I have to create a PHP that will return an image stream of one transparent dot (PNG or GIF)
Could you point me to an easy to use solution?
Transparent 1x1 PNG:
header('Content-Type: image/png');
echo base64_decode('iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAA1BMVEUAAACnej3aAAAAAXRSTlMAQObYZgAAAApJREFUCNdjYAAAAAIAAeIhvDMAAAAASUVORK5CYII=');
Transparent 1x1 GIF:
header('Content-Type: image/gif');
echo base64_decode('R0lGODlhAQABAJAAAP8AAAAAACH5BAUQAAAALAAAAAABAAEAAAICBAEAOw==');
In PHP 5.4 and higher it is possible to use hex2bin, which is roughly two times faster than base64_decode (tested with the blank GIF file below). The code to output images would be:
Transparent 1x1 PNG:
header('Content-Type: image/png');
die(hex2bin('89504e470d0a1a0a0000000d494844520000000100000001010300000025db56ca00000003504c5445000000a77a3dda0000000174524e530040e6d8660000000a4944415408d76360000000020001e221bc330000000049454e44ae426082'));
Transparent 1x1 GIF:
header('Content-Type: image/gif');
die(hex2bin('47494638396101000100900000ff000000000021f90405100000002c00000000010001000002020401003b'));
You can easily convert base64 encoded data into hexadecimal:
echo bin2hex(base64_decode($data));
Or a file:
echo bin2hex(base64_decode(file_get_contents($filename)));
However, using the native PHP escape method suggested by #Lukas Liesis is the fastest, about 12.5 times faster than base64_decode, according to my benchmark. And it would work with virtually any version of PHP. Here are the code snippets:
Transparent 1x1 PNG:
header('Content-Type: image/png');
die("\x89\x50\x4e\x47\x0d\x0a\x1a\x0a\x00\x00\x00\x0d\x49\x48\x44\x52\x00\x00\x00\x01\x00\x00\x00\x01\x01\x03\x00\x00\x00\x25\xdb\x56\xca\x00\x00\x00\x03\x50\x4c\x54\x45\x00\x00\x00\xa7\x7a\x3d\xda\x00\x00\x00\x01\x74\x52\x4e\x53\x00\x40\xe6\xd8\x66\x00\x00\x00\x0a\x49\x44\x41\x54\x08\xd7\x63\x60\x00\x00\x00\x02\x00\x01\xe2\x21\xbc\x33\x00\x00\x00\x00\x49\x45\x4e\x44\xae\x42\x60\x82");
Transparent 1x1 GIF:
header('Content-Type: image/gif');
die("\x47\x49\x46\x38\x39\x61\x01\x00\x01\x00\x90\x00\x00\xff\x00\x00\x00\x00\x00\x21\xf9\x04\x05\x10\x00\x00\x00\x2c\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02\x04\x01\x00\x3b");
Creating such a string is easy with regular expressions (as it's done once, it doesn't have to work fast):
echo preg_replace('/../','\\x\0',bin2hex($data));
Or from a file:
echo preg_replace('/../','\\x\0',bin2hex(file_get_contents($filename)));
To answer some people's questions:
You must echo the contents of an image. The Header only shows that are you are returning an image to the browser, instead of normal text. So if you only return a header, it's just a header - no data. However, print out data of an image and done, you just sent an image :)
Reading a file is not good, it could work, but it's better to return raw data like shown in main answer by Sjoerd. This way, you save time and server load not having to process a read operation. Reading from disk is a slow task. Over time, reading from disk has increased in speed with SSD disks, but still, No I/O to disk is better.
