Added accessors for Getting/Setting Page Margins (#497)

* Added accessors for Getting/Setting Page Margins

* Added test cases

sheet.go

@@ -1401,3 +1401,162 @@ func makeContiguousColumns(xlsx *xlsxWorksheet, fromRow, toRow, colCount int) {
 		fillColumns(rowData, colCount, fromRow)
 	}
 }
+
+type (
+	PageMarginBottom float64
+	PageMarginFooter float64
+	PageMarginHeader float64
+	PageMarginLeft   float64
+	PageMarginRight  float64
+	PageMarginTop    float64
+)
+
+// setPageMargins provides a method to set the bottom margin for the worksheet.
+func (p PageMarginBottom) setPageMargins(ps *xlsxPageMargins) {
+	ps.Bottom = float64(p)
+}
+
+// setPageMargins provides a method to get the bottom margin for the worksheet.
+func (o *PageMarginBottom) getPageMargins(ps *xlsxPageMargins) {
+	// Excel default: portrait
+	if ps == nil || ps.Bottom == 0 {
+		*o = 0.75
+		return
+	}
+	*o = PageMarginBottom(ps.Bottom)
+}
+
+// setPageMargins provides a method to set the Footer margin for the worksheet.
+func (p PageMarginFooter) setPageMargins(ps *xlsxPageMargins) {
+	ps.Footer = float64(p)
+}
+
+// setPageMargins provides a method to get the Footer margin for the worksheet.
+func (o *PageMarginFooter) getPageMargins(ps *xlsxPageMargins) {
+	// Excel default: portrait
+	if ps == nil || ps.Footer == 0 {
+		*o = 0.3
+		return
+	}
+	*o = PageMarginFooter(ps.Footer)
+}
+
+// setPageMargins provides a method to set the Header margin for the worksheet.
+func (p PageMarginHeader) setPageMargins(ps *xlsxPageMargins) {
+	ps.Header = float64(p)
+}
+
+// setPageMargins provides a method to get the Header margin for the worksheet.
+func (o *PageMarginHeader) getPageMargins(ps *xlsxPageMargins) {
+	// Excel default: portrait
+	if ps == nil || ps.Header == 0 {
+		*o = 0.3
+		return
+	}
+	*o = PageMarginHeader(ps.Header)
+}
+
+// setPageMargins provides a method to set the left margin for the worksheet.
+func (p PageMarginLeft) setPageMargins(ps *xlsxPageMargins) {
+	ps.Left = float64(p)
+}
+
+// setPageMargins provides a method to get the left margin for the worksheet.
+func (o *PageMarginLeft) getPageMargins(ps *xlsxPageMargins) {
+	// Excel default: portrait
+	if ps == nil || ps.Left == 0 {
+		*o = 0.7
+		return
+	}
+	*o = PageMarginLeft(ps.Left)
+}
+
+// setPageMargins provides a method to set the right margin for the worksheet.
+func (p PageMarginRight) setPageMargins(ps *xlsxPageMargins) {
+	ps.Right = float64(p)
+}
+
+// setPageMargins provides a method to get the right margin for the worksheet.
+func (o *PageMarginRight) getPageMargins(ps *xlsxPageMargins) {
+	// Excel default: portrait
+	if ps == nil || ps.Right == 0 {
+		*o = 0.7
+		return
+	}
+	*o = PageMarginRight(ps.Right)
+}
+
+// setPageMargins provides a method to set the top margin for the worksheet.
+func (p PageMarginTop) setPageMargins(ps *xlsxPageMargins) {
+	ps.Top = float64(p)
+}
+
+// setPageMargins provides a method to get the top margin for the worksheet.
+func (o *PageMarginTop) getPageMargins(ps *xlsxPageMargins) {
+	// Excel default: portrait
+	if ps == nil || ps.Top == 0 {
+		*o = 0.75
+		return
+	}
+	*o = PageMarginTop(ps.Top)
+}
+
+// PageMarginsOptions is an option of a page margin of a worksheet. See
+// SetPageMargins().
+type PageMarginsOptions interface {
+	setPageMargins(layout *xlsxPageMargins)
+}
+
+// PageMarginsOptionsPtr is a writable PageMarginsOptions. See GetPageMargins().
+type PageMarginsOptionsPtr interface {
+	PageMarginsOptions
+	getPageMargins(layout *xlsxPageMargins)
+}
+
+// SetPageMargins provides a function to set worksheet page lmargins.
+//
+// Available options:
+//   PageMarginBotom(float64)
+//   PageMarginFooter(float64)
+//   PageMarginHeader(float64)
+//   PageMarginLeft(float64)
+//   PageMarginRightfloat64)
+//   PageMarginTop(float64)
+func (f *File) SetPageMargins(sheet string, opts ...PageMarginsOptions) error {
+	s, err := f.workSheetReader(sheet)
+	if err != nil {
+		return err
+	}
+	ps := s.PageMargins
+	if ps == nil {
+		ps = new(xlsxPageMargins)
+		s.PageMargins = ps
+	}
+
+	for _, opt := range opts {
+		opt.setPageMargins(ps)
+	}
+	return err
+}
+
+// GetPageMargins provides a function to get worksheet page margins.
+//
+// Available options:
+//   PageMarginBotom(float64)
+//   PageMarginFooter(float64)
+//   PageMarginHeader(float64)
+//   PageMarginLeft(float64)
+//   PageMarginRightfloat64)
+//   PageMarginTop(float64)
+func (f *File) GetPageMargins(sheet string, opts ...PageMarginsOptionsPtr) error {
+	s, err := f.workSheetReader(sheet)
+	if err != nil {
+		return err
+	}
+	ps := s.PageMargins
+
+	for _, opt := range opts {
+		opt.getPageMargins(ps)
+	}
+	return err
+}

