Detecting an empty file and removing slashes from text

[helraizer1]

ChatPad

The layout so far is pretty amateur but it'll improve.

I spent an 1h30/2h or so in this tonight. The concept of ChatPad is basically a dynamic image acting as a shoutbox.

<?php
 
error_reporting(E_ALL);
 
ini_set('display_errors', true);
 
$lines = file("***.txt"); // load the lines of text into an array
 
//$image = ImageCreate(660,200); // create the image canvas
$image = imagecreatefromjpeg("***.jpg");
$blue = ImageColorAllocate($image, 200, 200, 255); // prepare some blueness
$black = ImageColorAllocate($image, 0, 0, 0); // ... and whiteness
 
$cur_line_y = 30;  // This stores how far down the image the current line will print
ImageFill($image, 0, 0, $blue); // fill the canvas
 
// reverse the order of the lines
$lines = array_reverse($lines);
 
 
// lets get the latest 10 entries
$i = 0; // current line pointer    
foreach($lines as $line) {
    if($i == 10) break;
    $latestlines[] = $line;
    $i++;
}
 
// reverse the order of the latest lines
$latestlines = array_reverse($latestlines);
foreach($latestlines as $line) {
    $cur_line_y += 15;
    ImageString($image, 3, 15, $cur_line_y, trim($line), $black);
}
 
 
 
header("Content-Type: image/png"); // tell the browser what we're gonna give it
ImagePng($image); // paint the image
ImageDestroy($image); // clean up resources
?>
 

On another page (the index page) the user inputs the Name and Message via a textbox, which is then written to a text file, the data from which is put into the image..

I changed the links to ***.. This page code (shown) is responsible for creating the image.

Anyways, to the question in hand!

At the moment, if the file ***.txt is empty (has no data within it) the image is not created and a broken link symbol appears, this is because of the array.

How do I make it so that if the file is blank, the $image (just the background file) is shown?

Also, everytime you enter a character such ' or \ it appears as \' or \\ - is there any way to get rid of the backslash?

Thanks,
Sam

[pbmods]

Heya, Sam.

Changed thread title to better describe the problem (did you know that threads whose titles do not follow the Posting Guidelines actually get FEWER responses?).

You'll want to look at empty() and stripslashes(), respectively.

You may also want to look into turning off magic quotes.

[helraizer1]

Awesome. I used the stripslashes function so that all now works. =D

Since the image uses the lines of text in lines.txt in an array and writes them to the image, how would I use the empty() function, with an if statement; so if lines.txt has no lines (it cannot create the array) and should display the background jpeg only.

How would I do this?

Sam

[pbmods]

Heya, Sam.

If file() detects an empty file, it will return array(), and:

empty(array()) === true

If file() cannot open the file, or if an error occurs, it will return false, and:

empty(false) === true

On the other hand, if there is actually data in the .txt file, then file() will return a non-empty array, and:

empty({non-empty array}) === false
 

So, check to see if $lines is empty(), and you'll know whether to load the background image.

[helraizer1]

Heya, Sam.

If file() detects an empty file, it will return array(), and:

empty(array()) === true

If file() cannot open the file, or if an error occurs, it will return false, and:

empty(false) === true

On the other hand, if there is actually data in the .txt file, then file() will return a non-empty array, and:

empty({non-empty array}) === false
 

So, check to see if $lines is empty(), and you'll know whether to load the background image.

Thanks for that, it worked.

I did

if (empty($lines)) 
{
       $lines[0] = " ";
}
 

So it creates an array with only a space, which suffices to create the image.

Thanks for that pbmods. =D

[pbmods]

Heya, Sam.

Glad to hear you got it working! Good luck with your project, and if you ever need anything, post back anytime :)

[helraizer1]

I think this could be a javascript question but.. Would there be a way to change the colour of the text inputted?

Say if they click on a link that says 'red' it would change the text they input (and only the text they input) to red.. Would that even be possible with php, or would it be javascript (if it's possible at all for a dynamic image).?

[pbmods]

Heya, Sam.

Since PHP is server-side, you'd have to reload the page to save the change.

Since you're dynamically generating an image, you'd have to do the color manipulation on the server side (using imagecolorallocate()).

However, have you thought about using the background image as simply a background image and using HTML and CSS to display the text over the image?

Then you can easily use JavaScript to change the color of the text.

[helraizer1]

Heya, pbmods.

ChatBox

I created the whole thing again (sort of) creating a .line file. and again loaded it into a dynamic image, so you can choose the colour, and it works =D

However I have come across a bug (will explain soon).

The showimage.php page is as follows:

<?php
include("linesfile.php");
$linesDataFile = new DataFile("data.line");
 
//$image = ImageCreate(550,200); // create the image canvas
$image = ImageCreateFromPNG("background.png");
$blue = ImageColorAllocate($image, 200, 200, 255); // prepare some blueness
$black = ImageColorAllocate($image, 0, 0, 0); // ... and whiteness
 
$cur_line_y = 45;  // This stores how far down the image the current line will print
$pagecharwidth = 75; // this is the maximum length of the line before it wraps;
$lineheight = 15; // This is how much to move down to print the next line
$pagelinelimit = 10; // This is the maximum number lines of text that can be displayed
 
ImageFill($image, 0, 0, $blue); // fill the canvas
 
//ImageString($image, 3, 15, $cur_line_y, trim(stripslashes($wordwrapped[0])), $black);
 
$numberOfLines = $linesDataFile->fileSize();
 
for($i=0;$i<$numberOfLines;$i++) {
    $data = $linesDataFile->getNextLine();
    $name = "[" . $data[0] . "] ";
    $color = $data[1];
    $line = $data[2];
 
    $line = $name . $line;
    ImageString($image, 3, 15, $cur_line_y, trim($line), getColor($color));
 
    $cur_line_y += $lineheight;
 
}
 
function getColor($color) {
    global $image;
 
    switch($color) {
        case "black" :
            return ImageColorAllocate($image, 0, 0, 0); 
        case "white" :
            return ImageColorAllocate($image, 255, 255, 255); 
        case "blue" :
            return ImageColorAllocate($image, 0, 0, 255); 
        case "red" :
            return ImageColorAllocate($image, 255, 0, 0); 
        case "yellow" :
            return ImageColorAllocate($image, 255, 255, 0); 
        case "green" :
            return ImageColorAllocate($image, 0, 255, 0); 
        default: 
            return ImageColorAllocate($image, 255, 255, 255); 
 
    }
}
 
 
header("Content-Type: image/png"); // tell the browser what we're gonna give it
ImagePng($image); // paint the image
ImageDestroy($image); // clean up resources
?>

The layout of the .line file information is:
Username
colour
message

CHATBOXTEXT
3
ben
red
hi sam
ben
white
hi sam
helraizer
yellow
This is a test of ChatBox
 

The bug is that, when the messages get to the bottom of the image, they carry on going, and just drop off the end.

With my last code I could get the last 10 lines, but since the messages that would need to to show in this one are on 3 lines, excluding lines 1 and 2. How would I get it so that it writes the message on the image and knocks the last one off the bottom, rather than carry on beyond the limits of the image?

Hope I was clear there,

Thanks,
Sam

[helraizer1]

Wasn't able to edit my post for some reason, sorry for the consecutive posting.

With most dynamic images on the web, you can view them and save them as .png or .jpg files, for mine you can only save or view it as a .php file... How would I output it to an image such as .jpg or.png? Or is the inability a side effect of Apache?

Thanks,
Sam