protected override SizeF CalculateInnerDesiredSize(SizeF totalSize)
{
ImageSourceState allocatedSource = GetLoadedSource(false);
if (allocatedSource == null)
{
_lastImageSourceSize = SizeF.Empty;
return(new SizeF(10, 10));
}
SizeF imageSize = allocatedSource.ImageSource.SourceSize;
float sourceFrameRatio = imageSize.Width / imageSize.Height;
// Adaptions when available size is not specified in any direction(s)
if (double.IsNaN(totalSize.Width) && double.IsNaN(totalSize.Height))
{
totalSize = imageSize;
}
else if (double.IsNaN(totalSize.Height))
{
totalSize.Height = totalSize.Width / sourceFrameRatio;
}
else if (double.IsNaN(totalSize.Width))
{
totalSize.Width = totalSize.Height * sourceFrameRatio;
}
_lastImageSourceSize = imageSize;
return(allocatedSource.ImageSource.StretchSource(totalSize, imageSize, Stretch, StretchDirection));
}
protected ImageSourceState GetLoadedSource(bool invalidateLayout)
{
if (_loadImageSource)
{
DisposeImageSources();
_fallbackSourceInUse = false;
_loadImageSource = false;
}
ImageSourceState allocatedSource = null;
// Find a new image source
if (_sourceState.ImageSource == null)
{
_sourceState.ImageSource = LoadImageSource(Source, true);
_sourceState.Setup = false;
}
if (_sourceState.ImageSource != null && !_sourceState.ImageSource.IsAllocated)
{
_sourceState.Setup = false;
_sourceState.ImageSource.Allocate();
}
if (_sourceState.ImageSource != null && _sourceState.ImageSource.IsAllocated)
{
allocatedSource = _sourceState;
}
else
{
// If the source image could not load yet, try fallback image
if (_fallbackSourceState.ImageSource == null)
{
_fallbackSourceState.ImageSource = LoadImageSource(FallbackSource, false);
_fallbackSourceState.Setup = false;
}
if (_fallbackSourceState.ImageSource != null && !_fallbackSourceState.ImageSource.IsAllocated)
{
_fallbackSourceState.Setup = false;
_fallbackSourceState.ImageSource.Allocate();
}
if (_fallbackSourceState.ImageSource != null && _fallbackSourceState.ImageSource.IsAllocated)
{
_fallbackSourceInUse = true;
allocatedSource = _fallbackSourceState;
}
}
if (invalidateLayout && allocatedSource != null && allocatedSource.ImageSource.SourceSize != _lastImageSourceSize)
{
InvalidateLayout(true, true);
}
HasImage = allocatedSource != null;
return(allocatedSource);
}
public override void RenderOverride(RenderContext localRenderContext)
{
ImageSourceState allocatedSource = GetLoadedSource(true);
if (allocatedSource == null)
{
base.RenderOverride(localRenderContext);
}
else
{
// Update source geometry if necessary (source has changed, layout has changed).
if (!allocatedSource.Setup)
{
allocatedSource.ImageSource.Setup(_innerRect, localRenderContext.ZOrder, SkinNeutralAR);
allocatedSource.Setup = true;
}
base.RenderOverride(localRenderContext);
allocatedSource.ImageSource.Render(localRenderContext, Stretch, StretchDirection);
}
}