Add partial support for spot colors. This does not yet include gradients, etc

4 files changed, 247 insertions, 17 deletions

diff --git a/def.go b/def.go
index fd6ef81..88e4dea 100644
--- a/def.go
+++ b/def.go
@@ -39,6 +39,34 @@ type gradientType struct {
 	objNum            int
 }
 
+type colorMode int
+
+const (
+	colorModeRGB colorMode = iota
+	colorModeSpot
+	colorModeCMYK
+)
+
+type colorType struct {
+	r, g, b    float64
+	ir, ig, ib int
+	mode       colorMode
+	spotStr    string // name of current spot color
+	gray       bool
+	str        string
+}
+
+// SpotColorType specifies a named spot color value
+type spotColorType struct {
+	id, objID int
+	val       cmykColorType
+}
+
+// CMYKColorType specifies an ink-based CMYK color value
+type cmykColorType struct {
+	c, m, y, k byte // 0% to 100%
+}
+
 // SizeType fields Wd and Ht specify the horizontal and vertical extents of a
 // document element such as a page.
 type SizeType struct {
@@ -254,8 +282,9 @@ type Fpdf struct {
 	colorFlag        bool                      // indicates whether fill and text colors are different
 	color            struct {
 		// Composite values of colors
-		draw, fill, text clrType
+		draw, fill, text colorType
 	}
+	spotColorMap map[string]spotColorType // Map of named ink-based colors
 }
 
 type encType struct {
diff --git a/fpdf.go b/fpdf.go
index 3b2d488..a590581 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -180,6 +180,7 @@ func fpdfNew(orientationStr, unitStr, sizeStr, fontDirStr string, size SizeType)
 	}
 	// Enable compression
 	f.SetCompression(!gl.noCompress)
+	f.spotColorMap = make(map[string]spotColorType)
 	f.blendList = make([]blendModeType, 0, 8)
 	f.blendList = append(f.blendList, blendModeType{}) // blendList[0] is unused (1-based)
 	f.blendMap = make(map[string]int)
@@ -721,13 +722,6 @@ func (f *Fpdf) PageNo() int {
 	return f.page
 }
 
-type clrType struct {
-	r, g, b    float64
-	ir, ig, ib int
-	gray       bool
-	str        string
-}
-
 func colorComp(v int) (int, float64) {
 	if v < 0 {
 		v = 0
@@ -737,10 +731,11 @@ func colorComp(v int) (int, float64) {
 	return v, float64(v) / 255.0
 }
 
-func colorValue(r, g, b int, grayStr, fullStr string) (clr clrType) {
+func rgbColorValue(r, g, b int, grayStr, fullStr string) (clr colorType) {
 	clr.ir, clr.r = colorComp(r)
 	clr.ig, clr.g = colorComp(g)
 	clr.ib, clr.b = colorComp(b)
+	clr.mode = colorModeRGB
 	clr.gray = clr.ir == clr.ig && clr.r == clr.b
 	if len(grayStr) > 0 {
 		if clr.gray {
@@ -759,13 +754,15 @@ func colorValue(r, g, b int, grayStr, fullStr string) (clr clrType) {
 // The method can be called before the first page is created. The value is
 // retained from page to page.
 func (f *Fpdf) SetDrawColor(r, g, b int) {
-	f.color.draw = colorValue(r, g, b, "G", "RG")
+	f.color.draw = rgbColorValue(r, g, b, "G", "RG")
 	if f.page > 0 {
 		f.out(f.color.draw.str)
 	}
 }
 
-// GetDrawColor returns the current draw color as RGB components (0 - 255).
+// GetDrawColor returns the most recently set draw color as RGB components (0 -
+// 255). This will not be the current value if a draw color of some other type
+// (for example, spot) has been more recently set.
 func (f *Fpdf) GetDrawColor() (int, int, int) {
 	return f.color.draw.ir, f.color.draw.ig, f.color.draw.ib
 }
@@ -775,14 +772,16 @@ func (f *Fpdf) GetDrawColor() (int, int, int) {
 // -255). The method can be called before the first page is created and the
 // value is retained from page to page.
 func (f *Fpdf) SetFillColor(r, g, b int) {
-	f.color.fill = colorValue(r, g, b, "g", "rg")
+	f.color.fill = rgbColorValue(r, g, b, "g", "rg")
 	f.colorFlag = f.color.fill.str != f.color.text.str
 	if f.page > 0 {
 		f.out(f.color.fill.str)
 	}
 }
 
-// GetFillColor returns the current fill color as RGB components (0 - 255).
+// GetFillColor returns the most recently set fill color as RGB components (0 -
+// 255). This will not be the current value if a fill color of some other type
+// (for example, spot) has been more recently set.
 func (f *Fpdf) GetFillColor() (int, int, int) {
 	return f.color.fill.ir, f.color.fill.ig, f.color.fill.ib
 }
@@ -791,11 +790,13 @@ func (f *Fpdf) GetFillColor() (int, int, int) {
 // components (0 - 255). The method can be called before the first page is
 // created. The value is retained from page to page.
 func (f *Fpdf) SetTextColor(r, g, b int) {
-	f.color.text = colorValue(r, g, b, "g", "rg")
+	f.color.text = rgbColorValue(r, g, b, "g", "rg")
 	f.colorFlag = f.color.fill.str != f.color.text.str
 }
 
