使用带有Swing的鼠标绘制(单色)数组的最简单方法是什么? [英] What's the easiest way to draw a (monochrome) array using a mouse with Swing?

问题描述

我一直在寻找在屏幕上绘制黑白阵列的方法.这是一个简单的数组，只有20x20.我计划做的是用鼠标绘制一个数组，以便每个像素在单击时从黑色到白色切换"并返回，然后将该数组作为一组布尔值(或整数)传递给另一个函数.目前，我正在使用Swing.我确实记得曾经使用Swing在画布上绘画，但是我仍然找不到实际的用法.我应该使用画布还是依靠JToggleButtons?

I've been searching for a way to draw a black-and-white array on screen. It's a simple array, just 20x20. What I plan to do is to draw on an array with the mouse so that each pixel "toggles" from black to white and back when clicked, then pass the array as a set of booleans (or integers) to another function. Currently I'm using Swing. I do remember to have used Swing for drawing on a canvas, but I still can't find the actual usage. Should I use a canvas, or instead rely on JToggleButtons?

推荐答案

您可以简单地使用 JFrame (或其他Swing组件)并覆盖 paint(Graphics)绘制布尔矩阵表示形式的方法(请注意，对于轻量级组件(例如 JPanel )，您应覆盖 paintComponent(Graphics).这将为您带来点击所需的拖放功能(使用单个Swing组件的网格很难实现).

You can simply use a JFrame (or other Swing component) and override the paint(Graphics) method to draw a representation of the boolean matrix (note that in the case of a lightweight component such as JPanel you should override paintComponent(Graphics). This will give you the click-and-drag capability you require (which is very difficult to achieve using a grid of individual Swing components).

正如其他人所评论的那样，AWT Canvas 并没有提供Swing组件未提供的任何内容，您将在下面的示例中看到我使用了 createBufferStrategy JFrame 上还提供了code>方法，以确保显示不闪烁.

As other people have commented, AWT Canvas doesn't give you anything not provided by Swing components and you'll see in the example below that I've used the createBufferStrategy method also present on JFrame to ensure a non-flicker display.

请注意，我的示例非常简单，它可以切换拖动的每个像素，而不是单击操作，从而确定您是处于绘画"模式还是擦除"模式，然后在整个持续时间内专门应用黑色或白色像素的阻力.

Note that my example is fairly simple in that it toggles every pixel you drag across rather than the click operation establishing whether you're in "paint" mode or "erase" mode and then exclusively applying black or white pixels for the duration of the drag.

public class Grid extends JFrame {
    private static final int SCALE = 10; // 1 boolean value == 10 x 10 pixels.
    private static final int SIZE = 20;

    private boolean[][] matrix = new boolean[SIZE][SIZE];
    private boolean painting;
    private int lastX = -1;
    private int lastY = -1;

    public Grid() throws HeadlessException {
        setPreferredSize(new Dimension(SIZE * SCALE, SIZE * SCALE));
        setResizable(false);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setBackground(Color.WHITE);

        addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent e) {
                painting = true;
                tryAdjustValue(e.getPoint());
            }

            public void mouseReleased(MouseEvent e) {
                painting = false;
                lastX = -1;
                lastY = -1;
            }
        });

        addMouseMotionListener(new MouseMotionListener() {
            public void mouseDragged(MouseEvent e) {
                tryAdjustValue(e.getPoint());
            }

            public void mouseMoved(MouseEvent e) {
                tryAdjustValue(e.getPoint());
            }
        });
    }

    private void tryAdjustValue(Point pt) {
        int newX = pt.x / SCALE;
        int newY = pt.y / SCALE;

        if (painting && isInRange(newX) && isInRange(newY) && (newX != lastX || newY != lastY)) {
            // Only invert "pixel" if we're currently in painting mode, both array indices are valid
            // and we're not attempting to adjust the same "pixel" as before (important for drag operations).
            matrix[newX][newY] = !matrix[newX][newY];
            lastX = newX;
            lastY = newY;
            repaint();
        }
    }

    private boolean isInRange(int val) {
        return val >= 0 && val < SIZE;
    }

    public void paint(Graphics g) {
        super.paint(g);

        for (int x=0; x<SIZE; ++x) {
            for (int y=0; y<SIZE; ++y) {
                if (matrix[x][y]) {
                    g.fillRect(x * SCALE, y * SCALE, SCALE, SCALE);
                }
            }
        }
    }

    public static void main(String[] args) {
        Grid grid = new Grid();
        grid.pack();
        grid.setLocationRelativeTo(null);
        grid.createBufferStrategy(2);
        grid.setVisible(true);
    }
}

这篇关于使用带有Swing的鼠标绘制(单色)数组的最简单方法是什么?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！