Jim - since you are plotting distinct blocks (of samples) then there will gaps between the curves (corresponding to the drawn block of data) on the axes. You would need to include the last point drawn for the previous block with the new block of data so that you get the continuous line being drawn from where the previous block ended and the new one begins. Or, you could just use one handle to the plot graphics object, and update its x and y data whenever your processData function gets called. Something like
function processData(src,data,fid,hObject)
% etc...
if (handles.doPlot)
% if first time, add the legend and create the plot
% graphics object
if(handles.newplot)
legend(handles.axes1,handles.sel_legend);
handles.newplot=false;
handles.hPlot = plot(NaN,NaN);
guidata(hObject,handles);
end
% update the x and y data
xdata = [get(handles.hPlot,'XData') data.TimeStamps];
ydata = [get(handles.hPlot,'YData') data.Data(:,handles.sel_index)];
set(handles.hPlot,'XData',xdata,'YData',ydata);
end
In the above, we use one plot graphics object to update the axes when new blocks of samples arrive..so it should ensure that there are no gaps between the data.
An alternative would be to keep track of the last point added to the axes, and insert that at the beginning of each of the timestamp and Data vectors prior to plotting it on the axes. This may be easier to implement - just update the handles structure with this point, and then insert it into your new data (always remembering to save the last point added).
