Use qrencode library to make qr code png

src/Makefile

@@ -2,7 +2,7 @@ CC=gcc
 PKGCONFIG = $(shell which pkg-config)
 
 CFLAGS=`pkg-config --cflags gtk+-3.0`
-LIBS=`pkg-config --libs gtk+-3.0 --libs x11` -lstdc++
+LIBS=`pkg-config --libs gtk+-3.0 --libs x11` -lstdc++ -lpng -lqrencode
 
 APP_NAME="wihotspot"
 APP_GUI_BINARY="wihotspot-gui"
@@ -16,7 +16,7 @@ GLIB_COMPILE_RESOURCES = $(shell $(PKGCONFIG) --variable=glib_compile_resources
 
 BUILT_SRC = resources.c
 
-_OBJ = main.o ui.o h_prop.o util.o read_config.o about_ui.o qr_ui.o $(BUILT_SRC:.c=.o)
+_OBJ = main.o ui.o h_prop.o util.o read_config.o about_ui.o qr_ui.o qrgen.o $(BUILT_SRC:.c=.o)
 OBJ = $(patsubst %,$(ODIR)/%,$(_OBJ))
 
 # Determine this makefile's path.

src/ui/qrgen.cpp

@@ -0,0 +1,206 @@
+//
+// Created by lakinduakash on 18/10/21.
+//
+/*
+Copyright (c) 2021, lakinduaksh
+        All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+        this list of conditions and the following disclaimer in the documentation
+and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+        IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+        FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+        CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+ */
+
+#include <stdio.h>
+#include <qrencode.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <fstream>
+#include <string>
+#include <iostream>
+#include <numeric>
+#include <png.h>
+#include <cstring>
+#include "qrgen.h"
+
+using namespace std;
+
+
+extern "C"{
+
+static int casesensitive = 0;
+static int eightbit = 0;
+static int version = 0;
+static int size = 8;
+static int margin = 5;
+static int dpi = 128;
+static int structured = 0;
+static int rle = 0;
+static int micro = 0;
+static QRecLevel level = QR_ECLEVEL_L;
+static QRencodeMode hint = QR_MODE_8;
+static unsigned int fg_color[4] = {0, 0, 0, 255};
+static unsigned int bg_color[4] = {255, 255, 255, 255};
+
+
+// int main()
+// {
+// const char * line = "The stuff you want to encode";
+//         QRcode *myqrcode;
+//         myqrcode = QRcode_encodeString(line, 4, QR_ECLEVEL_H, QR_MODE_8,1);
+//         writePNG(myqrcode,"filename.png");
+//         QRcode_free(myqrcode);
+// return 0;
+// }
+
+void qr_to_png(const char *qrstring,const char *outfile){
+
+    QRcode *myqrcode;
+        myqrcode = QRcode_encodeString(qrstring, 4, QR_ECLEVEL_H, QR_MODE_8,1);
+        writePNG(myqrcode,outfile);
+        QRcode_free(myqrcode);
+}
+
+
+
+
+static int writePNG(QRcode *qrcode, const char *outfile)
+{
+    static FILE *fp; // avoid clobbering by setjmp.
+    png_structp png_ptr;
+    png_infop info_ptr;
+    png_colorp palette;
+    png_byte alpha_values[2];
+    unsigned char *row, *p, *q;
+    int x, y, xx, yy, bit;
+    int realwidth;
+
+    realwidth = (qrcode->width + margin * 2) * size;
+    row = (unsigned char *)malloc((realwidth + 7) / 8);
+    if(row == NULL) {
+        fprintf(stderr, "Failed to allocate memory.\n");
+        exit(EXIT_FAILURE);
+    }
+
+    if(outfile[0] == '-' && outfile[1] == '\0') {
+        fp = stdout;
+    } else {
+        fp = fopen(outfile, "wb");
+        if(fp == NULL) {
+            fprintf(stderr, "Failed to create file: %s\n", outfile);
+            perror(NULL);
+            exit(EXIT_FAILURE);
+        }
+    }
+
