如何使用图形在多行上输出字符串 [英] How to output a String on multiple lines using Graphics

问题描述

为了使用 g.drawString（）来绘制一些stings，我的程序重写了 public void paint（Graphics g，int x，int y）; someString，x + 10，y + 30）;

现在someString可能很长，因此可能不适合一行。

在多行上写文本的最佳方法是什么？例如，在一个矩形（x1，y1，x2，y2）中？

解决方案

感谢Epaga的暗示和一些网上的例子（不是很明显找到！我主要用打破用于文本布局的行），我可以使组件显示包装文本。它是不完整的，但至少它显示了预期的效果。

  class TextContainer extends JPanel 
 {
 private int m_width; 
 private int m_height; 
 private String m_text; 
 private AttributedCharacterIterator m_iterator; 
 private int m_start; 
 private int m_end; 
 
 public TextContainer（String text，int width，int height）
 {
 m_text = text; 
 m_width = width; 
 m_height = height; 
 
 AttributedString styledText = new AttributedString（text）; 
 m_iterator = styledText.getIterator（）; 
 m_start = m_iterator.getBeginIndex（）; 
 m_end = m_iterator.getEndIndex（）; 
} 
 
 public String getText（）
 {
 return m_text; 
} 
 
 public Dimension getPreferredSize（）
 {
 return new Dimension（m_width，m_height）; 
} 
 
 public void paint（Graphics g）
 {
 super.paintComponent（g）; 
 
 Graphics2D g2 =（Graphics2D）g; 
 FontRenderContext frc = g2.getFontRenderContext（）; 
 
 LineBreakMeasurer measurer = new LineBreakMeasurer（m_iterator，frc）; 
 measurer.setPosition（m_start）; 
 
 float x = 0，y = 0; 
 while（measurer.getPosition（）< m_end）
 {
 TextLayout layout = measurer.nextLayout（m_width）; 
 
 y + = layout.getAscent（）; 
 float dx = layout.isLeftToRight（）？ 
 0：m_width  -  layout.getAdvance（）; 
 
 layout.draw（g2，x + dx，y）; 
 y + = layout.getDescent（）+ layout.getLeading（）; 
} 
} 
} 
  

它适合一个圆圈（唉，没有理由，似乎）：

  public void paint（Graphics g）
 { 
 super.paintComponent（g）; 
 
 Graphics2D g2 =（Graphics2D）g; 
 FontRenderContext frc = g2.getFontRenderContext（）; 
 
 LineBreakMeasurer measurer = new LineBreakMeasurer（m_iterator，frc）; 
 measurer.setPosition（m_start）; 
 
 float y = 0; $（测试者.getPosition（）< m_end）
 {
 double ix = Math.sqrt（（m_width / 2-y）* y）; 
 float x = m_width / 2.0F  - （float）ix; 
 int width =（int）ix * 2; 
 
 TextLayout layout = measurer.nextLayout（width）; 
 
 y + = layout.getAscent（）; 
 float dx = layout.isLeftToRight（）？ 
 0：width  -  layout.getAdvance（）; 
 
 layout.draw（g2，x + dx，y）; 
 y + = layout.getDescent（）+ layout.getLeading（）; 
} 
} 
  

虽然我不太确定dx计算。

My Program overrides public void paint(Graphics g, int x, int y); in order to draw some stings using g.drawString(someString, x+10, y+30);

Now someString can be quite long and thus, it may not fit on one line.

What is the best way to write the text on multiple line.
For instance, in a rectangle (x1, y1, x2, y2)?

解决方案

Thanks to Epaga's hint and a couple of examples on the Net (not so obvious to find! I used mainly Break a Line for text layout), I could make a component to display wrapped text. It is incomplete, but at least it shows the intended effect.

class TextContainer extends JPanel
{
    private int m_width;
    private int m_height;
    private String m_text;
    private AttributedCharacterIterator m_iterator;
    private int m_start;
    private int m_end;

    public TextContainer(String text, int width, int height)
    {
        m_text = text;
        m_width = width;
        m_height = height;

        AttributedString styledText = new AttributedString(text);
        m_iterator = styledText.getIterator();
        m_start = m_iterator.getBeginIndex();
        m_end = m_iterator.getEndIndex();
    }

    public String getText()
    {
        return m_text;
    }

    public Dimension getPreferredSize()
    {
        return new Dimension(m_width, m_height);
    }

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

        Graphics2D g2 = (Graphics2D) g;
        FontRenderContext frc = g2.getFontRenderContext();

        LineBreakMeasurer measurer = new LineBreakMeasurer(m_iterator, frc);
        measurer.setPosition(m_start);

        float x = 0, y = 0;
        while (measurer.getPosition() < m_end)
        {
            TextLayout layout = measurer.nextLayout(m_width);

            y += layout.getAscent();
            float dx = layout.isLeftToRight() ?
                    0 : m_width - layout.getAdvance();

            layout.draw(g2, x + dx, y);
            y += layout.getDescent() + layout.getLeading();
        }
    }
}

Just for fun, I made it fitting a circle (alas, no justification, it seems):

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

    Graphics2D g2 = (Graphics2D) g;
    FontRenderContext frc = g2.getFontRenderContext();

    LineBreakMeasurer measurer = new LineBreakMeasurer(m_iterator, frc);
    measurer.setPosition(m_start);

    float y = 0;
    while (measurer.getPosition() < m_end)
    {
        double ix = Math.sqrt((m_width / 2 - y) * y);
        float x = m_width / 2.0F - (float) ix;
        int width = (int) ix * 2;

        TextLayout layout = measurer.nextLayout(width);

        y += layout.getAscent();
        float dx = layout.isLeftToRight() ?
                0 : width - layout.getAdvance();

        layout.draw(g2, x + dx, y);
        y += layout.getDescent() + layout.getLeading();
    }
}

I am not too sure about dx computation, though.

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