OOP imagepng issues

[Jeffrey87]

Hi,

I'm trying to convert a charting app to  OOP.

So here I've simplified it down to just the bare bones issue of drawing a line to a png image and displaying it.

 

<?php
class chart {
  var $im;
  var $backgroundColor;
  var $textColor;
  function chart() {
    $this->im= @ImageCreate (100, 200) or die ("Cannot Initialize new GD image stream");
    $this->backgroundColor = ImageColorAllocate ($this->im, 224, 234, 234);
    $this->textColor = ImageColorAllocate($this->im, 233, 14, 91);
  }

  function display() {
    imageline ($this->im,0,0,100,200,$this->backgroundColor);
    imageline ($this->im,100,0,0,200,$this->textColor);

    ImagePng ($this->im);
  }
}
?>

 

Here is the code which instantiates the class.

 

<?php
  include "simple_draw.php";

$mychart = new chart();
$mychart->chart();
$mychart->display();

?>

 

Basically depending on how I rework it, one of two things happens: a)it generates a bunch of little boxes which say fffd, or b) I get a message saying the resource is invalid or nonexistent (this error isn't coming up right now so I can't be precise.)

 

If this is run outside the OOP environment it works fine. No sure. I'm really trying to work with classes but this kind of problem is frustrating and admittedly makes it tempting to just go back to regular functions.

 

Any ideas??

 

Thanks,

Jeff

[darkfreaks]

try removing the @ symbol that would be the reason your getting "invalid image resource"

 

it also covers up other errors within the script. 

 

let us know if you encounter any other errors

[darkfreaks]

also if you want to display it do something like

 

return $this->im;

Or:

echo $this->im;

 

 

fixed code:

 

<?php
class chart {
  var $im;
  var $backgroundColor;
  var $textColor;
  function chart() {
    $this->im= @ImageCreate (100, 200) or die ("Cannot Initialize new GD image stream");
    $this->backgroundColor = ImageColorAllocate ($this->im, 224, 234, 234);
    $this->textColor = ImageColorAllocate($this->im, 233, 14, 91);
  }

  function display() {
    imageline ($this->im,0,0,100,200,$this->backgroundColor); 
    imageline ($this->im,100,0,0,200,$this->textColor); 
    ImagePng ($this->im);
   return this->im;

   
  }
}
?>

[Jeffrey87]

Thanks for the replies.

 

Hey, I found the error! It was actually on the instantiation page. I had forgotten to include the header statement. The corrected version reads like this:

<?php
header ("Content-type: image/png");  
include "simple_draw.php";

$mychart = new chart();
$mychart->chart();
$mychart->display();

?>

 

Obvious now looking back on it :-\

Thanks again for the quick replies.