ID:               21630
 Updated by:       [EMAIL PROTECTED]
 Reported By:      [EMAIL PROTECTED]
-Status:           Open
+Status:           Closed
 Bug Type:         Documentation problem
 Operating System: Linux 2.4.20
 PHP Version:      4.3.0
 New Comment:

This has now been documented:

http://cvs.php.net/cvs.php/phpdoc/en/reference/image/functions/imagecopyresampled.xml
http://cvs.php.net/cvs.php/phpdoc/en/reference/image/functions/imagecopyresized.xml
http://cvs.php.net/cvs.php/phpdoc/en/reference/image/functions/imagecreate.xml

Thanks for the report :)


Previous Comments:
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[2003-01-14 16:16:53] [EMAIL PROTECTED]

I never look gdImageCopyResized until now :) (simply too bad thing ;-).
The problem seems to be the same. It uses the color resolver function,
which causes exactly the same thing.

To skip this problem, please use a truecolor image as a destination
image. That will not be fixed in a near futur. It's not really a bug.

thank's for your interest,

pierre

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[2003-01-14 14:42:39] [EMAIL PROTECTED]

http://www.boutell.com/gd/manual2.0.10.html

"Pixel values are only interpolated if the destination image is a
truecolor image. Otherwise, gdImageCopyResized is automatically
invoked. "

(doesn't this mean that it's a bug in GD library itself?)


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[2003-01-14 14:00:08] [EMAIL PROTECTED]

Hello,

I confirm (if necessary) the Derick's comment.

This a problem due to palette images limitations (255+1 colors).
Resampling or filtering an image needs commonly more colors than 255, a
kind of approximation is used to calc the new resampled pixel and its
color, with a palette image we try to allocate a new color, if that
failed, we choose the closest (in theory), the closest computed color
is not always the closest visual color. That produces weird result,
like blank (or visually blank) images.

You can reproduce this problem with imagerotate used with a palette
image (imagecreate), allocate 3 colors, draw 2 differents boxes, and
rotate the image with a custom angle (not a quarter angle), you will
get a blank image or near blank.

Hope that helps,

pierre

------------------------------------------------------------------------

[2003-01-14 13:32:25] [EMAIL PROTECTED]

Should be documented (better) then.

Derick

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[2003-01-14 13:20:41] [EMAIL PROTECTED]

I've managed to resolve this, it's not a bug with the
ImageCreateFromGIF function, but the ImageCopyResampled, the blank
image needs to be created with ImageCreateTrueColor or the resultant
image is blank.

Not sure whether this becomes a bogus bug or whether the real issue is
with ImageCopyResampled?

In fact, I've just looked at the user notes for ImageCopyResampled and
people are saying there to use Truecolor.

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The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
    http://bugs.php.net/21630

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Edit this bug report at http://bugs.php.net/?id=21630&edit=1


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