document: add support for controlling paragraph indentation

Fixes unidoc#123

_examples/document/simple/main.go

@@ -4,6 +4,7 @@ package main
 import (
 	"baliance.com/gooxml/color"
 	"baliance.com/gooxml/document"
+	"baliance.com/gooxml/measurement"
 	"baliance.com/gooxml/schema/soo/wml"
 )
 
@@ -31,6 +32,8 @@ func main() {
 	run.AddText("Some Heading Text")
 
 	para = doc.AddParagraph()
+	para.Properties().SetFirstLineIndent(0.5 * measurement.Inch)
+
 	run = para.AddRun()
 	run.AddText("A run is a string of characters with the same formatting. ")
 

document/paragraphproperties.go

@@ -138,3 +138,55 @@ func (p ParagraphProperties) SetWindowControl(b bool) {
 		p.x.WidowControl = wml.NewCT_OnOff()
 	}
 }
+
+// SetFirstLineIndent controls the indentation of the first line in a paragraph.
+func (p ParagraphProperties) SetFirstLineIndent(m measurement.Distance) {
+	if p.x.Ind == nil {
+		p.x.Ind = wml.NewCT_Ind()
+	}
+	if m == measurement.Zero {
+		p.x.Ind.FirstLineAttr = nil
+	} else {
+		p.x.Ind.FirstLineAttr = &sharedTypes.ST_TwipsMeasure{}
+		p.x.Ind.FirstLineAttr.ST_UnsignedDecimalNumber = gooxml.Uint64(uint64(m / measurement.Twips))
+	}
+}
+
+// SetStartIndent controls the start indentation.
+func (p ParagraphProperties) SetStartIndent(m measurement.Distance) {
+	if p.x.Ind == nil {
+		p.x.Ind = wml.NewCT_Ind()
+	}
+	if m == measurement.Zero {
+		p.x.Ind.StartAttr = nil
+	} else {
+		p.x.Ind.StartAttr = &wml.ST_SignedTwipsMeasure{}
+		p.x.Ind.StartAttr.Int64 = gooxml.Int64(int64(m / measurement.Twips))
+	}
+}
+
+// SetEndIdent controls the end indentation.
+func (p ParagraphProperties) SetEndIndent(m measurement.Distance) {
+	if p.x.Ind == nil {
+		p.x.Ind = wml.NewCT_Ind()
+	}
+	if m == measurement.Zero {
+		p.x.Ind.EndAttr = nil
+	} else {
+		p.x.Ind.EndAttr = &wml.ST_SignedTwipsMeasure{}
+		p.x.Ind.EndAttr.Int64 = gooxml.Int64(int64(m / measurement.Twips))
+	}
+}
+
+// SetHangingIndent controls the indentation of the non-first lines in a paragraph.
+func (p ParagraphProperties) SetHangingIndent(m measurement.Distance) {
+	if p.x.Ind == nil {
+		p.x.Ind = wml.NewCT_Ind()
+	}
+	if m == measurement.Zero {
+		p.x.Ind.HangingAttr = nil
+	} else {
+		p.x.Ind.HangingAttr = &sharedTypes.ST_TwipsMeasure{}
+		p.x.Ind.HangingAttr.ST_UnsignedDecimalNumber = gooxml.Uint64(uint64(m / measurement.Twips))
+	}
+}