private ResizeGroupState <TObject> UpdateContainerDimension(double oldDimension, double newDimension, TObject fullDimensionData, TObject renderedData)
{
ResizeGroupState <TObject> nextState;
if (double.IsNaN(oldDimension))
{
throw new Exception("The containerDimension was not supposed to be NaN");
}
if (newDimension > oldDimension)
{
if (OnGrowData != null)
{
nextState = new ResizeGroupState <TObject>(ResizeDirection.Grow, OnGrowData(renderedData));
}
else
{
nextState = new ResizeGroupState <TObject>(ResizeDirection.Shrink, fullDimensionData);
}
}
else
{
nextState = new ResizeGroupState <TObject>(ResizeDirection.Shrink, renderedData);
}
nextState.ContainerDimension = newDimension;
nextState.MeasureContainer = false;
return(nextState);
}
public void ReplaceProperties(ResizeGroupState <TObject> nextState)
{
if (nextState.RenderedData != null)
{
RenderedData = nextState.RenderedData;
}
if (nextState.DataToMeasure != null)
{
DataToMeasure = nextState.DataToMeasure;
}
if (nextState.ResizeDirection != ResizeDirection.None)
{
ResizeDirection = nextState.ResizeDirection;
}
if (nextState.ContainerDimension != 0)
{
ContainerDimension = nextState.ContainerDimension;
}
MeasureContainer = nextState.MeasureContainer;
if (nextState.NullifyDataToMeasure)
{
DataToMeasure = default;
}
if (nextState.NullifyRenderedData)
{
RenderedData = default;
}
if (nextState.ForceNoneResizeDirection)
{
ResizeDirection = ResizeDirection.None;
}
}
private async Task <ResizeGroupState <TObject> > GetNextStateAsync(double newContainerDimension, double oldContainerDimension, TObject dataToMeasure, TObject renderedData, ResizeDirection resizeDirection, CancellationToken cancellationToken)
{
double replacementContainerDimension = oldContainerDimension;
if (double.IsNaN(newContainerDimension) && dataToMeasure == null)
{
return(null);
}
if (!double.IsNaN(newContainerDimension))
{
// If we know what the last container size was and we rendered data at that width/height, we can do an optimized render
if (!double.IsNaN(oldContainerDimension) && renderedData != null && dataToMeasure == null)
{
var state = new ResizeGroupState <TObject>(renderedData, resizeDirection, dataToMeasure);
var alteredState = UpdateContainerDimension(oldContainerDimension, newContainerDimension, this.Data, renderedData);
state.ReplaceProperties(alteredState);
return(state);
}
replacementContainerDimension = newContainerDimension;
}
var nextState = new ResizeGroupState <TObject>(renderedData, resizeDirection, dataToMeasure);
nextState.MeasureContainer = false;
if (replacementContainerDimension != oldContainerDimension)
{
nextState.ContainerDimension = replacementContainerDimension;
}
if (dataToMeasure != null)
{
//get elementDimension here
var elementDimension = await GetElementDimensionsAsync(cancellationToken);
if (resizeDirection == ResizeDirection.Grow && this.OnGrowData != null)
{
var alteredState = GrowDataUntilItDoesNotFit(dataToMeasure, elementDimension, replacementContainerDimension);
nextState.ReplaceProperties(alteredState);
}
else
{
var alteredState = ShrinkContentsUntilTheyFit(dataToMeasure, elementDimension, replacementContainerDimension);
nextState.ReplaceProperties(alteredState);
}
}
return(nextState);
}
