OpenPeta » Image Processing

Watermark Images – A Software for Adding Text into Images

ANTHONIRAJ — Wed, 31 Mar 2010 02:06:38 +0000

Every time when i post article in my blog, i used to display some images, also i will think about adding “my blog name:OpenPeta.com” as a watermark into the images for ownership purpose [In OpenPeta all content and images are published under Open source and creative common licenses , so any one can copy and distribute the content with author name. for that purpose only i want to add watermark in images] . but In Ubuntu i could not do that task , Windows Live has that features of adding watermark and border to images . I always look into sourceforge.net for open source softwares, today i found one simple Java based watermark software for adding text into images. lets analyze it.

WatermarkImages from SourceForge.net

What is Image Watermarking?

Image watermarking is the technique for hiding data within the image, the data can be a text or image. This technique is used for preventing unauthorized ownership of particular image . There are two types of watermarking

Visible Watermarking – watermarked text will visible inside the image
Invisible Watermarking – watermarked text will not be visible to others , only the owner can extract the text using decoding algorithm and key.

Image Watermarking Software -WatermarkImages

WatermarkImages is a software which is used for adding text with various colors and fonts into image. it can be downloaded from http://sourceforge.net/projects/watermarkimages/ sourceforge website. This software is written in Java , so you need Java interpreter or run time environment to run this software .

Watermarker 2.0

Adding Watermark into Images

After downloading binary or jar file of this software from the net , simply extract the file and store it into some folder. for runnung this software , goto terminal and tyoe

#java -jar WaterMarker2.1.jar

Text Watermarking Panel

This command will open the GUI window of this software, then select the image which you want to add text , and Enter the text then click start button , The watermarked image will be ready for you within a second.

2D Graphics Using C in Linux [ Graphics.h in Linux ]

ANTHONIRAJ — Sun, 20 Sep 2009 00:18:22 +0000

Most of technical people are trying to migrate from windows to Linux now a days , but they are facing lot of problems with Linux . they do not even know the forums and blogs of Linux which would be useful for finding answer to their query. The main problem of open source is choosing right one for user need. Because so many open source softwares are available for a single thing. Surely user need some supportive forum or website to find that one . open Peta is also doing that job. The idea of this post coming to my mind from my college friend . One of my colleague asked me about computer graphics program in Linux using C programming language. the questions is

How to draw line, circle , or 2D graphics in Linux Using C or C++?

I was searching Internet and found some softwares for developing graphics applications in Linux. that softwares are listed here

GTK+ – Gnome Tool Kit
QT - The X toolkit
SVGALIB [ #include ]
libgraph [ #include ]

GTK and QT are simple and used for high level Graphical User Interface [ GUI ] development. SVGALIB and libgraph is used for 2D graphics in Linux . the syntax and functions are some what different for beginners [specially the user from windows ] but most of users familiar with windows graphics.h header file in C and C++ , so we can move for libgraph which is exact one for windows graphics user . libgraph is an implementation of the Turbo C graphics API (graphics.h) on GNU/Linux using SDL [ Simple Direct Media Player ]. The library requires SDL for primitive graphics and SDL. First you need to install the following dependency packages using synaptic package manager in Ubuntu Linux to develop the graphics applications properly.

SDL Library

Installing SDL Library

GUILE – GNU’s Ubiquitous Intelligent Language for Extension

GUILE Installation

After installing these two packages , download the libgraph and install in your system

#sudo su

#tar -xzvf libgraph-1.0.2.tar.gz

#cd libgraph-1.0.2

#make

# make install

For better understanding , watch this video given here ….

Developing Graphics Application

1. Open your favorite text editor and type the following code

#include "stdio.h"
#include "graphics.h"
int main()
{
int gd=DETECT, gm=VGAMAX;
initgraph(&amp;gd,&amp;gm, 0);
moveto(0, 0);
setcolor(4);
rectangle(50,50,500,200);
while(!kbhit());
closegraph();
return 0;
}

2. Now compile the program with lgraph library

#gcc line.c -lgraph -o output

#./output

If you get any error in this line like

./output: error while loading shared libraries: libgraph.so.1: cannot open shared object file: No such file or directory

Do the following

sudo cp /usr/local/lib/libgraph.* /usr/lib

3. Now one new window will open , there you will get the output Rectangle in Red color.

Output Window

The advantage of libgraph is very easy to remember the syntax [ all functions are same as turbo c graphics.h ] . still if you are facing any problem to develop graphics applications using this , send your problems through comment page of this post.

Grabbing Pixels from PGM Image using C

admin — Tue, 24 Mar 2009 18:18:00 +0000

#include
#include
#include
/*
* Auhtor : Anthoniraj.A
* Date : 24/03/2009
*/
int** imageRead(char imageName[]);
void imageWrite(int** pels);
int width, height;
int **pixels;
unsigned char *charImage;
 
int** imageRead(char imageName[]) {
FILE* fp;
 
//PGM Headers Variable Declaration
char* type;
int *ptr;
int q, i, j;
 
char header[100];
//Open file for Reading in Binary Mode
//fp = fopen("/home/anthoniraj/image.pgm","rb");
fp = fopen(imageName, "rb");
if (fp == NULL) {
printf("Image does not exist \n");
} else {
//Check the PGM file Type P2 or P5
fgets(header, 100, fp);
if ((header[0] != 80) || (header[1] != 53)) {
printf("Image is not PGM\n");
 
}
 
//Check the Commnets
fgets(header, 100, fp);
while (header[0] == '#') {
//printf("%c\n", header[0]);
fgets(header, 100, fp);
}
 
//Get Width and Height
width = strtol(header, &amp;amp; ptr, 0);
height = atoi(ptr);
 
// Get Maximum Gray Value
fgets(header, 100, fp);
q = strtol(header, &amp;amp; ptr, 0);
 
//Allocating Array Size
charImage = (unsigned char*) malloc(width * height * sizeof (unsigned char));
pixels = (int **) malloc(width * sizeof (int *));
for (i = 0; i &amp; lt; height; i++)
pixels[i] = (int *) malloc(height * sizeof (int));
 
// Pixel Extraction
fread(charImage, 1, (width * height) * sizeof (unsigned char), fp);
for (i = 0; i &amp; lt; height; i++) {
for (j = 0; j &amp; lt; width; j++) {
pixels[i][j] = (int) charImage[i * width + j];
// printf("%d ",pixels[i][j]);
}
//printf("\n");
}
 
// Pixel Extraction
fclose(fp);
}
return pixels;
}
 
void imageWrite(int** pels) {
int i, j;
FILE* fp1;
fp1 = fopen("out.pgm", "w");
 
for (i = 0; i &amp; lt; height; i++) {
for (j = 0; j &amp; lt; width; j++) {
charImage[i * width + j] = pels[i][j];
}
}
fprintf(fp1, "P5\n%d\n%d\n255\n", width, height);
fwrite(charImage, 1, width*height, fp1);
fclose(fp1);
}
 
int main() {
int** p = imageRead("sam1.pgm");
imageWrite(p);
return 0;
}