如何让条形图中的条形图从java中的x轴开始？ [英] How to get the bars in a bar chart start from the x-axis in java?

问题描述

如图所示，图表中的条形图从x轴下方开始。如何修复它，从x轴线开始？请建议我一个修复，我也会帮助我知道我在哪里错了。

  private int PAD = 20; 
 private int LPAD = 35; 
 private int DPAD = 25; 
 Graphics2D g2 =（Graphics2D）g; 
 
 g2.setColor（Color.BLACK）; 
 
 String DataString [] = dataset.split（，）; 
 
 double DataArray [] = new double [DataString.length]; 
 
 double MaxValue = 0; 
 int w = getWidth（）; 
 int h = getHeight（）; （int i = 0; i< DataString.length; i = i + 1）
 
 {
 
 try {
 
 double out = Double.parseDouble（DataString [I]）; 
 
 DataArray [i] = out; 
 
 if（out> MaxValue）{
 
 MaxValue = out; 
 
} 
 
 
} catch（NumberFormatException e）{
 
} 
 
} 
 
 double xScale =（w  -  1 *（PAD + LPAD））/（DataArray.length） -  1; 
 double yScale =（h  -  3 * DPAD）/ MaxValue; 
 //初始x，y（0）。 
 int x0 = LPAD; 
 
 try {
 if（DataArray.length> 1）{
 
 //绘制图
 g2.drawLine（PAD + LPAD，PAD， PAD + LPAD，h  - （PAD + LPAD））; 
 g2.drawLine（PAD + LPAD，h  -  PAD  -  LPAD，x0 +（int）（DataArray.length * xScale），h  - （PAD + LPAD））; 
颜色cd = new Color（135，90，185）; 
 g2.setPaint（cd）; 
 g2.drawString（title，w / 4，padding  -  15）; 
 g2.drawString（xAxis，w / 2  -  padding，h  - （padding  -  10））; 
 g2.rotate（Math.toRadians（270））; 
 g2.drawString（yAxis， - （h / 2 + padding） -  LPAD，PAD  -  5）; 
 g2.rotate（-Math.toRadians（270））; 
 
 g2.setPaint（Color.BLACK）; 
 double intin = Double.parseDouble（interval）; 
 double sin = Double.parseDouble（start）; （int j = 0; j< DataArray.length; j ++）{
 
 int x1 = x0 +（int）（j * xScale）+ PAD; 
 double y1 =（int）（（MaxValue  -  DataArray [j]）* yScale + PAD） -  2; 
 // g2.drawLine（x1-3，（int）y1-3，x1 + 3，（int）y1 + 3）; 
 // g2.drawLine（x1-3，（int）y1 + 3，x1 + 3，（int）y1-3）; 
 
 // g2.drawLine（x1，h  - （PAD + LPAD），x1，h  - （PAD + 
 // LPAD）+5）; 
 
 double intout =（sin +（intin * j））; 
 String interval = String.valueOf（intout）; 
 
 g2.drawString（interval，x1，h  -  LPAD）; （int i = 0; i< 9; i ++）{
} 
 
 {
 int x3 = PAD + LPAD; 
 int x1 = x3  -  5; 
 int y0 =（h  - （PAD）） - （（（i + 1）*（h  -  PAD * 3））/ 10 + DPAD） 
 int y3 = y0; 
 g2.drawLine（x3，y0，x1，y3）; 
 
 
 // g2.drawLine（PAD + LPAD，h  - （PAD + LPAD），PAD + LPAD  -  5，
 // h  - （PAD + LPAD） ）; 
 g2.drawLine（PAD + LPAD，PAD，PAD + LPAD  -  5，PAD）; 
 g2.drawString（start，LPAD  -  20，h  - （LPAD） -  20）; 
 
 Long L = Math.round（MaxValue）; 
 int MVi = Integer.valueOf（L.intValue（））; 
 String MVstring = String.valueOf（MVi）; 
 int MVmid = MVi / 2; 
 String MVmidstring = String.valueOf（MVmid）; 
 
 g2.drawString（MVmidstring，PAD，（h  -  PAD）/ 2）; 
 g2.drawString（MVstring，PAD，PAD）; 
 
 
 
 g2.setColor（Color.red）; （int j = 0; j< DataArray.length; j ++）{
 
 int x1 = x0 +（int）（j * xScale）+ PAD; 
 double y1 =（int）（（MaxValue  -  DataArray [j]）* yScale + PAD） -  2; 
 g2.fillRect（x1 + 2，（int）y1 + 1，w  - （PAD * 42），h）; 
 
} 
 
} 
} catch（异常e）{
 
} 
} 
 repaint（） ; 
 
} 
  

解决方案

你如何通常在x轴上放置一个酒吧？

一个酒吧的 fillRect （）参数应该是 left ， top ， width 和 height 。您只需要垂直尺寸和位置，如

要了解如何实现其他功能，请研究图表库提供的代码，如此回答< a>您以前关于此主题的问题。

As you can see in the picture, the bars in the chart starts below the x-axis. How do I fix it so that it starts from the x-axis line? Please suggest me a fix and also I would be helpful to know where I am going wrong.

