalFormat("0.00");
    private Point[] point;

    public Plot(Point[] point, Vector convexHull) {
        this.point=point;
        this.convexHull=convexHull;
    }

    @Override
        protected void paintComponent(Graphics g){
            super.paintComponent(g);
            Graphics2D g2 = (Graphics2D) g;

            double xScale = (maxX(point)+10)*2;
            double yScale = (maxY(point)+10)*2 ;
            List<Point> graphPoints =  new ArrayList<>();

            for(Point temp : convexHull){
                double x1 = temp.x;
                double y1 = temp.y;
                graphPoints.add(new Point(x1,y1));
            }

            double intervalY;
            intervalY = maxY(point)/5;

            g2.setColor(Color.WHITE);
            g2.fillRect(padding + labelPadding, padding, (int)xScale, (int)yScale);


            //Hatch marks for Y
        for(int i = 0;i<numberYDivisions/2;i++){
            if(point.length>0){
                g2.setColor(gridColor);
                g2.drawLine(padding+(100*i), padding, padding+(100*i), 1000);
                g2.setColor(Color.BLACK);
                String yLabel = df.format(maxY(point) - (intervalY * i)) + "";
                g2.drawLine(495, padding + (100 * i), 505, padding + (100 * i));
                g2.drawString(yLabel, 460, padding + (100 * i));

            }
        }
        for(int i = 0;i<=numberYDivisions/2;i++){
            if(point.length>0){
                g2.setColor(gridColor);
                g2.drawLine(500+padding+(100*i), padding, 500+padding+(100*i), 1000);
                g2.setColor(Color.BLACK);
                if(i!=0) {
                    String yLabel = df.format(0 - (intervalY * i)) + "";
                    g2.drawLine(495, 500 + (100 * (i)) - padding, 505, 500 + (100 * (i)) - padding);
                    g2.drawString(yLabel, 460, 500 + (100 * (i)) - padding);
                }
            }
        }

        Double intervalX;
        intervalX = maxX(point)/5;
        //Hatch marks and grid lines for x;
        for(int i = 0;i<numberYDivisions/2;i++){
            if(point.length>0){
                g2.setColor(gridColor);
                g2.drawLine(padding,padding+(100*i),1000,padding+(100*i));
                g2.setColor(Color.BLACK);
                String yLabel = df.format(-maxX(point) + (intervalX * i)) + "";
                g2.drawLine(padding + (100 * i), 495, padding + (100 * i), 505);
                g2.drawString(yLabel, padding + (100 * i), 480);
            }
        }
        for(int i = 0;i<=numberYDivisions/2;i++){
            if(point.length>0){
                g2.setColor(gridColor);
                g2.drawLine(padding,500+padding+(100*i),1000,500+padding+(100*i));
                if(i!=0) {
                    g2.setColor(Color.BLACK);
                    String yLabel = df.format(0 + (intervalX * i)) + "";
                    g2.drawLine(500 + (100 * i) - padding, 495, 500 + (100 * i) - padding, 505);
                    g2.drawString(yLabel, 500 + (100 * i) - padding, 480);
                }
            }
        }
        //x axis
        g2.drawLine(padding, 500, 1025-padding, 500);
        //y axis
        g2.drawLine(500,padding,500,1025-padding);



    }

    private double maxX(Point[] p){
        Double Max = Double.MIN_VALUE;
        for(int i = 0;i<p.length;i++){
            if(Max<p[i].x){
                Max = p[i].x;
            }
        }
        return Max;
    }

    private double minX(Point[] p){
        Double min = Double.MAX_VALUE;
        for(int i = 0;i<p.length;i++){
            if(min>p[i].x){
                min = p[i].x;
            }
        }
        return min;
    }

    private double maxY(Point[] p){
        Double Max = Double.MIN_VALUE;
        for(int i = 0;i<p.length;i++){
            if(Max<p[i].y){
                Max = p[i].y;
            }
        }
        return Max;
    }

    private double minY(Point[] p){
        Double min = Double.MAX_VALUE;
        for(int i = 0;i<p.length;i++){
            if(min>p[i].y){
                min = p[i].y;
            }
        }
        return min;
    }

在上面的代码中，点是从 CSV 文件中读取的，并使用 x 和 y 属性存储 point[]。为了正确显示该图，填充标记是根据 point[] 中的值计算的。但我不确定如何绘制每个点，因为创建椭圆需要屏幕上像素的 x 和 y 坐标，我不能只使用每个点的 x 和 y 坐标作为点的 x 和 y 坐标。有没有办法将 point[] 中的 x 和 y 坐标转换为像素 x 和 y 坐标？如有任何帮助，我们将不胜感激。

Answer 1

您需要分别根据数据的最大 x 和 y 以及面板的宽度和高度来放大或缩小它们。

如果您的data x最大x是xmax并且您的panel width是pwidth那么您需要乘以您的data x 坐标为pwidth/xmax。使用 double 类型执行此操作，然后根据需要转换为 int 类型。