我想知道是否可以使用渐变在图形面板上绘制弧线以及我将如何去做。
我的最终目标是将圆弧旋转一整圈，使其类似于旋转加载圈。但是，它不是加载栏。这将是自定义 JButton 的背景。
任何会产生类似效果的替代方案的建议将不胜感激。
这类似于 oi 想要绘制的内容。请记住，它将“旋转”
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1 回答
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public class TestArc {
public static void main(String[] args) {
new TestArc();
}
public TestArc() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
int radius = Math.min(getWidth(), getHeight());
int x = (getWidth() - radius) / 2;
int y = (getHeight() - radius) / 2;
RadialGradientPaint rgp = new RadialGradientPaint(
new Point(getWidth() / 2, getHeight() / 2),
radius,
new float[]{0f, 1f},
new Color[]{Color.RED, Color.YELLOW}
);
g2d.setPaint(rgp);
g2d.fill(new Arc2D.Float(x, y, radius, radius, 0, 45, Arc2D.PIE));
g2d.dispose();
}
}
}
您可能想查看2D 图形以获取更多信息
额外输入后更新
所以你想要一个锥形填充效果......
我的实现来自Harmonic Code，但我找不到直接引用它（我认为这是他（优秀）系列的一部分），但您可以在此处查看源代码
现在。我遇到了角度问题，因为看起来 0 从顶点（而不是左侧）开始，并且它不喜欢负角度......你可能会有更好的运气，但我所做的是在某个位置创建一个基本缓冲区我可以轻松开始工作，然后使用AffineTransformation...
public class TestArc {
public static void main(String[] args) {
new TestArc();
}
public TestArc() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private float angle = 0;
private float extent = 270;
private BufferedImage buffer;
public TestPane() {
Timer timer = new Timer(125, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
angle -= 5;
if (angle > 360) {
angle = 0;
}
repaint();
}
});
timer.setRepeats(true);
timer.setCoalesce(false);
timer.start();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
protected BufferedImage getBuffer() {
if (buffer == null) {
int radius = Math.min(getWidth(), getHeight());
int x = (getWidth() - radius) / 2;
int y = (getHeight() - radius) / 2;
buffer = new BufferedImage(radius, radius, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = buffer.createGraphics();
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
float startAngle = 0;
Color start = new Color(0, 128, 0, 128);
Color end = new Color(0, 128, 0, 0);
ConicalGradientPaint rgp = new ConicalGradientPaint(
true,
new Point(getWidth() / 2, getHeight() / 2),
0.5f,
new float[]{startAngle, extent},
new Color[]{start, end});
g2d.setPaint(rgp);
g2d.fill(new Arc2D.Float(x, y, radius, radius, startAngle + 90, -extent, Arc2D.PIE));
// g2d.fill(new Ellipse2D.Float(0, 0, radius, radius));
g2d.dispose();
g2d.dispose();
}
return buffer;
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
int radius = Math.min(getWidth(), getHeight());
int x = (getWidth()) / 2;
int y = (getHeight()) / 2;
BufferedImage buffer = getBuffer();
g2d.setTransform(AffineTransform.getRotateInstance(Math.toRadians(angle), x, y));
x = (getWidth() - buffer.getWidth()) / 2;
y = (getHeight() - buffer.getHeight()) / 2;
g2d.drawImage(buffer, x, y, this);
g2d.dispose();
}
}
public final class ConicalGradientPaint implements java.awt.Paint {
private final java.awt.geom.Point2D CENTER;
private final double[] FRACTION_ANGLES;
private final double[] RED_STEP_LOOKUP;
private final double[] GREEN_STEP_LOOKUP;
private final double[] BLUE_STEP_LOOKUP;
private final double[] ALPHA_STEP_LOOKUP;
private final java.awt.Color[] COLORS;
private static final float INT_TO_FLOAT_CONST = 1f / 255f;
/**
