Add SetHeaderFuncMode() method to automatically set position to left and top margin after header function is called. Backward compatibility is preserved. This addresses issue #174.

3 files changed, 23 insertions, 2 deletions

diff --git a/def.go b/def.go
index 53bd90a..d53e627 100644
--- a/def.go
+++ b/def.go
@@ -321,6 +321,7 @@ type Fpdf struct {
 	pageBreakTrigger float64                   // threshold used to trigger page breaks
 	inHeader         bool                      // flag set when processing header
 	headerFnc        func()                    // function provided by app and called to write header
+	headerHomeMode   bool                      // set position to home after headerFnc is called
 	inFooter         bool                      // flag set when processing footer
 	footerFnc        func()                    // function provided by app and called to write footer
 	footerFncLpi     func(bool)                // function provided by app and called to write footer with last page flag
diff --git a/fpdf.go b/fpdf.go
index 4afdb8c..0e7071f 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -350,6 +350,15 @@ func (f *Fpdf) SetFontLoader(loader FontLoader) {
 	f.fontLoader = loader
 }
 
+// SetHeaderFuncMode sets the function that lets the application render the
+// page header. See SetHeaderFunc() for more details. The value for homeMode
+// should be set to true to have the current position set to the left and top
+// margin after the header function is called.
+func (f *Fpdf) SetHeaderFuncMode(fnc func(), homeMode bool) {
+	f.headerFnc = fnc
+	f.headerHomeMode = homeMode
+}
+
 // SetHeaderFunc sets the function that lets the application render the page
 // header. The specified function is automatically called by AddPage() and
 // should not be called directly by the application. The implementation in Fpdf
@@ -676,6 +685,9 @@ func (f *Fpdf) AddPageFormat(orientationStr string, size SizeType) {
 		f.inHeader = true
 		f.headerFnc()
 		f.inHeader = false
+		if f.headerHomeMode {
+			f.SetHomeXY()
+		}
 	}
 	// 	Restore line width
 	if f.lineWidth != lw {
@@ -2702,6 +2714,13 @@ func (f *Fpdf) SetY(y float64) {
 	}
 }
 
+// SetHomeXY is a convenience method that sets the current position to the left
+// and top margins.
+func (f *Fpdf) SetHomeXY() {
+	f.SetY(f.tMargin)
+	f.SetX(f.lMargin)
+}
+
 // SetXY defines the abscissa and ordinate of the current position. If the
 // passed values are negative, they are relative respectively to the right and
 // bottom of the page.
diff --git a/fpdf_test.go b/fpdf_test.go
index bbeb5b0..9f0ee96 100644
--- a/fpdf_test.go
+++ b/fpdf_test.go
@@ -206,14 +206,15 @@ func Example() {
 // This example demonsrates the generation of headers, footers and page breaks.
 func ExampleFpdf_AddPage() {
 	pdf := gofpdf.New("P", "mm", "A4", "")
-	pdf.SetHeaderFunc(func() {
+	pdf.SetTopMargin(30)
+	pdf.SetHeaderFuncMode(func() {
 		pdf.Image(example.ImageFile("logo.png"), 10, 6, 30, 0, false, "", 0, "")
 		pdf.SetY(5)
 		pdf.SetFont("Arial", "B", 15)
 		pdf.Cell(80, 0, "")
 		pdf.CellFormat(30, 10, "Title", "1", 0, "C", false, 0, "")
 		pdf.Ln(20)
-	})
+	}, true)
 	pdf.SetFooterFunc(func() {
 		pdf.SetY(-15)
 		pdf.SetFont("Arial", "I", 8)