void OnChildPreferredSizeChanged()
{
IWidgetSurface surface = this;
if (Parent != null && resizeRequestQueue.Contains(Parent))
{
// Size for this widget will be checked when checking the parent
surface.ResetCachedSizes();
return;
}
// Determine if the size change of the child implies a size change
// of this widget. If it does, the size change notification
// has to be propagated to the parent
var oldWidth = width;
var oldHeight = height;
surface.ResetCachedSizes();
bool changed = true;
if (surface.SizeRequestMode == SizeRequestMode.HeightForWidth)
{
var nw = surface.GetPreferredWidth();
if (nw == oldWidth)
{
var nh = surface.GetPreferredHeightForWidth(Backend.Size.Width);
if (nh == oldHeight)
{
changed = false;
}
}
}
else
{
var nh = surface.GetPreferredHeight();
if (nh == oldHeight)
{
var nw = surface.GetPreferredWidthForHeight(Backend.Size.Height);
if (nw == oldWidth)
{
changed = false;
}
}
}
if (changed)
{
NotifySizeChangeToParent();
}
else
{
QueueForReallocate(this);
}
}
protected virtual void OnChildPreferredSizeChanged(Widget w)
{
if (Parent != null && (!widthCached || !heightCached))
{
Parent.OnChildPreferredSizeChanged(w);
return;
}
var oldWidth = width;
var oldHeight = height;
bool notifyParent = Parent != null;
IWidgetSurface surface = this;
surface.ResetCachedSizes();
if (surface.SizeRequestMode == SizeRequestMode.HeightForWidth)
{
var nw = surface.GetPreferredWidth();
if (nw == oldWidth)
{
var nh = surface.GetPreferredHeightForWidth(Backend.Size.Width);
if (nh == oldHeight)
{
notifyParent = false;
}
}
}
else
{
var nh = surface.GetPreferredHeight();
if (nh == oldHeight)
{
var nw = surface.GetPreferredWidthForHeight(Backend.Size.Height);
if (nw == oldWidth)
{
notifyParent = false;
}
}
}
if (notifyParent)
{
if (Parent != null)
{
Parent.OnChildPreferredSizeChanged(this);
}
}
else
{
surface.Reallocate();
}
}
protected virtual void OnPreferredSizeChanged()
{
IWidgetSurface surface = this;
surface.ResetCachedSizes();
Backend.UpdateLayout();
if (Parent != null)
{
if (resizeRequestQueue.Count == 0)
{
Application.Invoke(DelayedResizeRequest);
}
resizeRequestQueue.Add(this);
}
}
protected virtual void OnPreferredSizeChanged()
{
// When the preferred size changes, we reset the sizes we have cached
// The parent also has to be notified of the size change, since it
// may imply a change of the size of the parent. However, we don't do
// it immediately, but we queue the resizing request
IWidgetSurface surface = this;
surface.ResetCachedSizes();
Backend.UpdateLayout();
if (!Application.EngineBackend.HandlesSizeNegotiation)
{
NotifySizeChangeToParent();
}
}