* Standard constructor which takes the FRACTIONS in values from 0.0f to
* 1.0f
*
* @param CENTER
* @param GIVEN_FRACTIONS
* @param GIVEN_COLORS
* @throws IllegalArgumentException
*/
public ConicalGradientPaint(final java.awt.geom.Point2D CENTER, final float[] GIVEN_FRACTIONS, final java.awt.Color[] GIVEN_COLORS) throws IllegalArgumentException {
this(false, CENTER, 0.0f, GIVEN_FRACTIONS, GIVEN_COLORS);
}
/**
* Enhanced constructor which takes the FRACTIONS in degress from 0.0f to
* 360.0f and also an GIVEN_OFFSET in degrees around the rotation CENTER
*
* @param USE_DEGREES
* @param CENTER
* @param GIVEN_OFFSET
* @param GIVEN_FRACTIONS
* @param GIVEN_COLORS
* @throws IllegalArgumentException
*/
public ConicalGradientPaint(final boolean USE_DEGREES, final java.awt.geom.Point2D CENTER, final float GIVEN_OFFSET, final float[] GIVEN_FRACTIONS, final java.awt.Color[] GIVEN_COLORS) throws IllegalArgumentException {
// Check that fractions and colors are of the same size
if (GIVEN_FRACTIONS.length != GIVEN_COLORS.length) {
throw new IllegalArgumentException("Fractions and colors must be equal in size");
}
final java.util.ArrayList<Float> FRACTION_LIST = new java.util.ArrayList<Float>(GIVEN_FRACTIONS.length);
final float OFFSET;
if (USE_DEGREES) {
final double DEG_FRACTION = 1f / 360f;
if (Double.compare((GIVEN_OFFSET * DEG_FRACTION), -0.5) == 0) {
OFFSET = -0.5f;
} else if (Double.compare((GIVEN_OFFSET * DEG_FRACTION), 0.5) == 0) {
OFFSET = 0.5f;
} else {
OFFSET = (float) (GIVEN_OFFSET * DEG_FRACTION);
}
for (float fraction : GIVEN_FRACTIONS) {
FRACTION_LIST.add((float) (fraction * DEG_FRACTION));
}
} else {
// Now it seems to work with rotation of 0.5f, below is the old code to correct the problem
// if (GIVEN_OFFSET == -0.5)
// {
// // This is needed because of problems in the creation of the Raster
// // with a angle offset of exactly -0.5
// OFFSET = -0.49999f;
// }
// else if (GIVEN_OFFSET == 0.5)
// {
// // This is needed because of problems in the creation of the Raster
// // with a angle offset of exactly +0.5
// OFFSET = 0.499999f;
// }
// else
{
OFFSET = GIVEN_OFFSET;
}
for (float fraction : GIVEN_FRACTIONS) {
FRACTION_LIST.add(fraction);
}
}
// Check for valid offset
if (OFFSET > 0.5f || OFFSET < -0.5f) {
throw new IllegalArgumentException("Offset has to be in the range of -0.5 to 0.5");
}
// Adjust fractions and colors array in the case where startvalue != 0.0f and/or endvalue != 1.0f
final java.util.List<java.awt.Color> COLOR_LIST = new java.util.ArrayList<java.awt.Color>(GIVEN_COLORS.length);
COLOR_LIST.addAll(java.util.Arrays.asList(GIVEN_COLORS));
// Assure that fractions start with 0.0f
if (FRACTION_LIST.get(0) != 0.0f) {
FRACTION_LIST.add(0, 0.0f);
final java.awt.Color TMP_COLOR = COLOR_LIST.get(0);
COLOR_LIST.add(0, TMP_COLOR);
}
// Assure that fractions end with 1.0f
if (FRACTION_LIST.get(FRACTION_LIST.size() - 1) != 1.0f) {
FRACTION_LIST.add(1.0f);
COLOR_LIST.add(GIVEN_COLORS[0]);
}
// Recalculate the fractions and colors with the given offset
final java.util.Map<Float, java.awt.Color> FRACTION_COLORS = recalculate(FRACTION_LIST, COLOR_LIST, OFFSET);
// Clear the original FRACTION_LIST and COLOR_LIST
FRACTION_LIST.clear();
COLOR_LIST.clear();
