Another way to resize SVG in GXT 4 using Resizable.

ResizeSvg.java

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.dom.client.Style.Display;
import com.google.gwt.user.client.ui.InlineHTML;
import com.google.gwt.user.client.ui.RootPanel;
import com.sencha.gxt.core.client.dom.XElement;
import com.sencha.gxt.widget.core.client.Resizable;
import com.sencha.gxt.widget.core.client.container.FlowLayoutContainer;
import com.sencha.gxt.widget.core.client.event.ResizeEndEvent;
import com.sencha.gxt.widget.core.client.event.ResizeEndEvent.ResizeEndHandler;

public class ResizeSvg implements EntryPoint {

  @Override
  public void onModuleLoad() {
    String svg = "<svg width=\"100\" height=\"100\">\n" + 
        "<circle cx=\"50\" cy=\"50\" r=\"40\" stroke=\"brown\" stroke-width=\"4\" fill=\"orange\" />\n" + 
        "</svg>";
    
    InlineHTML html = new InlineHTML(svg);
    
    final FlowLayoutContainer wrapper = new FlowLayoutContainer();
    wrapper.getElement().getStyle().setDisplay(Display.INLINE_BLOCK);
    wrapper.setBorders(true);
    wrapper.add(html);
    
    Resizable resizable = new Resizable(wrapper);
    resizable.addResizeEndHandler(new ResizeEndHandler() {
      @Override
      public void onResizeEnd(ResizeEndEvent event) {
        GWT.log("resize ");
        
        int w = wrapper.getOffsetWidth();
        int h = wrapper.getOffsetHeight();
        
        int cx = w / 2;
        int cy = h / 2;
        
        int r1 = (int) (cx * .90);
        int r2 = (int) (cy * .90);
        
        int r = Math.min(r1, r2);
        
        GWT.log("cx=" + cx);
        
        XElement svgElement = wrapper.getElement().select("svg").getItem(0).cast();
        XElement svgCirclElement = wrapper.getElement().select("circle").getItem(0).cast();
        
        svgElement.setAttribute("width", w + "px");
        svgElement.setAttribute("height", h + "px");
        
        svgCirclElement.setAttribute("cx", cx + "");
        svgCirclElement.setAttribute("cy", cy + "");
        svgCirclElement.setAttribute("r", r + "");
      }
    });
    
    RootPanel.get().add(wrapper);
  }

}