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Improve minimum bounding box orientation v2

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BobLd
2020-01-23 11:46:47 +00:00
committed by Eliot Jones
parent bff18d81ca
commit 4c65cbc139
1 changed files with 28 additions and 34 deletions
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62
src/UglyToad.PdfPig/Content/Word.cs
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@@ -280,54 +280,48 @@
r.GlyphRectangle.TopRight
}).Distinct();
var convexHull = GeometryExtensions.GrahamScan(points).ToList();
// Candidates bounding boxes
var mbr = GeometryExtensions.ParametricPerpendicularProjection(convexHull);
var mbrPoints = new[] { mbr.TopLeft, mbr.TopRight, mbr.BottomLeft, mbr.BottomRight };
var mbr1 = new PdfRectangle(mbr.BottomLeft, mbr.TopLeft, mbr.BottomRight, mbr.TopRight);
var mbr2 = new PdfRectangle(mbr.TopRight, mbr.BottomRight, mbr.TopLeft, mbr.BottomLeft);
var mbr3 = new PdfRectangle(mbr.BottomRight, mbr.BottomLeft, mbr.TopRight, mbr.TopLeft);
// Find the orientation of the minimum bounding box, using the baseline angle.
// This method needs improvment as the baseline angle and the bbox angle can
// belong to different quadrants of the unit circle.
var firstLetter = letters[0];
var lastLetter = letters[letters.Count - 1];
var rotation = Math.Atan2(
var baseLineAngle = Math.Atan2(
lastLetter.EndBaseLine.Y - firstLetter.StartBaseLine.Y,
lastLetter.EndBaseLine.X - firstLetter.StartBaseLine.X);
if (rotation >= -Math.PI && rotation <= -1.570796) // (-180 to -90deg)
var bbox = mbr;
var deltaAngle = Math.Abs(baseLineAngle - Math.Atan2(mbr.BottomRight.Y - mbr.BottomLeft.Y,
mbr.BottomRight.X - mbr.BottomLeft.X));
double deltaAngle1 = Math.Abs(baseLineAngle - Math.Atan2(mbr1.BottomRight.Y - mbr1.BottomLeft.Y,
mbr1.BottomRight.X - mbr1.BottomLeft.X));
if (deltaAngle1 < deltaAngle)
{
var br = mbrPoints.OrderBy(p => p.X).ThenByDescending(p => p.Y).First();
var bl = mbrPoints.OrderByDescending(p => p.Y).ThenByDescending(p => p.X).First();
var tl = mbrPoints.OrderByDescending(p => p.Y).ThenBy(p => p.X).First();
var tr = mbrPoints.OrderBy(p => p.X).ThenBy(p => p.Y).First();
return new Tuple<string, PdfRectangle>(builder.ToString(), new PdfRectangle(tl, tr, bl, br));
deltaAngle = deltaAngle1;
bbox = mbr1;
}
else if (rotation > -1.570796 && rotation <= 0.0) // (-90deg to 0)
double deltaAngle2 = Math.Abs(baseLineAngle - Math.Atan2(mbr2.BottomRight.Y - mbr2.BottomLeft.Y,
mbr2.BottomRight.X - mbr2.BottomLeft.X));
if (deltaAngle2 < deltaAngle)
{
var bl = mbrPoints.OrderBy(p => p.X).ThenBy(p => p.Y).First();
var tl = mbrPoints.OrderByDescending(p => p.Y).ThenBy(p => p.X).First();
var tr = mbrPoints.OrderByDescending(p => p.X).ThenByDescending(p => p.Y).First();
var br = mbrPoints.OrderBy(p => p.Y).ThenByDescending(p => p.X).First();
return new Tuple<string, PdfRectangle>(builder.ToString(), new PdfRectangle(tl, tr, bl, br));
deltaAngle = deltaAngle2;
bbox = mbr2;
}
else if (rotation > 0.0 && rotation <= 1.570796) // (0 to 90deg)
double deltaAngle3 = Math.Abs(baseLineAngle - Math.Atan2(mbr3.BottomRight.Y - mbr3.BottomLeft.Y,
mbr3.BottomRight.X - mbr3.BottomLeft.X));
if (deltaAngle3 < deltaAngle)
{
var tl = mbrPoints.OrderBy(p => p.X).ThenByDescending(p => p.Y).First();
var bl = mbrPoints.OrderBy(p => p.Y).ThenBy(p => p.X).First();
var br = mbrPoints.OrderByDescending(p => p.X).ThenBy(p => p.Y).First();
var tr = mbrPoints.OrderByDescending(p => p.Y).ThenByDescending(p => p.X).First();
return new Tuple<string, PdfRectangle>(builder.ToString(), new PdfRectangle(tl, tr, bl, br));
}
else if (rotation > 1.570796 && rotation <= Math.PI) // (90 to 180deg)
{
var tr = mbrPoints.OrderBy(p => p.X).ThenBy(p => p.Y).First();
var bl = mbrPoints.OrderByDescending(p => p.X).ThenByDescending(p => p.Y).First();
var br = mbrPoints.OrderByDescending(p => p.Y).ThenBy(p => p.X).First();
var tl = mbrPoints.OrderBy(p => p.X).ThenByDescending(p => p.Y).First();
return new Tuple<string, PdfRectangle>(builder.ToString(), new PdfRectangle(tl, tr, bl, br));
}
else
{
throw new ArgumentOutOfRangeException(nameof(rotation), "Word orientation not handled.");
bbox = mbr3;
}
return new Tuple<string, PdfRectangle>(builder.ToString(), bbox);
}
#endregion