Re: [PHP] Advanced maths help (for GD image functionality)

[Chris Dowell]

Problem 1)
$h_1 = 600;
$w_1 = 800;
$h_2 = 120;
$w_2 = $w_1 * ($h_2 / $h_1);
Problem 2 a)
Assuming you're wanting the central portion of the original image (which 
I think you are from what you've written)

$h_1 = 600;
$w_1 = 800;
$h_2 = 120;
$w_2 = 90;
$x = ($h_1 - $h_2) / 2;
$y = ($w_1 - $w_2) / 2;
Problem 2 b)
If you're in fact trying to get the central portion of the new thumbnail
$h_1 = 600;
$w_1 = 800;
$h_2 = 120;
$w_2 = $w_1 * ($h_2 / $h_1);  // need to have the correct thumbnail 
width to start from

$x = ($w_2 - 90) / 2;
$y = 0;  // because the image is only 120px high
Hope this helps
Cheers
Chris

Mag wrote:<><>
> [snip]
> Heres my maths problems in 2 parts:
>
> Problem 1)
> I need to scale down an image (eg: example.jpg) to
> height of 120 pixels while maintaining the images
> proportions.
> [/snip]
> ...
> [snip]
> Problem 2)
> After getting the above image now I need the x and y
> parameters to cut a h120 x w90 thumb *from the center
> of the image*
> [/snip]
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