protected override void OnDraw(Canvas canvas)
{
base.OnDraw(canvas);
if (mGrandientMatrix != null)
{
mTranslate += mViewWidth / 5;
if (mTranslate > 2 * mViewWidth)
{
mTranslate = -mViewWidth;
}
mGrandientMatrix.SetTranslate(mTranslate, 0);
mLinearGradient.SetLocalMatrix(mGrandientMatrix);
PostInvalidateDelayed(30);
}
}
private void CalculateMatrices()
{
_shouldDraw = true;
if (!_isFoldPrepared)
{
return;
}
if (FloatNearlyEqual(_foldFactor, 1))
{
_shouldDraw = false;
return;
}
if (FloatNearlyEqual(_foldFactor, 0) && _previousFoldFactor > 0 && FoldEnded != null)
{
FoldEnded(this, EventArgs.Empty);
}
if (FloatNearlyEqual(_previousFoldFactor, 0) && _foldFactor > 0 && FoldStarted != null)
{
FoldStarted(this, EventArgs.Empty);
}
_previousFoldFactor = _foldFactor;
for (var i = 0; i < _numberOfFolds; i++)
{
_matrix[i].Reset();
}
var translationFactor = 1 - _foldFactor;
var translatedDistance = _isHorizontal
? _originalWidth * translationFactor
: _originalHeight * translationFactor;
var translatedDistancePerFold = Math.Round(translatedDistance / _numberOfFolds);
_foldDrawWidth =
(float)(_foldMaxWidth < translatedDistancePerFold ? translatedDistancePerFold : _foldMaxWidth);
_foldDrawHeight =
(float)(_foldMaxHeight < translatedDistancePerFold ? translatedDistancePerFold : _foldMaxHeight);
var translatedDistanceFoldSquared = translatedDistancePerFold * translatedDistancePerFold;
var depth = _isHorizontal
? (float)Math.Sqrt(_foldDrawWidth * _foldDrawWidth - translatedDistanceFoldSquared)
: (float)Math.Sqrt(_foldDrawHeight * _foldDrawHeight - translatedDistanceFoldSquared);
var scaleFactor = DepthConstant / (DepthConstant + depth);
float scaledWidth, scaledHeight;
if (_isHorizontal)
{
scaledWidth = _foldDrawWidth * translationFactor;
scaledHeight = _foldDrawHeight * scaleFactor;
}
else
{
scaledWidth = _foldDrawWidth * scaleFactor;
scaledHeight = _foldDrawHeight * translationFactor;
}
var topScaledPoint = (_foldDrawHeight - scaledHeight) / 2.0f;
var bottomScaledPoint = topScaledPoint + scaledHeight;
var leftScaledPoint = (_foldDrawWidth - scaledWidth) / 2.0f;
var rightScaledPoint = leftScaledPoint + scaledWidth;
var anchorPoint = _isHorizontal ? AnchorFactor * _originalWidth : AnchorFactor * _originalHeight;
var midFold = _isHorizontal ? (anchorPoint / _foldDrawWidth) : anchorPoint / _foldDrawHeight;
_src[0] = 0;
_src[1] = 0;
_src[2] = 0;
_src[3] = _foldDrawHeight;
_src[4] = _foldDrawWidth;
_src[5] = 0;
_src[6] = _foldDrawWidth;
_src[7] = _foldDrawHeight;
for (var i = 0; i < _numberOfFolds; i++)
{
var isEven = (i % 2 == 0);
if (_isHorizontal)
{
_dst[0] = (anchorPoint > i * _foldDrawWidth) ? anchorPoint
+ (i - midFold) * scaledWidth : anchorPoint
- (midFold - i) * scaledWidth;
_dst[1] = isEven ? 0 : topScaledPoint;
_dst[2] = _dst[0];
_dst[3] = isEven ? _foldDrawHeight : bottomScaledPoint;
_dst[4] = (anchorPoint > (i + 1) * _foldDrawWidth) ? anchorPoint
+ (i + 1 - midFold) * scaledWidth
: anchorPoint - (midFold - i - 1) * scaledWidth;
_dst[5] = isEven ? topScaledPoint : 0;
_dst[6] = _dst[4];
_dst[7] = isEven ? bottomScaledPoint : _foldDrawHeight;
}
else
{
_dst[0] = isEven ? 0 : leftScaledPoint;
_dst[1] = (anchorPoint > i * _foldDrawHeight) ? anchorPoint
+ (i - midFold) * scaledHeight : anchorPoint
- (midFold - i) * scaledHeight;
_dst[2] = isEven ? leftScaledPoint : 0;
_dst[3] = (anchorPoint > (i + 1) * _foldDrawHeight) ? anchorPoint
+ (i + 1 - midFold) * scaledHeight
: anchorPoint - (midFold - i - 1) * scaledHeight;
_dst[4] = isEven ? _foldDrawWidth : rightScaledPoint;
_dst[5] = _dst[1];
_dst[6] = isEven ? rightScaledPoint : _foldDrawWidth;
_dst[7] = _dst[3];
}
for (var j = 0; j < NumOfPolyPoints; j++)
{
_dst[j] = (float)Math.Round(_dst[j]);
}
if (_isHorizontal)
{
if (_dst[4] <= _dst[0] || _dst[6] <= _dst[2])
{
_shouldDraw = false;
return;
}
}
else
{
if (_dst[3] <= _dst[1] || _dst[7] <= _dst[5])
{
_shouldDraw = false;
return;
}
}
_matrix[i].SetPolyToPoly(_src, 0, _dst, 0, NumOfPolyPoints / 2);
}
var alpha = (int)(_foldFactor * 255 * ShadingAlpha);
_solidShadow.Color = Color.Argb(alpha, 0, 0, 0);
if (_isHorizontal)
{
_shadowGradientMatrix.SetScale(_foldDrawWidth, 1);
_shadowLinearGradient.SetLocalMatrix(_shadowGradientMatrix);
}
else
{
_shadowGradientMatrix.SetScale(1, _foldDrawHeight);
_shadowLinearGradient.SetLocalMatrix(_shadowGradientMatrix);
}
_gradientShadow.Alpha = alpha;
}