-// GetTextColor returns the current text color as RGB components (0 - 255).
+// GetTextColor returns the most recently set text color as RGB components (0 -
+// 255). This will not be the current value if a text color of some other type
+// (for example, spot) has been more recently set.
 func (f *Fpdf) GetTextColor() (int, int, int) {
 	return f.color.text.ir, f.color.text.ig, f.color.text.ib
 }
@@ -1183,8 +1184,8 @@ func (f *Fpdf) gradientClipEnd() {
 
 func (f *Fpdf) gradient(tp int, r1, g1, b1 int, r2, g2, b2 int, x1, y1 float64, x2, y2 float64, r float64) {
 	pos := len(f.gradientList)
-	clr1 := colorValue(r1, g1, b1, "", "")
-	clr2 := colorValue(r2, g2, b2, "", "")
+	clr1 := rgbColorValue(r1, g1, b1, "", "")
+	clr2 := rgbColorValue(r2, g2, b2, "", "")
 	f.gradientList = append(f.gradientList, gradientType{tp, clr1.str, clr2.str,
 		x1, y1, x2, y2, r, 0})
 	f.outf("/Sh%d sh", pos)
@@ -3477,6 +3478,7 @@ func (f *Fpdf) putresourcedict() {
 	}
 	// Layers
 	f.layerPutResourceDict()
+	f.spotColorPutResourceDict()
 }
 
