/*******************************************************************************
* Copyright (c) 2007, 2011 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
* Michael Krkoska - initial API and implementation (bug 188333)
*******************************************************************************/
package org.eclipse.jface.viewers;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.viewers.StyledString.Styler;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StyleRange;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.TextLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
/**
* A {@link StyledCellLabelProvider} supports styled labels by using owner
* draw.
* Besides the styles in labels, the label provider preserves native viewer behavior:
* <ul>
* <li>similar image and label positioning</li>
* <li>native drawing of focus and selection</li>
* </ul>
* <p>
* For providing the label's styles, create a subclass and overwrite
* {@link StyledCellLabelProvider#update(ViewerCell)} to
* return set all information needed to render a element. Use
* {@link ViewerCell#setStyleRanges(StyleRange[])} to set style ranges
* on the label.
* </p>
*
* @since 3.4
*/
public abstract class StyledCellLabelProvider extends OwnerDrawLabelProvider {
/**
* Style constant for indicating that the styled colors are to be applied
* even it the viewer's item is selected. Default is not to apply colors.
*/
public static final int COLORS_ON_SELECTION = 1 << 0;
/**
* Style constant for indicating to draw the focus if requested by the owner
* draw event. Default is to draw the focus.
*/
public static final int NO_FOCUS = 1 << 1;
/**
* Private constant to indicate if owner draw is enabled for the
* label provider's column.
*/
private static final int OWNER_DRAW_ENABLED = 1 << 4;
private int style;
// reused text layout
private TextLayout cachedTextLayout;
private ColumnViewer viewer;
private ViewerColumn column;
private int deltaOfLastMeasure;
/**
* Creates a new StyledCellLabelProvider. By default, owner draw is enabled, focus is drawn and no
* colors are painted on selected elements.
*/
public StyledCellLabelProvider() {
this(0);
}
/**
* Creates a new StyledCellLabelProvider. By default, owner draw is enabled.
*
* @param style
* the style bits
* @see StyledCellLabelProvider#COLORS_ON_SELECTION
* @see StyledCellLabelProvider#NO_FOCUS
*/
public StyledCellLabelProvider(int style) {
this.style = style & (COLORS_ON_SELECTION | NO_FOCUS)
| OWNER_DRAW_ENABLED;
}
/**
* Returns <code>true</code> is the owner draw rendering is enabled for this label provider.
* By default owner draw rendering is enabled. If owner draw rendering is disabled, rending is
* done by the viewer and no styled ranges (see {@link ViewerCell#getStyleRanges()})
* are drawn.
*
* @return <code>true</code> is the rendering of styles is enabled.
*/
public boolean isOwnerDrawEnabled() {
return (this.style & OWNER_DRAW_ENABLED) != 0;
}
/**
* Specifies whether owner draw rendering is enabled for this label
* provider. By default owner draw rendering is enabled. If owner draw
* rendering is disabled, rendering is done by the viewer and no styled
* ranges (see {@link ViewerCell#getStyleRanges()}) are drawn.
* It is the caller's responsibility to also call
* {@link StructuredViewer#refresh()} or similar methods to update the
* underlying widget.
*
* @param enabled
* specifies if owner draw rendering is enabled
*/
public void setOwnerDrawEnabled(boolean enabled) {
boolean isEnabled= isOwnerDrawEnabled();
if (isEnabled != enabled) {
if (enabled) {
this.style |= OWNER_DRAW_ENABLED;
} else {
this.style &= ~OWNER_DRAW_ENABLED;
}
if (this.viewer != null) {
setOwnerDrawEnabled(this.viewer, this.column, enabled);
}
}
}
/**
* Returns the viewer on which this label provider is installed on or <code>null</code> if the
* label provider is not installed.
*
* @return the viewer on which this label provider is installed on or <code>null</code> if the
* label provider is not installed.
*/
protected final ColumnViewer getViewer() {
return this.viewer;
}
/**
* Returns the column on which this label provider is installed on or <code>null</code> if the
* label provider is not installed.
*
* @return the column on which this label provider is installed on or <code>null</code> if the
* label provider is not installed.
