resize image before upload javascript

Question

First, i'm french and i'm sorry in advance for mistakes.
I have a cover photo displayed before sending the form.
The person can reposition the image , zoom , etc.
Script : https://github.com/matiasgagliano/guillotine exemple in french

The problem is that i don't know how to send the new image resized and not the default image. The API has set a function to get info about image :

var data = picture.guillotine('getData');

but i don't where how use this and where. I'm a beginner in JS.

Thanks much.

• Jérôme: what have you done so far ?
• user4278933: Good question. I have not tried yet, but I suggest you look at this: stackoverflow.com/questions/2434458/…
• user4278933: and this Q&A also looks promising stackoverflow.com/questions/23945494/…
• mike thomson: @NimS I tried to change value of a hidden input when the image is resized, but doesn't work.
• mike thomson: @fiprojects I will look at this, thks

Answer 1

I'm an idiot.
I put that code into the dragging function.

var data = picture.guillotine('getData');
getID("scale").value = data.scale;
getID("x").value = data.x;
getID("y").value = data.y;

The values 3 hidden inputs are used to resized the image in PHP with gb librairy