OrgGo/unipdf
1
0
Fork 0
mirror of https://github.com/unidoc/unipdf.git synced 2025-04-24 13:48:49 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

Add basic glyph metrics support for Type 0 CID fonts (#272)

Browse Source 
* Add basic glyph metrics support for Type 0 CID fonts
* Initialize font widths map if no W array is present
This commit is contained in:
Gunnsteinn Hall 2020-03-05 18:47:16 +00:00 committed by GitHub
parent d961079c5d
commit 937669cfed
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 128 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

186
model/font_composite.go
View File

@ -249,8 +249,18 @@ type pdfCIDFontType0 struct {
encoder textencoding.TextEncoder
// Table 117 – Entries in a CIDFont dictionary (page 269)
CIDSystemInfo *core.PdfObjectDictionary // (Required) Dictionary that defines the character
// collection of the CIDFont. See Table 116.
// (Required) Dictionary that defines the character collection of the CIDFont.
// See Table 116.
CIDSystemInfo *core.PdfObjectDictionary
// Glyph metrics fields (optional).
DW core.PdfObject // default glyph width.
W core.PdfObject // glyph widths array.
DW2 core.PdfObject // default glyph metrics for CID fonts used for vertical writing.
W2 core.PdfObject // glyph metrics for CID fonts used for vertical writing.
widths map[textencoding.CharCode]float64
defaultWidth float64
}
// pdfCIDFontType0FromSkeleton returns a pdfCIDFontType0 with its common fields initalized.
@ -277,12 +287,17 @@ func (font pdfCIDFontType0) Encoder() textencoding.TextEncoder {
// GetRuneMetrics returns the character metrics for the specified rune.
// A bool flag is returned to indicate whether or not the entry was found.
func (font pdfCIDFontType0) GetRuneMetrics(r rune) (fonts.CharMetrics, bool) {
return fonts.CharMetrics{}, true
return fonts.CharMetrics{Wx: font.defaultWidth}, true
}
// GetCharMetrics returns the char metrics for character code `code`.
func (font pdfCIDFontType0) GetCharMetrics(code textencoding.CharCode) (fonts.CharMetrics, bool) {
return fonts.CharMetrics{}, true
width := font.defaultWidth
if w, ok := font.widths[code]; ok {
width = w
}
return fonts.CharMetrics{Wx: width}, true
}
// ToPdfObject converts the pdfCIDFontType0 to a PDF representation.
@ -308,6 +323,28 @@ func newPdfCIDFontType0FromPdfObject(d *core.PdfObjectDictionary, base *fontComm
}
font.CIDSystemInfo = obj
// Optional attributes.
font.DW = d.Get("DW")
font.W = d.Get("W")
font.DW2 = d.Get("DW2")
font.W2 = d.Get("W2")
// Get font default glyph width.
font.defaultWidth = 1000.0
if dw, err := core.GetNumberAsFloat(font.DW); err == nil {
font.defaultWidth = dw
}
// Parse glyph widths array, if one is present.
fontWidths, err := parseCIDFontWidthsArray(font.W)
if err != nil {
return nil, err
}
if fontWidths == nil {
fontWidths = map[textencoding.CharCode]float64{}
}
font.widths = fontWidths
return font, nil
}
@ -322,12 +359,19 @@ type pdfCIDFontType2 struct {
// These fields are specific to Type 0 fonts.
encoder textencoding.TextEncoder
// Table 117 – Entries in a CIDFont dictionary (page 269)
// Dictionary that defines the character collection of the CIDFont (required).
// See Table 116.
CIDSystemInfo *core.PdfObjectDictionary
DW core.PdfObject
W core.PdfObject
DW2 core.PdfObject
W2 core.PdfObject
CIDToGIDMap core.PdfObject
// Glyph metrics fields (optional).
DW core.PdfObject // default glyph width.
W core.PdfObject // glyph widths array.
DW2 core.PdfObject // default glyph metrics for CID fonts used for vertical writing.
W2 core.PdfObject // glyph metrics for CID fonts used for vertical writing.
