scrollabe Img smartgwt

Question

i wrote a code to zoom in, and zoom out an image using smartGWT. but the problem is that the including canvas can't show it's scroll bars how to solve that

public class ImageViewer implements EntryPoint {

static int counter = 0;
int widths[] = new int[5];
int hights[] = new int[5];
int originalW=0;
int originalH=0;

public void onModuleLoad() {
    // -------tool bar ---------------
    ToolStrip toolbar = new ToolStrip();  
    toolbar.setWidth("100%"); 
    toolbar.addFill();

    ToolStripButton max = new ToolStripButton("  +  ");
    ToolStripButton min = new ToolStripButton("  -  ");
    ToolStripButton auto = new ToolStripButton(" auto ");

    ToolStripButton print = new ToolStripButton(" print ");
    ToolStripButton save = new ToolStripButton(" save ");

    toolbar.addButton(max);
    toolbar.addButton(min);
    toolbar.addButton(auto);

    toolbar.addSeparator();

    toolbar.addButton(print);
    toolbar.addButton(save);
    // -------------------------------
    HLayout hLayout = new HLayout();
    VLayout vLayout = new VLayout();


    SectionStack sectionStack = new SectionStack();
    sectionStack.setWidth("100%");
    sectionStack.setHeight("100%");
    sectionStack.setVisibilityMode(VisibilityMode.MULTIPLE);
    sectionStack.setAnimateSections(true);
    sectionStack.setOverflow(Overflow.HIDDEN);

    SectionStackSection summarySection = new SectionStackSection();
    summarySection.setTitle("Image Viewer");
    summarySection.setExpanded(true);
    summarySection.setItems(hLayout);

    sectionStack.setSections(summarySection);

    TreeGrid treeGrid = new TreeGrid();
    treeGrid.setWidth("20%");
    treeGrid.setShowConnectors(true);
    treeGrid.setShowResizeBar(true);


    final Canvas imgCanvas = new Canvas();
    imgCanvas.setShowEdges(true);

    final Img img = new Img("http://www.google.com/intl/en_ALL/images/srpr/logo1w.png");
    img.setParentElement(imgCanvas);
    img.draw();
    img.setImageType(ImageStyle.CENTER);
    originalW = img.getWidth();
    originalH = img.getHeight();
    widths[0] = originalW;
    hights[0] = originalH;

    widths[1] = widths[0]*2;
    hights[1] = hights[0]*2;

    widths[2] = widths[1]*2;
    hights[2] = hights[1]*2;

    widths[3] = widths[2]*2;
    hights[3] = hights[2]*2;

    widths[4] = widths[3]*2;
    hights[4] = hights[3]*2;



    hLayout.setMembers(treeGrid, vLayout);
    vLayout.setMembers(toolbar,imgCanvas);

    RootPanel.get("imgPanel").add(sectionStack);


    //-------------- handelers --------------------

    max.addClickHandler(new ClickHandler() {

        @Override
        public void onClick(ClickEvent event) {
            img.setImageType(ImageStyle.STRETCH);
            if (counter <4){
                counter++;
                img.animateRect(0, 0, widths[counter] , hights[counter]);   
            }
        }
    });

    min.addClickHandler(new ClickHandler() {

        @Override
        public void onClick(ClickEvent event) {
            img.setImageType(ImageStyle.STRETCH);
            if (counter > 0){
                counter--;
                img.animateRect(0, 0, widths[counter], hights[counter]);
            }               
        }
    });

    auto.addClickHandler(new ClickHandler() {

        @Override
        public void onClick(ClickEvent event) {
            img.setImageType(ImageStyle.CENTER);
            img.animateRect(0, 0, originalW, originalH);
            imgCanvas.adjustForContent(true);

        }
    });
    //---------------------------------------------
}

}

Answer 1

imgCanvas.setOverflow(Overflow.AUTO). imgCanvas will then show scrollbars as necessary if the Img is larger than the imgCanvas' specified size.