text_watermark.go

package main

import (
	"bytes"
	"fmt"
	"math"
	"text/template"

	"github.com/unidoc/unidoc/pdf/creator"
	"github.com/unidoc/unidoc/pdf/model/fonts"
)

var fontList = []string{
	"courier", "courier_bold", "courier_oblique", "courier_bold_oblique",
	"helvetica", "helvetica_bold", "helvetica_oblique", "helvetica_bold_oblique",
	"times", "times_bold", "times_italic", "times_bold_italic",
}

func drawText(p *creator.Paragraph, c *creator.Creator) {
	// Change to times bold font (default is helvetica).
	p.SetFont(getFontByName(font))
	p.SetFontSize(fontSize)
	p.SetPos(offsetX, offsetY)
	p.SetColor(creator.ColorRGBFromHex("#" + color))
	p.SetAngle(angle)

	// Encountering problem with tiles and text watermark. Contributions welcome.
	//if tiles {
	//	repeatTiles(p, c)
	//	return
	//}

	_ = c.Draw(p)
}

func adjustTextPosition(p *creator.Paragraph, c *creator.Creator) {
	p.SetTextAlignment(creator.TextAlignmentLeft)
	p.SetEnableWrap(false)

	if tiles {
		p.SetWidth(p.Width()) // Not working without setting it manually
		p.SetTextAlignment(creator.TextAlignmentCenter)
		offsetX, offsetY = 0, 0
	} else if center {
		p.SetWidth(p.Width()) // Not working without setting it manually
		p.SetTextAlignment(creator.TextAlignmentCenter)

		offsetX = (c.Context().PageWidth / 2) - (p.Width() / 2)
		offsetY = (c.Context().PageHeight / 2) - (p.Height() / 2)
	} else {
		if offsetX < 0 {
			p.SetWidth(p.Width()) // Not working without setting it manually
			p.SetTextAlignment(creator.TextAlignmentRight)

			offsetX = c.Context().PageWidth - (math.Abs(offsetX) + p.Width())
		}
		if offsetY < 0 {
			offsetY = c.Context().PageHeight - (math.Abs(offsetY) + p.Height())
		}

	}

	debugInfo(fmt.Sprintf("Paragraph width: %f", p.Width()))
	debugInfo(fmt.Sprintf("Paragraph height: %f", p.Height()))
	debugInfo(fmt.Sprintf("Offsets x: %f, y: %f", offsetX, offsetY))
}

func getFontByName(fontName string) fonts.Font {
	switch fontName {
	case "courier":
		return fonts.NewFontCourier()
	case "courier_bold":
		return fonts.NewFontCourierBold()
	case "courier_oblique":
		return fonts.NewFontCourierOblique()
	case "courier_bold_oblique":
		return fonts.NewFontCourierBoldOblique()
	case "helvetica":
		return fonts.NewFontHelvetica()
	case "helvetica_bold":
		return fonts.NewFontHelveticaBold()
	case "helvetica_oblique":
		return fonts.NewFontHelveticaOblique()
	case "helvetica_bold_oblique":
		return fonts.NewFontHelveticaBoldOblique()
	case "times":
		return fonts.NewFontTimesRoman()
	case "times_bold":
		return fonts.NewFontTimesBold()
	case "times_italic":
		return fonts.NewFontTimesItalic()
	case "times_bold_italic":
		return fonts.NewFontTimesBoldItalic()
	}

	debugInfo("No allowed font name didn't match the allowed list. Using helvetica_bold as default.")
	debugInfo(fmt.Sprintf("Allowed font names: %s", fontList))

	return fonts.NewFontHelveticaBold()
}

func isWatermarkATemplate(watermark string) bool {
	t := template.Must(template.New("watermark").Parse(watermark))
	buf := new(bytes.Buffer)
	err := t.Execute(buf, Recipient{0, 0, "out.pdf"})
	if err != nil {
		fatalIfError(err, fmt.Sprintf("Error parsing the template. [%s]", err))
	}
	return buf.String() != watermark
}

func applyTemplate(t *template.Template, rec *Recipient, para *creator.Paragraph) {
	buf := new(bytes.Buffer)
	err := t.Execute(buf, rec)
	fatalIfError(err, fmt.Sprintf("Failed to execute watermark template: [%s]", err))
	para.SetText(buf.String())
}