GeneralPath class implements the Shape interface and represents a geometric path constructed from lines, and quadratic and cubic curves. The three constructors in this class can create the GeneralPath object with the default winding rule (WIND_NON_ZERO), the given winding rule (WIND_NON_ZERO or WIND_EVEN_ODD), or the specified initial coordinate capacity. The winding rule specifies how the interior of a path is determined.
public void Paint (Graphics g) {
Graphics2D g2 = (Graphics2D) g;
...
}
To create an empty GeneralPath instance call new GeneralPath() and then add segments to the shape by using the following methods:
· moveTo(float x, float y) – Moves the current point of the path to the given point
· lineTo(float x, float y) – Adds a line segment to the current path
· quadTo(float ctrlx, float ctrly, float x2, floaty2) – Adds a quadratic curve segment to the current path
· curveTo(float ctrlx1, float ctrly1, float ctrlx2, float ctrly2, float x3, floaty3) – Adds a cubic curve segment to the current path
· closePath() – Closes the current path
The following example illustrates how to draw a polyline by using GeneralPath:
| // draw GeneralPath (polyline) int x2Points[] = {0, 100, 0, 100}; int y2Points[] = {0, 50, 50, 0}; GeneralPath polyline = new GeneralPath(GeneralPath.WIND_EVEN_ODD, x2Points.length); polyline.moveTo (x2Points[0], y2Points[0]); for (int index = 1; index < x2Points.length; index++) { polyline.lineTo(x2Points[index], y2Points[index]); }; g2.draw(polyline); |
This example illustrates how to draw a polygon by using GeneralPath:
| // draw GeneralPath (polygon) int x1Points[] = {0, 100, 0, 100}; int y1Points[] = {0, 50, 50, 0}; GeneralPath polygon = new GeneralPath(GeneralPath.WIND_EVEN_ODD, x1Points.length); polygon.moveTo(x1Points[0], y1Points[0]); for (int index = 1; index < x1Points.length; index++) { polygon.lineTo(x1Points[index], y1Points[index]); }; polygon.closePath(); g2.draw(polygon); |
Note that the only difference between two last code examples is the closePath() method. This method makes a polygon from a polyline by drawing a straight line back to the coordinates of the last moveTo.
public BasicStroke(float width,
int cap,
int join,
float miterlimit,
float[] dash,
float dash_phase)
Constructs a new BasicStroke with the specified attributes.
Parameters:
width - the width of this BasicStroke. The width must be greater than or equal to 0.0f. If width is set to 0.0f, the stroke is rendered as the thinnest possible line for the target device and the antialias hint setting.
cap - the decoration of the ends of a BasicStroke
join - the decoration applied where path segments meet
miterlimit - the limit to trim the miter join. The miterlimit must be greater than or equal to 1.0f.
dash - the array representing the dashing pattern
dash_phase - the offset to start the dashing pattern
Throws:
IllegalArgumentException - if width is negative
IllegalArgumentException - if cap is not either CAP_BUTT, CAP_ROUND or CAP_SQUARE
IllegalArgumentException - if miterlimit is less than 1 and join is JOIN_MITER
IllegalArgumentException - if join is not either JOIN_ROUND, JOIN_BEVEL, or JOIN_MITER
IllegalArgumentException - if dash_phase is negative and dash is not null
IllegalArgumentException - if the length of dash is zero
IllegalArgumentException - if dash lengths are all zero.
public GradientPaint(float x1,
float y1,
Color color1,
float x2,
float y2,
Color color2)
Constructs a simple acyclic GradientPaint object.
Parameters:
x1 - x coordinate of the first specified Point in user space
y1 - y coordinate of the first specified Point in user space
color1 - Color at the first specified Point
x2 - x coordinate of the second specified Point in user space
y2 - y coordinate of the second specified Point in user space
color2 - Color at the second specified Point
Throws:
NullPointerException - if either one of colors is null
Stroke stroke = new BasicStroke(5.0f , // Width of stroke
BasicStroke.CAP_ROUND, // End cap style
BasicStroke.JOIN_MITER, // Join style
15.0f, // Miter limit
new float[] {10.0,10.0} // Dash pattern
5.0); // Dash phase
/* * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of Oracle or the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ import java.awt.*; import java.awt.event.*; import java.awt.geom.*; import javax.swing.