basecombopaintingstrategy.java

利用它可以做出非常漂亮的swt界面,包含的组件有PShelf Plist

package com.swtplus.widgets.combo.internal;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;

import com.swtplus.internal.TextUtils;
import com.swtplus.widgets.PCombo;
import com.swtplus.widgets.combo.IComboLabelProvider;

public class BaseComboPaintingStrategy implements IComboPaintingStrategy {
	
	private PCombo pcombo;
	private int minWidth = 15;
	private Point textExtent = new Point(0,0);
	
	private int margin = 2;
	private int spacing = 4;
	private int rightExtraMargin = 3;
	
	private IComboLabelProvider labelProvider;
	private String text ="";
	private Image image;
	
	public BaseComboPaintingStrategy(IComboLabelProvider labelProvider){
		this.labelProvider = labelProvider;
	}

	public Point computeSize(int wHint, int hHint, boolean changed) {
		Point p = new Point(wHint,hHint);
		if (wHint == SWT.DEFAULT){
			p.x = margin;
			if (image != null){
				p.x += image.getBounds().width + spacing;
			}
			p.x += textExtent.x + rightExtraMargin + margin;
		}
		{
			int imageHeight = 0;
			int textHeight = 0;
			if (image != null){
				imageHeight = image.getBounds().height;
			}
			textHeight = margin + textExtent.y + margin;
			p.y = Math.max(imageHeight,textHeight);
		}
		
		if (p.x < minWidth)
			p.x = minWidth;
		
		
		return p;
	}

	public void paint(GC gc, boolean focused,Rectangle bounds) {
		gc.fillRectangle(bounds);
		if (focused){
			 gc.setBackground(pcombo.getDisplay().getSystemColor(SWT.COLOR_LIST_SELECTION));
			 gc.fillRectangle(margin-1,margin-1,bounds.width - (2*(margin -1)),bounds.height - (2*(margin-1)));
			 gc.setForeground(pcombo.getDisplay().getSystemColor(SWT.COLOR_LIST_SELECTION_TEXT));
		}
		int textX = margin;
		if (image != null){
			int y = (bounds.height - image.getBounds().height)/2;
			if ((bounds.height - image.getBounds().height) % 2 != 0)
				y++;
			gc.drawImage(image,margin,y);
			textX += image.getBounds().width + spacing;	
		}
		int textWidth = bounds.width - textX - margin;
		String shortText = TextUtils.getShortString(gc,text,textWidth);
		int textY = (bounds.height - textExtent.y)/2;
		gc.drawString(shortText,textX +1,textY,true);
	}

	public void valueChanged(Object newValue) {
		text = labelProvider.getText(newValue);
		if (text == null)
			text = "";
		image = labelProvider.getImage(newValue);

		GC gc = new GC(pcombo);
		textExtent = gc.stringExtent(text);
		gc.dispose();				
	}

	public void setPCombo(PCombo pcombo) {
		this.pcombo = pcombo;
	}
	
	public void dispose(){
		labelProvider.dispose();
	}
	
	public int getTextXStartPosition(){
		int textX = margin;
		if (image != null){
			textX += image.getBounds().width + spacing;	
		}
		return textX;
	}

}