Start with the conversion of indexed examples to ones that are associated with

a gofpdf method. This involves changes mostly in the test source file, but also
references in the main source files. After this conversion is complete, the
docWriter routine and interface can be scrapped. The current scheme will be
more straightforward for programmers using the library.

2 files changed, 62 insertions, 29 deletions

diff --git a/fpdf.go b/fpdf.go
index 55bb848..ea7c373 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -330,6 +330,8 @@ func (f *Fpdf) SetFontLoader(loader FontLoader) {
 // is empty, so you have to provide an appropriate function if you want page
 // headers. fnc will typically be a closure that has access to the Fpdf
 // instance and other document generation variables.
+//
+// This method is demonstrated in the example for AddPage().
 func (f *Fpdf) SetHeaderFunc(fnc func()) {
 	f.headerFnc = fnc
 }
@@ -340,6 +342,8 @@ func (f *Fpdf) SetHeaderFunc(fnc func()) {
 // implementation in Fpdf is empty, so you have to provide an appropriate
 // function if you want page footers. fnc will typically be a closure that has
 // access to the Fpdf instance and other document generation variables.
+//
+// This method is demonstrated in the example for AddPage().
 func (f *Fpdf) SetFooterFunc(fnc func()) {
 	f.footerFnc = fnc
 }
@@ -469,6 +473,8 @@ func (f *Fpdf) SetCreator(creatorStr string, isUTF8 bool) {
 // AliasNbPages defines an alias for the total number of pages. It will be
 // substituted as the document is closed. An empty string is replaced with the
 // string "{nb}". This method is demonstrated in tutorial 2.
+//
+// See the example for AddPage() for a demonstration of this method.
 func (f *Fpdf) AliasNbPages(aliasStr string) {
 	if aliasStr == "" {
 		aliasStr = "{nb}"
@@ -657,6 +663,8 @@ func (f *Fpdf) AddPage() {
 }
 
 // PageNo returns the current page number.
+//
+// See the example for AddPage() for a demonstration of this method.
 func (f *Fpdf) PageNo() int {
 	return f.page
 }
@@ -1640,8 +1648,8 @@ func (f *Fpdf) Text(x, y float64, txtStr string) {
 // mode selected by SetAutoPageBreak. The function provided should not be
 // called by the application.
 //
-// See tutorial 4 for an example of how this function can be used to manage
-// multiple columns.
+// See the example for SetLeftMargin() to see how this function can be used to
+// manage multiple columns.
 func (f *Fpdf) SetAcceptPageBreakFunc(fnc func() bool) {
 	f.acceptPageBreak = fnc
 }
@@ -2115,6 +2123,8 @@ func (f *Fpdf) WriteLinkID(h float64, displayStr string, linkID int) {
 // Ln performs a line break. The current abscissa goes back to the left margin
 // and the ordinate increases by the amount passed in parameter. A negative
 // value of h indicates the height of the last printed cell.
+//
+// This method is demonstrated in the example for MultiCell.
 func (f *Fpdf) Ln(h float64) {
 	f.x = f.lMargin
 	if h < 0 {
diff --git a/fpdf_test.go b/fpdf_test.go
index 3872331..eaed7d8 100644
--- a/fpdf_test.go
+++ b/fpdf_test.go
@@ -34,10 +34,11 @@ import (
 
 // Absolute path needed for gocov tool; relative OK for test
 const (
-	cnGofpdfDir = "."
-	cnFontDir   = cnGofpdfDir + "/font"
-	cnImgDir    = cnGofpdfDir + "/image"
-	cnTextDir   = cnGofpdfDir + "/text"
+	cnGofpdfDir  = "."
+	cnFontDir    = cnGofpdfDir + "/font"
+	cnImgDir     = cnGofpdfDir + "/image"
+	cnTextDir    = cnGofpdfDir + "/text"
+	cnExampleDir = cnGofpdfDir + "/pdf"
 )
 
 type nullWriter struct {
@@ -105,6 +106,10 @@ func textFile(fileStr string) string {
 	return filepath.Join(cnTextDir, fileStr)
 }
 
+func exampleFile(fileStr string) string {
+	return filepath.Join(cnExampleDir, fileStr)
+}
+
 type fontResourceType struct {
 }
 
@@ -137,27 +142,37 @@ func lorem() string {
 		"officia deserunt mollit anim id est laborum."
 }
 
