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Improve minimum bounding box orientation

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BobLd
2020-01-23 11:11:38 +00:00
committed by Eliot Jones
parent 483b30f44d
commit bff18d81ca
1 changed files with 38 additions and 26 deletions
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64
src/UglyToad.PdfPig/Content/Word.cs
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@@ -266,6 +266,12 @@
private Tuple<string, PdfRectangle> GetBoundingBoxOther(IReadOnlyList<Letter> letters) private Tuple<string, PdfRectangle> GetBoundingBoxOther(IReadOnlyList<Letter> letters)
{ {
var builder = new StringBuilder();
for (var i = 0; i < letters.Count; i++)
{
builder.Append(letters[i].Value);
}
var points = letters.SelectMany(r => new[] var points = letters.SelectMany(r => new[]
{ {
r.StartBaseLine, r.StartBaseLine,
@@ -274,47 +280,53 @@
r.GlyphRectangle.TopRight r.GlyphRectangle.TopRight
}).Distinct(); }).Distinct();
var convexHull = GeometryExtensions.GrahamScan(points).ToList(); var convexHull = GeometryExtensions.GrahamScan(points).ToList();
var minimalBoundingRectangle = GeometryExtensions.ParametricPerpendicularProjection(convexHull); var mbr = GeometryExtensions.ParametricPerpendicularProjection(convexHull);
var mbrPoints = new[] { mbr.TopLeft, mbr.TopRight, mbr.BottomLeft, mbr.BottomRight };
var builder = new StringBuilder();
for (var i = 0; i < letters.Count; i++)
{
builder.Append(letters[i].Value);
}
// 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 firstLetter = letters[0];
var lastLetter = letters[letters.Count - 1]; var lastLetter = letters[letters.Count - 1];
var rotation = Math.Atan2( var rotation = Math.Atan2(
lastLetter.EndBaseLine.Y - firstLetter.StartBaseLine.Y, lastLetter.EndBaseLine.Y - firstLetter.StartBaseLine.Y,
lastLetter.EndBaseLine.X - firstLetter.StartBaseLine.X); lastLetter.EndBaseLine.X - firstLetter.StartBaseLine.X);
if (rotation >= -0.785398 && rotation < 0.785398) if (rotation >= -Math.PI && rotation <= -1.570796) // (-180 to -90deg)
{ {
// top border on top var br = mbrPoints.OrderBy(p => p.X).ThenByDescending(p => p.Y).First();
//return new Tuple<string, PdfRectangle>(builder.ToString(), new PdfRectangle(minX, minY, maxX, maxY)); var bl = mbrPoints.OrderByDescending(p => p.Y).ThenByDescending(p => p.X).First();
return new Tuple<string, PdfRectangle>(builder.ToString(), minimalBoundingRectangle); 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));
} }
else if (rotation >= 0.785398 && rotation < 2.356194) else if (rotation > -1.570796 && rotation <= 0.0) // (-90deg to 0)
{ {
// top border on the left var bl = mbrPoints.OrderBy(p => p.X).ThenBy(p => p.Y).First();
//return new Tuple<string, PdfRectangle>(builder.ToString(), new PdfRectangle( var tl = mbrPoints.OrderByDescending(p => p.Y).ThenBy(p => p.X).First();
// new PdfPoint(minX, minY), new PdfPoint(minX, maxY), var tr = mbrPoints.OrderByDescending(p => p.X).ThenByDescending(p => p.Y).First();
// new PdfPoint(maxX, minY), new PdfPoint(maxX, maxY))); var br = mbrPoints.OrderBy(p => p.Y).ThenByDescending(p => p.X).First();
return new Tuple<string, PdfRectangle>(builder.ToString(), minimalBoundingRectangle); return new Tuple<string, PdfRectangle>(builder.ToString(), new PdfRectangle(tl, tr, bl, br));
} }
else if (rotation >= 2.356194 && rotation < 3.926991) else if (rotation > 0.0 && rotation <= 1.570796) // (0 to 90deg)
{ {
// top border on the bottom var tl = mbrPoints.OrderBy(p => p.X).ThenByDescending(p => p.Y).First();
//return new Tuple<string, PdfRectangle>(builder.ToString(), new PdfRectangle(minX, maxY, maxX, minY)); var bl = mbrPoints.OrderBy(p => p.Y).ThenBy(p => p.X).First();
return new Tuple<string, PdfRectangle>(builder.ToString(), minimalBoundingRectangle); 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 else
{ {
// top border on the right throw new ArgumentOutOfRangeException(nameof(rotation), "Word orientation not handled.");
//return new Tuple<string, PdfRectangle>(builder.ToString(), new PdfRectangle(
// new PdfPoint(maxX, maxY), new PdfPoint(maxX, minY),
// new PdfPoint(minX, maxY), new PdfPoint(minX, minY)));
return new Tuple<string, PdfRectangle>(builder.ToString(), minimalBoundingRectangle);
} }
} }
#endregion #endregion