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-rw-r--r--def.go7
-rw-r--r--doc.go5
-rw-r--r--fpdf.go72
-rw-r--r--fpdf_test.go17
4 files changed, 100 insertions, 1 deletions
diff --git a/def.go b/def.go
index 6d0e83a..ca31526 100644
--- a/def.go
+++ b/def.go
@@ -24,6 +24,11 @@ const (
FPDF_VERSION = "1.7"
)
+type blendModeType struct {
+ strokeStr, fillStr, modeStr string
+ objNum int
+}
+
type sizeType struct {
wd, ht float64
}
@@ -122,6 +127,8 @@ type Fpdf struct {
fontDirStr string // location of font definition files
capStyle int // line cap style: butt 0, round 1, square 2
joinStyle int // line segment join style: miter 0, round 1, bevel 2
+ blendList []blendModeType // slice[idx] of alpha transparency modes, 1-based
+ blendMap map[string]int // map into blendList
err error // Set if error occurs during life cycle of instance
}
diff --git a/doc.go b/doc.go
index abb8518..fcf9ba3 100644
--- a/doc.go
+++ b/doc.go
@@ -20,7 +20,10 @@ Package gofpdf implements a PDF document generator.
This package's code and documentation are closely derived from the FPDF library
created by Olivier Plathey, and a number of font and image resources are copied
directly from it. Drawing support is adapted from the FPDF geometric figures
-script by David Hernández Sanz. The FPDF website is http://www.fpdf.org/.
+script by David Hernández Sanz. Transparency support is adapted from the FPDF
+transparency script by Martin Hall-May
+
+The FPDF website is http://www.fpdf.org/.
Features
diff --git a/fpdf.go b/fpdf.go
index 2755891..78be090 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -175,6 +175,9 @@ func New(orientationStr, unitStr, sizeStr, fontDirStr string) (f *Fpdf) {
}
// Enable compression
f.SetCompression(true)
+ f.blendList = make([]blendModeType, 0, 8)
+ f.blendList = append(f.blendList, blendModeType{}) //blendMode[0] is unused (1-based)
+ f.blendMap = make(map[string]int)
// Set default PDF version number
f.pdfVersion = "1.3"
return
@@ -808,6 +811,46 @@ func (f *Fpdf) Arc(x, y, rx, ry, degRotate, degStart, degEnd float64, styleStr s
}
}
+// Set the alpha blending channel. The blending effect applies to text,
+// drawings and images. alpha must be a value between 0.0 (fully transparent)
+// to 1.0 (fully opaque). Values outside of this range result in an error.
+// blendModeStr must be one of "Normal", "Multiply", "Screen", "Overlay",
+// "Darken", "Lighten", "ColorDodge", "ColorBurn","HardLight", "SoftLight",
+// "Difference", "Exclusion", "Hue", "Saturation", "Color", or "Luminosity". An
+// empty string is replaced with "Normal". To reset normal rendering after
+// applying a blending mode, call this method with alpha set to 1.0 and
+// blendModeStr set to "Normal".
+func (f *Fpdf) SetAlpha(alpha float64, blendModeStr string) {
+ if f.err != nil {
+ return
+ }
+ var bl blendModeType
+ switch blendModeStr {
+ case "Normal", "Multiply", "Screen", "Overlay",
+ "Darken", "Lighten", "ColorDodge", "ColorBurn", "HardLight", "SoftLight",
+ "Difference", "Exclusion", "Hue", "Saturation", "Color", "Luminosity":
+ bl.modeStr = blendModeStr
+ case "":
+ bl.modeStr = "Normal"
+ default:
+ f.err = fmt.Errorf("Unrecognized blend mode \"%s\"", blendModeStr)
+ return
+ }
+ if alpha < 0.0 || alpha > 1.0 {
+ f.err = fmt.Errorf("Alpha value (0.0 - 1.0) is out of range: %.3f", alpha)
+ return
+ }
+ alphaStr := sprintf("%.3f", alpha)
+ keyStr := sprintf("%s %s", alphaStr, blendModeStr)
+ pos, ok := f.blendMap[keyStr]
+ if !ok {
+ pos = len(f.blendList) // at least 1
+ f.blendList = append(f.blendList, blendModeType{alphaStr, alphaStr, blendModeStr, 0})
+ f.blendMap[keyStr] = pos
+ }
+ f.outf("/GS%d gs", pos)
+}
+
// Imports a TrueType, OpenType or Type1 font and makes it available. It is
// necessary to generate a font definition file first with the makefont
// utility. It is not necessary to call this function for the core PDF fonts
@@ -1491,9 +1534,16 @@ func (f *Fpdf) Ln(h float64) {
//
// If x is negative, the current abscissa is used.