 func (f *Fpdf) putBlendModes() {
@@ -3542,6 +3544,7 @@ func (f *Fpdf) putresources() {
 	f.layerPutLayers()
 	f.putBlendModes()
 	f.putGradients()
+	f.putSpotColors()
 	f.putfonts()
 	if f.err != nil {
 		return
diff --git a/fpdf_test.go b/fpdf_test.go
index db46528..76ef558 100644
--- a/fpdf_test.go
+++ b/fpdf_test.go
@@ -2046,3 +2046,17 @@ func ExampleFpdf_SetJavascript() {
 	// Output:
 	// Successfully generated pdf/Fpdf_SetJavascript.pdf
 }
+
+// This example demonstrates spot color use
+func ExampleFpdf_AddSpotColor() {
+	pdf := gofpdf.New("P", "mm", "A4", "")
+	pdf.AddSpotColor("PANTONE 145 CVC", 0, 42, 100, 25)
+	pdf.AddPage()
+	pdf.SetFillSpotColor("PANTONE 145 CVC", 90)
+	pdf.Rect(80, 40, 50, 50, "F")
+	fileStr := example.Filename("Fpdf_AddSpotColor")
+	err := pdf.OutputFileAndClose(fileStr)
+	example.Summary(err, fileStr)
+	// Output:
+	// Successfully generated pdf/Fpdf_AddSpotColor.pdf
+}
diff --git a/spotcolor.go b/spotcolor.go
new file mode 100644
index 0000000..33aca82
--- /dev/null
+++ b/spotcolor.go
@@ -0,0 +1,184 @@
+// Copyright (c) Kurt Jung (Gmail: kurt.w.jung)
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+// Adapted from http://www.fpdf.org/en/script/script89.php by Olivier PLATHEY
+
+package gofpdf
+
+import (
+	"fmt"
+	"strings"
+)
+
+func byteBound(v byte) byte {
+	if v > 100 {
+		return 100
+	}
+	return v
+}
+
+// AddSpotColor adds an ink-based CMYK color to the gofpdf instance and
+// associates it with the specified name. The individual components specify
+// percentages ranging from 0 to 100. Values above this are quietly capped to
+// 100. An error occurs if the specified name is already associated with a
+// color.
+func (f *Fpdf) AddSpotColor(nameStr string, c, m, y, k byte) {
+	if f.err == nil {
+		_, ok := f.spotColorMap[nameStr]
+		if !ok {
+			id := len(f.spotColorMap) + 1
+			f.spotColorMap[nameStr] = spotColorType{
+				id: id,
+				val: cmykColorType{
+					c: byteBound(c),
+					m: byteBound(m),
+					y: byteBound(y),
+					k: byteBound(k),
+				},
+			}
+		} else {
+			f.err = fmt.Errorf("name \"%s\" is already associated with a spot color", nameStr)
+		}
+	}
+}
+
+func (f *Fpdf) getSpotColor(nameStr string) (clr spotColorType, ok bool) {
+	if f.err == nil {
+		clr, ok = f.spotColorMap[nameStr]
+		if !ok {
+			f.err = fmt.Errorf("spot color name \"%s\" is not registered", nameStr)
+		}
+	}
+	return
+}
+
+// SetDrawSpotColor sets the current draw color to the spot color associated
+// with nameStr. An error occurs if the name is not associated with a color.
+// The value for tint ranges from 0 (no intensity) to 100 (full intensity). It
+// is quietly bounded to this range.
+func (f *Fpdf) SetDrawSpotColor(nameStr string, tint byte) {
+	var clr spotColorType
+	var ok bool
+
+	clr, ok = f.getSpotColor(nameStr)
+	if ok {
+		f.color.draw.mode = colorModeSpot
+		f.color.draw.spotStr = nameStr
+		f.color.draw.str = sprintf("/CS%d CS %.3f SCN", clr.id, float64(byteBound(tint))/100)
+		if f.page > 0 {
+			f.out(f.color.draw.str)
+		}
+	}
+}
+
+// SetFillSpotColor sets the current fill color to the spot color associated
+// with nameStr. An error occurs if the name is not associated with a color.
+// The value for tint ranges from 0 (no intensity) to 100 (full intensity). It
+// is quietly bounded to this range.
+func (f *Fpdf) SetFillSpotColor(nameStr string, tint byte) {
+	var clr spotColorType
+	var ok bool
+
+	clr, ok = f.getSpotColor(nameStr)
+	if ok {
+		f.color.fill.mode = colorModeSpot
+		f.color.fill.spotStr = nameStr
+		f.color.fill.str = sprintf("/CS%d cs %.3f scn", clr.id, float64(byteBound(tint))/100)
+		f.colorFlag = f.color.fill.str != f.color.text.str
+		if f.page > 0 {
+			f.out(f.color.fill.str)
+		}
+	}
+}
+
+// SetTextSpotColor sets the current text color to the spot color associated
+// with nameStr. An error occurs if the name is not associated with a color.
+// The value for tint ranges from 0 (no intensity) to 100 (full intensity). It
+// is quietly bounded to this range.
+func (f *Fpdf) SetTextSpotColor(nameStr string, tint byte) {
+	var clr spotColorType
+	var ok bool
+
+	clr, ok = f.getSpotColor(nameStr)
+	if ok {
+		f.color.text.mode = colorModeSpot
+		f.color.text.spotStr = nameStr
+		f.color.text.str = sprintf("/CS%d cs %.3f scn", clr.id, float64(byteBound(tint))/100)
+		f.colorFlag = f.color.text.str != f.color.text.str
+	}
+}
+
+func (f *Fpdf) returnSpotColor(clr colorType) (name string, c, m, y, k byte) {
+	var spotClr spotColorType
+	var ok bool
+
+	name = clr.spotStr
+	if name != "" {
+		spotClr, ok = f.getSpotColor(name)
+		if ok {
+			c = spotClr.val.c
+			m = spotClr.val.m
+			y = spotClr.val.y
+			k = spotClr.val.k
+		}
+	}
+	return
+}
+
+// GetDrawSpotColor returns the most recently used spot color information for
+// drawing. This will not be the current drawing color if some other color type
+// such as RGB is active. If no spot color has been set for drawing, zero
+// values are returned.
+func (f *Fpdf) GetDrawSpotColor() (name string, c, m, y, k byte) {
+	return f.returnSpotColor(f.color.draw)
+}
+
+// GetTextSpotColor returns the most recently used spot color information for
+// text output. This will not be the current text color if some other color
+// type such as RGB is active. If no spot color has been set for text, zero
+// values are returned.
+func (f *Fpdf) GetTextSpotColor() (name string, c, m, y, k byte) {
+	return f.returnSpotColor(f.color.text)
+}
+
+// GetFillSpotColor returns the most recently used spot color information for
+// fill output. This will not be the current fill color if some other color
+// type such as RGB is active. If no fill spot color has been set, zero values
+// are returned.
+func (f *Fpdf) GetFillSpotColor() (name string, c, m, y, k byte) {
+	return f.returnSpotColor(f.color.fill)
+}
+
+func (f *Fpdf) putSpotColors() {
+	for k, v := range f.spotColorMap {
+		f.newobj()
+		f.outf("[/Separation /%s", strings.Replace(k, " ", "#20", -1))
+		f.out("/DeviceCMYK <<")
+		f.out("/Range [0 1 0 1 0 1 0 1] /C0 [0 0 0 0] ")
+		f.outf("/C1 [%.3f %.3f %.3f %.3f] ", float64(v.val.c)/100, float64(v.val.m)/100,
+			float64(v.val.y)/100, float64(v.val.k)/100)
+		f.out("/FunctionType 2 /Domain [0 1] /N 1>>]")
+		f.out("endobj")
+		v.objID = f.n
+		f.spotColorMap[k] = v
+	}
+}
+
+func (f *Fpdf) spotColorPutResourceDict() {
+	f.out("/ColorSpace <<")
+	for _, clr := range f.spotColorMap {
+		f.outf("/CS%d %d 0 R", clr.id, clr.objID)
+	}
+	f.out(">>")
+}