*/
protected final ViewerColumn getColumn() {
return this.column;
}
/* (non-Javadoc)
* @see org.eclipse.jface.viewers.OwnerDrawLabelProvider#initialize(org.eclipse.jface.viewers.ColumnViewer, org.eclipse.jface.viewers.ViewerColumn)
*/
public void initialize(ColumnViewer viewer, ViewerColumn column) {
Assert.isTrue(this.viewer == null && this.column == null, "Label provider instance already in use"); //$NON-NLS-1$
this.viewer= viewer;
this.column= column;
super.initialize(viewer, column, isOwnerDrawEnabled());
}
/*
* (non-Javadoc)
*
* @see org.eclipse.jface.viewers.BaseLabelProvider#dispose()
*/
public void dispose() {
if (this.cachedTextLayout != null) {
cachedTextLayout.dispose();
cachedTextLayout = null;
}
this.viewer= null;
this.column= null;
super.dispose();
}
/*
* (non-Javadoc)
*
* @see org.eclipse.jface.viewers.OwnerDrawLabelProvider#update(org.eclipse.jface.viewers.ViewerCell)
*/
public void update(ViewerCell cell) {
// clients must override and configure the cell and call super
super.update(cell); // calls 'repaint' to trigger the paint listener
}
private TextLayout getSharedTextLayout(Display display) {
if (cachedTextLayout == null) {
int orientation = viewer.getControl().getStyle() & (SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT);
cachedTextLayout = new TextLayout(display);
cachedTextLayout.setOrientation(orientation);
}
return cachedTextLayout;
}
private boolean useColors(Event event) {
return (event.detail & SWT.SELECTED) == 0
|| (this.style & COLORS_ON_SELECTION) != 0;
}
private boolean drawFocus(Event event) {
return (event.detail & SWT.FOCUSED) != 0
&& (this.style & NO_FOCUS) == 0;
}
/**
* Prepares the given style range before it is applied to the label. This method makes sure that
* no colors are drawn when the element is selected.
* The current version of the {@link StyledCellLabelProvider} will also ignore all font settings on the
* style range. Clients can override.
*
* @param styleRange
* the style range to prepare. the style range element must not be modified
* @param applyColors
* specifies if colors should be applied.
* @return
* returns the style range to use on the label
*/
protected StyleRange prepareStyleRange(StyleRange styleRange, boolean applyColors) {
// if no colors apply or font is set, create a clone and clear the
// colors and font
if (!applyColors && (styleRange.foreground != null || styleRange.background != null)) {
styleRange = (StyleRange) styleRange.clone();
if (!applyColors) {
styleRange.foreground = null;
styleRange.background = null;
}
}
return styleRange;
}
private ViewerCell getViewerCell(Event event, Object element) {
ViewerRow row= viewer.getViewerRowFromItem(event.item);
return new ViewerCell(row, event.index, element);
}
/**
* Handle the erase event. The default implementation does nothing to ensure
* keep native selection highlighting working.
