/// <summary>
/// Process items if IsDirty == true.
/// </summary>
/// <param name="idsrc">The context.</param>
public void Render(IDataSourceRenderContext idsrc)
{
if (IsDirty)
{
RenderPipeline(idsrc);
}
}
/// <summary>
/// Process the items through the list of <see cref="IDataSourceRenderer"/>.
/// Default impl.
/// </summary>
/// <param name="idsrc">Render context. icrc.Area is set to Rect.Empty.</param>
protected virtual void RenderPipeline(IDataSourceRenderContext idsrc)
{
_trace.Verbose($"RenderPipeline {Name} i:{Items} c:{_renderers.Count}");
if (Items == null)
{
return;
}
if (_renderers.Count == 0)
{
return;
}
var pmap = new Dictionary <IDataSourceRenderer, object>();
// Phase I: init each renderer; it may opt-out by returning NULL
foreach (var idsr in _renderers)
{
var state = idsr.Preamble(idsrc);
// TODO may want an exception instead
if (state != null)
{
pmap.Add(idsr, state);
}
}
if (pmap.Count > 0)
{
// Phase II: traverse the data and distribute to renderers
int ix = 0;
foreach (var item in Items)
{
foreach (var idsr in _renderers)
{
if (pmap.TryGetValue(idsr, out object state))
{
idsr.Render(state, ix, item);
}
}
ix++;
}
// Phase IIIa: post-traversal render bookkeeping
foreach (var idsr in _renderers)
{
if (pmap.TryGetValue(idsr, out object state))
{
idsr.RenderComplete(state);
}
}
// Phase IV: finalize renderers
foreach (var idsr in _renderers)
{
if (pmap.TryGetValue(idsr, out object state))
{
idsr.Postamble(state);
}
}
}
Clean();
}
