丸投げです…

import com.apple.cocoa.foundation.*;
import com.apple.cocoa.application.*;

public class MyView extends NSView {

    NSPopUpButton    ibColorSelect; // ComboBox
	
    NSImage    mDotImage;
	
    static NSSize DotSize = new NSSize(1.0f, 1.0f);
	
    public MyView(NSRect frameRect){
        super(frameRect);
        mDotImage = new NSImage(frameRect.size());
        clearDot();
    }
	
    public void drawRect(NSRect updateRect){
        mDotImage.drawAtPoint(NSPoint.ZeroPoint, updateRect, NSImage.CompositeCopy, 1.0f);
    }
	
    public void mouseDown(NSEvent event){
        drawDot(convertPointFromView(event.locationInWindow(), null));
        setNeedsDisplay(true);
    }
	
    public void rightMouseDown(NSEvent event){
        clearDot();
        setNeedsDisplay(true);
    }
	
    private void drawDot(NSPoint point){
        mDotImage.lockFocus();
        getSelectionColor().set();
        NSGraphics.fillRectList(new NSRect[]{new NSRect(point, DotSize)});
        mDotImage.unlockFocus();
    }
	
    private void clearDot(){
        mDotImage.lockFocus();
        NSColor.grayColor().set();
        NSGraphics.fillRectList(new NSRect[]{new NSRect(NSPoint.ZeroPoint, mDotImage.size())});
        mDotImage.unlockFocus();
    }
	
    private NSColor getSelectionColor(){
        switch(ibColorSelect.selectedItem().tag()){
        case 1:
            return NSColor.blackColor();
        case 2:
            return NSColor.whiteColor();
        }
        return NSColor.grayColor();
    }

}