Added SplitLines function by Bruno Michel and demonstration of its use.

2 files changed, 80 insertions, 0 deletions

diff --git a/fpdf.go b/fpdf.go
index e239a32..ff50b2f 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -1605,6 +1605,59 @@ func (f *Fpdf) Cellf(w, h float64, fmtStr string, args ...interface{}) {
 	f.CellFormat(w, h, sprintf(fmtStr, args...), "", 0, "L", false, 0, "")
 }
 
+// SplitLines splits text into several lines using the current font. Each line
+// has its length limited to a maximum width given by w. This function can be
+// used to determine the total height of wrapped text for vertical placement
+// purposes.
+//
+// You can use MultiCell if you want to print a text on several lines in a
+// simple way.
+//
+// See tutorial 19 for an example of this function.
+func (f *Fpdf) SplitLines(txt []byte, w float64) [][]byte {
+	// Function contributed by Bruno Michel
+	lines := [][]byte{}
+	cw := &f.currentFont.Cw
+	wmax := (w - 2*f.cMargin) * 1000 / f.fontSize
+	s := bytes.Replace(txt, []byte("\r"), []byte{}, -1)
+	nb := len(s)
+	for nb > 0 && s[nb-1] == '\n' {
+		nb--
+	}
+	s = s[0:nb]
+	sep := -1
+	i := 0
+	j := 0
+	l := 0.0
+	for i < nb {
+		c := s[i]
+		l += float64(cw[c])
+		if c == ' ' || c == '\t' || c == '\n' {
+			sep = i
+		}
+		if c == '\n' || l > wmax {
+			if sep == -1 {
+				if i == j {
+					i++
+				}
+				sep = i
+			} else {
+				i = sep + 1
+			}
+			lines = append(lines, s[j:sep])
+			sep = -1
+			j = i
+			l = 0
+		} else {
+			i++
+		}
+	}
+	if i != j {
+		lines = append(lines, s[j:i])
+	}
+	return lines
+}
+
 // MultiCell supports printing text with line breaks. They can be automatic (as
 // soon as the text reaches the right border of the cell) or explicit (via the
 // \n character). As many cells as necessary are output, one below the other.
diff --git a/fpdf_test.go b/fpdf_test.go
index 5edc6c8..d70875a 100644
--- a/fpdf_test.go
+++ b/fpdf_test.go
@@ -1131,3 +1131,30 @@ func ExampleFpdf_tutorial18() {
 	// Output:
 	// Successfully generated pdf/tutorial18.pdf
 }
+
+// Example to demonstrate Bruno Michel's line splitting function.
+func ExampleFpdf_tutorial19() {
+	const (
+		fontPtSize = 18.0
+		lineHt     = fontPtSize * 25.4 / 72.0
+		wd         = 100.0
+	)
+	pdf := gofpdf.New("P", "mm", "A4", cnFontDir) // A4 210.0 x 297.0
+	pdf.SetFont("Times", "", fontPtSize)
+	pdf.AddPage()
+	pdf.SetMargins(10, 10, 10)
+	lines := pdf.SplitLines([]byte(lorem()), wd)
+	ht := float64(len(lines)) * lineHt
+	y := (297.0 - ht) / 2.0
+	pdf.SetDrawColor(128, 128, 128)
+	pdf.SetFillColor(255, 255, 210)
+	x := (210.0 - (wd + 40.0)) / 2.0
+	pdf.Rect(x, y-20.0, wd+40.0, ht+40.0, "FD")
+	pdf.SetY(y)
+	for _, line := range lines {
+		pdf.CellFormat(190.0, lineHt, string(line), "", 1, "C", false, 0, "")
+	}
+	pdf.OutputAndClose(docWriter(pdf, 19))
+	// Output:
+	// Successfully generated pdf/tutorial19.pdf
+}