hmm.. could this be done?

[buddysal]

I'm not sure if this is in the right place because its not really a coding problem so if it needs moved.. sorry..

Question 1:
If i have a picture thats say.. 500 * 200 could i get the rgb value of each pixel? so it would be like x,y = rbg for each pixel in the image and then save the rgb and "pixel address" if you will to a database?

Question 2:
If thats possible could each rgb be assigned to a value... like if rgb value = this then rgb = value else if rgb = this then rgb = different value?

Question 3:
Could you generate a new image through php using all that information? and then saved by the script in a designated folder?

I know if all this is possible it will kill system resources using php.. but the script would only be ran once a day.. or would this be something that i would need to use C++ for?

Again if this is in the wrong place im sorry... I'm just alittle confused because my php book dont really go into alot of detail about images and php..

Also if this is all possible does anyone know of any good resources to read up on techniques or tips on doing this?

Thanks
Buddy

[drew010]

yeah technically it could be done...
you can use the [man]imagecolorat[/man] to get the color index of any given pixel.
i.e. $index = imagecolorat($im, 35, 22);
you can use [man]imagesetpixel[/man] to change the color of a single pixel. or use [man]imagecolorset[/man] to replace all pixels of a certain color index with another.

if you had all the pixel info saved, you could create a new image of the given size and loop through the information and call imagesetpixel.

you would be better off not saving the image data in the db but just keeping it as an image file and creating a new gd image when you need to process it.

good reading is www.php.net/gd

[buddysal]

thanks..

ill look at that site.. after digging around i found a documentation of gd on http://www.boutell.com/gd/ but the documentation is for a different version than the one on the host im using..

but ill see if i can make this work by playing with different things you listed 🙂

EDIT:
could you just use an array for x and then another one for y to get each pixel value automatically? of course you would have to use an array to get the value of each one also... I think... lol

Thanks again
Buddy

[drew010]

well the documentation on boutell.com is for the c api, not the php so yes its different but not what you want to be reading.

for ($y = 0; $y < imagesy($im); ++$y) {
  for ($x = 0; $x < imagesx($im); ++$x) {
    echo imagecolorat($im, $x, $y) . "\n";
  }
}

loops over all pixels