Add TOC component

pdf/creator/toc.go

@@ -0,0 +1,199 @@
+/*
+ * This file is subject to the terms and conditions defined in
+ * file 'LICENSE.md', which is part of this source code package.
+ */
+
+package creator
+
+import "github.com/unidoc/unidoc/pdf/model/fonts"
+
+// TOC represents a table of contents component. It consists of a paragraph
+// heading and a collection of table of contents lines.
+type TOC struct {
+	// The heading of the table of contents.
+	heading *StyledParagraph
+
+	// The lines of the table of contents.
+	lines []*TOCLine
+
+	// Positioning: relative/absolute.
+	positioning positioning
+
+	// The style of the number part of new lines.
+	lineNumberStyle TextStyle
+
+	// The style of the title part of new lines.
+	lineTitleStyle TextStyle
+
+	// The style of the separator part of new lines.
+	lineSeparatorStyle TextStyle
+
+	// The style of the page part of new lines.
+	linePageStyle TextStyle
+}
+
+// NewTOC creates a new table of contents.
+func NewTOC(title string) *TOC {
+	headingStyle := NewTextStyle()
+	headingStyle.Font = fonts.NewFontHelveticaBold()
+	headingStyle.FontSize = 14
+
+	heading := NewStyledParagraph(title, headingStyle)
+	heading.SetEnableWrap(true)
+	heading.SetTextAlignment(TextAlignmentLeft)
+	heading.SetMargins(0, 0, 0, 5)
+
+	lineStyle := NewTextStyle()
+
+	return &TOC{
+		heading:            heading,
+		lines:              []*TOCLine{},
+		lineNumberStyle:    lineStyle,
+		lineTitleStyle:     lineStyle,
+		lineSeparatorStyle: lineStyle,
+		linePageStyle:      lineStyle,
+	}
+}
+
+// Heading returns the heading component of the table of contents.
+func (t *TOC) Heading() *StyledParagraph {
+	return t.heading
+}
+
+// SetHeadings sets the text and the style of the heading
+// of the table of contents.
+func (t *TOC) SetHeading(text string, style TextStyle) {
+	t.heading.Reset(text, style)
+}
+
+// Add adds a new line with the default style to the table of contents.
+func (t *TOC) Add(number, title, page string, level uint) *TOCLine {
+	tl := t.AddLine(NewStyledTOCLine(
+		TextChunk{
+			Text:  number,
+			Style: t.lineNumberStyle,
+		},
+		TextChunk{
+			Text:  title,
+			Style: t.lineTitleStyle,
+		},
+		TextChunk{
+			Text:  page,
+			Style: t.linePageStyle,
+		},
+		level,
+	))
+
+	tl.Separator.Style = t.lineSeparatorStyle
+	return tl
+}
+
+// Add adds a new line with the provided style to the table of contents.
+func (t *TOC) AddLine(line *TOCLine) *TOCLine {
+	if line == nil {
+		return nil
+	}
+
+	t.lines = append(t.lines, line)
+	return line
+}
+
+// SetSeparator sets the separator for all the lines of the table of contents.
+func (t *TOC) SetLineSeparator(separator string) {
+	for _, line := range t.lines {
+		line.Separator.Text = separator
+	}
+}
+
+// SetMargins sets the margins for all the lines of the table of contents.
+func (t *TOC) SetLineMargins(left, right, top, bottom float64) {
+	for _, line := range t.lines {
+		line.SetMargins(left, right, top, bottom)
+	}
+}
+
+// SetLineNumberStyle sets the style for numbers part of  all the lines
+// the table of contents has.
+func (t *TOC) SetLineNumberStyle(style TextStyle) {
+	t.lineNumberStyle = style
+	for _, line := range t.lines {
+		line.Number.Style = style
+	}
+}
+
+// SetLineTitleStyle sets the style for page part of  all the lines
+// the table of contents has.
+func (t *TOC) SetLineTitleStyle(style TextStyle) {
+	t.lineTitleStyle = style
+	for _, line := range t.lines {
+		line.Title.Style = style
+	}
+}
+
+// SetLineSeparatorStyle sets the style for separator part of  all the lines
+// the table of contents has.
+func (t *TOC) SetLineSeparatorStyle(style TextStyle) {
+	t.lineSeparatorStyle = style
+	for _, line := range t.lines {
+		line.Separator.Style = style
+	}
+}
+
+// SetLinePageStyle sets the style for the page for all the lines
+// the table of contents has.
+func (t *TOC) SetLinePageStyle(style TextStyle) {
+	t.linePageStyle = style
+	for _, line := range t.lines {
+		line.Page.Style = style
+	}
+}
+
+// SetLineLevelOffset sets the amount of space an indentation level occupies
+// for all the lines the table of contents has.
+func (t *TOC) SetLineLevelOffset(levelOffset float64) {
+	for _, line := range t.lines {
+		line.SetLevelOffset(levelOffset)
+	}
+}
+
+// GeneratePageBlocks generate the Page blocks.  Multiple blocks are generated if the contents wrap over
+// multiple pages.
+func (t *TOC) GeneratePageBlocks(ctx DrawContext) ([]*Block, DrawContext, error) {
+	origCtx := ctx
+
+	// Generate heading blocks
+	blocks, ctx, err := t.heading.GeneratePageBlocks(ctx)
+	if err != nil {
+		return blocks, ctx, err
+	}
+
+	// Generate blocks for the table of contents lines
+	for _, line := range t.lines {
+		newBlocks, c, err := line.GeneratePageBlocks(ctx)
+		if err != nil {
+			return blocks, ctx, err
+		}
+		if len(newBlocks) < 1 {
+			continue
+		}
+
+		// The first block is always appended to the last..
+		blocks[len(blocks)-1].mergeBlocks(newBlocks[0])
+		blocks = append(blocks, newBlocks[1:]...)
+
+		ctx = c
+	}
+
+	if t.positioning.isRelative() {
+		// Move back X to same start of line.
+		ctx.X = origCtx.X
+	}
+
+	if t.positioning.isAbsolute() {
+		// If absolute: return original context.
+		return blocks, origCtx, nil
+
+	}
+
+	return blocks, ctx, nil
+}

pdf/creator/toc_line.go

@@ -20,6 +20,9 @@ type TOCLine struct {
 	level       uint
 	offset      float64
 	levelOffset float64
+
+	// Positioning: relative/absolute.
+	positioning positioning
 }
 
 func NewTOCLine(number, title, page string, level uint) *TOCLine {
@@ -48,6 +51,7 @@ func NewStyledTOCLine(number, title, page TextChunk, level uint) *TOCLine {
 	sp := NewStyledParagraph("", style)
 	sp.SetEnableWrap(true)
 	sp.SetTextAlignment(TextAlignmentLeft)
+	sp.SetMargins(0, 0, 2, 2)
 
 	tl := &TOCLine{
 		sp:     sp,
@@ -167,17 +171,13 @@ func (tl *TOCLine) GeneratePageBlocks(ctx DrawContext) ([]*Block, DrawContext, e
 	if err != nil {
 		return blocks, ctx, err
 	}
-	if len(blocks) > 1 {
-		// Did not fit, moved to new Page block.
-		ctx.Page++
-	}
 
-	if tl.sp.positioning.isRelative() {
+	if tl.positioning.isRelative() {
 		// Move back X to same start of line.
 		ctx.X = origCtx.X
 	}
 
-	if tl.sp.positioning.isAbsolute() {
+	if tl.positioning.isAbsolute() {
 		// If absolute: return original context.
 		return blocks, origCtx, nil
 	}