public LayoutInformation(ImageState state)
{
this.instructions = new NameValueCollection(state.settings);
this.sourceRect = new SizeOnly(state.originalSize);
this.finalRect = new SizeOnly(state.destSize);
this.imageSourcePoly = new PolyRect(state.copyRect);
if (state.layout.ContainsRing("image"))
{
this.imageDestPoly = new PolyRect(state.layout["image"]);
}
if (state.layout.ContainsRing("imageArea"))
{
this.imageDestAreaPoly = new PolyRect(state.layout["imageArea"]);
}
// Check to see if sFlip/sRotate has altered the original raw image
// rectangle. The check must be the same as in
// ImageBuilder.PrepareSourceBitmap(). Note that the adjustment
// happens only when there's an actual bitmap, regardless of the
// sFlip/sRotate settings.
if (state.sourceBitmap != null &&
(state.settings.SourceFlip != RotateFlipType.RotateNoneFlipNone ||
!string.IsNullOrEmpty(state.settings["sRotate"])))
{
// We need to calculate the original rect/poly by *reversing* the
// requested sFlip/sRotate. We determine what the requested change
// was, then calculate the reverse.
var angle = state.settings.Get <double>("sRotate", 0);
var flipRotate = (int)PolygonMath.CombineFlipAndRotate(state.settings.SourceFlip, angle);
var copyPoly = PolygonMath.ToPoly(state.copyRect);
var trueOriginalSize = state.originalSize;
// The RotateFlipType values are ordered such that odd values
// transpose the size of the rectangle, %4 gives the rotation
// and /4 (=> 0 or 1) whether there's been an x-flip. We can
// use this to streamline our calculations.
if (flipRotate % 2 == 1)
{
trueOriginalSize = new Size(state.originalSize.Height, state.originalSize.Width);
}
this.preAdjustedSourceRect = new SizeOnly(trueOriginalSize);
// Remember that the sFlip/sRotate change performed the rotation
// first and then the flip, so we have to do the opposite to go
// backwards.
if (flipRotate / 4 == 1)
{
copyPoly = PolygonMath.ScalePoints(copyPoly, -1, 1, PointF.Empty);
copyPoly = PolygonMath.MovePoly(copyPoly, new PointF(trueOriginalSize.Width, 0));
}
// It's possible to calculate a rotation-origin that will place
// the original pre-sRotate (0,0) point back at (0,0) again...
// but since it involves sqrt(), there would be rounding errors
// that we should be able to avoid. (We might, in fact, want to
// avoid using PolygonMath entirely, and hand-map the points
// backwards for accuracy.)
switch (flipRotate % 4)
{
case 0: // no rotation
// no-op!
break;
case 1: // 90 degrees, clockwise
copyPoly = PolygonMath.RotatePoly(copyPoly, -90);
copyPoly = PolygonMath.MovePoly(copyPoly, new PointF(0, trueOriginalSize.Height));
break;
case 2: // 180 degrees, clockwise
copyPoly = PolygonMath.RotatePoly(copyPoly, -180);
copyPoly = PolygonMath.MovePoly(copyPoly, new PointF(trueOriginalSize.Width, trueOriginalSize.Height));
break;
case 3: // 270 degrees, clockwise
copyPoly = PolygonMath.RotatePoly(copyPoly, -270);
copyPoly = PolygonMath.MovePoly(copyPoly, new PointF(trueOriginalSize.Width, 0));
break;
}
this.preAdjustedImageSourcePoly = new PolyRect(copyPoly);
}
}