Working with images

[cheechm]

I've got some code that basically draws a wavefrom line by line (going horizontally). I was hoping to be able to get a vertical gradient, however I'm not too sure where to start.

 

            imageline(
             $img,
             // x1
             (int) ($data_point / DETAIL),
             // y1: height of the image minus $v as a percentage of the height for the wave amplitude
            $height * $wav - $v,
                          // x2
             (int) ($data_point / DETAIL),
             // y2: same as y1, but from the bottom of the image
             $height * $wav - ($height - $v),
             imagecolorallocate($img, $r, $g, $B)
           );         

 

The full code is available here:

 

Github

 

Another question I have: Is it possible to fill every part of the PNG image which isn't transparent with a solid colour?

 

Thanks

[Barand]

Do you have a question?

[cheechm]

Do you have a question?

 

Another question I have: Is it possible to fill every part of the PNG image which isn't transparent with a solid colour?

 

Admittedly my first question wasn't as clear. How might I go around drawing a single pixel line with a vertical gradient?

[Barand]

vertical gradient

$height = 200;
$xpos = 23;
$ypos = 50;

$c1 = array(0xFF, 0x00, 0x00);
$c2 = array(0x00, 0x00, 0xFF);

$interval = 20;

$im = imagecreatetruecolor(50,300);
$bg = imagecolorallocate($im, 0xFF, 0xFF, 0xFF);
$border = imagecolorallocate($im, 0x00, 0x00, 0x00);
imagefill($im,0,0,$bg);
imagerectangle($im, 0,0,imagesx($im)-1,imagesy($im)-1,$border);
imagesetthickness($im, 4);

$y1 = $ypos;
for ($y2 = $ypos+$interval; $y2 <= $ypos+$height; $y2+=$interval) {
   $c=array();
   for ($i=0; $i<3; $i++) {
    $c[$i] = $c1[$i] + ($c2[$i]-$c1[$i])*($y2-$ypos)/$height;
   }

   $col = imagecolorallocate($im, $c[0], $c[1], $c[2]);
   imageline($im, $xpos, $y1, $xpos, $y2, $col);
   $y1 = $y2;
}

header("content-type: image/png");
imagepng($im);
imagedestroy($im);