clabel.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

		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();
			// tile image to fill space
			gc.setBackground(getBackground());
			gc.fillRectangle(rect);
			int xPos = 0;
			while (xPos < rect.width) {
				int yPos = 0;
				while (yPos < rect.height) {
					gc.drawImage(backgroundImage, xPos, yPos);
					yPos += imageRect.height;
				}
				xPos += imageRect.width;
			}
		} 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;
				int pos = 0;
				for (int i = 0; i < gradientPercents.length; ++i) {
					gc.setForeground(lastColor);
					lastColor = gradientColors[i + 1];
					if (lastColor == null) lastColor = oldBackground;
					gc.setBackground(lastColor);
					if (gradientVertical) {
						final int gradientHeight = (gradientPercents[i] * rect.height / 100) - pos;
						gc.fillGradientRectangle(0, pos, rect.width, gradientHeight, true);
						pos += gradientHeight;
					} else {
						final int gradientWidth = (gradientPercents[i] * rect.width / 100) - pos;
						gc.fillGradientRectangle(pos, 0, gradientWidth, rect.height, false);
						pos += gradientWidth;
					}
				}
				if (gradientVertical && pos < rect.height) {
					gc.setBackground(getBackground());
					gc.fillRectangle(0, pos, rect.width, rect.height - pos);
				}
				if (!gradientVertical && pos < rect.width) {
					gc.setBackground(getBackground());
					gc.fillRectangle(pos, 0, rect.width - pos, rect.height);
				}
				gc.setForeground(oldForeground);
			}
			gc.setBackground(oldBackground);
		} else {
			if ((getStyle() & SWT.NO_BACKGROUND) != 0) {
				gc.setBackground(getBackground());
				gc.fillRectangle(rect);
			}
		}
	} catch (SWTException e) {
		if ((getStyle() & SWT.NO_BACKGROUND) != 0) {
			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.
 * 
 * @param align the alignment style of LEFT, RIGHT or CENTER
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the value of align is not one of SWT.LEFT, SWT.RIGHT or SWT.CENTER</li>
 * </ul>
 */
public void setAlignment(int align) {
	checkWidget();
	if (align != SWT.LEFT && align != SWT.RIGHT && align != SWT.CENTER) {
		SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	}
	if (this.align != align) {
		this.align = align;
		redraw();
	}
}

public void setBackground (Color color) {
	super.setBackground (color);
	// Are these settings the same as before?
	if (color != null && backgroundImage == null && 
		gradientColors == null && gradientPercents == null) {
		Color background = getBackground();
		if (color.equals(background)) {
			return;
		}		
	}
	backgroundImage = null;
	gradientColors = null;
	gradientPercents = null;
	redraw ();
}

/**
 * Specify a gradient of colours to be drawn in the background of the CLabel.
 * <p>For example, to draw a gradient that varies from dark blue to blue and then to
 * white and stays white for the right half of the label, use the following call 
 * to setBackground:</p>
 * <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 gradient 
 *               in order of appearance from left to right;  The value <code>null</code> 
 *               clears the background gradient; 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.
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the values of colors and percents are not consistant</li>
 * </ul>
 */
public void setBackground(Color[] colors, int[] percents) {
	setBackground(colors, percents, false);
}
/**
 * Specify a gradient of colours to be drawn in the background of the CLabel.
 * <p>For example, to draw a gradient that varies from dark blue to white in the vertical,
 * direction use the following call 
 * to setBackground:</p>
 * <pre>
 *	clabel.setBackground(new Color[]{display.getSystemColor(SWT.COLOR_DARK_BLUE), 
 *		                           display.getSystemColor(SWT.COLOR_WHITE)},
 *		                 new int[] {100}, true);
 * </pre>
 *
 * @param colors an array of Color that specifies the colors to appear in the gradient 
 *               in order of appearance from left/top to right/bottom;  The value <code>null</code> 
 *               clears the background gradient; 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/height 
 *                 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.
 * @param vertical indicate the direction of the gradient.  True is vertical and false is horizontal.
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the values of colors and percents are not consistant</li>
 * </ul>
 * 
 * @since 3.0
 */
public void setBackground(Color[] colors, int[] percents, boolean vertical) {	
	checkWidget();
	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[colors.length - 1]};
			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 && this.gradientVertical == vertical) return;
		}
	} else {
		backgroundImage = null;
	}
	// Store the new settings
	if (colors == null) {
		gradientColors = null;
		gradientPercents = null;
		gradientVertical = false;
	} 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];
		gradientVertical = vertical;
	}
	// Refresh with the new settings
	redraw();
}
/**
 * Set the image to be drawn in the background of the label.
 * 
 * @param image the image to be drawn in the background
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setBackground(Image image) {
	checkWidget();
	if (image == backgroundImage) return;
	if (image != null) {
		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.
 * 
 * @param image the image to be displayed in the label or null
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setImage(Image image) {
	checkWidget();
	if (image != this.image) {
		this.image = image;
		redraw();
	}
}
/**
 * Set the label's text.
 * The value <code>null</code> clears it.
 * 
 * @param text the text to be displayed in the label or null
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setText(String text) {
	checkWidget();
	if (text == null) text = ""; //$NON-NLS-1$
	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;
}
}