*; /* * This is like the FontDemo applet in volume 1, except that it * uses the Java 2D APIs to define and render the graphics and text. */ public class ShapesDemo2D extends JApplet { final static int maxCharHeight = 15; final static int minFontSize = 6; final static Color bg = Color.white; final static Color fg = Color.black; final static Color red = Color.red; final static Color white = Color.white; final static BasicStroke stroke = new BasicStroke(2.0f); final static BasicStroke wideStroke = new BasicStroke(8.0f); final static float dash1[] = {10.0f}; final static BasicStroke dashed = new BasicStroke(1.0f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER, 10.0f, dash1, 0.0f); Dimension totalSize; FontMetrics fontMetrics; public void init() { //Initialize drawing colors setBackground(bg); setForeground(fg); } FontMetrics pickFont(Graphics2D g2, String longString, int xSpace) { boolean fontFits = false; Font font = g2.getFont(); FontMetrics fontMetrics = g2.getFontMetrics(); int size = font.getSize(); String name = font.getName(); int style = font.getStyle(); while ( !fontFits ) { if ( (fontMetrics.getHeight() <= maxCharHeight) && (fontMetrics.stringWidth(longString) <= xSpace) ) { fontFits = true; } else { if ( size <= minFontSize ) { fontFits = true; } else { g2.setFont(font = new Font(name, style, --size)); fontMetrics = g2.getFontMetrics(); } } } return fontMetrics; } public void paint(Graphics g) { Graphics2D g2 = (Graphics2D) g; g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); Dimension d = getSize(); int gridWidth = d.width / 6; int gridHeight = d.height / 2; fontMetrics = pickFont(g2, "Filled and Stroked GeneralPath", gridWidth); Color fg3D = Color.lightGray; g2.setPaint(fg3D); g2.draw3DRect(0, 0, d.width - 1, d.height - 1, true); g2.draw3DRect(3, 3, d.width - 7, d.height - 7, false); g2.setPaint(fg); int x = 5; int y = 7; int rectWidth = gridWidth - 2*x; int stringY = gridHeight - 3 - fontMetrics.getDescent(); int rectHeight = stringY - fontMetrics.getMaxAscent() - y - 2; // draw Line2D.Double g2.draw(new Line2D.Double(x, y+rectHeight-1, x + rectWidth, y)); g2.drawString("Line2D", x, stringY); x += gridWidth; // draw Rectangle2D.Double g2.setStroke(stroke); g2.draw(new Rectangle2D.Double(x, y, rectWidth, rectHeight)); g2.drawString("Rectangle2D", x, stringY); x += gridWidth; // draw RoundRectangle2D.Double g2.setStroke(dashed); g2.draw(new RoundRectangle2D.Double(x, y, rectWidth, rectHeight, 10, 10)); g2.drawString("RoundRectangle2D", x, stringY); x += gridWidth; // draw Arc2D.Double g2.setStroke(wideStroke); g2.draw(new Arc2D.Double(x, y, rectWidth, rectHeight, 90, 135, Arc2D.OPEN)); g2.drawString("Arc2D", x, stringY); x += gridWidth; // draw Ellipse2D.Double g2.setStroke(stroke); g2.draw(new Ellipse2D.Double(x, y, rectWidth, rectHeight)); g2.drawString("Ellipse2D", x, stringY); x += gridWidth; // draw GeneralPath (polygon) int x1Points[] = {x, x+rectWidth, x, x+rectWidth}; int y1Points[] = {y, y+rectHeight, y+rectHeight, y}; GeneralPath polygon = new GeneralPath(GeneralPath.WIND_EVEN_ODD, x1Points.length); polygon.moveTo(x1Points[0], y1Points[0]); for ( int index = 1; index < x1Points.length; index++ ) { polygon.lineTo(x1Points[index], y1Points[index]); }; polygon.closePath(); g2.draw(polygon); g2.drawString("GeneralPath", x, stringY); // NEW ROW x = 5; y += gridHeight; stringY += gridHeight; // draw GeneralPath (polyline) int x2Points[] = {x, x+rectWidth, x, x+rectWidth}; int y2Points[] = {y, y+rectHeight, y+rectHeight, y}; GeneralPath polyline = new GeneralPath(GeneralPath.WIND_EVEN_ODD, x2Points.length); polyline.moveTo (x2Points[0], y2Points[0]); for ( int index = 1; index < x2Points.length; index++ ) { polyline.lineTo(x2Points[index], y2Points[index]); }; g2.draw(polyline); g2.drawString("GeneralPath (open)", x, stringY); x += gridWidth; // fill Rectangle2D.Double (red) g2.setPaint(red); g2.fill(new Rectangle2D.Double(x, y, rectWidth, rectHeight)); g2.setPaint(fg); g2.drawString("Filled Rectangle2D", x, stringY); x += gridWidth; // fill RoundRectangle2D.Double GradientPaint redtowhite = new GradientPaint(x,y,red,x+rectWidth, y,white); g2.setPaint(redtowhite); g2.fill(new RoundRectangle2D.Double(x, y, rectWidth, rectHeight, 10, 10)); g2.setPaint(fg); g2.drawString("Filled RoundRectangle2D", x, stringY); x += gridWidth; // fill Arc2D g2.setPaint(red); g2.fill(new Arc2D.Double(x, y, rectWidth, rectHeight, 90, 135, Arc2D.OPEN)); g2.setPaint(fg); g2.drawString("Filled Arc2D", x, stringY); x += gridWidth; // fill Ellipse2D.Double redtowhite = new GradientPaint(x,y,red,x+rectWidth, y,white); g2.setPaint(redtowhite); g2.fill (new Ellipse2D.Double(x, y, rectWidth, rectHeight)); g2.setPaint(fg); g2.drawString("Filled Ellipse2D", x, stringY); x += gridWidth; // fill and stroke GeneralPath int x3Points[] = {x, x+rectWidth, x, x+rectWidth}; int y3Points[] = {y, y+rectHeight, y+rectHeight, y}; GeneralPath filledPolygon = new GeneralPath(GeneralPath.WIND_EVEN_ODD, x3Points.length); filledPolygon.moveTo(x3Points[0], y3Points[0]); for ( int index = 1; index < x3Points.length; index++ ) { filledPolygon.lineTo(x3Points[index], y3Points[index]); }; filledPolygon.closePath(); g2.setPaint(red); g2.fill(filledPolygon); g2.setPaint(fg); g2.draw(filledPolygon); g2.drawString("Filled and Stroked GeneralPath", x, stringY); } public static void main(String s[]) { JFrame f = new JFrame("ShapesDemo2D"); f.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) {System.exit(0);} }); JApplet applet = new ShapesDemo2D(); f.getContentPane().add("Center", applet); applet.init(); f.pack(); f.setSize(new Dimension(550,100)); f.setVisible(true); } }
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