//
+// If flow is true, the current y value is advanced after placing the image and
+// a page break may be made if necessary.
+//
// tp specifies the image format. Possible values are (case insensitive):
// "JPG", "JPEG", "PNG" and "GIF". If not specified, the type is inferred from
// the file extension.
+//
+// If link refers to an internal page anchor (that is, it is non-zero; see
+// AddLink()), the image will be a clickable internal link. Otherwise, if
+// linkStr specifies a URL, the image will be a clickable external link.
func (f *Fpdf) Image(fileStr string, x, y, w, h float64, flow bool, tp string, link int, linkStr string) {
if f.err != nil {
return
@@ -2381,12 +2431,31 @@ func (f *Fpdf) putresourcedict() {
f.out("/XObject <<")
f.putxobjectdict()
f.out(">>")
+ f.out("/ExtGState <<")
+ count := len(f.blendList)
+ for j := 1; j < count; j++ {
+ f.outf("/GS%d %d 0 R", j, f.blendList[j].objNum)
+ }
+ f.out(">>")
+}
+
+func (f *Fpdf) putBlendModes() {
+ count := len(f.blendList)
+ for j := 1; j < count; j++ {
+ bl := f.blendList[j]
+ f.newobj()
+ f.blendList[j].objNum = f.n
+ f.outf("<</Type /ExtGState /ca %s /CA %s /BM /%s>>",
+ bl.fillStr, bl.strokeStr, bl.modeStr)
+ f.out("endobj")
+ }
}
func (f *Fpdf) putresources() {
if f.err != nil {
return
}
+ f.putBlendModes()
f.putfonts()
if f.err != nil {
return
@@ -2446,6 +2515,9 @@ func (f *Fpdf) putcatalog() {
}
func (f *Fpdf) putheader() {
+ if len(f.blendMap) > 0 && f.pdfVersion < "1.4" {
+ f.pdfVersion = "1.4"
+ }
f.outf("%%PDF-%s", f.pdfVersion)
}
diff --git a/fpdf_test.go b/fpdf_test.go
index 494d281..c121260 100644
--- a/fpdf_test.go
+++ b/fpdf_test.go
@@ -704,3 +704,20 @@ func ExampleFpdf_tutorial11() {
// Output:
// Successfully generated pdf/tutorial11.pdf
}
+
+// Transparency
+func ExampleFpdf_tutorial12() {
+ pdf := New("", "", "", FONT_DIR)
+ pdf.SetFont("Helvetica", "", 48)
+ pdf.SetLineWidth(4)
+ pdf.SetFillColor(180, 180, 180)
+ pdf.AddPage()
+ pdf.SetXY(55, 60)
+ pdf.CellFormat(100, 40, "Go", "1", 0, "C", true, 0, "")
+ pdf.SetAlpha(0.5, "Normal")
+ pdf.Image(IMG_DIR+"/golang-gopher.png", 30, 10, 150, 0, false, "", 0, "")
+ pdf.SetAlpha(1.0, "Normal")
+ pdf.OutputAndClose(docWriter(pdf, 12))
+ // Output:
+ // Successfully generated pdf/tutorial12.pdf
+}