Stani Michiels' full support for fill styles and excellent tutorial to

demonstrate it.

2 files changed, 103 insertions, 5 deletions

diff --git a/fpdf.go b/fpdf.go
index ea4b384..55bb848 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -858,14 +858,26 @@ func (f *Fpdf) Line(x1, y1, x2, y2 float64) {
 	f.outf("%.2f %.2f m %.2f %.2f l S", x1*f.k, (f.h-y1)*f.k, x2*f.k, (f.h-y2)*f.k)
 }
 
+// fillDrawOp corrects path painting operators
 func fillDrawOp(styleStr string) (opStr string) {
 	switch strings.ToUpper(styleStr) {
+	case "", "D":
+		// Stroke the path.
+		opStr = "S"
 	case "F":
+		// fill the path, using the nonzero winding number rule
 		opStr = "f"
+	case "F*":
+		// fill the path, using the even-odd rule
+		opStr = "f*"
 	case "FD", "DF":
+		// fill and then stroke the path, using the nonzero winding number rule
 		opStr = "B"
+	case "FD*", "DF*":
+		// fill and then stroke the path, using the even-odd rule
+		opStr = "B*"
 	default:
-		opStr = "S"
+		opStr = styleStr
 	}
 	return
 }
@@ -931,7 +943,7 @@ func (f *Fpdf) Polygon(points []PointType, styleStr string) {
 			}
 		}
 		f.outf("%.5f %.5f l ", points[0].X*f.k, (f.h-points[0].Y)*f.k)
-		f.outf(fillDrawOp(styleStr))
+		f.DrawPath(styleStr)
 	}
 }
 
@@ -966,7 +978,7 @@ func (f *Fpdf) Beziergon(points []PointType, styleStr string) {
 		points = points[3:]
 	}
 
-	f.outf(fillDrawOp(styleStr))
+	f.DrawPath(styleStr)
 }
 
 // Outputs current point
@@ -3507,8 +3519,18 @@ func (f *Fpdf) ClosePath() {
 // DrawPath actually draws the path on the page.
 //
 // styleStr can be "F" for filled, "D" for outlined only, or "DF" or "FD" for
-// outlined and filled. An empty string will be replaced with "D". Drawing uses
-// the current draw color, line width, and cap style centered on the
+// outlined and filled. An empty string will be replaced with "D".
+// Path-painting operators as defined in the PDF specification are also
+// allowed: "S" (Stroke the path), "s" (Close and stroke the path),
+// "f" (fill the path, using the nonzero winding number), "f*"
+// (Fill the path, using the even-odd rule), "B" (Fill and then stroke
+// the path, using the nonzero winding number rule), "B*" (Fill and
+// then stroke the path, using the even-odd rule), "b" (Close, fill,
+// and then stroke the path, using the nonzero winding number rule) and
+// "b*" (Close, fill, and then stroke the path, using the even-odd
+// rule).
+// Drawing uses the current draw color, line width, and cap style
+// centered on the
 // path. Filling uses the current fill color.
 //
 // See tutorial 30 for an example of this function.
diff --git a/fpdf_test.go b/fpdf_test.go
index 9ac1e18..3872331 100644
--- a/fpdf_test.go
+++ b/fpdf_test.go
@@ -26,6 +26,7 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
 
 	"github.com/jung-kurt/gofpdf"
@@ -1516,3 +1517,78 @@ func ExampleFpdf_tutorial31() {
 	// Output:
 	// Successfully generated pdf/tutorial31.pdf
 }
+
+// This example demonstrates the Path Drawing functions, such as: MoveTo,
+// LineTo, CurveTo, ..., ClosePath and DrawPath.
+func ExampleFpdf_tutorial32() {
+	pdf := gofpdf.New("P", "mm", "A4", "")
+	pdf.SetDrawColor(0xff, 0x00, 0x00)
+	pdf.SetFillColor(0x99, 0x99, 0x99)
+	pdf.SetFont("Helvetica", "", 15)
+	pdf.AddPage()
+	pdf.SetAlpha(1, "Multiply")
+	var (
+		polygon = func(cx, cy, r, n, dir float64) {
+			da := 2 * math.Pi / n
+			pdf.MoveTo(cx+r, cy)
+			pdf.Text(cx+r, cy, "0")
+			i := 1
+			for a := da; a < 2*math.Pi; a += da {
+				x, y := cx+r*math.Cos(dir*a), cy+r*math.Sin(dir*a)
+				pdf.LineTo(x, y)
+				pdf.Text(x, y, strconv.Itoa(i))
+				i++
+			}
+			pdf.ClosePath()
+		}
+		polygons = func(cx, cy, r, n, dir float64) {
+			d := 1.0
+			for rf := r; rf > 0; rf -= 10 {
+				polygon(cx, cy, rf, n, d)
+				d *= dir
+			}
+		}
+		star = func(cx, cy, r, n float64) {
+			da := 4 * math.Pi / n
+			pdf.MoveTo(cx+r, cy)
+			for a := da; a < 4*math.Pi+da; a += da {
+				x, y := cx+r*math.Cos(a), cy+r*math.Sin(a)
+				pdf.LineTo(x, y)
+			}
+			pdf.ClosePath()
+		}
+	)
+	// triangle
+	polygons(55, 45, 40, 3, 1)
+	pdf.DrawPath("B")
+	pdf.Text(15, 95, "B (same direction, non zero winding)")
+
+	// square
+	polygons(155, 45, 40, 4, 1)
+	pdf.DrawPath("B*")
+	pdf.Text(115, 95, "B* (same direction, even odd)")
+
+	// pentagon
+	polygons(55, 145, 40, 5, -1)
+	pdf.DrawPath("B")
+	pdf.Text(15, 195, "B (different direction, non zero winding)")
+
+	// hexagon
+	polygons(155, 145, 40, 6, -1)
+	pdf.DrawPath("B*")
+	pdf.Text(115, 195, "B* (different direction, even odd)")
+
+	// star
+	star(55, 245, 40, 5)
+	pdf.DrawPath("B")
+	pdf.Text(15, 290, "B (non zero winding)")
+
+	// star
+	star(155, 245, 40, 5)
+	pdf.DrawPath("B*")
+	pdf.Text(115, 290, "B* (even odd)")
+
+	pdf.OutputAndClose(docWriter(pdf, 32))
+	// Output:
+	// Successfully generated pdf/tutorial32.pdf
+}