// Sort the hashmap by fraction and add the values to the FRACION_LIST and COLOR_LIST
final java.util.SortedSet<Float> SORTED_FRACTIONS = new java.util.TreeSet<Float>(FRACTION_COLORS.keySet());
final java.util.Iterator<Float> ITERATOR = SORTED_FRACTIONS.iterator();
while (ITERATOR.hasNext()) {
final float CURRENT_FRACTION = ITERATOR.next();
FRACTION_LIST.add(CURRENT_FRACTION);
COLOR_LIST.add(FRACTION_COLORS.get(CURRENT_FRACTION));
}
// Set the values
this.CENTER = CENTER;
COLORS = COLOR_LIST.toArray(new java.awt.Color[]{});
// Prepare lookup table for the angles of each fraction
final int MAX_FRACTIONS = FRACTION_LIST.size();
this.FRACTION_ANGLES = new double[MAX_FRACTIONS];
for (int i = 0; i < MAX_FRACTIONS; i++) {
FRACTION_ANGLES[i] = FRACTION_LIST.get(i) * 360;
}
// Prepare lookup tables for the color stepsize of each color
RED_STEP_LOOKUP = new double[COLORS.length];
GREEN_STEP_LOOKUP = new double[COLORS.length];
BLUE_STEP_LOOKUP = new double[COLORS.length];
ALPHA_STEP_LOOKUP = new double[COLORS.length];
for (int i = 0; i < (COLORS.length - 1); i++) {
RED_STEP_LOOKUP[i] = ((COLORS[i + 1].getRed() - COLORS[i].getRed()) * INT_TO_FLOAT_CONST) / (FRACTION_ANGLES[i + 1] - FRACTION_ANGLES[i]);
GREEN_STEP_LOOKUP[i] = ((COLORS[i + 1].getGreen() - COLORS[i].getGreen()) * INT_TO_FLOAT_CONST) / (FRACTION_ANGLES[i + 1] - FRACTION_ANGLES[i]);
BLUE_STEP_LOOKUP[i] = ((COLORS[i + 1].getBlue() - COLORS[i].getBlue()) * INT_TO_FLOAT_CONST) / (FRACTION_ANGLES[i + 1] - FRACTION_ANGLES[i]);
ALPHA_STEP_LOOKUP[i] = ((COLORS[i + 1].getAlpha() - COLORS[i].getAlpha()) * INT_TO_FLOAT_CONST) / (FRACTION_ANGLES[i + 1] - FRACTION_ANGLES[i]);
}
}
/**
* Recalculates the fractions in the FRACTION_LIST and their associated
* colors in the COLOR_LIST with a given OFFSET. Because the conical
* gradients always starts with 0 at the top and clockwise direction you
* could rotate the defined conical gradient from -180 to 180 degrees which
* equals values from -0.5 to +0.5
*
* @param FRACTION_LIST
* @param COLOR_LIST
* @param OFFSET
* @return Hashmap that contains the recalculated fractions and colors after
* a given rotation
*/
private java.util.HashMap<Float, java.awt.Color> recalculate(final java.util.List<Float> FRACTION_LIST, final java.util.List<java.awt.Color> COLOR_LIST, final float OFFSET) {
// Recalculate the fractions and colors with the given offset
final int MAX_FRACTIONS = FRACTION_LIST.size();
final java.util.HashMap<Float, java.awt.Color> FRACTION_COLORS = new java.util.HashMap<Float, java.awt.Color>(MAX_FRACTIONS);
for (int i = 0; i < MAX_FRACTIONS; i++) {
// Add offset to fraction
final float TMP_FRACTION = FRACTION_LIST.get(i) + OFFSET;
// Color related to current fraction
final java.awt.Color TMP_COLOR = COLOR_LIST.get(i);
// Check each fraction for limits (0...1)
if (TMP_FRACTION <= 0) {
FRACTION_COLORS.put(1.0f + TMP_FRACTION + 0.0001f, TMP_COLOR);
final float NEXT_FRACTION;
final java.awt.Color NEXT_COLOR;
if (i < MAX_FRACTIONS - 1) {
NEXT_FRACTION = FRACTION_LIST.get(i + 1) + OFFSET;
NEXT_COLOR = COLOR_LIST.get(i + 1);
} else {
NEXT_FRACTION = 1 - FRACTION_LIST.get(0) + OFFSET;
NEXT_COLOR = COLOR_LIST.get(0);
}
if (NEXT_FRACTION > 0) {