    private int PAD = 20;
private int LPAD = 35;
private int DPAD = 25;
Graphics2D g2 = (Graphics2D) g;

        g2.setColor(Color.BLACK);

        String DataString[] = dataset.split(", ");

        double DataArray[] = new double[DataString.length];

        double MaxValue = 0;
        int w = getWidth();
        int h = getHeight();

        for (int i = 0; i < DataString.length; i = i + 1) {

            try {

                double out = Double.parseDouble(DataString[i]);

                DataArray[i] = out;

                if (out > MaxValue) {

                    MaxValue = out;

                }


            } catch (NumberFormatException e) {

            }

        }

        double xScale = (w - 1 * (PAD + LPAD)) / (DataArray.length) - 1;
        double yScale = (h - 3 * DPAD) / MaxValue;
        // The initial x,y (0).
        int x0 = LPAD;

        try {
            if (DataArray.length > 1) {

                // Draw Graph
                g2.drawLine(PAD + LPAD, PAD, PAD + LPAD, h - (PAD + LPAD));
                g2.drawLine(PAD + LPAD, h - PAD - LPAD, x0 + (int) (DataArray.length * xScale), h - (PAD + LPAD));
                Color cd = new Color(135, 90, 185);
                g2.setPaint(cd);
                g2.drawString(title, w / 4, padding - 15);
                g2.drawString(xAxis, w / 2 - padding, h - (padding - 10));
                g2.rotate(Math.toRadians(270));
                g2.drawString(yAxis, -(h / 2 + padding) - LPAD, PAD - 5);
                g2.rotate(-Math.toRadians(270));

                g2.setPaint(Color.BLACK);
                double intin = Double.parseDouble(interval);
                double sin = Double.parseDouble(start);

                for (int j = 0; j < DataArray.length; j++) {

                    int x1 = x0 + (int) (j * xScale) + PAD;
                    double y1 = (int) ((MaxValue - DataArray[j]) * yScale + PAD) - 2;
                    // g2.drawLine(x1-3, (int) y1-3, x1+3, (int) y1+3);
                    // g2.drawLine(x1-3,(int) y1+3,x1+3,(int) y1-3);

                    // g2.drawLine(x1, h - (PAD + LPAD), x1, h - (PAD +
                    // LPAD)+5);

                    double intout = (sin + (intin * j));
                    String interval = String.valueOf(intout);

                    g2.drawString(interval, x1, h - LPAD);
                }

                for (int i = 0; i < 9; i++) {
                    int x3 = PAD + LPAD;
                    int x1 = x3 - 5;
                    int y0 = (h - (PAD)) - (((i + 1) * (h - PAD * 3)) / 10 + DPAD) - 2;
                    int y3 = y0;
                    g2.drawLine(x3, y0, x1, y3);
                }

                // g2.drawLine(PAD + LPAD, h - (PAD + LPAD), PAD + LPAD - 5,
                // h - (PAD + LPAD));
                g2.drawLine(PAD + LPAD, PAD, PAD + LPAD - 5, PAD);
                g2.drawString(start, LPAD - 20, h - (LPAD) - 20);

                Long L = Math.round(MaxValue);
                int MVi = Integer.valueOf(L.intValue());
                String MVstring = String.valueOf(MVi);
                int MVmid = MVi / 2;
                String MVmidstring = String.valueOf(MVmid);

                g2.drawString(MVmidstring, PAD, (h - PAD) / 2);
                g2.drawString(MVstring, PAD, PAD);



                g2.setColor(Color.red);
                for (int j = 0; j < DataArray.length; j++) {

                    int x1 = x0 + (int) (j * xScale) + PAD;
                    double y1 = (int) ((MaxValue - DataArray[j]) * yScale + PAD) - 2;
                    g2.fillRect(x1 + 2, (int) y1 + 1 , w - (PAD * 42), h);

                }

            }
        } catch (Exception e) {

        }
    }
    repaint();

}

解决方案

How do you normally position a bar over the x-axis?

A bar's fillRect() parameters should be left, top, width and height. Focusing on just the vertical size and position, as shown here, you can scale the bar height to the plot area height using a proportion:

barHeightInPixels : plotHeightInPixels :: value : maxDataValue

Solving for barHeightInPixels,

panelHeightInPixels = panel.getHeight();
plotHeightInPixels  = panelHeightInPixels - axisOffset;
barHeightInPixels   = value * plotHeightInPixels / maxDataValue;

Now use the scaled height:

g2.fillRect(
    barCenter - (barWidth / 2),                           //left
    panelHeightInPixels - barHeightInPixels - axisOffset, //top
    barWidth,                                             //width
    barHeightInPixels);                                   //height

To see how additional features are implemented, study the code provided by a chart library, as suggested in this answer to your previous question on this topic.

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