package org.eclipse.swt.custom;
/*
* (c) Copyright IBM Corp. 2000, 2001.
* All Rights Reserved
*/
import org.eclipse.swt.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.events.*;
/* Start ACCESSIBILITY */
import org.eclipse.swt.accessibility.*;
/* End ACCESSIBILITY */
/**
* A Label which supports aligned text and/or an image and different border styles.
* <p>
* If there is not enough space a SmartLabel uses the following strategy to fit the
* information into the available space:
* <pre>
* ignores the indent in left align mode
* ignores the image and the gap
* shortens the text by replacing the center portion of the label with an ellipsis
* shortens the text by removing the center portion of the label
* </pre>
* <p>
* <dl>
* <dt><b>Styles:</b>
* <dd>SHADOW_IN, SHADOW_OUT, SHADOW_NONE</dd>
* <dt><b>Events:</b>
* <dd></dd>
* </dl>
*/
public class CLabel extends Canvas {
/** Gap between icon and text */
private static final int GAP = 5;
/** Left and right margins */
private static final int INDENT = 3;
/** a string inserted in the middle of text that has been shortened */
private static final String ellipsis = "...";
/** the alignment. Either CENTER, RIGHT, LEFT. Default is LEFT*/
private int align = SWT.LEFT;
private int hIndent = INDENT;
private int vIndent = INDENT;
/** the current text */
private String text;
/** the current icon */
private Image image;
// The tooltip is used for two purposes - the application can set
// a tooltip or the tooltip can be used to display the full text when the
// the text has been truncated due to the label being too short.
// The appToolTip stores the tooltip set by the application. Control.tooltiptext
// contains whatever tooltip is currently being displayed.
private String appToolTipText;
private Image backgroundImage;
private Color[] gradientColors;
private int[] gradientPercents;
/**
* Create a CLabel with the given border style as a child of parent.
*/
public CLabel(Composite parent, int style) {
super(parent, checkStyle(style));
if ((style & SWT.CENTER) != 0) align = SWT.CENTER;
if ((style & SWT.RIGHT) != 0) align = SWT.RIGHT;
if ((style & SWT.LEFT) != 0) align = SWT.LEFT;
addPaintListener(new PaintListener(){
public void paintControl(PaintEvent event) {
onPaint(event);
}
});
addDisposeListener(new DisposeListener(){
public void widgetDisposed(DisposeEvent event) {
onDispose(event);
}
});
/* Start ACCESSIBILITY */
getAccessibleObject().addAccessibleListener(new AccessibleAdapter() {
public void getName(AccessibleEvent e) {
if (e.childID == ACC.CHILDID_SELF) {
e.result = getText();
}
}
public void getHelp(AccessibleEvent e) {
if (e.childID == ACC.CHILDID_SELF) {
e.result = getToolTipText();
}
}
public void getDescription(AccessibleEvent e) {
if (e.childID == ACC.CHILDID_SELF) {
e.result = "This is a CLabel";
}
}
});
getAccessibleObject().addAccessibleControlListener(new AccessibleControlAdapter() {
public void accHitTest(AccessibleControlEvent e) {
Point testPoint = toControl(new Point(e.x, e.y));
if (getBounds().contains(testPoint)) {
e.childID = ACC.CHILDID_SELF;
}
}
public void accLocation(AccessibleControlEvent e) {
if (e.childID == ACC.CHILDID_SELF) {
Rectangle location = getBounds();
Point pt = toDisplay(new Point(location.x, location.y));
e.x = pt.x;
e.y = pt.y;
e.width = location.width;
e.height = location.height;
}
}
public void getChildCount(AccessibleControlEvent e) {
e.code = 0;
}
public void getRole(AccessibleControlEvent e) {
if (e.childID == ACC.CHILDID_SELF) {
e.code = ACC.ROLE_SYSTEM_STATICTEXT;
}
}
public void getState(AccessibleControlEvent e) {
if (e.childID == ACC.CHILDID_SELF) {
e.code = ACC.STATE_SYSTEM_NORMAL;
}
}
});
/* End ACCESSIBILITY */
}
/**
* Check the style bits to ensure that no invalid styles are applied.
*/
private static int checkStyle (int style) {
int mask = SWT.SHADOW_IN | SWT.SHADOW_OUT | SWT.SHADOW_NONE;
style = style & mask;
style |= SWT.NO_FOCUS | SWT.NO_BACKGROUND;
return style;
}
public Point computeSize(int wHint, int hHint, boolean changed) {
Point e = getTotalSize(image, text);
if (wHint == SWT.DEFAULT){
e.x += 2*hIndent;
} else {
e.x = wHint;
}
if (hHint == SWT.DEFAULT) {
e.y += 2*vIndent;
} else {
e.y = hHint;
}
return e;
}
/**
* Draw a rectangle in the given colors.
