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In this custom border class, I define a RoundRectangle2D shape. This object is used to paint the border. Unfortunately, since the paint method of a JComponent invokes paintComponent before paintBorder, setting the Graphics clip to the RoundRectangle2D shape has no effect; even if I issue a repaint. Therefore, the component will paint outside it's border, which is understandably undesirable.
So, I was wondering: how do I get the component to paint exclusively inside a custom border?
One approach I considered was obtaining the component's Border object in the paintComponent method. And then casting this object to the appropriate class, wherein I define parameters that will influence the clip. But this didn't seem like a "sound" design.
Edit -
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.RenderingHints;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.border.AbstractBorder;
class JRoundedCornerBorder extends AbstractBorder
{
private static final long serialVersionUID = 7644739936531926341L;
private static final int THICKNESS = 2;
JRoundedCornerBorder()
{
super();
}
@Override
public void paintBorder(Component c, Graphics g, int x, int y, int width, int height)
{
Graphics2D g2 = (Graphics2D)g.create();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
if(c.hasFocus())
{
g2.setColor(Color.BLUE);
}
else
{
g2.setColor(Color.BLACK);
}
g2.setStroke(new BasicStroke(THICKNESS, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
g2.drawRoundRect(THICKNESS, THICKNESS, width - THICKNESS - 2, height - THICKNESS - 2, 20, 20);
g2.dispose();
}
@Override
public Insets getBorderInsets(Component c)
{
return new Insets(THICKNESS, THICKNESS, THICKNESS, THICKNESS);
}
@Override
public Insets getBorderInsets(Component c, Insets insets)
{
insets.left = insets.top = insets.right = insets.bottom = THICKNESS;
return insets;
}
public boolean isBorderOpaque() {
return false;
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
@Override
public void run()
{
final JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new FlowLayout());
// Add button with custom border
final JButton button = new JButton("Hello");
button.setBorder(new JRoundedCornerBorder());
button.setBackground(Color.YELLOW);
button.setPreferredSize(new Dimension(200, 200));
frame.add(button);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}
The red circles highlight where the component extends beyond it's border.
382
ahh ... at last I got it (missed the roundBorder for some reason, my fault :-) The button is simply complying to its contract: it states being opaque, so must fill its complete area, including that of the border. So setting a clip (which you could do in paintComponent) would make violate the contract:
// DO NOT - a opaque component violates its contract, as it will not fill
// its complete area
@Override
protected void paintComponent(Graphics g) {
if (getBorder() instanceof JRoundedCornerBorder) {
Shape borderShape = ((JRoundedCornerBorder) getBorder()).
getBorderShape(getWidth(), getHeight());
g.setClip(borderShape);
}
super.paintComponent(g);
}
Ugly but safe would be to report itself as transparent and take over the background painting yourself:
@Override
protected void paintComponent(Graphics g) {
if (getBorder() instanceof JRoundedCornerBorder) {
g.setColor(getBackground());
Shape borderShape = ((JRoundedCornerBorder) getBorder())
.getBorderShape(getWidth(), getHeight());
((Graphics2D) g).fill(borderShape);
}
super.paintComponent(g);
}
@Override
public boolean isContentAreaFilled() {
if (getBorder() instanceof JRoundedCornerBorder) return false;
return super.isContentAreaFilled();
}
// using
button.setOpaque(false);
not an answer to your question, just another idea how to do it
from very long code
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
import javax.swing.event.*;
