Java Custom Color Chooser, Importing colors, Reusing colors, SwatchPanel, ColorTracker

Custom Color Chooser

2012.9.23

Language

Last update: 2013.06.05

Topics

Mouse hit test for a closed shape
2010.08.26

Mouse hit test for an unclosed shape
2010.08.26

Intersection between two arbitrary curves
2010.09.01

Normal lines to a arbitrary curve
2010.09.01

Common normal lines between two shapes
2016.10.20

Text Editor using the Input Method Framework
2010.12.01

Component Library
2012.09.16

Costom Color Chooser
2012.9.23

1. Source code download

=> CustomColorChooser1.zip, CustomColorChooser2.zip
The two zip files are corresponding to the test code (1) and the test code (2) described below. They must be executed in different projects.

2. Features of CustomColorChooser


(a) Dialog of javax.swing.JColorChooser	(b) Dialog of CustomColorChooserDialog

Features

Description

(1)Importing colors

The purpose of a custom color chooser is to be able to reuse the colors of drawings already designed. For this purpose we add an ability to the current color chooser which ability can import colors from existing drawings.
The "Imported colors" panel at the lower right of the Figure (b) is such an example.

As a method for importing colors, there may be several ways as follows.

(a) Import all the colors used in the drawings file.

(b) Import all the colors used in a page of drawings file.

In this article, we will configure test codes aiming at the method (c).

:The colors that should be imported must be the outline colors of shapes, the fill color of shapes and the text colors if the shapes have texts.

(2)Reusing colors

The following functions are required.
(a) If a color is clicked on the color palette of "Imported colors" panel, the color must be displayed on the preview panel immediately.
(b) If a color is clicked on the color palette of the javax.swing.JColorChooser (the upper side of the figure (b) ), the color must be also displayed on a preview panel.
(c) If the OK button is pressed, the color on the preview panel must be passed to the application that set the color to the selected shapes or the selected text.

3. Test code (1)

❐ Key components

Component	Description
CustomColor Chooser1	public class CustomColorChooser1 The class implementing the main method. This object receives a selected color from the CustomColorChooserDialog as follows. Color color=CustomColorChooserDialog.showDialog(frame, colors); The colors is an array of colors to be passed from the application, those colors are displayed in the "Imported colors" panel in the figure (b). The above CustomColorChooserDialog.showDialog static method works completely like the JColorChooser.showDialog method.
CustomColor ChooserDialog	class CustomColorChooserDialog extends JDialog implements ActionListener, ComponentListener The dialog shown in figure (b). (1) Set up the JColorChooser, PreviewPanel, ImportedColorsPanel, OK button and Cancel button in this dialog. this.colorChooser = new JColorChooser(); this.colorChooser.setBorder(BorderFactory.createTitledBorder("Color chooser")); this.colorChooser.setPreviewPanel(new JLabel("Preview", JLabel.CENTER)); The above third line sets a dummy to the PreviewPanel of the JColorChooser. The new PreviewPanel is added to the CustomColorChooserDialog (JDialog extended). (2) Return of the showDialog method return dialog.getPreviewColor(); The getPreviewColor method returns the color displayed in the Preview Panel. In the case of the Figure (b), the method returns red.
PreviewPanel	class PreviewPanel extends JComponent implements ChangeListener, ColorSelectionListener, MouseListener The new PreviewPanel which is different from the PreviewPanel attached to JColorChooser. This new PreviewPanel displays the color to the panel which was selected on the JColorChooser or the ImportedColorsPanel. (1) Receiving the selected color from the JColorChooser Register this object to the ColorSelectionModel of the JColorChooser as a ChangeListener. Add the following line to the Constructor of this class. dialog.getColorChooser().getSelectionModel().addChangeListener(this); :The dialog represents the CustomColorChooserDialog object. (2) Receiving the selected color from the ImportedColorsPanel. Register this object to the ImportedColorsPanel as a ColorSelectionListener by the addColorSelectionListener method of the ImportedColorsPanel. Add the following line to the Constructor of this class. dialog.getImportedColorsPanel().addColorSelectionListener(this);
ImportedColorsPanel	class ImportedColorsPanel extends JComponent implements MouseListener Receive an array of colors from an external application and display them on the color palette on this panel. A color on the color palette can be selected with a mouse click and the selected color must be reported to the PreviewPanel. So the color selection mechanism and color reporting mechanism to other object is required for this panel. (1) Receive an array of colors from the external application Receive them by the following line (=> CustomColorChooser1) Color color=CustomColorChooserDialog.showDialog(frame, colors); The argument colors is the array of colors from an external application. (2)Display the colors The colors are displayed in the same way as that of SwatchPanel in the javax.swing.colorchooser.DefaultSwatchChooserPanel.java (3) Select a color with a mouse This class is implemented with the MouseListener in order to be able to select a color using the mousePressed method. (4) Notification to the selected color to the PreviewPanel Create a ColorSelectionEvent and notify a color selection event to other object with the ColorSelectionEvent by the fireEvent method of this class. For this reason, the addColorSelectionListener and the removeColorSelectionListener methods are required in this object to register a ColorSelectionListener and remove it. The recipient (in this case, the PreviewPanel) must implements the colorSelected method defined by the ColorSelectionListener to receive the selected color.