final java.awt.Color NEW_FRACTION_COLOR = getColorFromFraction(TMP_COLOR, NEXT_COLOR, (int) ((NEXT_FRACTION - TMP_FRACTION) * 10000), (int) ((-TMP_FRACTION) * 10000));
FRACTION_COLORS.put(0.0f, NEW_FRACTION_COLOR);
FRACTION_COLORS.put(1.0f, NEW_FRACTION_COLOR);
}
} else if (TMP_FRACTION >= 1) {
FRACTION_COLORS.put(TMP_FRACTION - 1.0f - 0.0001f, TMP_COLOR);
final float PREVIOUS_FRACTION;
final java.awt.Color PREVIOUS_COLOR;
if (i > 0) {
PREVIOUS_FRACTION = FRACTION_LIST.get(i - 1) + OFFSET;
PREVIOUS_COLOR = COLOR_LIST.get(i - 1);
} else {
PREVIOUS_FRACTION = FRACTION_LIST.get(MAX_FRACTIONS - 1) + OFFSET;
PREVIOUS_COLOR = COLOR_LIST.get(MAX_FRACTIONS - 1);
}
if (PREVIOUS_FRACTION < 1) {
final java.awt.Color NEW_FRACTION_COLOR = getColorFromFraction(TMP_COLOR, PREVIOUS_COLOR, (int) ((TMP_FRACTION - PREVIOUS_FRACTION) * 10000), (int) (TMP_FRACTION - 1.0f) * 10000);
FRACTION_COLORS.put(1.0f, NEW_FRACTION_COLOR);
FRACTION_COLORS.put(0.0f, NEW_FRACTION_COLOR);
}
} else {
FRACTION_COLORS.put(TMP_FRACTION, TMP_COLOR);
}
}
// Clear the original FRACTION_LIST and COLOR_LIST
FRACTION_LIST.clear();
COLOR_LIST.clear();
return FRACTION_COLORS;
}
/**
* With the START_COLOR at the beginning and the DESTINATION_COLOR at the
* end of the given RANGE the method will calculate and return the color
* that equals the given VALUE. e.g. a START_COLOR of BLACK (R:0, G:0, B:0,
* A:255) and a DESTINATION_COLOR of WHITE(R:255, G:255, B:255, A:255) with
* a given RANGE of 100 and a given VALUE of 50 will return the color that
* is exactly in the middle of the gradient between black and white which is
* gray(R:128, G:128, B:128, A:255) So this method is really useful to
* calculate colors in gradients between two given colors.
*
* @param START_COLOR
* @param DESTINATION_COLOR
* @param RANGE
* @param VALUE
* @return Color calculated from a range of values by given value
*/
public java.awt.Color getColorFromFraction(final java.awt.Color START_COLOR, final java.awt.Color DESTINATION_COLOR, final int RANGE, final int VALUE) {
final float SOURCE_RED = START_COLOR.getRed() * INT_TO_FLOAT_CONST;
final float SOURCE_GREEN = START_COLOR.getGreen() * INT_TO_FLOAT_CONST;
final float SOURCE_BLUE = START_COLOR.getBlue() * INT_TO_FLOAT_CONST;
final float SOURCE_ALPHA = START_COLOR.getAlpha() * INT_TO_FLOAT_CONST;
final float DESTINATION_RED = DESTINATION_COLOR.getRed() * INT_TO_FLOAT_CONST;
final float DESTINATION_GREEN = DESTINATION_COLOR.getGreen() * INT_TO_FLOAT_CONST;
final float DESTINATION_BLUE = DESTINATION_COLOR.getBlue() * INT_TO_FLOAT_CONST;
final float DESTINATION_ALPHA = DESTINATION_COLOR.getAlpha() * INT_TO_FLOAT_CONST;
final float RED_DELTA = DESTINATION_RED - SOURCE_RED;
final float GREEN_DELTA = DESTINATION_GREEN - SOURCE_GREEN;
final float BLUE_DELTA = DESTINATION_BLUE - SOURCE_BLUE;
final float ALPHA_DELTA = DESTINATION_ALPHA - SOURCE_ALPHA;
final float RED_FRACTION = RED_DELTA / RANGE;
final float GREEN_FRACTION = GREEN_DELTA / RANGE;
final float BLUE_FRACTION = BLUE_DELTA / RANGE;
final float ALPHA_FRACTION = ALPHA_DELTA / RANGE;
//System.out.println(DISTANCE + " " + CURRENT_FRACTION);
return new java.awt.Color(SOURCE_RED + RED_FRACTION * VALUE, SOURCE_GREEN + GREEN_FRACTION * VALUE, SOURCE_BLUE + BLUE_FRACTION * VALUE, SOURCE_ALPHA + ALPHA_FRACTION * VALUE);
}
