gopdf/layer.go

122 lines
3.4 KiB
Go

/*
* Copyright (c) 2014 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.
*/
package gofpdf
// Routines in this file are translated from
// http://www.fpdf.org/en/script/script97.php
type layerType struct {
name string
visible bool
objNum int // object number
}
type layerRecType struct {
list []layerType
currentLayer int
openLayerPane bool
}
func (f *Fpdf) layerInit() {
f.layer.list = make([]layerType, 0)
f.layer.currentLayer = -1
f.layer.openLayerPane = false
}
// AddLayer defines a layer that can be shown or hidden when the document is
// displayed. name specifies the layer name that the document reader will
// display in the layer list. visible specifies whether the layer will be
// initially visible. The return value is an integer ID that is used in a call
// to BeginLayer().
func (f *Fpdf) AddLayer(name string, visible bool) (layerID int) {
layerID = len(f.layer.list)
f.layer.list = append(f.layer.list, layerType{name: name, visible: visible})
return
}
// BeginLayer is called to begin adding content to the specified layer. All
// content added to the page between a call to BeginLayer and a call to
// EndLayer is added to the layer specified by id. See AddLayer for more
// details.
func (f *Fpdf) BeginLayer(id int) {
f.EndLayer()
if id >= 0 && id < len(f.layer.list) {
f.outf("/OC /OC%d BDC", id)
f.layer.currentLayer = id
}
}
// EndLayer is called to stop adding content to the currently active layer. See
// BeginLayer for more details.
func (f *Fpdf) EndLayer() {
if f.layer.currentLayer >= 0 {
f.out("EMC")
f.layer.currentLayer = -1
}
}
// OpenLayerPane advises the document reader to open the layer pane when the
// document is initially displayed.
func (f *Fpdf) OpenLayerPane() {
f.layer.openLayerPane = true
}
func (f *Fpdf) layerEndDoc() {
if len(f.layer.list) > 0 {
if f.pdfVersion < "1.5" {
f.pdfVersion = "1.5"
}
}
}
func (f *Fpdf) layerPutLayers() {
for j, l := range f.layer.list {
f.newobj()
f.layer.list[j].objNum = f.n
f.outf("<</Type /OCG /Name %s>>", f.textstring(utf8toutf16(l.name)))
f.out("endobj")
}
}
func (f *Fpdf) layerPutResourceDict() {
if len(f.layer.list) > 0 {
f.out("/Properties <<")
for j, layer := range f.layer.list {
f.outf("/OC%d %d 0 R", j, layer.objNum)
}
f.out(">>")
}
}
func (f *Fpdf) layerPutCatalog() {
if len(f.layer.list) > 0 {
onStr := ""
offStr := ""
for _, layer := range f.layer.list {
onStr += sprintf("%d 0 R ", layer.objNum)
if !layer.visible {
offStr += sprintf("%d 0 R ", layer.objNum)
}
}
f.outf("/OCProperties <</OCGs [%s] /D <</OFF [%s] /Order [%s]>>>>", onStr, offStr, onStr)
if f.layer.openLayerPane {
f.out("/PageMode /UseOC")
}
}
}