[英]Use geometric shapes as components
我试图创建一个类似于Paint的应用程序,在其中必须使用一些基本形状才能创建更复杂的形状。
我将使用Swing。 我必须能够将对象从一个JEditorPane
拖放到另一个。 我想使用直线或圆形之类的图元。
我想知道的是-原语是否必须是Components才能拖放它们? 如果是这样,我怎么能做到这一点?
我实际上计划在本周末在“ Playing With Shapes”上做一个博客条目。 我有一个可以根据Shape创建组件的类。 该组件可以直接使用:
ShapeComponent组件=新的ShapeComponent(shape,Color。???);
这是该代码的早期版本:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Shape;
import javax.swing.JComponent;
/**
* A component that will paint a Shape object. Click detection will be
* determined by the Shape itself, not the bounding Rectangle of the Shape.
*
* Shape objects can be created with an X/Y offset. These offsets will
* be ignored and the Shape will always be painted at (0, 0) so the Shape is
* fully contained within the component.
*
* The foreground color will be used to "fill" the Shape.
*/
public class ShapeComponent extends JComponent
{
private Shape shape;
private boolean antiAliasing = true;
/**
* Create a ShapeComponent that is painted black.
*
* @param shape the Shape to be painted
*/
public ShapeComponent(Shape shape)
{
this(shape, Color.BLACK);
}
/**
* Create a ShapeComponent that is painted filled and outlined.
*
* @param shape the Shape to be painted
* @param color the color of the Shape
*/
public ShapeComponent(Shape shape, Color color)
{
setShape( shape );
setForeground( color );
setOpaque( false );
}
/**
* Get the Shape of the component
*
* @returns the the Shape of the compnent
*/
public Shape getShape()
{
return shape;
}
/**
* Set the Shape for this component
*
* @param shape the Shape of the component
*/
public void setShape(Shape shape)
{
this.shape = shape;
revalidate();
repaint();
}
/**
* Use AntiAliasing when painting the shape
*
* @returns true for AntiAliasing false otherwise
*/
public boolean isAntiAliasing()
{
return antiAliasing;
}
/**
* Set AntiAliasing property for painting the Shape
*
* @param antiAliasing true for AntiAliasing, false otherwise
*/
public void setAntiAliasing(boolean antiAliasing)
{
this.antiAliasing = antiAliasing;
revalidate();
repaint();
}
/**
* {@inheritDoc}
*/
@Override
public Dimension getPreferredSize()
{
// Include Border insets and Shape bounds
Insets insets = getInsets();
Rectangle bounds = shape.getBounds();
// Determine the preferred size
int width = insets.left + insets.right + bounds.width;
int height = insets.top + insets.bottom + bounds.height;
return new Dimension(width, height);
}
/**
* {@inheritDoc}
*/
@Override
public Dimension getMinimumSize()
{
return getPreferredSize();
}
/**
* {@inheritDoc}
*/
@Override
public Dimension getMaximumSize()
{
return getPreferredSize();
}
@Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
// Graphics2D is required for antialiasing and painting Shapes
Graphics2D g2d = (Graphics2D)g.create();
if (isAntiAliasing())
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// Shape translation (ie. non-zero X/Y position in bounding rectangle)
// and Border insets.
Rectangle bounds = shape.getBounds();
Insets insets = getInsets();
// Do all translations at once
g2d.translate(insets.left - bounds.x, insets.top - bounds.y);
// Fill the Shape
g2d.fill( shape );
g2d.dispose();
}
/**
* Determine if the point is in the bounds of the Shape
*
* {@inheritDoc}
*/
@Override
public boolean contains(int x, int y)
{
Rectangle bounds = shape.getBounds();
Insets insets = getInsets();
// Check to see if the Shape contains the point. Take into account
// the Shape X/Y coordinates, Border insets and Shape translation.
int translateX = x + bounds.x - insets.left;
int translateY = y + bounds.y - insets.top;
return shape.contains(translateX, translateY);
}
}
它将帮助您解决问题的组成部分。
JPanel
用作绘制形状的区域 JPanel
,您无法前后JPanel
某些形状。 因此,理想的选择是使用JLayeredPane
以便在绘制后可以通过设置适当的Z顺序来前后移动形状。 JLayeredPane
添加一个新的JPanel
。 这样做可以轻松地在多个JLayeredPane
内部和之间移动形状。
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