A custom component that lets the user select a color. The available colors are bright, saturated colors in a full range of hues. The possible colors are shown in a strip. The user clicks on this strip to select a color. The selected color is hilited with a white frame. A program that uses this component can find out which color is currently selected by calling the getSelectedColor() method. The preferred size of this component is 108-by-24. There is a gray border around the component, two pixels wide on top and bottom and four pixels on left and right.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | /******************************************************* * MYCPLUS Sample Code - https://www.mycplus.com * * * * This code is made available as a service to our * * visitors and is provided strictly for the * * purpose of illustration. * * * * Please direct all inquiries to saqib at mycplus.com * *******************************************************/ // A custom component that lets the user select a color. // The available colors are bright, saturated colors in // a full range of hues. The possible colors are shown // in a strip. The user clicks on this strip to select // a color. The selected color is hilited with a white // frame. A program that uses this component can find // out which color is currently selected by calling // the getSelectedColor() method. The preferred size // of this component is 108-by-24. There is a // gray border around the component, two pixels wide // on top and bottom and four pixels on left and right. import java.awt.*; import java.awt.event.*; import javax.swing.*; class RainbowPalette extends JPanel implements MouseListener { /* The currently selected color is stored in the variable selectedColor. The hue of this color -- a float value in the range 0.0F to 1.0F is stored in selectedHue. The value of selectedHue is used to determine where to draw the hilite on the palette */ private float selectedHue = 0; private Color selectedColor = Color.getHSBColor(0,1,1); RainbowPalette() { // Constructor. Set the component to listen for mouse clicks // on itself, and set the preferred size. The gray background // color will show around the edges of the colored palette. addMouseListener(this); setPreferredSize( new Dimension(256, 24) ); setBackground(Color.gray); } public Color getSelectedColor() { // Return the color that is currently selected in the palette. return selectedColor; } public void paintComponent(Graphics g) { // Draw the palette, and add a white rectangle to hilite // the selected color. super.paintComponent(g); int width = getWidth(); int height = getHeight(); for (int i = 0; i < width - 8; i++) { float hue = (float)i / (width-8); g.setColor( Color.getHSBColor(hue, 1, 1) ); g.drawLine(i+4,4,i+4,height-5); } int x = 4 + (int)(selectedHue*(width-8)); // x-coord of selected color. g.setColor(Color.white); g.drawRect(x-2,3,2,height-7); // Draw the hilite. g.drawRect(x-3,2,4,height-5); } public void mousePressed(MouseEvent evt) { // When the user clicks on the component, select the // color that the user clicked. But make sure that // the selectedHue is in the legal range, 0 to 1. int x = evt.getX(); selectedHue = (float)x / (getSize().width - 4); if (selectedHue < 0) selectedHue = 0; else if (selectedHue > 1) selectedHue = 1; selectedColor = Color.getHSBColor(selectedHue, 1, 1); repaint(); } public void mouseReleased(MouseEvent evt) { } public void mouseClicked(MouseEvent evt) { } public void mouseEntered(MouseEvent evt) { } public void mouseExited(MouseEvent evt) { } } // end class RainbowPalette |
