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/* -*- mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*- */
/* cc-qr-code.c
*
* Copyright 2019 Purism SPC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Author(s):
* Mohammed Sadiq <sadiq@sadiqpk.org>
*
* SPDX-License-Identifier: GPL-3.0-or-later
*/
#undef G_LOG_DOMAIN
#define G_LOG_DOMAIN "cc-qr-code"
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "cc-qr-code.h"
#include "qrcodegen.c"
/**
* SECTION: cc-qr_code
* @title: CcQrCode
* @short_description: A Simple QR Code wrapper around libqrencode
* @include: "cc-qr-code.h"
*
* Generate a QR image from a given text.
*/
struct _CcQrCode
{
GObject parent_instance;
gchar *text;
cairo_surface_t *surface;
gint size;
gint scale;
};
G_DEFINE_TYPE (CcQrCode, cc_qr_code, G_TYPE_OBJECT)
static void
cc_qr_code_finalize (GObject *object)
{
CcQrCode *self = (CcQrCode *)object;
g_clear_pointer (&self->surface, cairo_surface_destroy);
g_clear_pointer (&self->text, g_free);
G_OBJECT_CLASS (cc_qr_code_parent_class)->finalize (object);
}
static void
cc_qr_code_class_init (CcQrCodeClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
object_class->finalize = cc_qr_code_finalize;
}
static void
cc_qr_code_init (CcQrCode *self)
{
}
CcQrCode *
cc_qr_code_new (void)
{
return g_object_new (CC_TYPE_QR_CODE, NULL);
}
gboolean
cc_qr_code_set_text (CcQrCode *self,
const gchar *text)
{
g_return_val_if_fail (CC_IS_QR_CODE (self), FALSE);
g_return_val_if_fail (!text || *text, FALSE);
if (g_strcmp0 (text, self->text) == 0)
return FALSE;
/* Clear cairo surface that is cached */
g_clear_pointer (&self->surface, cairo_surface_destroy);
g_free (self->text);
self->text = g_strdup (text);
return TRUE;
}
static void
cc_cairo_fill_pixel (cairo_t *cr,
int x,
int y,
int padding,
int scale)
{
cairo_rectangle (cr,
x * scale + padding,
y * scale + padding,
scale, scale);
cairo_fill (cr);
}
cairo_surface_t *
cc_qr_code_get_surface (CcQrCode *self,
gint size,
gint scale)
{
uint8_t qr_code[qrcodegen_BUFFER_LEN_FOR_VERSION (qrcodegen_VERSION_MAX)];
uint8_t temp_buf[qrcodegen_BUFFER_LEN_FOR_VERSION (qrcodegen_VERSION_MAX)];
cairo_t *cr;
gint pixel_size, padding, qr_size;
gboolean success = FALSE;
g_return_val_if_fail (CC_IS_QR_CODE (self), NULL);
g_return_val_if_fail (size > 0, NULL);
g_return_val_if_fail (scale > 0, NULL);
if (!self->text || !*self->text)
{
g_warn_if_reached ();
cc_qr_code_set_text (self, "invalid text");
}
if (self->surface &&
self->size == size &&
self->scale == scale)
return self->surface;
self->size = size;
self->scale = scale;
g_clear_pointer (&self->surface, cairo_surface_destroy);
success = qrcodegen_encodeText (self->text,
temp_buf,
qr_code,
qrcodegen_Ecc_LOW,
qrcodegen_VERSION_MIN,
qrcodegen_VERSION_MAX,
qrcodegen_Mask_AUTO,
FALSE);
if (!success)
return NULL;
self->surface = cairo_image_surface_create (CAIRO_FORMAT_RGB24, size * scale, size * scale);
cairo_surface_set_device_scale (self->surface, scale, scale);
cr = cairo_create (self->surface);
cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);
/* Draw white background */
cairo_set_source_rgba (cr, 1, 1, 1, 1);
cairo_rectangle (cr, 0, 0, size * scale, size * scale);
cairo_fill (cr);
qr_size = qrcodegen_getSize(qr_code);
pixel_size = MAX (1, size / (qr_size));
padding = (size - qr_size * pixel_size) / 2;
/* If subpixel size is big and margin is pretty small,
* increase the margin */
if (pixel_size > 4 && padding < 12)
{
pixel_size--;
padding = (size - qr_size * pixel_size) / 2;
}
/* Now draw the black QR code pixels */
cairo_set_source_rgba (cr, 0, 0, 0, 1);
for (int row = 0; row < qr_size; row++)
{
for (int column = 0; column < qr_size; column++)
{
if (qrcodegen_getModule (qr_code, row, column))
cc_cairo_fill_pixel (cr, column, row, padding, pixel_size);
}
}
cairo_destroy (cr);
return self->surface;
}
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