mirror of
https://github.com/unidoc/unipdf.git
synced 2025-04-30 13:48:51 +08:00
Document signature related code in the annotator package
This commit is contained in:
Adrian-George Bostan
parent
b33ad302be
commit
8e17705e7c
@ -7,7 +7,9 @@ package annotator
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import (
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"errors"
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"math"
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"strings"
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"unicode"
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"github.com/unidoc/unidoc/common"
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"github.com/unidoc/unidoc/pdf/contentstream"
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@ -1157,3 +1159,179 @@ func (fa FieldAppearance) WrapContentStream(page *model.PdfPage) error {
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func defStreamEncoder() core.StreamEncoder {
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return core.NewFlateEncoder()
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}
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// genFieldSignatureAppearance generates the appearance dictionary for a
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// signature appearance widget.
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func genFieldSignatureAppearance(fields []*SignatureLine, opts *SignatureFieldOpts) (*core.PdfObjectDictionary, error) {
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if opts == nil {
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opts = NewSignatureFieldOpts()
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}
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// Get font.
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var err error
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var fontName *core.PdfObjectName
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font := opts.Font
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if font != nil {
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descriptor, _ := font.GetFontDescriptor()
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if descriptor != nil {
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if f, ok := descriptor.FontName.(*core.PdfObjectName); ok {
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fontName = f
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}
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}
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if fontName == nil {
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fontName = core.MakeName("Font1")
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}
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} else {
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if font, err = model.NewStandard14Font("Helvetica"); err != nil {
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return nil, err
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}
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fontName = core.MakeName("Helv")
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}
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// Get font size and line height.
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fontSize := opts.FontSize
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if fontSize <= 0 {
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fontSize = 10
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}
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if opts.LineHeight <= 0 {
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opts.LineHeight = 1
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}
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lineHeight := opts.LineHeight * fontSize
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// Get space character width.
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spaceMetrics, found := font.GetRuneMetrics(' ')
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if !found {
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return nil, errors.New("the font does not have a space glyph")
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}
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spaceWidth := spaceMetrics.Wx
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// Generate lines.
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var maxLineWidth float64
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var lines []string
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for _, field := range fields {
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if field.Text == "" {
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continue
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}
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line := field.Text
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if field.Desc != "" {
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line = field.Desc + ": " + line
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}
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lines = append(lines, line)
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var lineWidth float64
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for _, r := range line {
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metrics, has := font.GetRuneMetrics(r)
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if !has {
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continue
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}
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lineWidth += metrics.Wx
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}
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if lineWidth > maxLineWidth {
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maxLineWidth = lineWidth
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}
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}
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maxLineWidth = maxLineWidth * fontSize / 1000.0
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height := float64(len(lines)) * lineHeight
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// Calculate annotation rectangle.
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rect := opts.Rect
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if rect == nil {
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rect = []float64{0, 0, maxLineWidth, height}
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opts.Rect = rect
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}
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rectWidth := rect[2] - rect[0]
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rectHeight := rect[3] - rect[1]
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// Fit contents
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var offsetY float64
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if opts.AutoSize {
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if maxLineWidth > rectWidth || height > rectHeight {
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scale := math.Min(rectWidth/maxLineWidth, rectHeight/height)
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fontSize *= scale
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}
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lineHeight = opts.LineHeight * fontSize
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offsetY += (rectHeight - float64(len(lines))*lineHeight) / 2
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}
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// Draw annotation rectangle.
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cc := contentstream.NewContentCreator()
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if opts.BorderSize <= 0 {
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opts.BorderSize = 0
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opts.BorderColor = model.NewPdfColorDeviceGray(1)
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}
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if opts.BorderColor == nil {
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opts.FillColor = model.NewPdfColorDeviceGray(1)
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}
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if opts.FillColor == nil {
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opts.FillColor = model.NewPdfColorDeviceGray(1)
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}
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cc.Add_q().
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Add_re(rect[0], rect[1], rectWidth, rectHeight).
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Add_w(opts.BorderSize).
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SetStrokingColor(opts.BorderColor).
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SetNonStrokingColor(opts.FillColor).
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Add_B().
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Add_Q()
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// Draw signature.
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cc.Add_q()
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cc.Translate(rect[0], rect[3]-lineHeight-offsetY)
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cc.Add_BT()
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encoder := font.Encoder()
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for _, line := range lines {
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var encStr []byte
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for _, r := range line {
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if unicode.IsSpace(r) {
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if len(encStr) > 0 {
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cc.SetNonStrokingColor(opts.TextColor).
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Add_Tf(*fontName, fontSize).
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Add_TL(lineHeight).
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Add_TJ([]core.PdfObject{core.MakeStringFromBytes(encStr)}...)
