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/* Copyright 2014, Sebastian Reichel <sre@ring0.de>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
public class EAN {
Cairo.Context ctx;
double width;
double height;
const double marker_length_diff = 10.0;
double basex;
double basey;
static const uint8[] C = { 0x00, 0x0b, 0x0d, 0x0e, 0x13, 0x19, 0x1c, 0x15, 0x16, 0x1a };
static uint8[,] lookup = {
{ 0x0d, 0x19, 0x13, 0x3d, 0x23, 0x31, 0x2f, 0x3b, 0x37, 0x0b }, /* L */
{ 0x27, 0x33, 0x1b, 0x21, 0x1d, 0x39, 0x05, 0x11, 0x09, 0x17 }, /* G */
{ 0x72, 0x66, 0x6c, 0x42, 0x5c, 0x4e, 0x50, 0x44, 0x48, 0x74 } /* R */
};
public EAN(Cairo.Context ctx, double width, double height) {
this.ctx = ctx;
this.width = width / 95.0;
this.height = height;
}
private void draw_line(bool black) {
double x,y;
if(black)
ctx.set_source_rgb(0, 0, 0);
else
ctx.set_source_rgb(1, 1, 1);
ctx.rel_line_to(0,height);
ctx.rel_move_to(width,-height);
ctx.get_current_point(out x, out y);
ctx.stroke();
ctx.move_to(x,y);
}
private void draw_startstop() {
draw_line(true);
draw_line(false);
draw_line(true);
}
private void draw_middle() {
draw_line(false);
draw_line(true);
draw_line(false);
draw_line(true);
draw_line(false);
}
private void draw_number_text(uint8 number) {
double x, y;
ctx.get_current_point(out x, out y);
ctx.set_source_rgb(0, 0, 0);
ctx.stroke();
ctx.move_to(x,y);
}
private void draw_number(uint8 number, uint8 type) {
draw_number_text(number);
for(int i=6; i>=0; i--) {
var bit = (lookup[type,number] >> i) & 1;
draw_line(bit == 1);
}
}
private uint8 get_number(string ean, int pos) {
return (uint8) int.parse("%c".printf(ean[pos]));
}
private void draw13(string ean) {
/* need some extra space for the checksum */
width = (width * 95.0) / 102.0;
uint8 LG = C[get_number(ean, 0)];
draw_startstop();
for(int i=1, x = 5; i<7; i++, x--) {
uint8 type = (uint8) (LG >> x) & 1;
draw_number(get_number(ean,i), type);
}
draw_middle();
for(int i=7; i<13; i++)
draw_number(get_number(ean,i), 2);
draw_startstop();
/* remove extra space for the checksum */
width = (width * 102.0) / 95.0;
}
private void draw8(string ean) {
draw_startstop();
for(int i=0; i<4; i++)
draw_number(get_number(ean,i), 0);
draw_middle();
for(int i=4; i<8; i++)
draw_number(get_number(ean,i), 2);
draw_startstop();
}
public void draw(string ean) throws BarcodeError {
ctx.save();
ctx.set_line_width(width);
ctx.get_current_point(out basex, out basey);
ctx.rel_move_to(0.5*width,0);
for(int i=0; i<ean.length; i++) {
if(ean[i] < '0' || ean[i] > '9') {
throw new BarcodeError.UNEXPECTED_CHARACTER("Character '%c' is not allowed in EAN".printf(ean[i]));
}
}
if(ean.length == 13)
draw13(ean);
else if(ean.length == 8)
draw8(ean);
else
throw new BarcodeError.UNEXPECTED_LENGTH("length of EAN is incorrect (must be 8 or 13)");
ctx.restore();
}
}
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