Suggestion to add zoom in and out button

[weiliang2]

HI there,

trying to add a zoom button to make it work better.

``

private void addZoomInButton() {
	Button button = new Button(new Icon(VaadinIcon.PLUS));
	button.getElement().setAttribute("aria-label", "Zoom In");
	button.setThemeName("download-button");
	getElement().appendChild(button.getElement());
	button.addClickListener(e -> {
		ZoomLevel nextZoom = ZoomLevel.getNextZoom(getZoom());
		setZoom(nextZoom.getName());
	});
} 

private void addZoomOutButton() {
	Button button = new Button(new Icon(VaadinIcon.MINUS));
	button.getElement().setAttribute("aria-label", "Zoom Out");
	button.setThemeName("download-button");
	getElement().appendChild(button.getElement());
	button.addClickListener(e -> {
		ZoomLevel previousZoom = ZoomLevel.getPreviousZoom(getZoom());
		setZoom(previousZoom.getName());
	});
}

public enum ZoomLevel {

	Automatic_Zoom("auto", 1), 
	PAGE_FIT("page-fit", 2), 
	PERCENT_50("0.5", 3), 
	PERCENT_75("0.75", 4), 
	PERCENT_100("1.0", 5), 
	PERCENT_125("1.25", 6), 
	PERCENT_150("1.5", 7), 
	PERCENT_200("2.0", 8), 
	PERCENT_300("3.0", 9), 
	PERCENT_400("4.0", 10);

	@Getter
	private final String name;
	@Getter
	private int order;

	ZoomLevel(String name, int order) {
		this.name = name;
		this.order = order;
	}

	public static final ZoomLevel getByValue(String name) {
		return Stream.of(ZoomLevel.values()).filter(e -> e.name.equals(name)).findFirst().orElse(PAGE_FIT);
	}

	public static ZoomLevel getPreviousZoom(String name) {
		ZoomLevel value = getByValue(name);
		switch (value.getOrder()) {
		case 4:
			return PERCENT_50;
		case 5:
			return PERCENT_75;
		case 6:
			return PERCENT_100;
		case 7:
			return PERCENT_125;
		case 8:
			return PERCENT_150;
		case 9:
			return PERCENT_200;
		case 10:
			return PERCENT_300;
		default:
			return PAGE_FIT;
		}
	}

	public static ZoomLevel getNextZoom(String name) {
		ZoomLevel value = getByValue(name);
		switch (value.getOrder()) {
		case 1:
			return PAGE_FIT;
		case 2:
			return PERCENT_50;
		case 3:
			return PERCENT_75;
		case 4:
			return PERCENT_100;
		case 5:
			return PERCENT_125;
		case 6:
			return PERCENT_150;
		case 7:
			return PERCENT_200;
		case 8:
			return PERCENT_300;
		case 9:
			return PERCENT_400;
		default:
			return PAGE_FIT;
		}
	}
}

``

[weiliang2]

__zoomChanged(value) {
if (!this.__viewer || this.__loading) {
return;
}
// This logs error 'TextLayerBuilder._bindEvents: this.cancel() should have
// been called when the page was reset, or rendering cancelled.'
//
// There is a problem deep inside pdfjs viewer that causes an console.error()
// to be logged, but the component still works. It seems to be due to
// webcomponents/shadow dom messing with
// TODO: Fix the issue so that we get rid of the error in log
this.__viewer.currentScaleValue = value;
// Added Manualy
this.__viewer.forceRendering();
}