A ColorChooserApplet shows six scroll bars that the user can manipulate to set the red, gree, blue, hue, brightness, and saturation components of a color. A color patch shows the selected color, and there are six labels that show the numerical values of all the components. RGB components are specified as integers in the range 0 to 255.
HSB components are specified as float values in the range 0.0F to 1.0F.
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 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 | /******************************************************* * 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 * *******************************************************/ import java.awt.*; import java.awt.event.*; import java.applet.*; public class ColorChooserApplet extends Applet implements AdjustmentListener { private float[] hsb = new float[3]; // For holding HSB color components. private int r = 0, g = 0, b = 0; // The RGB color components. private Scrollbar hueScroll, brightnessScroll, saturationScroll, // Scroll bars. redScroll, greenScroll, blueScroll; private Label hueLabel, brightnessLabel, saturationLabel, // Display component values. redLabel, greenLabel, blueLabel; private Canvas colorCanvas; // Color patch for displaying the color. public void init() { Color.RGBtoHSB(0,0,0,hsb); // Get HSB equivalent of RGB = (0,0,0); /* Create Scrollbars with possible values from 0 to 255. */ hueScroll = new Scrollbar(Scrollbar.HORIZONTAL, (int)(255*hsb[0]), 10, 0, 265); saturationScroll = new Scrollbar(Scrollbar.HORIZONTAL, (int)(255*hsb[1]), 10, 0, 265); brightnessScroll = new Scrollbar(Scrollbar.HORIZONTAL, (int)(255*hsb[2]), 10, 0, 265); redScroll = new Scrollbar(Scrollbar.HORIZONTAL, 0, 10, 0, 265); greenScroll = new Scrollbar(Scrollbar.HORIZONTAL, 0, 10, 0, 265); blueScroll = new Scrollbar(Scrollbar.HORIZONTAL, 0, 10, 0, 265); /* Create Labels showing current RGB and HSB values. */ hueLabel = new Label(" H = " + hsb[0]); saturationLabel = new Label(" S = " + hsb[1]); brightnessLabel = new Label(" B = " + hsb[2]); redLabel = new Label(" R = 0"); greenLabel = new Label(" G = 0"); blueLabel = new Label(" B = 0"); /* Set background colors for Scrollbars and Labels, so they don't inherit the gray background of the applet. */ hueScroll.setBackground(Color.lightGray); saturationScroll.setBackground(Color.lightGray); brightnessScroll.setBackground(Color.lightGray); redScroll.setBackground(Color.lightGray); greenScroll.setBackground(Color.lightGray); blueScroll.setBackground(Color.lightGray); hueLabel.setBackground(Color.white); saturationLabel.setBackground(Color.white); brightnessLabel.setBackground(Color.white); redLabel.setBackground(Color.white); greenLabel.setBackground(Color.white); blueLabel.setBackground(Color.white); /* Set the applet to listen for changes to the Scrollbars' values */ hueScroll.addAdjustmentListener(this); saturationScroll.addAdjustmentListener(this); brightnessScroll.addAdjustmentListener(this); redScroll.addAdjustmentListener(this); greenScroll.addAdjustmentListener(this); blueScroll.addAdjustmentListener(this); /* Create a canvas whose background color will always be set to the currently selected color. */ colorCanvas = new Canvas(); colorCanvas.setBackground(Color.black); /* Create the applet format, which consists of a row of three equal-sized regions holding the Scrollbars, the Labels, and the color patch. The background color of the applet is gray, which will show around the edges and between components. */ setLayout(new GridLayout(1,3,3,3)); setBackground(Color.gray); Panel scrolls = new Panel(); Panel labels = new Panel(); add(scrolls); add(labels); add(colorCanvas); /* Add the Scrollbars and the Labels to their respective panels. */ scrolls.setLayout(new GridLayout(6,1,2,2)); scrolls.add(redScroll); scrolls.add(greenScroll); scrolls.add(blueScroll); scrolls.add(hueScroll); scrolls.add(saturationScroll); scrolls.add(brightnessScroll); labels.setLayout(new GridLayout(6,1,2,2)); labels.add(redLabel); labels.add(greenLabel); labels.add(blueLabel); labels.add(hueLabel); labels.add(saturationLabel); labels.add(brightnessLabel); } // end init(); public void adjustmentValueChanged(AdjustmentEvent evt) { // This is called when the user has changed the values on // one of the scrollbars. All the scrollbars and labels // and the color patch are reset to correspond to the new color. int r1, g1, b1; r1 = redScroll.getValue(); g1 = greenScroll.getValue(); b1 = blueScroll.getValue(); if (r != r1 || g != g1 || b != b1) { // One of the RGB components has changed. r = r1; g = g1; b = b1; Color.RGBtoHSB(r,g,b,hsb); } else { // One of the HSB components has changed. hsb[0] = hueScroll.getValue()/255.0F; hsb[1] = saturationScroll.getValue()/255.0F; hsb[2] = brightnessScroll.getValue()/255.0F; int rgb = Color.HSBtoRGB(hsb[0],hsb[1],hsb[2]); r = (rgb >> 16) & 0xFF; g = (rgb >> 8) & 0xFF; b = rgb & 0xFF; } redLabel.setText(" R = " + r); greenLabel.setText(" G = " + g); blueLabel.setText(" B = " + b); hueLabel.setText(" H = " + hsb[0]); saturationLabel.setText(" S = " + hsb[1]); brightnessLabel.setText(" B = " + hsb[2]); redScroll.setValue(r); greenScroll.setValue(g); blueScroll.setValue(b); hueScroll.setValue((int)(255*hsb[0])); saturationScroll.setValue((int)(255*hsb[1])); brightnessScroll.setValue((int)(255*hsb[2])); colorCanvas.setBackground(new Color(r,g,b)); colorCanvas.repaint(); // Tell the system to redraw the canvas in its new color. } // end adjustmentValueChanged public Insets getInsets() { // The system calls this method to find out how much space to // leave between the edges of the applet and the components that // it contains. I want a 3-pixel border at each edge. return new Insets(3,3,3,3); } } // end class ColorChooserApplet |