I had this code even without base64 decode, but this image has white color:
header('Content-Type: image/gif');
// 1x1px white gif
die("\x47\x49\x46\x38\x37\x61\x1\x0\x1\x0\x80\x0\x0\xfc\x6a\x6c\x0\x0\x0\x2a\x0\x0\x0\x0\x1\x0\x1\x0\x0\x2\x2\x44\x1\x0\x3b");
Maybe someone knows how to convert any file to such data string?
header('Content-Type: image/gif');
printf('%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%', 71, 73, 70, 56, 57, 97, 1, 0, 1, 0, 128, 255, 0, 192, 192, 192, 0, 0, 0, 33, 249, 4, 1, 0, 0, 0, 0, 44, 0, 0, 0, 0, 1, 0, 1, 0, 0, 2, 2, 68, 1, 0, 59);
In Linux you can convert it by typing in console:
hexdump -v -e '"\\\x" 1/1 "%X"' image.gif; echo
Related
I need to merge the following images, however my solution is not working.
My code is the following (I pass the URL of the images to the script via GET parameter)
<?php
$dest = imagecreatefrompng($_GET['img1']);
$src = imagecreatefrompng($_GET['img2']);
imagecopymerge($dest, $src, 0, 0, 0, 0, 1500, 1500, 50);
$white = imagecolorallocate($dest, 255, 255, 255);
imagecolortransparent($dest, $white);
header('Content-Type: image/png');
imagepng($dest);
?>
Both image are PNG with transparent background and both are 1500x1500.
First image:
Second image:
What I get:
Why can't I make the final image have the right opacity? I tried changing the last value of imagecopymerge() to 0 or 100 but in those cases I only get one image or another. I need them both, exactly overlapped on one another!
Also, if you look carefully around the gem in the final image, there is some extra blue color... how is this possible?
This is caused by setting the resulting image to use image transparency rather than per-pixel alpha-channel transparency by your call to imagecolortransparent which sets any white (#ffffff) pixels to 100% transparent.
The artefacts ('extra blue colour' and edge pixels) on the resulting image are caused by the alpha-channel transparency from the original images not being saved and the pixels (which were 100% transparent but not white) showing their original colour.
The 'washed out' look of your result comes from telling imagecopymerge to merge the two images with 50% transparency.
The solution is to use the correct alpha settings:
<?php
$dest = imagecreatefrompng($_GET['img1']);
$src = imagecreatefrompng($_GET['img2']);
imagesavealpha($dest, true);
imagecopy($dest, $src, 0, 0, 0, 0, 1500, 1500);
header('Content-Type: image/png');
imagepng($dest);
While reading up on the issues merging transparent images in PHP, it seems that everyone is in the "it works" or "it doesn't work" camps. I have found a way to demonstrate each case.
I wish to take a PNG, cut an ALPHA hole in it and then merge it on top of another image. In this case, I cut a hole in an image from google maps, and paste it over a red block. I have two images from google maps. One is of Manhattan and one is of my house. One works, and one does not. The only difference is one was "saved" via a browser.
If you run the code below, you will see the difference in outputs. Does anyone know why the same code would treat two PNG files completely differently? It must be the difference in the PNG files themselves, but then what would it be?
<?php
sometimesworks("https://maps.googleapis.com/maps/api/staticmap?center=40.714728,-73.998672&zoom=12&size=400x400&maptype=hybrid", "google");
sometimesworks("https://lh4.googleusercontent.com/UQvV_dpBa3_rVf25pvLXKD3OwzF4FtPnHBHkzdWqjCQ5mlFqcFfId9echIgDMv_xYRRYzLaKEXphw7g=w2447-h1106", "myhouse");
function sometimesworks($p_image, $p_prefix)
{
$image_top =imagecreatefrompng($p_image);
$brush = imagecolorallocate($image_top, 0, 0, 0); //create a black brush
imagefilledpolygon($image_top, explode(",", "10,10, 120,22, 80,280, 200, 191"), 4, $brush); //fill a polygon
imagecolortransparent($image_top, $brush); //turn the black to be transparent
imagepng($image_top, './'.$p_prefix.'.transparent.png'); //save the file to confirm that it is working.
//create a big red square
$image_bottom = imagecreatetruecolor(imagesx($image_top), imagesy($image_top));
$red = imagecolorallocate($image_bottom, 255, 0, 0);
imagefill($image_bottom, 0, 0, $red);
imagepng($image_bottom, './'.$p_prefix.'.red.png');
//merge the top onto the bottom.
