Add SetSheetViewOptions and GetSheetViewOptions (#145)

Two new methods:
- SetSheetViewOptions(sheetName string, viewIndex int, opts ...SheetViewOption) error
- GetSheetViewOptions(sheetName string, viewIndex int, opts ...SheetViewOptionPtr) error

The option values are given by the user through types that have privates methods
that implement the private SheetViewOption and SheetViewOptionPtr interfaces:
- DefaultGridColor(bool)
- RightToLeft(bool)
- ShowFormulas(bool)
- ShowGridLines(bool)
- ShowRowColHeaders(bool)

Examples:
    err := xl.SetSheetViewOptions("Sheet1", -1, excelize.ShowGridLines(true))

    var showGridLines excelize.ShowGridLines
    err := xl.GetSheetViewOptions("Sheet1", -1, &showGridLines)

Fixes #145.

1 files changed, 138 insertions, 0 deletions

diff --git a/sheetview.go b/sheetview.go
new file mode 100644
index 0000000..d26b8cb
--- /dev/null
+++ b/sheetview.go
@@ -0,0 +1,138 @@
+package excelize
+
+import "fmt"
+
+// SheetViewOption is an option of a view of a worksheet. See SetSheetViewOptions().
+type SheetViewOption interface {
+	setSheetViewOption(view *xlsxSheetView)
+}
+
+// SheetViewOptionPtr is a writable SheetViewOption. See GetSheetViewOptions().
+type SheetViewOptionPtr interface {
+	getSheetViewOption(view *xlsxSheetView)
+}
+
+type (
+	// DefaultGridColor is a SheetViewOption.
+	DefaultGridColor bool
+	// RightToLeft is a SheetViewOption.
+	RightToLeft bool
+	// ShowFormulas is a SheetViewOption.
+	ShowFormulas bool
+	// ShowGridLines is a SheetViewOption.
+	ShowGridLines bool
+	// ShowRowColHeaders is a SheetViewOption.
+	ShowRowColHeaders bool
+	/* TODO
+	// ShowWhiteSpace is a SheetViewOption.
+	ShowWhiteSpace bool
+	// ShowZeros is a SheetViewOption.
+	ShowZeros bool
+	// WindowProtection is a SheetViewOption.
+	WindowProtection bool
+	*/
+)
+
+// Defaults for each option are described in XML schema for CT_SheetView
+
+func (o DefaultGridColor) setSheetViewOption(view *xlsxSheetView) {
+	view.DefaultGridColor = boolPtr(bool(o))
+}
+
+func (o *DefaultGridColor) getSheetViewOption(view *xlsxSheetView) {
+	*o = DefaultGridColor(defaultTrue(view.DefaultGridColor)) // Excel default: true
+}
+
+func (o RightToLeft) setSheetViewOption(view *xlsxSheetView) {
+	view.RightToLeft = bool(o) // Excel default: false
+}
+
+func (o *RightToLeft) getSheetViewOption(view *xlsxSheetView) {
+	*o = RightToLeft(view.RightToLeft)
+}
+
+func (o ShowFormulas) setSheetViewOption(view *xlsxSheetView) {
+	view.ShowFormulas = bool(o) // Excel default: false
+}
+
+func (o *ShowFormulas) getSheetViewOption(view *xlsxSheetView) {
+	*o = ShowFormulas(view.ShowFormulas) // Excel default: false
+}
+
+func (o ShowGridLines) setSheetViewOption(view *xlsxSheetView) {
+	view.ShowGridLines = boolPtr(bool(o))
+}
+
+func (o *ShowGridLines) getSheetViewOption(view *xlsxSheetView) {
+	*o = ShowGridLines(defaultTrue(view.ShowGridLines)) // Excel default: true
+}
+
+func (o ShowRowColHeaders) setSheetViewOption(view *xlsxSheetView) {
+	view.ShowRowColHeaders = boolPtr(bool(o))
+}
+
+func (o *ShowRowColHeaders) getSheetViewOption(view *xlsxSheetView) {
+	*o = ShowRowColHeaders(defaultTrue(view.ShowRowColHeaders)) // Excel default: true
+}
+
+// getSheetView returns the SheetView object
+func (f *File) getSheetView(sheetName string, viewIndex int) (*xlsxSheetView, error) {
+	xlsx := f.workSheetReader(sheetName)
+	if viewIndex < 0 {
+		if viewIndex < -len(xlsx.SheetViews.SheetView) {
+			return nil, fmt.Errorf("view index %d out of range", viewIndex)
+		}
+		viewIndex = len(xlsx.SheetViews.SheetView) + viewIndex
+	} else if viewIndex >= len(xlsx.SheetViews.SheetView) {
+		return nil, fmt.Errorf("view index %d out of range", viewIndex)
+	}
+
+	return &(xlsx.SheetViews.SheetView[viewIndex]), nil
+}
+
+// SetSheetViewOptions sets sheet view options.
+// The viewIndex may be negative and if so is counted backward (-1 is the last view).
+//
+// Available options:
+//    DefaultGridColor(bool)
+//    RightToLeft(bool)
+//    ShowFormulas(bool)
+//    ShowGridLines(bool)
+//    ShowRowColHeaders(bool)
+// Example:
+//    err = f.SetSheetViewOptions("Sheet1", -1, ShowGridLines(false))
+func (f *File) SetSheetViewOptions(name string, viewIndex int, opts ...SheetViewOption) error {
+	view, err := f.getSheetView(name, viewIndex)
+	if err != nil {
+		return err
+	}
+
+	for _, opt := range opts {
+		opt.setSheetViewOption(view)
+	}
+	return nil
+}
+
+// GetSheetViewOptions gets the value of sheet view options.
+// The viewIndex may be negative and if so is counted backward (-1 is the last view).
+//
+// Available options:
+//    DefaultGridColor(bool)
+//    RightToLeft(bool)
+//    ShowFormulas(bool)
+//    ShowGridLines(bool)
+//    ShowRowColHeaders(bool)
+// Example:
+//    var showGridLines excelize.ShowGridLines
+//    err = f.GetSheetViewOptions("Sheet1", -1, &showGridLines)
+func (f *File) GetSheetViewOptions(name string, viewIndex int, opts ...SheetViewOptionPtr) error {
+	view, err := f.getSheetView(name, viewIndex)
+	if err != nil {
+		return err
+	}
+
+	for _, opt := range opts {
+		opt.getSheetViewOption(view)
+	}
+	return nil
+}