Java:通过fillRect()绘制直方图 [英] Java: Paint a histogram via fillRect()

问题描述

我喜欢制作直方图.对于drawLine()来说，这对我来说并不是真正的问题，但是当我尝试使用fillRect()进行操作时，矩形会从上到下移动.我想用drawLine()绘制类似于我的直方图的直方图.

I like to make a histogram. With drawLine(), it's not really a problem for me, but when I try to do it with fillRect() the rectangles are going from top to bottom. I would like to paint the histogram looking similar to my histogram with drawLine().

这是我的代码:

public void paint(Graphics g) {

    super.paint(g); 
    int height = getHeight();
    int width = getWidth();
    int x =10;
    haufigkeit=model.getMap();
    for(int i = 1; i <= 45; i++) {
        int y;
        y = haufigkeit.get(i);            
        Color color = new Color(0, 0, (int)(150 + Math.random() * 100));
        g.setColor(color);

        // g.fillRect(x, 50, 10, y);

        // g.drawLine(x, height - 50, x, height- y);

        x+=20;
    }

}

需要更改什么?

推荐答案

但是当我尝试使用fillRect时，矩形从上到下."

"but when i try to do it with fillRect the Rectangles are going from top to bottom."

您需要考虑的几件事.

1. 水平线，例如，如果面板尺寸为500，则您希望水平线为450.因此，我们从此开始

1. A horizon line, for example if your panel size is 500, you'll want the horizon line to be something like 450. So let's start with that

int horizon = 450;

您需要考虑每个数据栏的高度.为此，您需要一个增量，让每个单位说5 px.因此，要获得高度，请将单位数量乘以增量量

You need to consider the height of each data bar. To do that you need an increment amount, lets just say for every unit, an increment of 5 px. So to get the height you multiply the number of units by the increment amount

int increment = 5;
...
int height = increment * units;

现在您所要做的就是从horizon中减去height，您便有了y的起点，而fillOval

Now all you need to do is subtract the height from the horizon and you have your y starting point for the fillOval

int y = horizon - height

---

 0  +---------------------
    |
    |
    |
    |    +----+   horizon - height = 150 = y point for fillRect
    |    |    |
    |    |    |
    |    |    |
 y  |    |    |   height = 300
    |    |    |
    |    |    |
    |    |    |
    |----------------------  450 horizon
    |
    +----------------------  500

g.fillRect(x, y, width, height);

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