[SOLVED] Image Functions

[loganbest]

Is there a way in PHP to take three grayscale images (red channel, green channel, and blue channel) and combine them like photoshop does to create an RGB colour image? I know there has to be a way with GD Library's powerful backend.

[littledragon]

Not unless you make one, mate :-)  can be done, you need to combine the hex value of each pixel in each file one by one.  Googled it?

[loganbest]

I'm not sure how to do that.

[MadTechie]

Googled it?

 

I'm not sure how to do that.

 

Erm... 

 

back to the books then (or the freelance section)

[loganbest]

so you don't know what the other guy is talking about doing it pixel by pixel?

[MadTechie]

yes do i know, but this is for helping with current script problems not a site for getting scription written for you..

 

But

 

Heres a starting block.. this will convert color to grayscale..its not great needs a few improvments (as the quality drops if used over and over) but it works.. you should be able to alter this to suite your needs

 

<?php
function convert($filename)
{
$filename = imagecreatefromjpeg($filename);
list($width, $height) = getimagesize($filename);

$bwimage= imagecreate($width, $height);

for ($c=0;$c<256;$c++)
{
	$palette[$c] = imagecolorallocate($bwimage,$c,$c,$c);
}

//Reads the origonal colors pixel by pixel
for ($y=0;$y<$height;$y++)
{
	for ($x=0;$x<$width;$x++)
	{
		$rgb = imagecolorat($source,$x,$y);
		$r = ($rgb >> 16) & 0xFF;
		$g = ($rgb >>  & 0xFF;
		$b = $rgb & 0xFF;

		//This is where we actually use yiq to modify our rbg values, 
		//and then convert them to grayscale palette

		$gs = $this->yiq($r,$g,$b);
		imagesetpixel($bwimage,$x,$y,$palette[$gs]);
	}
}
// Outputs a jpg image, but you can change this to png or gif if that is what you are working with
imagejpeg($bwimage, $filename);
imagedestroy($bwimage);
}
?>

 

hope this helps

[Barand]

or you could just use

 

imagefilter ($image, IMG_FILTER_GRAYSCALE);

[loganbest]

I got it working with Imagemagick

[MadTechie]

or you could just use

 

imagefilter ($image, IMG_FILTER_GRAYSCALE);

 

True, but the code above is old (php 4 version) imagefilter came out in php5