sheet_test.go

@@ -247,3 +247,65 @@ func TestGetSheetMap(t *testing.T) {
 	}
 	assert.Equal(t, len(sheetMap), 2)
 }
+
+func TestPageMarginsOption(t *testing.T) {
+	const sheet = "Sheet1"
+
+	testData := []struct {
+		container  excelize.PageMarginsOptionsPtr
+		nonDefault excelize.PageMarginsOptions
+	}{
+		{new(excelize.PageMarginTop), excelize.PageMarginTop(1.0)},
+		{new(excelize.PageMarginBottom), excelize.PageMarginBottom(1.0)},
+		{new(excelize.PageMarginLeft), excelize.PageMarginLeft(1.0)},
+		{new(excelize.PageMarginRight), excelize.PageMarginRight(1.0)},
+		{new(excelize.PageMarginHeader), excelize.PageMarginHeader(1.0)},
+		{new(excelize.PageMarginFooter), excelize.PageMarginFooter(1.0)},
+	}
+
+	for i, test := range testData {
+		t.Run(fmt.Sprintf("TestData%d", i), func(t *testing.T) {
+
+			opt := test.nonDefault
+			t.Logf("option %T", opt)
+
+			def := deepcopy.Copy(test.container).(excelize.PageMarginsOptionsPtr)
+			val1 := deepcopy.Copy(def).(excelize.PageMarginsOptionsPtr)
+			val2 := deepcopy.Copy(def).(excelize.PageMarginsOptionsPtr)
+
+			f := excelize.NewFile()
+			// Get the default value
+			assert.NoError(t, f.GetPageMargins(sheet, def), opt)
+			// Get again and check
+			assert.NoError(t, f.GetPageMargins(sheet, val1), opt)
+			if !assert.Equal(t, val1, def, opt) {
+				t.FailNow()
+			}
+			// Set the same value
+			assert.NoError(t, f.SetPageMargins(sheet, val1), opt)
+			// Get again and check
+			assert.NoError(t, f.GetPageMargins(sheet, val1), opt)
+			if !assert.Equal(t, val1, def, "%T: value should not have changed", opt) {
+				t.FailNow()
+			}
+			// Set a different value
+			assert.NoError(t, f.SetPageMargins(sheet, test.nonDefault), opt)
+			assert.NoError(t, f.GetPageMargins(sheet, val1), opt)
+			// Get again and compare
+			assert.NoError(t, f.GetPageMargins(sheet, val2), opt)
+			if !assert.Equal(t, val1, val2, "%T: value should not have changed", opt) {
+				t.FailNow()
+			}
+			// Value should not be the same as the default
+			if !assert.NotEqual(t, def, val1, "%T: value should have changed from default", opt) {
+				t.FailNow()
+			}
+			// Restore the default value
+			assert.NoError(t, f.SetPageMargins(sheet, def), opt)
+			assert.NoError(t, f.GetPageMargins(sheet, val1), opt)
+			if !assert.Equal(t, def, val1) {
+				t.FailNow()
+			}
+		})
+	}
+}

xmlWorksheet.go

@@ -801,3 +801,13 @@ type FormatHeaderFooter struct {
 	FirstFooter      string
 	FirstHeader      string
 }
+
+// FormatPageMargins directly maps the settings of page margins
+type FormatPageMargins struct {
+	Bottom string
+	Footer string
+	Header string
+	Left   string
+	Right  string
+	Top    string
+}