// CIDs to glyph indices mapping (optional).
CIDToGIDMap core.PdfObject
widths map[textencoding.CharCode]float64
defaultWidth float64
@ -443,60 +487,86 @@ func newPdfCIDFontType2FromPdfObject(d *core.PdfObjectDictionary, base *fontComm
font.W2 = d.Get("W2")
font.CIDToGIDMap = d.Get("CIDToGIDMap")
if arr2, ok := core.GetArray(font.W); ok {
font.widths = make(map[textencoding.CharCode]float64)
for i := 0; i < arr2.Len()-1; i++ {
obj0 := (*arr2).Get(i)
n, ok0 := core.GetIntVal(obj0)
if !ok0 {
return nil, fmt.Errorf("Bad font W obj0: i=%d %#v", i, obj0)
}
i++
if i > arr2.Len()-1 {
return nil, fmt.Errorf("Bad font W array: arr2=%+v", arr2)
}
obj1 := (*arr2).Get(i)
switch obj1.(type) {
case *core.PdfObjectArray:
arr, _ := core.GetArray(obj1)
if widths, err := arr.ToFloat64Array(); err == nil {
for j := 0; j < len(widths); j++ {
font.widths[textencoding.CharCode(n+j)] = widths[j]
}
} else {
return nil, fmt.Errorf("Bad font W array obj1: i=%d %#v", i, obj1)
}
case *core.PdfObjectInteger:
n1, ok1 := core.GetIntVal(obj1)
if !ok1 {
return nil, fmt.Errorf("Bad font W int obj1: i=%d %#v", i, obj1)
}
i++
if i > arr2.Len()-1 {
return nil, fmt.Errorf("Bad font W array: arr2=%+v", arr2)
}
obj2 := (*arr2).Get(i)
v, err := core.GetNumberAsFloat(obj2)
if err != nil {
return nil, fmt.Errorf("Bad font W int obj2: i=%d %#v", i, obj2)
}
for j := n; j <= n1; j++ {
font.widths[textencoding.CharCode(j)] = v
}
default:
return nil, fmt.Errorf("Bad font W obj1 type: i=%d %#v", i, obj1)
}
}
}
if defaultWidth, err := core.GetNumberAsFloat(font.DW); err == nil {
font.defaultWidth = defaultWidth
} else {
font.defaultWidth = 1000.0
// Get font default glyph width.
font.defaultWidth = 1000.0
if dw, err := core.GetNumberAsFloat(font.DW); err == nil {
font.defaultWidth = dw
}
// Parse glyph widths array, if one is present.
fontWidths, err := parseCIDFontWidthsArray(font.W)
if err != nil {
return nil, err
}
if fontWidths == nil {
fontWidths = map[textencoding.CharCode]float64{}
}
font.widths = fontWidths
return font, nil
}
func parseCIDFontWidthsArray(w core.PdfObject) (map[textencoding.CharCode]float64, error) {
if w == nil {
return nil, nil
}
wArr, ok := core.GetArray(w)
if !ok {
return nil, nil
}
fontWidths := map[textencoding.CharCode]float64{}
wArrLen := wArr.Len()
for i := 0; i < wArrLen-1; i++ {
obj0 := wArr.Get(i)
n, ok0 := core.GetIntVal(obj0)
if !ok0 {
return nil, fmt.Errorf("Bad font W obj0: i=%d %#v", i, obj0)
}
i++
if i > wArrLen-1 {
return nil, fmt.Errorf("Bad font W array: arr2=%+v", wArr)
}
obj1 := wArr.Get(i)
switch obj1.(type) {
case *core.PdfObjectArray:
arr, _ := core.GetArray(obj1)
if widths, err := arr.ToFloat64Array(); err == nil {
for j := 0; j < len(widths); j++ {
fontWidths[textencoding.CharCode(n+j)] = widths[j]
}
} else {
return nil, fmt.Errorf("Bad font W array obj1: i=%d %#v", i, obj1)
}
case *core.PdfObjectInteger:
n1, ok1 := core.GetIntVal(obj1)
if !ok1 {
return nil, fmt.Errorf("Bad font W int obj1: i=%d %#v", i, obj1)
}
i++
if i > wArrLen-1 {
return nil, fmt.Errorf("Bad font W array: arr2=%+v", wArr)
}
obj2 := wArr.Get(i)
v, err := core.GetNumberAsFloat(obj2)
if err != nil {
return nil, fmt.Errorf("Bad font W int obj2: i=%d %#v", i, obj2)
}
for j := n; j <= n1; j++ {
fontWidths[textencoding.CharCode(j)] = v
}
default:
return nil, fmt.Errorf("Bad font W obj1 type: i=%d %#v", i, obj1)
}
}
return fontWidths, nil
}
// NewCompositePdfFontFromTTFFile loads a composite font from a TTF font file. Composite fonts can
// be used to represent unicode fonts which can have multi-byte character codes, representing a wide
// range of values.