$out = imagecreatetruecolor(imagesx($image_top), imagesy($image_top));
imagecopy($out, $image_bottom, 0, 0, 0, 0, imagesx($image_top), imagesy($image_top));
imagecopy($out, $image_top, 0, 0, 0, 0, imagesx($image_top), imagesy($image_top));
imagepng($out, './'.$p_prefix.'.out.png');
}
The issue with the above code is that the PNG files were of different type. One was a truecolor image and the other was a palette. The code to merge files differs depending on what is being done.
This is a good reference for the merging of "palette" based PNG files with transparency.
Not sure why it looks so bad, but when I copy an image over another image, it looks extremely terrible, like it lost almost all its colors for some reason.
$img = imagecreate(240, 140);
$wall = imagecreatefrompng($src);
imagecopyresampled($img, $wall, 0, 0, 40, 340, 240, 140, 240, 140);
I've been trying to find a solution myself but I can't seem to find one, anybody really good with GD that can help? I can't use imagemagick.
You need to create your canvas image with imagecreatetruecolor() rather than imagecreate() as the former creates a palette based canvas with limited colour support.
I presume you are then using imagepng() to save our output the image. The third argument accepted by this function defines the quality of the image, or the compression level (0-9)
I 'm trying to add text on a specific image. Its working perfectly but the quality of image is low especially for papyrus.ttf font. How can i improve the quality of text in the image. But i need high quality to print the output.
Here is my code.. its very simple.
header("Content-Type: image/jpeg");
$im = imagecreatefromjpeg("cosmos.jpg");
$black = ImageColorAllocate($im, 0, 0, 0);
Imagettftext($im, 14, 0, 10, 15, $black, 'papyrus.ttf', "Corey and Lisa ");
Imagettftext($im, 14, 0, 10, 35, $black, 'papyrus.ttf', " 1994, june");
Imagejpeg($im, '', 100);
ImageDestroy($im);
Download: http://wneeds.com/gdtest.zip
If imageTTFText fails in Quality, the next step to try is ImageFTText(). It uses the FreeType library to render fonts, which usually means significantly better quality. It needs to be installed and compiled into PHP to work, which it most often is. Try calling the function and you'll see whether that is the case.
If that doesn't do, the next step is using ImageMagick either through the command line, or through the appropriate PHP extension. But try Freetype first, it could already be enough.
I have a Ubuntu server and PHP5, and the PHP script files, and all output are in UTF-8.
I'm trying to send an image to the output stream, but just garbled chinese characters shows up in the output:
$im = imagecreatetruecolor(120, 20);
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 1, 5, 5, 'A Simple Text String', $text_color);
header('Content-type: image/jpeg');
imagejpeg($im);
imagedestroy($im);
any suggestions?
Your code works perfectly fine on my machine :
<?php
$im = imagecreatetruecolor(120, 20);
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 1, 5, 5, 'A Simple Text String', $text_color);
header('Content-type: image/jpeg');
imagejpeg($im);
imagedestroy($im);
die;
?>
Are you sure you are not outputing anything before or after that code ? Even any kind of whitespace would be a source of troubles.
Or maybe your script is doing something else somewhere ?
If it still doesn't work, maybe trying with imagettftext, to use a "better" / more complete font than the ones used by imagestring might help ?
Using something like this, for instance :
$font = '/usr/share/fonts/truetype/msttcorefonts/arial.ttf';
imagettftext($im, 20, 0, 10, 20, $text_color, $font, 'A Simple éléphant String');
BTW, did you try without those line :
header('Content-type: image/jpeg');
imagejpeg($im);
imagedestroy($im);
If there is an error/warning/notice, removing those lines might help you seeing those.
And, as a sidenote : using JPEG for images that contain some text generally doesn't give great results, as JPEG is a destructive compression mechanism. Using PNG, in that kind of situation, might get you better results ;-)
Try removing the UTF-8 byte order mark, because it gets prepended to the contents of your JPEG image, rendering it invalid.