Re: GD2 gif resizing problem

From: Date: Wed, 15 Mar 2006 19:36:20 +0000
Subject: Re: GD2 gif resizing problem
References: 1 2 3  Groups: php.general 
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Al wrote:
Philip Hallstrom wrote:
I'm trying to resize GIF images and up with very large files For example: Original width = 720 New width = 980 Original height = 1008 New height = 1274 Original filesize = 80kb After resizing = 235kb Based on the area increase; I'd expect the file size to about double, not be 4x as large. $src_img = imagecreatefromgif($filename); $dest_img = imagecreatetruecolor($new_width, $new_height); imagecopyresampled($dest_img, $src_img, 0, 0, 0, 0, $new_width, $new_height, $org_width, $org_height); imagegif($dest_img, $filename); I tried using imagetruecolortopalette() and it helped a little; but screwed up the image quality. Can anyone explain or have a solution?
What's the image? If it's photo-like, save it as a PNG or JPEG and you'll get much smaller files. GIF's don't do very well with some images as it can't encode them very efficiently. I don't remember which way it goes, but a 1x500 gif of a solid color will be much much much larger than a 500x1 gif of a solid color. The latter it can compress by sayign something like "x color for the next 500 columns on this row". If it were me, I'd try jpeg/png first.
The image is a simple 4 color street map. Out of the image editor, these images are always much smaller than reasonably compressed jpgs or pngs. I need to keep the file size small as many of our users still use dial-up.
If your original is only 4 color, I'm guessing that your new image is 256 colors, giving you the 'out of proportion' filesize. -- John C. Nichel IV Programmer/System Admin (ÜberGeek) Dot Com Holdings of Buffalo 716.856.9675 jnichel@dotcomholdingsofbuffalo.com

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