public class Panel2Test {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
ShadeOptionsPanel shadeOptions = new ShadeOptionsPanel();
ShadowSelector shadowSelector = new ShadowSelector(shadeOptions);
//ComponentSource componentSource = new ComponentSource(shadeOptions);
JFrame f = new JFrame("Rounded Concept Demo with Shadows");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(shadowSelector, "North");
f.add(shadeOptions);
//f.add(componentSource, "South");
f.setSize(300, 200);
f.setLocation(150, 150);
f.setVisible(true);
}
});
}
private Panel2Test() {
}
}
class ShadeOptionsPanel extends JPanel {
private static final long serialVersionUID = 1L;
private final int PAD, DIA, BORDER;
private Color colorIn, colorOut;
private int xc, yc;
private Ellipse2D eIn, eOut;
private GradientPaint gradient;
private CustomPaint customPaint;
private Area arcBorder;
private int width, height;
private Point2D neOrigin, nwOrigin, swOrigin, seOrigin, neDiag, nwDiag, swDiag, seDiag;
private final static int NORTHEAST = 0, NORTHWEST = 1, SOUTHWEST = 2, SOUTHEAST = 3;
public int shadowVertex = 3;
public ShadeOptionsPanel() {
PAD = 25;
DIA = 75;
BORDER = 10;
colorIn = Color.black;
colorOut = getBackground();
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
width = getWidth();
height = getHeight();
g2.drawRoundRect(PAD, PAD, width - 2 * PAD, height - 2 * PAD, DIA, DIA);
calculateArcOrigins();
calculateCardinalDiagonals();
drawVertexArc(g2, shadowVertex);
switch (shadowVertex) {
case NORTHEAST:
drawNorthSide(g2);
drawEastSide(g2);
xc = PAD + DIA / 2; // draw northwest arc
yc = PAD + DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = getInnerEllipse(nwOrigin, nwDiag);
eOut = getOuterEllipse(nwOrigin, nwDiag);
arcBorder = getArcArea(eIn, eOut, 90.0);
g2.fill(arcBorder);
xc = width - PAD - DIA / 2; // draw southeast arc
yc = height - PAD - DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = getInnerEllipse(seOrigin, seDiag);
eOut = getOuterEllipse(seOrigin, seDiag);
arcBorder = getArcArea(eIn, eOut, 270.0);
g2.fill(arcBorder);
break;
case NORTHWEST:
drawNorthSide(g2);
drawWestSide(g2);
xc = width - PAD - DIA / 2;// draw northeast arc
yc = PAD + DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = getInnerEllipse(neOrigin, neDiag);
eOut = getOuterEllipse(neOrigin, neDiag);
arcBorder = getArcArea(eIn, eOut, 0.0);
g2.fill(arcBorder);
xc = PAD + DIA / 2;// draw southwest arc
yc = height - PAD - DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = getInnerEllipse(swOrigin, swDiag);
eOut = getOuterEllipse(swOrigin, swDiag);
arcBorder = getArcArea(eIn, eOut, 180.0);
g2.fill(arcBorder);
break;
case SOUTHWEST:
drawWestSide(g2);
drawSouthSide(g2);
xc = PAD + DIA / 2; // draw northwest arc
yc = PAD + DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = getInnerEllipse(nwOrigin, nwDiag);
eOut = getOuterEllipse(nwOrigin, nwDiag);
arcBorder = getArcArea(eIn, eOut, 90.0);
g2.fill(arcBorder);
xc = width - PAD - DIA / 2; // draw the southeast arc
yc = height - PAD - DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = getInnerEllipse(seOrigin, seDiag);
eOut = getOuterEllipse(seOrigin, seDiag);
arcBorder = getArcArea(eIn, eOut, 270.0);
g2.fill(arcBorder);
break;
case SOUTHEAST:
drawEastSide(g2);
drawSouthSide(g2);
xc = width - PAD - DIA / 2; // draw northeast arc
yc = PAD + DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = getInnerEllipse(neOrigin, neDiag);
eOut = getOuterEllipse(neOrigin, neDiag);
arcBorder = getArcArea(eIn, eOut, 0.0);
g2.fill(arcBorder);
xc = PAD + DIA / 2; // draw southwest arc
yc = height - PAD - DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = getInnerEllipse(swOrigin, swDiag);
eOut = getOuterEllipse(swOrigin, swDiag);
arcBorder = getArcArea(eIn, eOut, 180.0);
g2.fill(arcBorder);
}
}
private Ellipse2D getInnerEllipse(Point2D center, Point2D corner) {
return new Ellipse2D.Double(center.getX() - DIA / 2,