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if(png_ptr == NULL) {
+        fprintf(stderr, "Failed to initialize PNG writer.\n");
+        exit(EXIT_FAILURE);
+    }
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if(info_ptr == NULL) {
+        fprintf(stderr, "Failed to initialize PNG write.\n");
+        exit(EXIT_FAILURE);
+    }
+
+    if(setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        fprintf(stderr, "Failed to write PNG image.\n");
+        exit(EXIT_FAILURE);
+    }
+
+    palette = (png_colorp) malloc(sizeof(png_color) * 2);
+    if(palette == NULL) {
+        fprintf(stderr, "Failed to allocate memory.\n");
+        exit(EXIT_FAILURE);
+    }
+    palette[0].red   = fg_color[0];
+    palette[0].green = fg_color[1];
+    palette[0].blue  = fg_color[2];
+    palette[1].red   = bg_color[0];
+    palette[1].green = bg_color[1];
+    palette[1].blue  = bg_color[2];
+    alpha_values[0] = fg_color[3];
+    alpha_values[1] = bg_color[3];
+    png_set_PLTE(png_ptr, info_ptr, palette, 2);
+    png_set_tRNS(png_ptr, info_ptr, alpha_values, 2, NULL);
+
+    png_init_io(png_ptr, fp);
+    png_set_IHDR(png_ptr, info_ptr,
+        realwidth, realwidth,
+        1,
+        PNG_COLOR_TYPE_PALETTE,
+        PNG_INTERLACE_NONE,
+        PNG_COMPRESSION_TYPE_DEFAULT,
+        PNG_FILTER_TYPE_DEFAULT);
+png_set_pHYs(png_ptr, info_ptr,
+        dpi * INCHES_PER_METER,
+        dpi * INCHES_PER_METER,
+        PNG_RESOLUTION_METER);
+png_write_info(png_ptr, info_ptr);
+
+/* top margin */
+memset(row, 0xff, (realwidth + 7) / 8);
+for(y=0; y<margin * size; y++) {
+    png_write_row(png_ptr, row);
+}
+
+/* data */
+p = qrcode->data;
+for(y=0; y<qrcode->width; y++) {
+    bit = 7;
+    memset(row, 0xff, (realwidth + 7) / 8);
+    q = row;
+    q += margin * size / 8;
+    bit = 7 - (margin * size % 8);
+    for(x=0; x<qrcode->width; x++) {
+        for(xx=0; xx<size; xx++) {
+            *q ^= (*p & 1) << bit;
+            bit--;
+            if(bit < 0) {
+                q++;
+                bit = 7;
+            }
+        }
+        p++;
+    }
+    for(yy=0; yy<size; yy++) {
+        png_write_row(png_ptr, row);
+    }
+}
+/* bottom margin */
+memset(row, 0xff, (realwidth + 7) / 8);
+for(y=0; y<margin * size; y++) {
+    png_write_row(png_ptr, row);
+}
+
+png_write_end(png_ptr, info_ptr);
+png_destroy_write_struct(&png_ptr, &info_ptr);
+
+fclose(fp);
+free(row);
+free(palette);
+
+return 0;
+}
+
+}

src/ui/qrgen.h

@@ -0,0 +1,52 @@
+//
+// Created by lakinduakash on 18/10/21.
+//
+/*
+Copyright (c) 2021, lakinduaksh
+        All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+        this list of conditions and the following disclaimer in the documentation
+and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+        IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+        FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+        CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+ */
+
+#ifndef WIHOTSPOT_QRGEN_H
+#define WIHOTSPOT_QRGEN_H
+
+#include <qrencode.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define INCHES_PER_METER (100.0/2.54)
+
+static int writePNG(QRcode *qrcode, const char *outfile);
+
+void qr_to_png(const char *qrstring,const char *outfile);
+
+#ifdef __cplusplus
+}
+#endif
+
+
+
+#endif //WIHOTSPOT_QRGEN_H