Trigger an error when attempting to render text if font has not been set

2 files changed, 34 insertions, 1 deletions

diff --git a/fpdf.go b/fpdf.go
index 78a7c65..c862364 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -1793,6 +1793,9 @@ func (f *Fpdf) SetAcceptPageBreakFunc(fnc func() bool) {
 // current position moves to the right or to the next line. It is possible to
 // put a link on the text.
 //
+// An error will be returned if a call to SetFont() has not already taken
+// place before this method is called.
+//
 // If automatic page breaking is enabled and the cell goes beyond the limit, a
 // page break is done before outputting.
 //
@@ -1823,11 +1826,18 @@ func (f *Fpdf) SetAcceptPageBreakFunc(fnc func() bool) {
 //
 // linkStr is a target URL or empty for no external link. A non--zero value for
 // link takes precedence over linkStr.
-func (f *Fpdf) CellFormat(w, h float64, txtStr string, borderStr string, ln int, alignStr string, fill bool, link int, linkStr string) {
+func (f *Fpdf) CellFormat(w, h float64, txtStr string, borderStr string, ln int,
+	alignStr string, fill bool, link int, linkStr string) {
 	// dbg("CellFormat. h = %.2f, borderStr = %s", h, borderStr)
 	if f.err != nil {
 		return
 	}
+
+	if f.currentFont.Name == "" {
+		f.err = fmt.Errorf("font has not been set; unable to render text")
+		return
+	}
+
 	borderStr = strings.ToUpper(borderStr)
 	k := f.k
 	if f.y+h > f.pageBreakTrigger && !f.inHeader && !f.inFooter && f.acceptPageBreak() {
diff --git a/fpdf_test.go b/fpdf_test.go
index 5781ad6..7da45aa 100644
--- a/fpdf_test.go
+++ b/fpdf_test.go
@@ -28,6 +28,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"testing"
 
 	"github.com/jung-kurt/gofpdf"
 	"github.com/jung-kurt/gofpdf/internal/example"
@@ -55,6 +56,28 @@ func cleanup() {
 		})
 }
 
+// TestIssue0116 addresses issue 116 in which library silently fails after
+// calling CellFormat when no font has been set.
+func TestIssue0116(t *testing.T) {
+	var pdf *gofpdf.Fpdf
+
+	pdf = gofpdf.New("P", "mm", "A4", "")
+	pdf.AddPage()
+	pdf.SetFont("Arial", "B", 16)
+	pdf.Cell(40, 10, "OK")
+	if pdf.Error() != nil {
+		t.Fatalf("not expecting error when rendering text")
+	}
+
+	pdf = gofpdf.New("P", "mm", "A4", "")
+	pdf.AddPage()
+	pdf.Cell(40, 10, "Not OK") // Font not set
+	if pdf.Error() == nil {
+		t.Fatalf("expecting error when rendering text without having set font")
+	}
+
+}
+
 type fontResourceType struct {
 }