*/
private void drawBevelRect(GC gc, int x, int y, int w, int h, Color topleft, Color bottomright) {
gc.setForeground(bottomright);
gc.drawLine(x+w, y, x+w, y+h);
gc.drawLine(x, y+h, x+w, y+h);
gc.setForeground(topleft);
gc.drawLine(x, y, x+w-1, y);
gc.drawLine(x, y, x, y+h-1);
}
/**
* Returns the alignment.
* The alignment style (LEFT, CENTER or RIGHT) is returned.
*/
public int getAlignment() {
return align;
}
/**
* Return the CLabel's image or <code>null</code>.
*/
public Image getImage() {
return image;
}
/**
* Compute the minimum size.
*/
private Point getTotalSize(Image image, String text) {
Point size = new Point(0, 0);
if (image != null) {
Rectangle r = image.getBounds();
size.x += r.width;
size.y += r.height;
}
GC gc = new GC(this);
if (text != null && text.length() > 0) {
Point e = gc.textExtent(text);
size.x += e.x;
size.y = Math.max(size.y, e.y);
if (image != null) size.x += GAP;
} else {
size.y = Math.max(size.y, gc.getFontMetrics().getHeight());
}
gc.dispose();
return size;
}
public void setToolTipText (String string) {
super.setToolTipText (string);
appToolTipText = super.getToolTipText();
}
/**
* Return the Label's text.
*/
public String getText() {
return text;
}
public String getToolTipText () {
return appToolTipText;
}
/**
* Paint the Label's border.
*/
private void paintBorder(GC gc, Rectangle r) {
Display disp= getDisplay();
Color c1 = null;
Color c2 = null;
int style = getStyle();
if ((style & SWT.SHADOW_IN) != 0) {
c1 = disp.getSystemColor(SWT.COLOR_WIDGET_NORMAL_SHADOW);
c2 = disp.getSystemColor(SWT.COLOR_WIDGET_HIGHLIGHT_SHADOW);
}
if ((style & SWT.SHADOW_OUT) != 0) {
c1 = disp.getSystemColor(SWT.COLOR_WIDGET_LIGHT_SHADOW);
c2 = disp.getSystemColor(SWT.COLOR_WIDGET_NORMAL_SHADOW);
}
if (c1 != null && c2 != null) {
gc.setLineWidth(1);
drawBevelRect(gc, r.x, r.y, r.width-1, r.height-1, c1, c2);
}
}
private void onDispose(DisposeEvent event) {
gradientColors = null;
gradientPercents = null;
backgroundImage = null;
}
/*
* Process the paint event
*/
private void onPaint(PaintEvent event) {
Rectangle rect = getClientArea();
if (rect.width == 0 || rect.height == 0) return;
boolean shortenText = false;
String t = text;
Image img = image;
int availableWidth = rect.width - 2*hIndent;
Point extent = getTotalSize(img, t);
if (extent.x > availableWidth) {
img = null;
extent = getTotalSize(img, t);
if (extent.x > availableWidth) {
shortenText = true;
}
}
GC gc = event.gc;
// shorten the text
if (shortenText) {
t = shortenText(gc, text, availableWidth);
extent = getTotalSize(img, t);
if (appToolTipText == null) {
super.setToolTipText(text);
}
} else {
super.setToolTipText(appToolTipText);
}
// determine horizontal position
int x = rect.x + hIndent;
if (align == SWT.CENTER) {
x = (rect.width-extent.x)/2;
}
if (align == SWT.RIGHT) {
x = rect.width-extent.x - hIndent;
}
// draw a background image behind the text
try {
if (backgroundImage != null) {
// draw a background image behind the text
Rectangle imageRect = backgroundImage.getBounds();
gc.drawImage(backgroundImage, 0, 0, imageRect.width, imageRect.height,
0, 0, rect.width, rect.height);
} else if (gradientColors != null) {
// draw a gradient behind the text
final Color oldBackground = gc.getBackground();
if (gradientColors.length == 1) {
if (gradientColors[0] != null) gc.setBackground(gradientColors[0]);
gc.fillRectangle(0, 0, rect.width, rect.height);
} else {
final Color oldForeground = gc.getForeground();
Color lastColor = gradientColors[0];
if (lastColor == null) lastColor = oldBackground;
for (int i = 0, pos = 0; i < gradientPercents.length; ++i) {
gc.setForeground(lastColor);
lastColor = gradientColors[i + 1];
if (lastColor == null) lastColor = oldBackground;
gc.setBackground(lastColor);
final int gradientWidth = (gradientPercents[i] * rect.width / 100) - pos;
gc.fillGradientRectangle(pos, 0, gradientWidth, rect.height, false);
pos += gradientWidth;
}
gc.setForeground(oldForeground);
}
gc.setBackground(oldBackground);
} else {
gc.setBackground(getBackground());
gc.fillRectangle(rect);
}
} catch (SWTException e) {
gc.setBackground(getBackground());
gc.fillRectangle(rect);
}
// draw border
int style = getStyle();
if ((style & SWT.SHADOW_IN) != 0 || (style & SWT.SHADOW_OUT) != 0) {
paintBorder(gc, rect);
}
// draw the image
if (img != null) {
Rectangle imageRect = img.getBounds();
gc.drawImage(img, 0, 0, imageRect.width, imageRect.height,
x, (rect.height-imageRect.height)/2, imageRect.width, imageRect.height);
x += imageRect.width + GAP;
}
// draw the text
if (t != null) {
int textHeight = gc.getFontMetrics().getHeight();
gc.setForeground(getForeground());
gc.drawText(t, x, rect.y + (rect.height-textHeight)/2, true);
}
}
/**
* Set the alignment of the CLabel.
