example: support writing barcode as SVG

zxing-cpp · May 9, 2022 · a2c64fe · a2c64fe
1 parent f009fe7
commit a2c64fe
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Showing 3 changed files with 35 additions and 4 deletions.
diff --git a/core/src/BitMatrixIO.cpp b/core/src/BitMatrixIO.cpp
@@ -20,6 +20,7 @@
 #include "BitArray.h"
 
 #include <fstream>
+#include <sstream>
 
 namespace ZXing {
 
@@ -44,6 +45,29 @@ std::string ToString(const BitMatrix& matrix, char one, char zero, bool addSpace
 	return result;
 }
 
+std::string ToSVG(const BitMatrix& matrix)
+{
+	// see https://stackoverflow.com/questions/10789059/create-qr-code-in-vector-image/60638350#60638350
+
+	const int width = matrix.width();
+	const int height = matrix.height();
+	std::ostringstream out;
+
+	out << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+		<< "<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" viewBox=\"0 0 " << width << " " << height
+		<< "\" stroke=\"none\">\n"
+		<< "<path d=\"";
+
+	for (int y = 0; y < height; ++y)
+		for (int x = 0; x < width; ++x)
+			if (matrix.get(x, y))
+				out << "M" << x << "," << y << "h1v1h-1z";
+
+	out << "\"/>\n</svg>";
+
+	return out.str();
+}
+
 BitMatrix ParseBitMatrix(const std::string& str, char one, bool expectSpace)
 {
 	auto lineLength = str.find('\n');

diff --git a/core/src/BitMatrixIO.h b/core/src/BitMatrixIO.h
@@ -22,8 +22,8 @@
 
 namespace ZXing {
 
-std::string ToString(const BitMatrix& matrix, char one = 'X', char zero = ' ', bool addSpace = true,
-					 bool printAsCString = false);
+std::string ToString(const BitMatrix& matrix, char one = 'X', char zero = ' ', bool addSpace = true, bool printAsCString = false);
+std::string ToSVG(const BitMatrix& matrix);
 BitMatrix ParseBitMatrix(const std::string& str, char one = 'X', bool expectSpace = true);
 void SaveAsPBM(const BitMatrix& matrix, const std::string filename, int quietZone = 0);
 

diff --git a/example/ZXingWriter.cpp b/example/ZXingWriter.cpp
@@ -16,13 +16,15 @@
 
 #include "BarcodeFormat.h"
 #include "BitMatrix.h"
+#include "BitMatrixIO.h"
 #include "MultiFormatWriter.h"
 #include "TextUtfEncoding.h"
 #include "CharacterSetECI.h"
 
 #include <algorithm>
 #include <cctype>
 #include <cstring>
+#include <fstream>
 #include <iostream>
 #include <string>
 
@@ -42,7 +44,9 @@ static void PrintUsage(const char* exePath)
 			  << "Supported formats are:\n";
 	for (auto f : BarcodeFormatsFromString("Aztec Codabar Code39 Code93 Code128 DataMatrix EAN8 EAN13 ITF PDF417 QRCode UPCA UPCE"))
 		std::cout << "    " << ToString(f) << "\n";
-	std::cout << "Format can be lowercase letters, with or without '-'.\n";
+
+	std::cout << "Format can be lowercase letters, with or without '-'.\n"
+			  << "Output format is determined by file name, supported are png, jpg and svg.\n";
 }
 
 static bool ParseSize(std::string str, int* width, int* height)
@@ -128,14 +132,17 @@ int main(int argc, char* argv[])
 
 	try {
 		auto writer = MultiFormatWriter(format).setMargin(margin).setEncoding(encoding).setEccLevel(eccLevel);
-		auto bitmap = ToMatrix<uint8_t>(writer.encode(TextUtfEncoding::FromUtf8(text), width, height));
+		auto matrix = writer.encode(TextUtfEncoding::FromUtf8(text), width, height);
+		auto bitmap = ToMatrix<uint8_t>(matrix);
 
 		auto ext = GetExtension(filePath);
 		int success = 0;
 		if (ext == "" || ext == "png") {
 			success = stbi_write_png(filePath.c_str(), bitmap.width(), bitmap.height(), 1, bitmap.data(), 0);
 		} else if (ext == "jpg" || ext == "jpeg") {
 			success = stbi_write_jpg(filePath.c_str(), bitmap.width(), bitmap.height(), 1, bitmap.data(), 0);
+		} else if (ext == "svg") {
+			success = (std::ofstream(filePath) << ToSVG(matrix)).good();
 		}
 
 		if (!success) {