❐ColorSelectionListener

Item	Description
code	interface ColorSelectionListener extends EventListener { public void colorSelected(ColorSelectionEvent event); }
implementation	Implement to PreviewPanel.

❐ColorSelectionEvent

Item	Description
code	class ColorSelectionEvent extends EventObject { Color color=null; public ColorSelectionEvent(Object source, Color color) { super(source); this.color=color; } public Color getColor(){ return this.color; } }

❐SwatchPanel
javax.swing.colorchooser.DefaultSwatchChooserPanel.javaのSwatchPanel class
Display colors by the paintComponent method.

Item

Description

code

public void paintComponent(Graphics g) {
g.setColor(getBackground());
g.fillRect(0, 0, getWidth(), getHeight());
for (int row = 0; row < numSwatches.height; row++) {
for (int column = 0; column < numSwatches.width; column++) {
g.setColor(getColorForCell(column, row));
int x;
if ((!this.getComponentOrientation().isLeftToRight())
&& (this instanceof RecentSwatchPanel)) {
x = (numSwatches.width - column - 1) * (swatchSize.width + gap.width);
} else {
x = column * (swatchSize.width + gap.width);
}
int y = row * (swatchSize.height + gap.height);
g.fillRect(x, y, swatchSize.width, swatchSize.height);
g.setColor(Color.black);
g.drawLine(x + swatchSize.width - 1, y, x + swatchSize.width - 1,
y + swatchSize.height - 1);
g.drawLine(x, y + swatchSize.height - 1, x + swatchSize.width - 1,
y + swatchSize.height - 1);
}
}
}

4. Test code (2)

❐Dialog

Item

Description

"Imported colors"

panel

In the CustomColorChooser1, an array of the colors imported from an application is passed to the argument of the showDialog method as folloes.

Color color=CustomColorChooserDialog.showDialog(frame, colors);

Since this method may have little flexibility, we implement the "Import colors" button which imports an array of colors into the palette of the "Imported colors" panel, and the "delete colors" button which deletes a imported color from the palette.

For importing an array of colors, we select shapes on the canvas and click the "Import colors" button , then the colors of the selected shapes will be imported.
However this is a test code and shape selection mechanism is not implemented, so when the button is clicked, an array of colors prepared beforehand are imported.

Figure (c) Dialog of the CustomColorChooserDialog

❐ Changed points of the key components

Component	Description
CustomColor Chooser2	public class CustomColorChooser2 implements ColorSelectionListener This object receives a selected color from the CustomColorChooserDialog as follows. In the Test code (1), the modal color-chooser dialog shown by the JColorChooser.showDialog method blocks until the dialog is hidden. => (3)Receiving the selected color from javax.swing.JColorChooser This method doesn't allow selection mechanism of shapes by clicking the mouse button on the canvas. Therefor, we implement the ColorSelectionListener to an application (in this case, the application is CustomColorChooser2) and the application receives the array of colors by the colorSelected method. (2)Code public static void main(String[] args) .............................. CustomColorChooser2 chooser=new CustomColorChooser2(); CustomColorChooserDialog dialog=new CustomColorChooserDialog(frame); dialog.addColorSelectionListener(chooser); dialog.showDialog(); } public void colorSelected(ColorSelectionEvent event) { Color color = event.getColor(); System.out.println("** CustomColorChooser colorSelected event.getColor()=" + event.getColor()); }
CustomColor ChooserDialog	class CustomColorChooserDialog extends JDialog implements ActionListener Additional parts to the Test code (1) are as follows. (1) "Import colors" button and "delete colors" button (2) actionPerformed method In this method, the action processing for the events from the "Import colors" button and "delete colors" button are described.
PreviewPanel	class PreviewPanel extends JComponent implements ChangeListener, ColorSelectionListener, MouseListener Same as the Test code (1)
ImportedColorsPanel	class ImportedColorsPanel extends JComponent implements MouseListener Additional parts to the Test code (1) are as follows. (1) Implement the method to import an array of colors when the "Import colors" button is clicked. public void setImportedColors(Color[] colors) : Implement a color duplication check and color sorting functions to the setImportedColors method. (2) Implement a color selection method by a mouse click. This method can be easily implemented using the MouseListener's methods. In addition, implementing the following two functions will be better. • Deselect a color which is already selected. • Select multiple colors with holding down the Shift-key or Ctrl-key. In addition, the dark gray frames will be displayed around the selected colors. (3)Implement a method to delete selected colors from the color palette. public void removeCurrentColors()