* Use the values LEFT, CENTER and RIGHT to align image and text within the available space.
*/
public void setAlignment(int align) {
if (align != SWT.LEFT && align != SWT.RIGHT && align != SWT.CENTER) {
SWT.error(SWT.ERROR_INVALID_ARGUMENT);
}
if (this.align != align) {
this.align = align;
redraw();
}
}
/**
* Specify a gradiant of colours to be draw in the background of the CLabel.
* For example to draw a gradiant that varies from dark blue to blue and then to
* white, use the following call to setBackground:
* <pre>
* clabel.setBackground(new Color[]{display.getSystemColor(SWT.COLOR_DARK_BLUE),
* display.getSystemColor(SWT.COLOR_BLUE),
* display.getSystemColor(SWT.COLOR_WHITE),
* display.getSystemColor(SWT.COLOR_WHITE)},
* new int[] {25, 50, 100});
* </pre>
*
* @param colors an array of Color that specifies the colors to appear in the gradiant
* in order of appearance left to right. The value <code>null</code> clears the
* background gradiant. The value <code>null</code> can be used inside the array of
* Color to specify the background color.
* @param percents an array of integers between 0 and 100 specifying the percent of the width
* of the widget at which the color should change. The size of the percents array must be one
* less than the size of the colors array.
*/
public void setBackground(Color[] colors, int[] percents) {
if (colors != null) {
if (percents == null || percents.length != colors.length - 1) {
SWT.error(SWT.ERROR_INVALID_ARGUMENT);
}
if (getDisplay().getDepth() < 15) {
// Don't use gradients on low color displays
colors = new Color[] { colors[0] };
percents = new int[] { };
}
for (int i = 0; i < percents.length; i++) {
if (percents[i] < 0 || percents[i] > 100) {
SWT.error(SWT.ERROR_INVALID_ARGUMENT);
}
if (i > 0 && percents[i] < percents[i-1]) {
SWT.error(SWT.ERROR_INVALID_ARGUMENT);
}
}
}
// Are these settings the same as before?
final Color background = getBackground();
if (backgroundImage == null) {
if ((gradientColors != null) && (colors != null) &&
(gradientColors.length == colors.length)) {
boolean same = false;
for (int i = 0; i < gradientColors.length; i++) {
same = (gradientColors[i] == colors[i]) ||
((gradientColors[i] == null) && (colors[i] == background)) ||
((gradientColors[i] == background) && (colors[i] == null));
if (!same) break;
}
if (same) {
for (int i = 0; i < gradientPercents.length; i++) {
same = gradientPercents[i] == percents[i];
if (!same) break;
}
}
if (same) return;
}
} else {
backgroundImage = null;
}
// Store the new settings
if (colors == null) {
gradientColors = null;
gradientPercents = null;
} else {
gradientColors = new Color[colors.length];
for (int i = 0; i < colors.length; ++i)
gradientColors[i] = (colors[i] != null) ? colors[i] : background;
gradientPercents = new int[percents.length];
for (int i = 0; i < percents.length; ++i)
gradientPercents[i] = percents[i];
}
// Refresh with the new settings
redraw();
}
public void setBackground(Image image) {
if (image == backgroundImage) return;
gradientColors = null;
gradientPercents = null;
backgroundImage = image;
redraw();
}
public void setFont(Font font) {
super.setFont(font);
redraw();
}
/**
* Set the label's Image.
* The value <code>null</code> clears it.
*/
public void setImage(Image image) {
if (image != this.image) {
this.image = image;
redraw();
}
}
/**
* Set the label's text.
* The value <code>null</code> clears it.
*/
public void setText(String text) {
if (text == null) text = "";
if (! text.equals(this.text)) {
this.text = text;
redraw();
}
}
/**
* Shorten the given text <code>t</code> so that its length doesn't exceed
* the given width. The default implementation replaces characters in the
* center of the original string with an ellipsis ("...").
* Override if you need a different strategy.
*/
protected String shortenText(GC gc, String t, int width) {
if (t == null) return null;
int w = gc.textExtent(ellipsis).x;
int l = t.length();
int pivot = l/2;
int s = pivot;
int e = pivot+1;
while (s >= 0 && e < l) {
String s1 = t.substring(0, s);
String s2 = t.substring(e, l);
int l1 = gc.textExtent(s1).x;
int l2 = gc.textExtent(s2).x;
if (l1+w+l2 < width) {
t = s1 + ellipsis + s2;
break;
}
s--;
e++;
}
return t;
}
}
