[英]Use geometric shapes as components
我試圖創建一個類似於Paint的應用程序,在其中必須使用一些基本形狀才能創建更復雜的形狀。
我將使用Swing。 我必須能夠將對象從一個JEditorPane
拖放到另一個。 我想使用直線或圓形之類的圖元。
我想知道的是-原語是否必須是Components才能拖放它們? 如果是這樣,我怎么能做到這一點?
我實際上計划在本周末在“ Playing With Shapes”上做一個博客條目。 我有一個可以根據Shape創建組件的類。 該組件可以直接使用:
ShapeComponent組件=新的ShapeComponent(shape,Color。???);
這是該代碼的早期版本:
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);
}
}
它將幫助您解決問題的組成部分。
JPanel
用作繪制形狀的區域 JPanel
,您無法前后JPanel
某些形狀。 因此,理想的選擇是使用JLayeredPane
以便在繪制后可以通過設置適當的Z順序來前后移動形狀。 JLayeredPane
添加一個新的JPanel
。 這樣做可以輕松地在多個JLayeredPane
內部和之間移動形狀。
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