center.getY() - DIA / 2, DIA, DIA);
}
private Ellipse2D getOuterEllipse(Point2D center, Point2D corner) {
int w = DIA, h = DIA;
if (shadowVertex < 2) {
if (center.getY() > corner.getY()) {
h += 2 * BORDER;
} else {
w += 2 * BORDER;
}
} else if (center.getY() > corner.getY()) {
w += 2 * BORDER;
} else {
h += 2 * BORDER;
}
return new Ellipse2D.Double(center.getX() - w / 2, center.getY() - h / 2, w, h);
}
private Area getArcArea(Ellipse2D e1, Ellipse2D e2, double start) {
Arc2D arc1 = new Arc2D.Double(e1.getBounds2D(), start, 90.0, Arc2D.PIE);
Arc2D arc2 = new Arc2D.Double(e2.getBounds2D(), start, 90.0, Arc2D.PIE);
Area arc = new Area(arc2);
arc.subtract(new Area(arc1));
return arc;
}
private void drawNorthSide(Graphics2D g2) {
gradient = new GradientPaint(width / 2, PAD - BORDER, colorOut,
width / 2, PAD, colorIn);
g2.setPaint(gradient);
g2.fill(new Rectangle2D.Double(PAD + DIA / 2, PAD - BORDER,
width - 2 * (PAD + DIA / 2) + 1, BORDER));
}
private void drawWestSide(Graphics2D g2) {
gradient = new GradientPaint(PAD - BORDER, height / 2, colorOut,
PAD, height / 2, colorIn);
g2.setPaint(gradient);
g2.fill(new Rectangle2D.Double(PAD - BORDER, PAD + DIA / 2,
BORDER, height - 2 * (PAD + DIA / 2) + 1));
}
private void drawSouthSide(Graphics2D g2) {
gradient = new GradientPaint(width / 2, height - PAD, colorIn,
width / 2, height - PAD + BORDER, colorOut);
g2.setPaint(gradient);
g2.fill(new Rectangle2D.Double(PAD + DIA / 2, height - PAD,
width - 2 * (PAD + DIA / 2) + 1, BORDER));
}
private void drawEastSide(Graphics2D g2) {
gradient = new GradientPaint(width - PAD, height / 2, colorIn,
width - PAD + BORDER, height / 2, colorOut);
g2.setPaint(gradient);
g2.fill(new Rectangle2D.Double(width - PAD, PAD + DIA / 2,
BORDER, height - 2 * (PAD + DIA / 2) + 1));
}
/**
* Draws the central, full-shaded arc (opposite of the unshaded arc).
*/
private void drawVertexArc(Graphics2D g2, int index) {
switch (index) {
case NORTHEAST:
xc = width - PAD - DIA / 2;
yc = PAD + DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = new Ellipse2D.Double(width - PAD - DIA, PAD, DIA, DIA);
eOut = new Ellipse2D.Double(width - PAD - DIA - BORDER, PAD - BORDER,
DIA + 2 * BORDER, DIA + 2 * BORDER);
arcBorder = getArcArea(eIn, eOut, 0.0);
g2.fill(arcBorder);
break;
case NORTHWEST:
xc = PAD + DIA / 2;
yc = PAD + DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = new Ellipse2D.Double(PAD, PAD, DIA, DIA);
eOut = new Ellipse2D.Double(PAD - BORDER, PAD - BORDER,
DIA + 2 * BORDER, DIA + 2 * BORDER);
arcBorder = getArcArea(eIn, eOut, 90.0);
g2.fill(arcBorder);
break;
case SOUTHWEST:
xc = PAD + DIA / 2;
yc = height - PAD - DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = new Ellipse2D.Double(PAD, height - PAD - DIA, DIA, DIA);
eOut = new Ellipse2D.Double(PAD - BORDER, height - PAD - DIA - BORDER,
DIA + 2 * BORDER, DIA + 2 * BORDER);
arcBorder = getArcArea(eIn, eOut, 180.0);
g2.fill(arcBorder);
break;
case SOUTHEAST:
xc = width - PAD - DIA / 2;
yc = height - PAD - DIA / 2;
customPaint = new CustomPaint(xc, yc, new Point2D.Double(0, DIA / 2),
DIA / 2, BORDER, colorIn, colorOut);
g2.setPaint(customPaint);
eIn = new Ellipse2D.Double(width - PAD - DIA, height - PAD - DIA, DIA, DIA);
eOut = new Ellipse2D.Double(width - PAD - DIA - BORDER,
height - PAD - DIA - BORDER, DIA + 2 * BORDER, DIA + 2 * BORDER);
arcBorder = getArcArea(eIn, eOut, 270.0);
g2.fill(arcBorder);
}
}
private void calculateArcOrigins() {
neOrigin = new Point2D.Double(width - PAD - DIA / 2, PAD + DIA / 2);
nwOrigin = new Point2D.Double(PAD + DIA / 2, PAD + DIA / 2);
swOrigin = new Point2D.Double(PAD + DIA / 2, height - PAD - DIA / 2);
seOrigin = new Point2D.Double(width - PAD - DIA / 2, height - PAD - DIA / 2);
}
private void calculateCardinalDiagonals() {
neDiag = new Point2D.Double(neOrigin.getX()
+ DIA * Math.cos(Math.toRadians(45)) / 2,
neOrigin.getY() - DIA * Math.sin(Math.toRadians(45)) / 2);
