128 lines
4.6 KiB
Go
128 lines
4.6 KiB
Go
// Copyright 2020 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package qrbill
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import (
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"fmt"
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"strings"
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"time"
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"github.com/makiuchi-d/gozxing"
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"github.com/makiuchi-d/gozxing/qrcode/encoder"
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)
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// renderResultEPS is a copy of renderResult from
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// gozxing/qrcode/qrcode_writer.go, adapted to output to SVG.
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func renderResultEPS(code *encoder.QRCode, width, height, quietZone int) ([]byte, error) {
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input := code.GetMatrix()
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if input == nil {
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return nil, gozxing.NewWriterException("IllegalStateException")
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}
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inputWidth := input.GetWidth()
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inputHeight := input.GetHeight()
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qrWidth := inputWidth + (quietZone * 2)
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qrHeight := inputHeight + (quietZone * 2)
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outputWidth := qrWidth
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if outputWidth < width {
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outputWidth = width
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}
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outputHeight := qrHeight
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if outputHeight < height {
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outputHeight = height
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}
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multiple := outputWidth / qrWidth
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if h := outputHeight / qrHeight; multiple > h {
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multiple = h
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}
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// Padding includes both the quiet zone and the extra white pixels to accommodate the requested
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// dimensions. For example, if input is 25x25 the QR will be 33x33 including the quiet zone.
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// If the requested size is 200x160, the multiple will be 4, for a QR of 132x132. These will
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// handle all the padding from 100x100 (the actual QR) up to 200x160.
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leftPadding := (outputWidth - (inputWidth * multiple)) / 2
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topPadding := (outputHeight - (inputHeight * multiple)) / 2
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// --------------------------------------------------------------------------------
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var eps strings.Builder
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// See postscript language document structuring conventions specification version 3.0
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// https://www-cdf.fnal.gov/offline/PostScript/5001.PDF
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// See Encapsulated PostScript File Format Specification
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// https://www.adobe.com/content/dam/acom/en/devnet/actionscript/articles/5002.EPSF_Spec.pdf
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// EPS files must not have lines of ASCII text that exceed 255 characters,
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// excluding line-termination characters.
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// Lines must be terminated with one of the following combinations:
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// - CR (carriage return, ASCII decimal 13)
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// - LF (line feed, ASCII decimal 10)
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// - CR LF
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// - LF CR
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// BoundingBox parameters are lower-left (llx, lly) and upper-right (urx, ury)
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eps.WriteString("%!PS-Adobe-3.0 EPSF-3.0\n")
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eps.WriteString("%%Creator: https://github.com/stapelberg/qrbill\n")
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// TODO: summarize message and recipient in title
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// TODO: is there a max length for the title?
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eps.WriteString("%%Title: QR-Bill\n")
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eps.WriteString("%%CreationDate: " + time.Now().Format("2006-01-02") + "\n")
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eps.WriteString("%%BoundingBox: 0 0 1265 1265\n")
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eps.WriteString("%%EndComments\n")
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eps.WriteString("/F { rectfill } def\n")
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// Change the application coordinate system to work like the SVG one does,
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// for consistency between the different code paths. See also General
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// Coordinate System Transformation, Page 18, Encapsulated PostScript File
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// Format Specification:
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// https://www.adobe.com/content/dam/acom/en/devnet/actionscript/articles/5002.EPSF_Spec.pdf
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eps.WriteString("0 1265 translate\n")
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eps.WriteString("1 -1 scale\n")
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// Explicitly fill the background with white:
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eps.WriteString("1 1 1 setrgbcolor\n")
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// or 1 setgray?
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eps.WriteString("0 0 1265 1265 F\n")
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// Explicitly set color to black:
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eps.WriteString("0 0 0 setrgbcolor\n")
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// or 0 setgray?
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for inputY, outputY := 0, topPadding; inputY < inputHeight; inputY, outputY = inputY+1, outputY+multiple {
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// Write the contents of this row of the barcode
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for inputX, outputX := 0, leftPadding; inputX < inputWidth; inputX, outputX = inputX+1, outputX+multiple {
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if input.Get(inputX, inputY) == 1 {
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eps.WriteString(fmt.Sprintf("%d %d %d %d F\n", outputX, outputY, multiple, multiple))
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}
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}
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}
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eps.WriteString("549 549 translate\n")
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// overlay an EPS version of the swiss cross
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eps.WriteString("1 1 1 setrgbcolor\n")
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eps.WriteString("0 0 166 166 F\n")
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eps.WriteString("0 0 0 setrgbcolor\n")
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eps.WriteString("12 12 142 142 F\n")
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eps.WriteString("1 1 1 setrgbcolor\n")
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eps.WriteString("36 66 94 28 F\n")
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eps.WriteString("68 34 30 92 F\n")
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eps.WriteString("%%EOF")
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return []byte(eps.String()), nil
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}
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