From 31bda30724de44bdca992eae1bd341a9924d956b Mon Sep 17 00:00:00 2001 From: Michael Stapelberg Date: Sat, 14 Nov 2020 11:12:02 +0100 Subject: [PATCH] implement a native EPS writer --- cmd/qrbill-api/api.go | 15 ++++- go.mod | 3 +- go.sum | 6 +- qrbill.go | 15 +++++ qrcodegeneratoreps.go | 127 ++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 162 insertions(+), 4 deletions(-) create mode 100644 qrcodegeneratoreps.go diff --git a/cmd/qrbill-api/api.go b/cmd/qrbill-api/api.go index 4db2e64..02d411d 100644 --- a/cmd/qrbill-api/api.go +++ b/cmd/qrbill-api/api.go @@ -105,7 +105,8 @@ func logic() error { format != "svg" && format != "txt" && format != "html" && - format != "wv" { + format != "wv" && + format != "eps" { msg := fmt.Sprintf("format (%q) must be one of png, svg, txt or html", format) log.Printf("%s %s", prefix, msg) http.Error(w, msg, http.StatusBadRequest) @@ -157,6 +158,18 @@ func logic() error { w.Header().Add("Content-Type", "image/svg+xml") + case "eps": + var err error + b, err = bill.EncodeToEPS() + if err != nil { + log.Printf("%s %s", prefix, err) + http.Error(w, err.Error(), http.StatusInternalServerError) + return + } + + w.Header().Add("Content-Type", "image/eps") + w.Header().Add("Content-Disposition", `attachment; filename="qr.eps"`) + case "txt": w.Header().Add("Content-Type", "text/plain; charset=utf-8") spew.Fdump(w, qrch.Validate()) diff --git a/go.mod b/go.mod index 4b02798..a440806 100644 --- a/go.mod +++ b/go.mod @@ -3,10 +3,11 @@ module github.com/stapelberg/qrbill go 1.14 require ( - github.com/ajstarks/svgo v0.0.0-20200320125537-f189e35d30ca + github.com/ajstarks/svgo v0.0.0-20200725142600-7a3c8b57fecb github.com/davecgh/go-spew v1.1.1 github.com/makiuchi-d/gozxing v0.0.0-20200903113411-25f730ed83da github.com/mattn/go-isatty v0.0.12 + golang.org/x/sys v0.0.0-20200724161237-0e2f3a69832c // indirect golang.org/x/text v0.3.4 // indirect golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect ) diff --git a/go.sum b/go.sum index bf9c193..3b63c55 100644 --- a/go.sum +++ b/go.sum @@ -1,5 +1,5 @@ -github.com/ajstarks/svgo v0.0.0-20200320125537-f189e35d30ca h1:kWzLcty5V2rzOqJM7Tp/MfSX0RMSI1x4IOLApEefYxA= -github.com/ajstarks/svgo v0.0.0-20200320125537-f189e35d30ca/go.mod h1:K08gAheRH3/J6wwsYMMT4xOr94bZjxIelGM0+d/wbFw= +github.com/ajstarks/svgo v0.0.0-20200725142600-7a3c8b57fecb h1:EVl3FJLQCzSbgBezKo/1A4ADnJ4mtJZ0RvnNzDJ44nY= +github.com/ajstarks/svgo v0.0.0-20200725142600-7a3c8b57fecb/go.mod h1:K08gAheRH3/J6wwsYMMT4xOr94bZjxIelGM0+d/wbFw= github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c= github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= github.com/makiuchi-d/gozxing v0.0.0-20200903113411-25f730ed83da h1:OgNu1PPD9EvZckyKDAc8DA4KymNXuc6vaCLsdOGyjOE= @@ -8,6 +8,8 @@ github.com/mattn/go-isatty v0.0.12 h1:wuysRhFDzyxgEmMf5xjvJ2M9dZoWAXNNr5LSBS7uHX github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU= golang.org/x/sys v0.0.0-20200116001909-b77594299b42 h1:vEOn+mP2zCOVzKckCZy6YsCtDblrpj/w7B9nxGNELpg= golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= +golang.org/x/sys v0.0.0-20200724161237-0e2f3a69832c h1:UIcGWL6/wpCfyGuJnRFJRurA+yj8RrW7Q6x2YMCXt6c= +golang.org/x/sys v0.0.0-20200724161237-0e2f3a69832c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= golang.org/x/text v0.3.4 h1:0YWbFKbhXG/wIiuHDSKpS0Iy7FSA+u45VtBMfQcFTTc= golang.org/x/text v0.3.4/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ= golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ= diff --git a/qrbill.go b/qrbill.go index c39e4c7..c457d96 100644 --- a/qrbill.go +++ b/qrbill.go @@ -287,6 +287,21 @@ func (b *Bill) EncodeToSVG() ([]byte, error) { return bytes.ReplaceAll(qrCodeSVG, []byte(``), append(cross, []byte("")...)), nil } +func (b *Bill) EncodeToEPS() ([]byte, error) { + var err error + code, err := encoder.Encoder_encode(b.qrcontents, decoder.ErrorCorrectionLevel_M, qrEncodeHints()) + if err != nil { + return nil, err + } + + const quietzone = 4 + qrCodeEPS, err := renderResultEPS(code, qrCodeEdgeSidePx, qrCodeEdgeSidePx, quietzone) + if err != nil { + return nil, err + } + return qrCodeEPS, nil +} + func (b *Bill) EncodeToImage() (image.Image, error) { return generateSwissQrCode(b.qrcontents) } diff --git a/qrcodegeneratoreps.go b/qrcodegeneratoreps.go new file mode 100644 index 0000000..8a81677 --- /dev/null +++ b/qrcodegeneratoreps.go @@ -0,0 +1,127 @@ +// Copyright 2020 Google LLC +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package qrbill + +import ( + "fmt" + "strings" + "time" + + "github.com/makiuchi-d/gozxing" + "github.com/makiuchi-d/gozxing/qrcode/encoder" +) + +// renderResultEPS is a copy of renderResult from +// gozxing/qrcode/qrcode_writer.go, adapted to output to SVG. +func renderResultEPS(code *encoder.QRCode, width, height, quietZone int) ([]byte, error) { + input := code.GetMatrix() + if input == nil { + return nil, gozxing.NewWriterException("IllegalStateException") + } + inputWidth := input.GetWidth() + inputHeight := input.GetHeight() + qrWidth := inputWidth + (quietZone * 2) + qrHeight := inputHeight + (quietZone * 2) + outputWidth := qrWidth + if outputWidth < width { + outputWidth = width + } + outputHeight := qrHeight + if outputHeight < height { + outputHeight = height + } + + multiple := outputWidth / qrWidth + if h := outputHeight / qrHeight; multiple > h { + multiple = h + } + // Padding includes both the quiet zone and the extra white pixels to accommodate the requested + // dimensions. For example, if input is 25x25 the QR will be 33x33 including the quiet zone. + // If the requested size is 200x160, the multiple will be 4, for a QR of 132x132. These will + // handle all the padding from 100x100 (the actual QR) up to 200x160. + leftPadding := (outputWidth - (inputWidth * multiple)) / 2 + topPadding := (outputHeight - (inputHeight * multiple)) / 2 + + // -------------------------------------------------------------------------------- + + var eps strings.Builder + // See postscript language document structuring conventions specification version 3.0 + // https://www-cdf.fnal.gov/offline/PostScript/5001.PDF + + // See Encapsulated PostScript File Format Specification + // https://www.adobe.com/content/dam/acom/en/devnet/actionscript/articles/5002.EPSF_Spec.pdf + + // EPS files must not have lines of ASCII text that exceed 255 characters, + // excluding line-termination characters. + + // Lines must be terminated with one of the following combinations: + // - CR (carriage return, ASCII decimal 13) + // - LF (line feed, ASCII decimal 10) + // - CR LF + // - LF CR + + // BoundingBox parameters are lower-left (llx, lly) and upper-right (urx, ury) + eps.WriteString("%!PS-Adobe-3.0 EPSF-3.0\n") + eps.WriteString("%%Creator: https://github.com/stapelberg/qrbill\n") + // TODO: summarize message and recipient in title + // TODO: is there a max length for the title? + eps.WriteString("%%Title: QR-Bill\n") + eps.WriteString("%%CreationDate: " + time.Now().Format("2006-01-02") + "\n") + eps.WriteString("%%BoundingBox: 0 0 1265 1265\n") + eps.WriteString("%%EndComments\n") + eps.WriteString("/F { rectfill } def\n") + + // Change the application coordinate system to work like the SVG one does, + // for consistency between the different code paths. See also General + // Coordinate System Transformation, Page 18, Encapsulated PostScript File + // Format Specification: + // https://www.adobe.com/content/dam/acom/en/devnet/actionscript/articles/5002.EPSF_Spec.pdf + eps.WriteString("0 1265 translate\n") + eps.WriteString("1 -1 scale\n") + + // Explicitly fill the background with white: + eps.WriteString("1 1 1 setrgbcolor\n") + // or 1 setgray? + eps.WriteString("0 0 1265 1265 F\n") + + // Explicitly set color to black: + eps.WriteString("0 0 0 setrgbcolor\n") + // or 0 setgray? + + for inputY, outputY := 0, topPadding; inputY < inputHeight; inputY, outputY = inputY+1, outputY+multiple { + // Write the contents of this row of the barcode + for inputX, outputX := 0, leftPadding; inputX < inputWidth; inputX, outputX = inputX+1, outputX+multiple { + if input.Get(inputX, inputY) == 1 { + eps.WriteString(fmt.Sprintf("%d %d %d %d F\n", outputX, outputY, multiple, multiple)) + } + } + } + + eps.WriteString("549 549 translate\n") + + // overlay an EPS version of the swiss cross + eps.WriteString("1 1 1 setrgbcolor\n") + eps.WriteString("0 0 166 166 F\n") + + eps.WriteString("0 0 0 setrgbcolor\n") + eps.WriteString("12 12 142 142 F\n") + + eps.WriteString("1 1 1 setrgbcolor\n") + eps.WriteString("36 66 94 28 F\n") + eps.WriteString("68 34 30 92 F\n") + + eps.WriteString("%%EOF") + return []byte(eps.String()), nil +}