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encStr = nil
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}
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cc.Add_Tf(*fontName, fontSize).
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Add_TL(lineHeight).
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Add_TJ([]core.PdfObject{core.MakeFloat(-spaceWidth)}...)
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} else {
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encStr = append(encStr, encoder.Encode(string(r))...)
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}
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}
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if len(encStr) > 0 {
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cc.SetNonStrokingColor(opts.TextColor).
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Add_Tf(*fontName, fontSize).
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Add_TL(lineHeight).
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Add_TJ([]core.PdfObject{core.MakeStringFromBytes(encStr)}...)
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}
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cc.Add_Td(0, -lineHeight)
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}
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cc.Add_ET()
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cc.Add_Q()
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// Create appearance dictionary.
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resources := model.NewPdfPageResources()
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resources.SetFontByName(*fontName, font.ToPdfObject())
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xform := model.NewXObjectForm()
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xform.Resources = resources
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xform.BBox = core.MakeArrayFromFloats(rect)
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xform.SetContentStream(cc.Bytes(), defStreamEncoder())
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apDict := core.MakeDict()
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apDict.Set("N", xform.ToPdfObject())
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return apDict, nil
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}
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@ -8,8 +8,6 @@ package annotator
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import (
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"bytes"
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"errors"
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"math"
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"unicode"
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"github.com/unidoc/unidoc/pdf/contentstream"
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"github.com/unidoc/unidoc/pdf/core"
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@ -206,11 +204,14 @@ func NewComboboxField(page *model.PdfPage, name string, rect []float64, opt Comb
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return chfield, nil
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}
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// SignatureLine represents a line of information in the signature field appearance.
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type SignatureLine struct {
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Desc string
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Text string
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}
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// NewSignatureLine returns a new signature line displayed as a part of the
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// signature field appearance.
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func NewSignatureLine(desc, text string) *SignatureLine {
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return &SignatureLine{
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Desc: desc,
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@ -218,20 +219,40 @@ func NewSignatureLine(desc, text string) *SignatureLine {
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}
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}
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// SignatureFieldOpts represents a set of options used to configure
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// an appearance widget dictionary.
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type SignatureFieldOpts struct {
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Rect []float64
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// Rect represents the area the signature annotation is displayed on.
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Rect []float64
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// AutoSize specifies is the content of the appearance should be
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// scaled to fit in the annotation rectangle.
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AutoSize bool
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Font *model.PdfFont
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FontSize float64
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LineHeight float64
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TextColor model.PdfColor
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// Font specifies the font of the text content.
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Font *model.PdfFont
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FillColor model.PdfColor
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BorderSize float64
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// FontSize specifies the size of the text content.
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FontSize float64
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// LineHeight specifies the height of a line of text in the appearance annotation.
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LineHeight float64
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// TextColor represents the color of the text content displayed.
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TextColor model.PdfColor
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// FillColor represents the background color of the appearance annotation area.
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FillColor model.PdfColor
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// BorderSize represents border size of the appearance annotation area.
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BorderSize float64
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// BorderColor represents the border color of the appearance annotation area.
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BorderColor model.PdfColor
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}
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// NewSignatureFieldOpts returns a new initialized instance of options
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// used to generate a signature appearance.
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func NewSignatureFieldOpts() *SignatureFieldOpts {
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return &SignatureFieldOpts{
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Font: model.DefaultFont(),
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@ -244,12 +265,15 @@ func NewSignatureFieldOpts() *SignatureFieldOpts {
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}
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}
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func NewSignatureField(signature *model.PdfSignature, fields []*SignatureLine, opts *SignatureFieldOpts) (*model.PdfFieldSignature, error) {
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// NewSignatureField returns a new signature field with a visible appearance
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// containing the specified signature lines and styled according to the
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// specified options.
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func NewSignatureField(signature *model.PdfSignature, lines []*SignatureLine, opts *SignatureFieldOpts) (*model.PdfFieldSignature, error) {
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if signature == nil {
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return nil, errors.New("signature cannot be nil")
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}
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apDict, err := genFieldSignatureAppearance(fields, opts)
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apDict, err := genFieldSignatureAppearance(lines, opts)
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if err != nil {
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return nil, err
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}
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@ -260,177 +284,3 @@ func NewSignatureField(signature *model.PdfSignature, fields []*SignatureLine, o
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field.AP = apDict
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return field, nil
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}
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func genFieldSignatureAppearance(fields []*SignatureLine, opts *SignatureFieldOpts) (*core.PdfObjectDictionary, error) {
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if opts == nil {
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opts = NewSignatureFieldOpts()
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}
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// Get font.