nwDiag = new Point2D.Double(nwOrigin.getX()
+ DIA * Math.cos(Math.toRadians(135)) / 2,
nwOrigin.getY() - DIA * Math.sin(Math.toRadians(135)) / 2);
swDiag = new Point2D.Double(swOrigin.getX()
+ DIA * Math.cos(Math.toRadians(225)) / 2,
swOrigin.getY() - DIA * Math.sin(Math.toRadians(225)) / 2);
seDiag = new Point2D.Double(seOrigin.getX()
+ DIA * Math.cos(Math.toRadians(315)) / 2,
seOrigin.getY() - DIA * Math.sin(Math.toRadians(315)) / 2);
}
public Dimension getInnerSize() {
return new Dimension((int) nwOrigin.distance(neOrigin),
(int) nwOrigin.distance(swOrigin));
}
}
class ShadowSelector extends JPanel {
private static final long serialVersionUID = 1L;
private ShadeOptionsPanel soPanel;
private String[] directions = {"northeast", "northwest", "southwest", "southeast"};
public ShadowSelector(ShadeOptionsPanel sop) {
soPanel = sop;
final SpinnerListModel model = new SpinnerListModel(directions);
model.setValue(directions[3]);
JSpinner spinner = new JSpinner(model);
spinner.setPreferredSize(new Dimension(90, spinner.getPreferredSize().height));
spinner.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
String value = (String) model.getValue();
soPanel.shadowVertex = model.getList().indexOf(value);
soPanel.repaint();
}
});
add(new JLabel("shadow vertex", JLabel.RIGHT));
add(spinner);
}
}
class CustomPaint implements Paint {
Point2D originP, radiusP;
int radius, border;
Color colorIn, colorOut;
public CustomPaint(int x, int y, Point2D radiusP,
int radius, int border,
Color colorIn, Color colorOut) {
originP = new Point2D.Double(x, y);
this.radiusP = radiusP;
this.radius = radius;
this.border = border;
this.colorIn = colorIn;
this.colorOut = colorOut;
}
@Override
public PaintContext createContext(ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform xform, RenderingHints hints) {
Point2D xformOrigin = xform.transform(originP, null), xformRadius = xform.deltaTransform(radiusP, null);
return new CustomPaintContext(xformOrigin, xformRadius, radius, border, colorIn, colorOut);
}
@Override
public int getTransparency() {
int alphaIn = colorIn.getAlpha();
int alphaOut = colorOut.getAlpha();
return (((alphaIn & alphaOut) == 0xff) ? OPAQUE : TRANSLUCENT);
}
}
class CustomPaintContext implements PaintContext {
Point2D originP, radiusP;
Color colorIn, colorOut;
int radius, border;
public CustomPaintContext(Point2D originP, Point2D radiusP, int radius, int border, Color colorIn, Color colorOut) {
this.originP = originP;
this.radiusP = radiusP;
this.radius = radius;
this.border = border;
this.colorIn = colorIn;
this.colorOut = colorOut;
}
@Override
public void dispose() {
}
@Override
public ColorModel getColorModel() {
return ColorModel.getRGBdefault();
}
@Override
public Raster getRaster(int x, int y, int w, int h) {
WritableRaster raster = getColorModel().createCompatibleWritableRaster(w, h);
int[] data = new int[w * h * 4];
for (int j = 0; j < h; j++) {
for (int i = 0; i < w; i++) {
double distance = originP.distance(x + i, y + j);
double r = radiusP.distance(radius, radius);
double ratio = distance - r < 0 ? 0.0 : (distance - r) / border;
if (ratio > 1.0) {
ratio = 1.0;
}
int base = (j * w + i) * 4;
data[base + 0] = (int) (colorIn.getRed() + ratio * (colorOut.getRed() - colorIn.getRed()));
data[base + 1] = (int) (colorIn.getGreen() + ratio * (colorOut.getGreen() - colorIn.getGreen()));
data[base + 2] = (int) (colorIn.getBlue() + ratio * (colorOut.getBlue() - colorIn.getBlue()));
data[base + 3] = (int) (colorIn.getAlpha() + ratio * (colorOut.getAlpha() - colorIn.getAlpha()));
}
}
raster.setPixels(0, 0, w, h, data);
return raster;
}
}
How do you paint the border? Did you implement Border interface?
There are 3 methods to place all your border logic there
void paintBorder(Component c, Graphics g, int x, int y, int width, int height);
Insets getBorderInsets(Component c);
boolean isBorderOpaque();
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