计算单元格大小并绘制（与之间的线）他们
我想绘制一个网格，并在单元格中绘制东西（为了保持容易，只需填充它们）。 总的来说，我只是在一些面板尺寸下工作得非常好，单元距离它应该放置的位置大约1个像素（重叠线）。 TBH我没有做足够的计算来自己找到答案，所以我很抱歉，我真的不太清楚如何处理这个“错误”。
无论如何，这是代码：
public class Gui extends JFrame {
public static void main(String[] args) {
new Gui().setVisible(true);
}
public Gui() {
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
add(new JPanel() {
public static final int SIZE = 3;
/** Line thickness ratio to a block */
public static final float LINE_THICKNESS = 0.1f;
/** @return the width of a block. */
protected final int getBlockWidth() {
return getWidth() / SIZE;
}
/** @return the height of a block. */
protected final int getBlockHeight() {
return getHeight() / SIZE;
}
/** @return the width of a cell. */
protected final int getCellWidth() {
return (int) Math.ceil(getBlockWidth()*(1-LINE_THICKNESS));
}
/** @return the height of a cell. */
protected final int getCellHeight() {
return (int) Math.ceil(getBlockHeight()*(1-LINE_THICKNESS));
}
@Override
public void paintComponent(Graphics g) {
g.setColor(new Color(0, 0, 255, 100));
int lineWidth = (int) (LINE_THICKNESS * getBlockWidth());
int lineHeight = (int) (LINE_THICKNESS * getBlockHeight());
for(int i = 0; i <= SIZE; i++) {
g.fillRect(i * getBlockWidth() - lineWidth / 2, 0, lineWidth, getHeight());
g.fillRect(0, i * getBlockHeight() - lineHeight/2, getWidth(), lineHeight);
}
g.setColor(new Color(255, 0, 0, 100));
for(int i = 0; i < SIZE; i++) {
for(int j = 0; j < SIZE; j++) {
int x = j * getBlockWidth() + lineWidth/2;
int y = i * getBlockHeight() + lineHeight/2;
Graphics temp = g.create(x, y, getCellWidth(), getCellHeight());
drawCell(temp, i, j);
}
}
}
private void drawCell(Graphics g, int i, int j) {
g.fillRect(0, 0, getCellWidth(), getCellHeight());
}
});
setLocation(new Point(500, 200));
setSize(new Dimension(600, 600));
}
}
如果你运行它，你可能会明白我的意思。 我想不出一个好的解释。 起初我想我必须在x和y上加1，因为我想在线旁边画，但是这（显然）只是把问题转移到了另一边。
使用更大的SIZE（如30）来运行它会给我带来另一个错误，它会给双方留出空间。 我知道（或假设）这是因为我使用整数，但它并没有太大的交易。 但总是欢迎提供更好的方法（通常）。
有几种方法可以解决这个问题。 我不会给你代码，因为我相信（根据你问你的问题）你是那些喜欢自己思考和解决问题的人之一。
首先：首先在整个面板上绘制背景，然后绘制线条。 不会有线条，画面会稍微快一些。
第二种方式：绘图的顺序很重要。 您可以先安全地绘制背景（即使它重叠），然后用边框覆盖它。
第三种方式：不要使用整数。 使用花车或双打。 你所有的麻烦都会消失。
第四种方式：计算余数。 您可以预测何时绘制线条，何时不绘制线条，仔细想想。 预测并适当绘制。
您好，我有同样的问题，但我实现的解决方案受Java教程中的示例的启发，用于绘制多行文本，并使用文本API在单元格上绘制文本。
http://java.sun.com/docs/books/tutorial/2d/text/drawmulstring.html
import java.awt.Component;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.font.FontRenderContext;
import java.awt.font.LineBreakMeasurer;
import java.awt.font.TextLayout;
import java.text.AttributedCharacterIterator;
import java.text.AttributedString;
import java.text.BreakIterator;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.TableCellRenderer;
public class MultilineTableCell
implements TableCellRenderer {
class CellArea extends DefaultTableCellRenderer {
/**
*
*/
private static final long serialVersionUID = 1L;
private String text;
protected int rowIndex;
protected int columnIndex;
protected JTable table;
protected Font font;
private int paragraphStart,paragraphEnd;
private LineBreakMeasurer lineMeasurer;
public CellArea(String s, JTable tab, int row, int column,boolean isSelected) {
text = s;
rowIndex = row;
columnIndex = column;
table = tab;
font = table.getFont();
if (isSelected) {
setForeground(table.getSelectionForeground());
setBackground(table.getSelectionBackground());
}
}
public void paintComponent(Graphics gr) {
super.paintComponent(gr);
if ( text != null && !text.isEmpty() ) {
Graphics2D g = (Graphics2D) gr;
if (lineMeasurer == null) {
AttributedCharacterIterator paragraph = new AttributedString(text).getIterator();
paragraphStart = paragraph.getBeginIndex();
paragraphEnd = paragraph.getEndIndex();
FontRenderContext frc = g.getFontRenderContext();
lineMeasurer = new LineBreakMeasurer(paragraph,BreakIterator.getWordInstance(), frc);
}
float breakWidth = (float)table.getColumnModel().getColumn(columnIndex).getWidth();
float drawPosY = 0;
// Set position to the index of the first character in the paragraph.
lineMeasurer.setPosition(paragraphStart);
// Get lines until the entire paragraph has been displayed.
while (lineMeasurer.getPosition() < paragraphEnd) {
// Retrieve next layout. A cleverer program would also cache
// these layouts until the component is re-sized.
TextLayout layout = lineMeasurer.nextLayout(breakWidth);
// Compute pen x position. If the paragraph is right-to-left we
// will align the TextLayouts to the right edge of the panel.
// Note: this won't occur for the English text in this sample.
// Note: drawPosX is always where the LEFT of the text is placed.
float drawPosX = layout.isLeftToRight()
? 0 : breakWidth - layout.getAdvance();
// Move y-coordinate by the ascent of the layout.
drawPosY += layout.getAscent();
// Draw the TextLayout at (drawPosX, drawPosY).
layout.draw(g, drawPosX, drawPosY);
// Move y-coordinate in preparation for next layout.
drawPosY += layout.getDescent() + layout.getLeading();
}
table.setRowHeight(rowIndex,(int) drawPosY);
}
}
}
public Component getTableCellRendererComponent(
JTable table, Object value,boolean isSelected, boolean hasFocus, int row,int column
)
{
CellArea area = new CellArea(value.toString(),table,row,column,isSelected);
return area;
}
}
It resizes row heigth too but it does it well only when this renderer is used for a single column.
And this is the way I used to invoke it for render my table.
final int wordWrapColumnIndex = ...;
myTable = new JTable() {
public TableCellRenderer getCellRenderer(int row, int column) {
if (column == wordWrapColumnIndex ) {
return wordWrapRenderer;
}
else {
return super.getCellRenderer(row, column);
}
}
};
上一篇: Calculate cell sizes and draw (with lines in between) them