*
* @param event
* the erase event
* @param element
* the model object
* @see SWT#EraseItem
*/
protected void erase(Event event, Object element) {
// use native erase
if (isOwnerDrawEnabled()) {
// info has been set by 'update': announce that we paint ourselves
event.detail &= ~SWT.FOREGROUND;
}
}
/*
* (non-Javadoc)
*
* @see org.eclipse.jface.viewers.OwnerDrawLabelProvider#measure(org.eclipse.swt.widgets.Event,
* java.lang.Object)
*/
protected void measure(Event event, Object element) {
if (!isOwnerDrawEnabled())
return;
ViewerCell cell= getViewerCell(event, element);
boolean applyColors = useColors(event);
TextLayout layout = getSharedTextLayout(event.display);
int textWidthDelta = deltaOfLastMeasure = updateTextLayout(layout, cell, applyColors);
event.width += textWidthDelta;
}
/**
* @param layout
* @param cell
* @param applyColors
* @return the text width delta (0 if the text layout contains no other font)
*/
private int updateTextLayout(TextLayout layout, ViewerCell cell,
boolean applyColors) {
layout.setStyle(null, 0, Integer.MAX_VALUE); // clear old styles
layout.setText(cell.getText());
layout.setFont(cell.getFont()); // set also if null to clear previous usages
int originalTextWidth = layout.getBounds().width; // text width without any styles
boolean containsOtherFont= false;
StyleRange[] styleRanges = cell.getStyleRanges();
if (styleRanges != null) { // user didn't fill styled ranges
for (int i = 0; i < styleRanges.length; i++) {
StyleRange curr = prepareStyleRange(styleRanges[i], applyColors);
layout.setStyle(curr, curr.start, curr.start + curr.length - 1);
if (curr.font != null) {
containsOtherFont= true;
}
}
}
int textWidthDelta = 0;
if (containsOtherFont) {
textWidthDelta = layout.getBounds().width - originalTextWidth;
}
return textWidthDelta;
}
/*
* (non-Javadoc)
*
* @see org.eclipse.jface.viewers.OwnerDrawLabelProvider#paint(org.eclipse.swt.widgets.Event,
* java.lang.Object)
*/
protected void paint(Event event, Object element) {
if (!isOwnerDrawEnabled())
return;
ViewerCell cell= getViewerCell(event, element);
boolean applyColors= useColors(event);
GC gc = event.gc;
// remember colors to restore the GC later
Color oldForeground = gc.getForeground();
Color oldBackground = gc.getBackground();
if (applyColors) {
Color foreground= cell.getForeground();
if (foreground != null) {
gc.setForeground(foreground);
}
Color background= cell.getBackground();
if (background != null) {
gc.setBackground(background);
}
}
Image image = cell.getImage();
if (image != null) {
Rectangle imageBounds = cell.getImageBounds();
if (imageBounds != null) {
Rectangle bounds = image.getBounds();
// center the image in the given space
int x = imageBounds.x
+ Math.max(0, (imageBounds.width - bounds.width) / 2);
int y = imageBounds.y
+ Math.max(0, (imageBounds.height - bounds.height) / 2);
gc.drawImage(image, x, y);
}
}
Rectangle textBounds = cell.getTextBounds();
if (textBounds != null) {
TextLayout textLayout= getSharedTextLayout(event.display);
// text layout already configured in measure(Event, Object)
Rectangle layoutBounds = textLayout.getBounds();
int x = textBounds.x;
int y = textBounds.y
+ Math.max(0, (textBounds.height - layoutBounds.height) / 2);
textLayout.draw(gc, x, y);
}
if (drawFocus(event)) {
Rectangle focusBounds = cell.getViewerRow().getBounds();
gc.drawFocus(focusBounds.x, focusBounds.y, focusBounds.width + deltaOfLastMeasure,
focusBounds.height);
}
if (applyColors) {
gc.setForeground(oldForeground);
gc.setBackground(oldBackground);
}
}
/**
* Applies decoration styles to the decorated string and adds the styles of the previously
* undecorated string.
* <p>
* If the <code>decoratedString</code> contains the <code>styledString</code>, then the result
* keeps the styles of the <code>styledString</code> and styles the decorations with the
* <code>decorationStyler</code>. Otherwise, the decorated string is returned without any
* styles.
*
* @param decoratedString the decorated string
* @param decorationStyler the styler to use for the decoration or <code>null</code> for no
* styles
* @param styledString the original styled string
*
* @return the styled decorated string (can be the given <code>styledString</code>)
* @since 3.5
*/
public static StyledString styleDecoratedString(String decoratedString, Styler decorationStyler, StyledString styledString) {
String label= styledString.getString();
int originalStart= decoratedString.indexOf(label);
if (originalStart == -1) {
return new StyledString(decoratedString); // the decorator did something wild
}
if (decoratedString.length() == label.length())
return styledString;
if (originalStart > 0) {
StyledString newString= new StyledString(decoratedString.substring(0, originalStart), decorationStyler);
newString.append(styledString);
styledString= newString;
}
if (decoratedString.length() > originalStart + label.length()) { // decorator appended something
return styledString.append(decoratedString.substring(originalStart + label.length()), decorationStyler);
}
return styledString; // no change
}
}