SWT Treeviewer flickers while scrolling - treeview

Question

I have a SWT Treeviewer with custom labelprovider. But it flickers while scrolling even if it is not very large. I think it is because of the paint method. How can I improve performance of the it.
Thank you in advance.
Here is my paint method :
public class TreeLabelProvider extends OwnerDrawLabelProvider {
public ImageData[] getImage(Object element) {
//This function just have if else to return corrent imageData
}
public String getText(Object element) {
//This function also just have if else to return matching text to display
}
#Override
protected void measure(Event event, Object element) {
TreeItem item = (TreeItem) event.item;
Tree tree = item.getParent();
ImageData[] images = getImage(element);
int imgWidht = 0;
int imgHeight = 0;
if (images != null) {
for (int i = 0; i < images.length; i++) {
imgWidht += images[i].width;
int imgHeightTemp = images[i].height;
if (imgHeightTemp > imgHeight) {
imgHeight = imgHeightTemp;
}
}
}
if (!event.gc.isDisposed()) {
Point point = event.gc.textExtent(getText(element));
int rectangleWidth = 0;
rectangleWidth = imgWidht + point.x + 10;
event.setBounds(new Rectangle(event.x, event.y, rectangleWidth, imgHeight));
event.height = imgHeight + 3;
}
}
#Override
protected void paint(Event event, Object element) {
Rectangle bounds = event.getBounds();
int imgWidth = 0;
int x = bounds.width > 0 ? bounds.x + bounds.width : bounds.x;
ImageData[] img = getImage(element);
if (img != null) {
for (int imgIndex = 0; imgIndex < img.length; imgIndex++) {
event.gc.setAntialias(SWT.ON);
// make the image transparent
ImageData ideaData = img[imgIndex];
int whitePixel = ideaData.palette.getPixel(new RGB(255, 255, 255));
ideaData.transparentPixel = whitePixel;
Image transparentIdeaImage = new Image(Display.getDefault(), ideaData);
if (imgIndex > 0) {
event.gc.drawImage(transparentIdeaImage,
x + transparentIdeaImage.getBounds().width - 4, bounds.y + 2);
} else {
event.gc.drawImage(transparentIdeaImage, x - 5, bounds.y + 2);
}
imgWidth += transparentIdeaImage.getBounds().width;
// dispose Image
transparentIdeaImage.dispose();
}
}
event.gc.drawText(getText(element), x + imgWidth + 1, bounds.y + 3, true);
}
#Override
protected void erase(Event event, Object element) {}
}