@Override
public java.awt.PaintContext createContext(final java.awt.image.ColorModel COLOR_MODEL, final java.awt.Rectangle DEVICE_BOUNDS, final java.awt.geom.Rectangle2D USER_BOUNDS, final java.awt.geom.AffineTransform TRANSFORM, final java.awt.RenderingHints HINTS) {
final java.awt.geom.Point2D TRANSFORMED_CENTER = TRANSFORM.transform(CENTER, null);
return new ConicalGradientPaintContext(TRANSFORMED_CENTER);
}
@Override
public int getTransparency() {
return java.awt.Transparency.TRANSLUCENT;
}
private final class ConicalGradientPaintContext implements java.awt.PaintContext {
final private java.awt.geom.Point2D CENTER;
public ConicalGradientPaintContext(final java.awt.geom.Point2D CENTER) {
this.CENTER = new java.awt.geom.Point2D.Double(CENTER.getX(), CENTER.getY());
}
@Override
public void dispose() {
}
@Override
public java.awt.image.ColorModel getColorModel() {
return java.awt.image.ColorModel.getRGBdefault();
}
@Override
public java.awt.image.Raster getRaster(final int X, final int Y, final int TILE_WIDTH, final int TILE_HEIGHT) {
final double ROTATION_CENTER_X = -X + CENTER.getX();
final double ROTATION_CENTER_Y = -Y + CENTER.getY();
final int MAX = FRACTION_ANGLES.length;
// Create raster for given colormodel
final java.awt.image.WritableRaster RASTER = getColorModel().createCompatibleWritableRaster(TILE_WIDTH, TILE_HEIGHT);
// Create data array with place for red, green, blue and alpha values
int[] data = new int[(TILE_WIDTH * TILE_HEIGHT * 4)];
double dx;
double dy;
double distance;
double angle;
double currentRed = 0;
double currentGreen = 0;
double currentBlue = 0;
double currentAlpha = 0;
for (int py = 0; py < TILE_HEIGHT; py++) {
for (int px = 0; px < TILE_WIDTH; px++) {
// Calculate the distance between the current position and the rotation angle
dx = px - ROTATION_CENTER_X;
dy = py - ROTATION_CENTER_Y;
distance = Math.sqrt(dx * dx + dy * dy);
// Avoid division by zero
if (distance == 0) {
distance = 1;
}
// 0 degree on top
angle = Math.abs(Math.toDegrees(Math.acos(dx / distance)));
if (dx >= 0 && dy <= 0) {
angle = 90.0 - angle;
} else if (dx >= 0 && dy >= 0) {
angle += 90.0;
} else if (dx <= 0 && dy >= 0) {
angle += 90.0;
} else if (dx <= 0 && dy <= 0) {
angle = 450.0 - angle;
}
// Check for each angle in fractionAngles array
for (int i = 0; i < (MAX - 1); i++) {
if ((angle >= FRACTION_ANGLES[i])) {
currentRed = COLORS[i].getRed() * INT_TO_FLOAT_CONST + (angle - FRACTION_ANGLES[i]) * RED_STEP_LOOKUP[i];
currentGreen = COLORS[i].getGreen() * INT_TO_FLOAT_CONST + (angle - FRACTION_ANGLES[i]) * GREEN_STEP_LOOKUP[i];
currentBlue = COLORS[i].getBlue() * INT_TO_FLOAT_CONST + (angle - FRACTION_ANGLES[i]) * BLUE_STEP_LOOKUP[i];
currentAlpha = COLORS[i].getAlpha() * INT_TO_FLOAT_CONST + (angle - FRACTION_ANGLES[i]) * ALPHA_STEP_LOOKUP[i];
continue;
}
}
// Fill data array with calculated color values
final int BASE = (py * TILE_WIDTH + px) * 4;
data[BASE + 0] = (int) (currentRed * 255);
data[BASE + 1] = (int) (currentGreen * 255);
data[BASE + 2] = (int) (currentBlue * 255);
data[BASE + 3] = (int) (currentAlpha * 255);
}
}
// Fill the raster with the data
RASTER.setPixels(0, 0, TILE_WIDTH, TILE_HEIGHT, data);
return RASTER;
}
}
}
}
于 2013-01-20T05:56:28.103 回答