Java:图形对齐字符串

Question

我目前正在尝试创建一个滚动文本方法，其中将采用String 参数。很快，它将开始从左到右绘制，并随着时间的推移进入新行，这样它就不会从屏幕上绘制出来。我正在使用 FontMetrics 来尝试实现我的目标。

我从主类中的渲染方法将参数传递给我的 RollingText.render(Graphics g, int x, int y) 。在我的 render 方法中，我开始设置 Graphics 字体和颜色，并获取所有 FontMetrics，然后我开始获取不同的内容来自FontMetrics。此外，我进入 for 循环将文本绘制到字符串中。

public void render(Graphics g, int x, int y) {
    // text is the field that a grab the index of the string from
    // the index is the max part of the string I'm grabbing from,
    // increments using the update() method
    String str = text.substring(0, index);
    String[] words = str.split(" ");

    Font f = new Font(g.getFont().getName(), 0, 24);
    FontMetrics fmetrics = g.getFontMetrics(f);
    g.setColor(Color.white);
    g.setFont(f);

    int line = 1;
    int charsDrawn = 0;
    int wordsDrawn = 0;
    int charWidth = fmetrics.charWidth('a');
    int fontHeight = fmetrics.getHeight();
    for (int i = 0; i < words.length; i++) {
        int wordWidth = fmetrics.stringWidth(words[i]);
        if (wordWidth* wordsDrawn + charWidth * charsDrawn > game.getWidth()) {
            line++;
            charsDrawn = 0;
            wordsDrawn = 0;
        }

        g.drawString(words[i], x * charsDrawn + charWidth, y + fontHeight * line);

        charsDrawn += words[i].length();
        wordsDrawn += 1;
    }
}

目前，此时一切都会正常工作，但剩下的问题是 drawString 方法中每个单词之间的空格被严重夸大，如下所示:

行:

g.drawString(words[i], x * charsDrawn + charWidth, y + fontHeight * line);

我目前遇到的唯一问题是找到正确的方法来计算 x 位置。目前，它的间距很大，并且根据字长动态变化，我不知道如何让它看起来至少正常。我已经尝试了与当前定义的整数的不同组合，等等。出现的问题可能包括不正确的间距、不适当的定位和闪烁，以及文本运行在一起。

最后，我的问题是，使用什么样的算法来帮助我正确定位 x 坐标，使文本看起来正确？

Answer 1

我不知道为什么你在简单地添加 FontMetrics#stringWidth 时尝试根据各种不同的变量来计算 x/y 位置或FontMetrics#getHeight在我看来，x/y 值会更简单......

您似乎也在使用 FontMetrics#stringWidth 之间切换并根据“样本”宽度计算单个字符的宽度... wordsDrawn + charWidth ，这使您的计算变得简单......令人困惑。您似乎也存在优先级问题...

不应该x * charsDrawn + charWidth是x + (charsDrawn * charWidth) ？

我实际上无法让您的示例代码重现您的结果，相反，我简化了它......

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class RenderText {

    public static void main(String[] args) {
        new RenderText();
    }

    public RenderText() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private String text;
        private int index;

        public TestPane() {
            text = "A long time ago, in a galaxy far, far, away..."
                    + "A vast sea of stars serves as the backdrop for the main title. "
                    + "War drums echo through the heavens as a rollup slowly crawls "
                    + "into infinity."
                    + "     It is a period of civil war. Rebel spaceships, "
                    + "     striking from a hidden base, have won their first "
                    + "     victory against the evil Galactic Empire."
                    + "     During the battle, Rebel spies managed to steal "
                    + "     secret plans to the Empire's ultimate weapon, the "
                    + "     Death Star, an armored space station with enough "
                    + "     power to destroy an entire planet."
                    + "     Pursued by the Empire's sinister agents, Princess "
                    + "     Leia races home aboard her starship, custodian of "
                    + "     the stolen plans that can save her people and "
                    + "     restore freedom to the galaxy...";

            index = text.length() - 1;
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            render(g, 0, 0);
            g2d.dispose();
        }

        public void render(Graphics g, int x, int y) {
            // text is the field that a grab the index of the string from
            // the index is the max part of the string I'm grabbing from,
            // increments using the update() method
            String str = text.substring(0, index);
            String[] words = str.split(" ");

            Font f = new Font(g.getFont().getName(), 0, 24);
            FontMetrics fmetrics = g.getFontMetrics(f);
//            g.setColor(Color.white);
            g.setFont(f);

            int fontHeight = fmetrics.getHeight();

            int spaceWidth = fmetrics.stringWidth(" ");

            int xPos = x;
            int yPos = y;
            for (String word : words) {
                int wordWidth = fmetrics.stringWidth(word);
                if (wordWidth + xPos > getWidth()) {
                    yPos += fontHeight;
                    xPos = x;
                }
                g.drawString(word, x + xPos, yPos + fmetrics.getAscent());
                xPos += wordWidth + spaceWidth;
            }
        }
    }

}

直到您可以提供实际的 runnable example that demonstrates your problem ，这是我能做的最好的了...