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var err error
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var fontName *core.PdfObjectName
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font := opts.Font
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if font != nil {
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descriptor, _ := font.GetFontDescriptor()
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if descriptor != nil {
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if f, ok := descriptor.FontName.(*core.PdfObjectName); ok {
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fontName = f
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}
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}
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if fontName == nil {
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fontName = core.MakeName("Font1")
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}
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} else {
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if font, err = model.NewStandard14Font("Helvetica"); err != nil {
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return nil, err
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}
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fontName = core.MakeName("Helv")
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}
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// Get font size and line height.
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fontSize := opts.FontSize
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if fontSize <= 0 {
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fontSize = 10
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}
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if opts.LineHeight <= 0 {
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opts.LineHeight = 1
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}
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lineHeight := opts.LineHeight * fontSize
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// Get space character width.
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spaceMetrics, found := font.GetRuneMetrics(' ')
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if !found {
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return nil, errors.New("the font does not have a space glyph")
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}
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spaceWidth := spaceMetrics.Wx
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// Generate lines.
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var maxLineWidth float64
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var lines []string
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for _, field := range fields {
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if field.Text == "" {
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continue
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}
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line := field.Text
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if field.Desc != "" {
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line = field.Desc + ": " + line
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}
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lines = append(lines, line)
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var lineWidth float64
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for _, r := range line {
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metrics, has := font.GetRuneMetrics(r)
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if !has {
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continue
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}
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lineWidth += metrics.Wx
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}
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if lineWidth > maxLineWidth {
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maxLineWidth = lineWidth
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}
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}
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maxLineWidth = maxLineWidth * fontSize / 1000.0
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height := float64(len(lines)) * lineHeight
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// Calculate annotation rectangle.
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rect := opts.Rect
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if rect == nil {
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rect = []float64{0, 0, maxLineWidth, height}
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opts.Rect = rect
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}
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rectWidth := rect[2] - rect[0]
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rectHeight := rect[3] - rect[1]
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// Fit contents
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var offsetY float64
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if opts.AutoSize {
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if maxLineWidth > rectWidth || height > rectHeight {
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scale := math.Min(rectWidth/maxLineWidth, rectHeight/height)
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fontSize *= scale
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}
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lineHeight = opts.LineHeight * fontSize
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offsetY += (rectHeight - float64(len(lines))*lineHeight) / 2
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}
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// Draw annotation rectangle.
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cc := contentstream.NewContentCreator()
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if opts.BorderSize <= 0 {
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opts.BorderSize = 0
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opts.BorderColor = model.NewPdfColorDeviceGray(1)
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}
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if opts.BorderColor == nil {
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opts.FillColor = model.NewPdfColorDeviceGray(1)
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}
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if opts.FillColor == nil {
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opts.FillColor = model.NewPdfColorDeviceGray(1)
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}
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cc.Add_q().
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Add_re(rect[0], rect[1], rectWidth, rectHeight).
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Add_w(opts.BorderSize).
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SetStrokingColor(opts.BorderColor).
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SetNonStrokingColor(opts.FillColor).
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Add_B().
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Add_Q()
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// Draw signature.
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cc.Add_q()
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cc.Translate(rect[0], rect[3]-lineHeight-offsetY)
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cc.Add_BT()
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encoder := font.Encoder()
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for _, line := range lines {
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var encStr []byte
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for _, r := range line {
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if unicode.IsSpace(r) {
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if len(encStr) > 0 {
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cc.SetNonStrokingColor(opts.TextColor).
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Add_Tf(*fontName, fontSize).
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Add_TL(lineHeight).
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Add_TJ([]core.PdfObject{core.MakeStringFromBytes(encStr)}...)
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encStr = nil
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}
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cc.Add_Tf(*fontName, fontSize).
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Add_TL(lineHeight).
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Add_TJ([]core.PdfObject{core.MakeFloat(-spaceWidth)}...)
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} else {
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encStr = append(encStr, encoder.Encode(string(r))...)
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}
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}
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if len(encStr) > 0 {
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cc.SetNonStrokingColor(opts.TextColor).
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Add_Tf(*fontName, fontSize).
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Add_TL(lineHeight).
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Add_TJ([]core.PdfObject{core.MakeStringFromBytes(encStr)}...)
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}
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cc.Add_Td(0, -lineHeight)
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}
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cc.Add_ET()
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cc.Add_Q()
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// Create appearance dictionary.
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resources := model.NewPdfPageResources()
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resources.SetFontByName(*fontName, font.ToPdfObject())
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xform := model.NewXObjectForm()
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xform.Resources = resources
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xform.BBox = core.MakeArrayFromFloats(rect)
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xform.SetContentStream(cc.Bytes(), defStreamEncoder())
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apDict := core.MakeDict()
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apDict.Set("N", xform.ToPdfObject())
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return apDict, nil
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}
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