imagecreatefrompng | 易学教程

How to prevent having the “is not a valid image file” error when using GD function imagecreatefrom* in php?

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问题 I am using imagecreatefromgif / imagecreatefromjpeg / imagecreatefromjpeg functions with uploaded images and sometimes get an error (e.g. Warning: imagecreatefromgif(): ... is not a valid GIF file) when the image is corrupted. I read lots of posts about this topic and couldn't find a "working" answer. I did try some of the following to validate the image (as suggested on other posts) but none of them worked in ALL situations. If the image does not have the header info, the following works,

PHP imagecreatefrompng losing color

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问题 I'm doing a simple load of an image using imagecreatefrompng. The background of the image is #E5DDBB. Using the code below, it renders the image but the background is now #DED6AD. http://www.letslogic.com/test.php contains the following: <img src="images/skins/yoshi/0.png"> <img src="dyn_image.php"> dyn_image.php contains: <?php $im = imagecreatefrompng('images/skins/yoshi/0.png'); header("Content-Type: image/png"); imagepng($im); ?> If you look at the two images that test.php shows, the

imagecreatefrompng() failed to open stream: HTTP request failed

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问题 On my local host this code works well: $im = imagecreatefrompng('BBcode.png'); But when I use the same code in the server $im = imagecreatefrompng('http://lazertag.elitno.net/drupal/BBcode.png'); I got the folloowing error: Warning: imagecreatefrompng(http://lazertag.elitno.net/drupal/BBcode.png) [function.imagecreatefrompng]: failed to open stream: HTTP request failed! HTTP/1.1 403 Forbidden in /www/elitno.net/l/a/lazertag/home/site/drupal/renderImage.php on line 46 How do I solve this? 回答1:

PHP imagecopy with transparent background

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问题 I use this code to create an image from another png image, the background is black by default. My question is how to set a transparent background? $input = imagecreatefrompng('image.png'); $output = imagecreatetruecolor(50, 50); imagecopy($output, $input, 4,0, 8,8, 8,8); imagecopy... etc. header('Content-Type: image/png'); imagepng($output); Is there a easy way of doing this? Thanks 回答1: Sets the transparent color in the given image . int imagecolortransparent ( resource $image [, int $color

Create a transparent png file using PHP

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问题 Currently I would like to create a transparent png with the lowest quality . The code: <?php function createImg ($src, $dst, $width, $height, $quality) { $newImage = imagecreatetruecolor($width,$height); $source = imagecreatefrompng($src); //imagecreatefrompng() returns an image identifier representing the image obtained from the given filename. imagecopyresampled($newImage,$source,0,0,0,0,$width,$height,$width,$height); imagepng($newImage,$dst,$quality); //imagepng() creates a PNG file from

Create a transparent png file using PHP

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Currently I would like to create a transparent png with the lowest quality . The code: <?php function createImg ($src, $dst, $width, $height, $quality) { $newImage = imagecreatetruecolor($width,$height); $source = imagecreatefrompng($src); //imagecreatefrompng() returns an image identifier representing the image obtained from the given filename. imagecopyresampled($newImage,$source,0,0,0,0,$width,$height,$width,$height); imagepng($newImage,$dst,$quality); //imagepng() creates a PNG file from the given image. return $dst; } createImg ('test.png','test.png','1920','1080','1'); ?> However, there

Trying to extract pixel values from a given PNG image

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问题 Trying to understand PNG format. Consider this PNG Image: The Image is taken from here In Hex Editor , it looks like this: 89 50 4E 47 0D 0A 1A 0A 00 00 00 0D 49 48 44 52 00 00 00 80 00 00 00 44 08 02 00 00 00 C6 25 AA 3E 00 00 00 C2 49 44 41 54 78 5E ED D4 81 06 C3 30 14 40 D1 B7 34 DD FF FF 6F B3 74 56 EA 89 12 6C 28 73 E2 AA 34 49 03 87 D6 FE D8 7B 89 BB 52 8D 3B 87 FE 01 00 80 00 00 10 00 00 02 00 40 00 00 08 00 00 01 00 20 00 00 04 00 80 00 00 10 00 00 02 00 40 00 00 08 00 00 01 00 20 00

PHP imagecopy with transparent background

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I use this code to create an image from another png image, the background is black by default. My question is how to set a transparent background? $input = imagecreatefrompng('image.png'); $output = imagecreatetruecolor(50, 50); imagecopy($output, $input, 4,0, 8,8, 8,8); imagecopy... etc. header('Content-Type: image/png'); imagepng($output); Is there a easy way of doing this? Thanks Sets the transparent color in the given image . int imagecolortransparent ( resource $image [, int $color ] ) Here's the link Since the PHP function imagecopymerge doesn't work with the Alpha channel, you'll want

Trying to extract pixel values from a given PNG image

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Trying to understand PNG format. Consider this PNG Image: The Image is taken from here In Hex Editor , it looks like this: 89 50 4E 47 0D 0A 1A 0A 00 00 00 0D 49 48 44 52 00 00 00 80 00 00 00 44 08 02 00 00 00 C6 25 AA 3E 00 00 00 C2 49 44 41 54 78 5E ED D4 81 06 C3 30 14 40 D1 B7 34 DD FF FF 6F B3 74 56 EA 89 12 6C 28 73 E2 AA 34 49 03 87 D6 FE D8 7B 89 BB 52 8D 3B 87 FE 01 00 80 00 00 10 00 00 02 00 40 00 00 08 00 00 01 00 20 00 00 04 00 80 00 00 10 00 00 02 00 40 00 00 08 00 00 01 00 20 00 00 00 D4 5E 6A 64 4B 94 F5 98 7C D1 F4 92 5C 5C 3E CF 9C 3F 73 71 58 5F AF 8B 79 5B EE 96 B6 47 EB F1

Can I use a URL as the source for imagecreatefromjpeg() without enabling fopen wrappers?

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I know it’s possible to use imagecreatefromjpeg(), imagecreatefrompng(), etc. with a URL as the ‘filename’ with fopen(), but I'm unable to enable the wrappers due to security issues. Is there a way to pass a URL to imagecreatefromX() without enabling them? I’ve also tried using cURL, and that too is giving me problems: $ch = curl_init(); curl_setopt($ch, CURLOPT_URL,"http://www.../image31.jpg"); //Actually complete URL to image curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); $data = curl_exec($ch); curl_close($ch); $image = imagecreatefromstring($data); var_dump($image); imagepng($image);