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How to fill a specific zone with a color ?
http://wiki.pchart.net/forum/viewtopic.php?f=3&t=394		 Page 1 of 1
Author:  Jilimay [ Thu Apr 14, 2011 3:00 pm ]
Post subject:  How to fill a specific zone with a color ?
Hi everyone,

I am trying to draw a kind of mercury thermometer, very simply created with the mix of a rectangle and circle.

I actually have to problems that are almost the same :

- First, since my objects are layered, I cannot use transparency properly ;
- Second, I would like to fill the thermometer dynamically with two different colors, depending on some parameters (to enable it to play its thermometer's role ^^).

So my question is : is there a way to fill in a specific zone of a picture ?

Thanks for reading ! :)
Author:  jean-damien [ Fri Apr 15, 2011 12:19 pm ]
Post subject:  Re: How to fill a specific zone with a color ?
Maybe the drawPolygon function could help you. Transparency will work as you'll only draw one object.

JD.
Author:  Jilimay [ Fri Apr 15, 2011 1:22 pm ]
Post subject:  Re: How to fill a specific zone with a color ?
Hi,

Thanks for your answer.
Actually, I am not sure I am able to draw that kind of things with
only one polygon.

But I found something that might be interesting with the gd library,
the function imagecolorset.
But now the question is : is there a way to use these functions with your
objects ? Since your work is based on this library ?
Author:  Jilimay [ Fri Apr 15, 2011 2:04 pm ]
Post subject:  Re: How to fill a specific zone with a color ?
Well it seems I got a bit confused, but imagecolorset is used on an existing image, so I can use it as a kind of post-treatment.

I think it can be a possible solution.
Author:  jean-damien [ Fri Apr 15, 2011 2:12 pm ]
Post subject:  Re: How to fill a specific zone with a color ?
If you need to access directly the GD image from your script you can use the $myPicture->picture handle :
Code:
$myPicture = new pImage(100,100);

$black = imagecolorallocate($myPicture->picture, 0, 0, 0);
imagefilledrectangle($myPicture->picture, 10, 10, 90, 90, $black);

$myPicture->picture;

$myPicture->autoOutput("picture.png");
Author:  Jilimay [ Fri Apr 15, 2011 2:39 pm ]
Post subject:  Re: How to fill a specific zone with a color ?
Ok, i assume you're rather talking about $myPicture->Picture ?

I tried to do it that way ($myPicture being of course a pImage object) :

Code:
$color = imagecolorat($myPicture->Picture, 150, 300);
imagecolorset($myPicture->Picture, $color, 0, 255, 0);

$myPicture->Render("pictures/basic.png");


But the imagecolorset function returns false :? .

What do I get wrong ?
Author:  Jilimay [ Fri Apr 15, 2011 2:49 pm ]
Post subject:  Re: How to fill a specific zone with a color ?
I am thinking maybe this has to do with my function, so I give you the code in case it's usefull, as well as the picture generated in attachment :

Code:
function buildThermometer($width=300, $height=600, $ratio=0.5, $goal=0.8) {

  /* All the pChart classes needed */
  require_once("application/third_party/pChart2.1.1/class/pDraw.class.php");
  require_once("application/third_party/pChart2.1.1/class/pImage.class.php");
  require_once("application/third_party/pChart2.1.1/class/pSurface.class.php");


  /* the thermometer to be returned */
  $picture = new pImage($width, $height);
  /* margin if the picture */
  $margin = 10;
  /* transparency */
  $alpha = 10;

  /*
   * The thermometer is represented thanks to a circle (the basis)
   * and a rectangle (the pipe).
   */
 
  /* Circle's caracteristics */
  /* the base must be a small part of the thermometre (obviously) */
  $cRadius = ($height - 2*$margin ) / 8 ;
  $cAbs    =  $width / 2;
  $cOrd    =  $height - $margin - $cRadius ;
  $CircleSettings =
                array("R"=>209,"G"=>134,"B"=>27,"Alpha"=>$alpha ,"Surrounding"=>30);

  /* Adding circle to the picture */
  $picture->drawFilledCircle($cAbs,$cOrd,$cRadius, $CircleSettings);
   
 
  /* rectangle's caracteristics */
  $lAbs = ($width - $cRadius)/2 ;    /* left top angle abscissa     */
  $lOrd = $margin;                   /* left top angle ordinate     */
  $rAbs = $width  - $lAbs;           /* right bottom angle abscissa */
  $rOrd = $height - $margin*2;       /* right bottom angle ordinate */

  $RectangleSettings = array("R"=>209,"G"=>134,"B"=>27, "Alpha"=>$alpha);

  /* TODO : find how to optimise the radius value for rectangle's corner */
  /* Adding rectangle to the picture */
  $picture->drawRoundedFilledRectangle($lAbs,$lOrd,$rAbs,$rOrd, 34 ,$RectangleSettings);

    return $picture;
}


Attachments:
basic.png
basic.png [ 6.53 KiB | Viewed 10577 times ]
Author:  Jilimay [ Tue Apr 19, 2011 8:24 am ]
Post subject:  Re: How to fill a specific zone with a color ?
Hello again,

I haven't found any solution to this issue, even if I believe the trick to be related with the
picture's resolution. But I found a way to bypass the problem, by using another function : bool imagefill ( resource $image , int $x , int $y , int $color ).

It basically acts like the paint's filling function, and allow me to do what I wanted to.

Hope it will help someone else ;) !
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