PHP Forum

**ginnybrighton** · 06-07-2010, 07:18 AM

Hi Guys,
Im new to the forum but i am at a loss and i really need some help solving this problem. I know that the answer is obvious but I just can’t seem to find a solution. And, believe me, i’ve been at this for a week.
I am trying to build a family tree by generating an image with php with vertical and horizontal lines connecting one generation to the next. I am only starting so am just drawing the horizontal lines and already i am having problems.
I pull the generations from a mysql database and depending if that mother has had any children a series of horizontal lines will connect the mother to her children
--- John
--- Anne
Liz --- Mary
--- Bill
--- Tom
All these x, y coordinates are defined in a previous function and stored in a two dimensional array. This array is then passed to the function domake($array) which extracts the $x = $array[0][0], $y = $array[0][1] and so on until all the horizontal x and y coordinates are extracted. Each time i extract the $x and $y coordinates they get stored in $x1 and $y1 then $x2 = $x1 + 45 and $y2 = $y1. This makes the 4 coordinates required for the imageline($image, $x1, $y1, $x2, $y2, $black) function.
Now i will post my code in full:
I have attempted many different variations of my code this is the most condensed version and I think i have tracked my problem down to the contents of the array passed from the previous function and extracted here, manipulated and then drawn using the imageline($image, $x1, $y1, $x2, $y2, $black) . I say this because if i hard code in the x1, y1, x2, y2 coordinates the lines are drawn and everything looks fine. Even if the lines are in the same place imageline($image, 1, 1, 200, 1, $black) and imageline($image, 1, 1, 200, 1, $black) it still works fine. Even if i store everything in an array at the beginning of the function using
$array[0][0]=1; //x for line1
$array[0][1]=1; //y for line 1

$array[1][0]=100; //x for line2
$array[1][1]=100; //y for line2
It works fine too. So, now i am out of options, so i need someone who knows what they are doing to look at my function with fresh eyes and tell me what I am doing wrong.

PHP Code:

$myImage = ""; $myWhite = ""; $myBlack = ""; $array = ""; $width = ""; $height = ""; $image = ""; $black = ""; function domake($a1){ global $width; global $height; global $image; global $black; $array = $a1; $count = count($array); $width = 1000; $height = 1000; $image = imagecreate($width, $height); $black = imagecolorallocate($image, 0, 0, 0); for ($i = 0; $i <= $width; ++$i) { for ($j = 0; $j <= $height; ++$j) { $col = imagecolorallocate($image, 255, 255, 255); imagesetpixel($image, $i, $j, $col); } } $x = -1; $y = -1; //// get contents of array for($arr=0; $arr<$count; $arr++){ $key = $arr%2; $x = $array[$arr][0]*1; $y = $array[$arr][1]*1; //if x and y are both greater than -1 make line $x1 = $x; $y1 = $y; $x2 = $x+450; $y2 = $y; if(($x>=0)&&($y>=0)){ imageline($image, $x1, $y1, $x2, $y2, $black); } } //finish image header("Content-type: image/png"); imagepng($image); imagedestroy($image); }

Thanks a million for all your help

**ginnybrighton** · 06-07-2010, 07:21 AM

Oops, i forgot to say in my post above that instead of an image a little box with an x appears on the page.

**tripy** · 06-07-2010, 10:51 AM

ok, but what error does php gives you back?
Did you look at the log, did you tried to open the picture directly?
If it helps, comment the header() call, it won't switch your browser to an image rendering mode, and you will be able to see the error messages, if any.

Just thinking of it, it could be that you have a space at the beginning, before the php opening tag that corrupts the image.

**ginnybrighton** · 06-07-2010, 11:16 AM

Thanks so much for your ideas. I am still finding my way so i am not sure what you mean by the log? I checked the cgierror.log - whatever that is - and there was nothing in that. Then, i checked the web.log and there was nothing in that that related to today. Not sure if that is what you meant tho.

Then i commented out the header information and as far as i could tell, it just returned garbage... but maybe it might mean something to you...

(hopefully)

Thanks a mill again

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**lynxus** · 06-07-2010, 12:11 PM

If your on Linux, Check out the logfile.

/var/log/httpd/error.log

**lynxus** · 06-07-2010, 12:12 PM

Also insure your not doing ANY! output from your code until you reach
header("Content-type: image/png");
imagepng($image);
imagedestroy($image);

**ginnybrighton** · 06-07-2010, 12:45 PM

Hi ya Lynxus,

Thanks a million for your replies. There is definately no output : by this, i assume you mean printr or echo and all that. I have some echos for testing but i have commented these out using //.

The server isnt mine so i dont think i have access to that log. I use winscp to upload my files and i cant get to the directory:

/var/log/httpd/error.log

Sorry for coming across completly thick!

**tripy** · 02:24 PM

Quote:

i assume you mean printr or echo and all that

Not only...
Do you have a space before the php opening tag?
Then it could be that.

That "garbage", is the binary of the png file you are creating.
If it appears with a "broken" image, then it means that something corrupts the generated image.

Try to add this at the beginning of your script:
http://www.php.net/manual/en/function.ob-start.php

PHP Code:


			
ob_start();

and this at the end of the script:
http://www.php.net/manual/en/function.ob-end-clean.php

PHP Code:


			
ob_end_clean();

If there is already output before the php opening tag, you will see an error message telling you where the first character has been outputted.

Another good thing would be to raise your error reporting to E_ALL, to be sure you don't have a warning at all.
Put this at the beginning of the file too:
http://www.php.net/manual/en/functio...-reporting.php

PHP Code:


			
error_reporting(E_ALL);

Quote:

The server isnt mine so i dont think i have access to that log

Not a problem, you can tell apache to use a specific php log file via .htaccess

Code:

php_flag display_errors false
php_value error_log /var/www/whatever.com/php.log

And this means that every php scripts located in the same directory than the htacces (or in child directories) will save the php error to /var/www/whatever.com/php.log
Adapt to your needs.

**ginnybrighton** · 06-08-2010, 09:21 AM

Hi tripy and linxus

I read through your advice and stripped my php right back to the bare essentials and kept looking for ANY output before the header("Content-type: image/png");

And lo and behold, there in the include("database.php") script was the culprit return causing all the trouble...

Once, i fixed that problem, I then realised i had messed up my array so that was another problem but if it helps anyone I will post the updated php which now works for horizontal lines only... (no doubt i will be back looking for more advice before the end of this family tree)

and youre right: beware of any OUTPUT - even return characters... I am so happy that im using netbeans or I may never have seen it... :

function domake($a1){
global $width;
global $height;
global $image;
global $black;
$array = $a1;
$width = 1000;
$height = 1000;
$image = imagecreate($width, $height);
$black = imagecolorallocate($image, 0, 0, 0);

for ($i = 0; $i <= $width; ++$i) {
for ($j = 0; $j <= $height; ++$j) {
$col = imagecolorallocate($image, 255, 255, 255);
imagesetpixel($image, $i, $j, $col);
}
}
$x = -1;
$y = -1;
// get contents of array
for($arr=0; $arr<count($array); $arr++){

$key = $arr%2;
$x = $array[$arr][0]*1;
$y = $array[$arr][1]*1;
//if x and y are both greater than -1 make line
$x1 = $x;
$y1 = $y;
$x2 = $x+45;
$y2 = $y;
if(($x>=0)&&($y>=0)){
imageline($image, $x1, $y1, $x2, $y2, $black);
}
}

// imageline($image, 10, 10, 450, 10, $black);
//finish image
header("Content-type: image/png");
imagepng($image);
imagedestroy($image);
}