-// Hello, world. Note that since only core fonts are used (in this case Arial,
-// a synonym for Helvetica), an empty string can be specified for the font
-// directory in the call to New().
-func ExampleFpdf_tutorial01() {
+func exampleFilename(baseStr string) string {
+	return filepath.Join(cnExampleDir, baseStr+".pdf")
+}
+
+func summary(err error, fileStr string) {
+	if err == nil {
+		fmt.Printf("Successfully generated %s\n", fileStr)
+	} else {
+		fmt.Println(err)
+	}
+}
+
+// This example demonstrates the generation of a simple PDF document. Note that
+// since only core fonts are used (in this case Arial, a synonym for
+// Helvetica), an empty string can be specified for the font directory in the
+// call to New(). Note also that the exampleFilename and summary functions are
+// local to the test file and are not part of the gofpdf library.
+func Example() {
 	pdf := gofpdf.New("P", "mm", "A4", "")
 	pdf.AddPage()
 	pdf.SetFont("Arial", "B", 16)
 	pdf.Cell(40, 10, "Hello World!")
-	fileStr := filepath.Join(cnGofpdfDir, "pdf/tutorial01.pdf")
+	fileStr := exampleFilename("basic")
 	err := pdf.OutputFileAndClose(fileStr)
-	if err == nil {
-		fmt.Println("Successfully generated pdf/tutorial01.pdf")
-	} else {
-		fmt.Println(err)
-	}
+	summary(err, fileStr)
 	// Output:
-	// Successfully generated pdf/tutorial01.pdf
+	// Successfully generated pdf/basic.pdf
 }
 
-// Header, footer and page-breaking
-func ExampleFpdf_tutorial02() {
+// This example demonsrates the generation of headers, footers and page breaks.
+func ExampleFpdf_AddPage() {
 	pdf := gofpdf.New("P", "mm", "A4", "")
 	pdf.SetHeaderFunc(func() {
 		pdf.Image(imageFile("logo.png"), 10, 6, 30, 0, false, "", 0, "")
@@ -178,13 +193,16 @@ func ExampleFpdf_tutorial02() {
 	for j := 1; j <= 40; j++ {
 		pdf.CellFormat(0, 10, fmt.Sprintf("Printing line number %d", j), "", 1, "", false, 0, "")
 	}
-	pdf.OutputAndClose(docWriter(pdf, 2))
+	fileStr := exampleFilename("addpage")
+	err := pdf.OutputFileAndClose(fileStr)
+	summary(err, fileStr)
 	// Output:
-	// Successfully generated pdf/tutorial02.pdf
+	// Successfully generated pdf/addpage.pdf
 }
 
-// Word-wrapping, line justification and page-breaking
-func ExampleFpdf_tutorial03() {
+// This example demonstrates word-wrapping, line justification and
+// page-breaking.
+func ExampleFpdf_MultiCell() {
 	pdf := gofpdf.New("P", "mm", "A4", "")
 	titleStr := "20000 Leagues Under the Seas"
 	pdf.SetTitle(titleStr, false)
@@ -249,13 +267,16 @@ func ExampleFpdf_tutorial03() {
 	}
 	printChapter(1, "A RUNAWAY REEF", textFile("20k_c1.txt"))
 	printChapter(2, "THE PROS AND CONS", textFile("20k_c2.txt"))
-	pdf.OutputAndClose(docWriter(pdf, 3))
+	fileStr := exampleFilename("multicell")
+	err := pdf.OutputFileAndClose(fileStr)
+	summary(err, fileStr)
 	// Output:
-	// Successfully generated pdf/tutorial03.pdf
+	// Successfully generated pdf/multicell.pdf
 }
 
-// Multiple column layout
-func ExampleFpdf_tutorial04() {
+// This example demonstrates the generation of a PDF document that has multiple
+// columns. This is accomplished with the SetLeftMargin() and Cell() methods.
+func ExampleFpdf_SetLeftMargin() {
 	var y0 float64
 	var crrntCol int
 	pdf := gofpdf.New("P", "mm", "A4", "")
@@ -350,9 +371,11 @@ func ExampleFpdf_tutorial04() {
 	})
 	printChapter(1, "A RUNAWAY REEF", textFile("20k_c1.txt"))
 	printChapter(2, "THE PROS AND CONS", textFile("20k_c2.txt"))
-	pdf.OutputAndClose(docWriter(pdf, 4))
+	fileStr := exampleFilename("multicolumn")
+	err := pdf.OutputFileAndClose(fileStr)
+	summary(err, fileStr)
 	// Output:
-	// Successfully generated pdf/tutorial04.pdf
+	// Successfully generated pdf/multicolumn.pdf
 }
 
 // Various table styles