// The GeneralTransform returned by Effect is in unit space. The
// invocation of GeneralTransform is in world space. This method
// returns a GeneralTransform that maps between the two.
internal GeneralTransform CoerceToUnitSpaceGeneralTransform(GeneralTransform gt,
Rect worldBounds)
{
GeneralTransform result;
// First, if the gt is identity, just return it straight away.
if (gt == Transform.Identity)
{
result = Transform.Identity;
}
else
{
// Maintain an MRU cache of GeneralTransforms with exactly one in
// it. May want to extend in the future. Note that this will
// thrash if the effect is used on multiple elements with different
// sizes, but that's not our sweetspot.
if (_mruWorldBounds != worldBounds || _mruInnerGeneralTransform != gt)
{
_mruWorldBounds = worldBounds;
_mruInnerGeneralTransform = gt;
_mruWorldSpaceGeneralTransform = new UnitSpaceCoercingGeneralTransform(worldBounds, gt);
}
result = _mruWorldSpaceGeneralTransform;
}
return(result);
}
// The GeneralTransform returned by Effect is in unit space. The
// invocation of GeneralTransform is in world space. This method
// returns a GeneralTransform that maps between the two.
internal GeneralTransform CoerceToUnitSpaceGeneralTransform(GeneralTransform gt,
Rect worldBounds)
{
GeneralTransform result;
// First, if the gt is identity, just return it straight away.
if (gt == Transform.Identity)
{
result = Transform.Identity;
}
else
{
// Maintain an MRU cache of GeneralTransforms with exactly one in
// it. May want to extend in the future. Note that this will
// thrash if the effect is used on multiple elements with different
// sizes, but that's not our sweetspot.
if (_mruWorldBounds != worldBounds || _mruInnerGeneralTransform != gt)
{
_mruWorldBounds = worldBounds;
_mruInnerGeneralTransform = gt;
_mruWorldSpaceGeneralTransform = new UnitSpaceCoercingGeneralTransform(worldBounds, gt);
}
result = _mruWorldSpaceGeneralTransform;
}
return result;
}
