I have a Facebook app with which I'd like to display an image in a user's feed. It's just a small circle, which will be different colours depending on what the user does within my app.
Instead of creating lots of different images to display, one for each possible colour the circle could be, it would be ideal if I could put up a PNG with transparency, and then just change the colour by filling a DIV behind the image with Javascript.
However, it's not clear to me if Facebook will allow that in the feed.
Can include some Javascript in the feed, or is that strictly forbidden?
Or is my only option to have a library of images for all the different colours and have a PHP function which selects the right one to output?
Facebook doesn't allow any scriptable content within feed stories, and this isn't possible to implement what you want this way.
You can easily create simple script that will return colored image according to passed arguments and use it as source for the image.
Something like this may provide you some points:
<?
// create a 200*200 image
$img = imagecreatetruecolor(200, 200);
// get the color from URL arguments or use default one
$rgb = isset($_REQUEST['color']) ? $_REQUEST['color'] : 'FFEEDD';
$color = array(
base_convert(substr($rgb, 0, 2), 16, 10),
base_convert(substr($rgb, 2, 2), 16, 10),
base_convert(substr($rgb, 4, 2), 16, 10),
);
// allocate some colors
$white = imagecolorallocate($img, 255, 255, 255);
$red = imagecolorallocate($img, $color[0], $color[1], $color[2]);
// draw the head
imagefilledarc($img, 100, 100, 200, 200, 0, 360, $red, IMG_ARC_PIE);
// output image in the browser
header("Content-type: image/png");
imagepng($img);
// free memory
imagedestroy($img);
No, facebook doesn't allow embedding JavaScript in feeds for security reasons. Even if you manage to do it, it won't work because certain characters such as <, >, etc will be converted into html entities which means the JavaScript won't work.
Related
I'm trying to create images from dynamic text data in GD and put a logo in the top corner. The background color of the image will change based on the data passed in so I can't just save the logo as an image with no alpha channel.
I create the image, fill it with the dynamic background color using imagefill(), then add the text using imagettftext() and then load my logo in. I'm having a problem getting the logo into the image without it keeping its background color of 'transparent'. So I would like it to have the dynamic background color behind it that is set with imagefill(). However, it keeps the transparency background it was loaded in with and so writes this part of the png as transparent. I tried calling imagefill() on the logo after it had been loaded in (using the same rgb that sets the background of the destination image) but this didn't do anything.
Below is my code:
$background = $_GET['background'];
$data1 = $_GET['data1'];
$data2 = $_GET['data2'];
$r = $_GET['r'];
$g = $_GET['g'];
$b = $_GET['b'];
$png_image = imagecreate(400, 200);
$gd_text_color = imagecolorallocate($png_image, 255, 255, 255);
$gd_background_color = imagecolorallocate($png_image, $r, $g, $b);
imagefill($png_image, 0, 0, $gd_background);
$text1 = "test test $data1";
$text2 = "test test again $data2";
$font = 'Lato-regular.ttf';
imagettftext($png_image, 18, 0, 20, 20, $gd_text_color, $font, $text1);
imagettftext($png_image, 18, 0, 20, 50, $gd_text_color, $font, $text2);
//trying to get this logo and place it in the corner.
$logo = imagecreatefrompng("images/logo.png");
imagecopy($png_image, $logo, 10, 10, 0, 0, 100, 30);
header('Content-type: image/png');
imagepng($png_image, $filename);
imagedestroy($png_image);
Here's the output of that code: http://i.imgur.com/n25h9Js.png
And here's what the image looks like when loaded into a program that accepts an alpha channel: http://i.imgur.com/3OIRupN.png
Does anyone know how I'd achieve what I'm attempting?
Thanks for your time.
EDIT
To try and explain what I want here's another image. The top image is what I currently get, and the bottom image is what I want. I'm simply trying to load in a transparent PNG that can sit ontop of different colored backgrounds. However I either get it like how it is shown here (transparent background) or as a black background (because I guess the alpha channel isn't being looked at?). Hope this helps. Image:
Edit 2
As per the comment below, I changed it from imagecreate() to imagecreatetruecolor() and now it works fine! I would love an explanation why this solved it if anyone has the time but for now, thank you all who commented or even spent your time looking at this question.
I suspect your imagecreate() may be causing you problems as it creates a palettised image which doesn't have the flexibility or breadth of expression of a true-colour image.
I suggest you replace it with imagecreatetruecolor().
I was recently hired by a school that provides distance (online) education to young children. They want to be able to generate and send certificates (jpg or png images) via email once a child has completed certain tests, assignments, etc. Obviously they won't get all of their teachers to re-create each certificate in Photoshop or something and change each childs name, etc; that would be way too time consuming and I doubt their teachers even know how to use Photoshop.
Therefore, I was wondering what the best way to add text to an image in PHP is. The certificate will be like a standard school certificate and the name line will be blank. I'd like the text to go there.
The reason I'm doing this in PHP is because that way the teachers can go to whatever.com/generate-certificate and then type in the child's name in a field and then the certificate will be generated and sent off to the student via email on the fly. Very easy for the teachers.
Hopefully this question made sense. So in a nutshell I just want a library or some other simple way in PHP to add a line of text to an image (probably a jpeg).
Thanks a lot!
If you don't like procedural type, you can use imagick
<?php
/* Create some objects */
$image = new Imagick();
$draw = new ImagickDraw();
$pixel = new ImagickPixel( 'gray' );
/* New image */
$image->newImage(800, 75, $pixel);
/* Black text */
$draw->setFillColor('black');
/* Font properties */
$draw->setFont('Bookman-DemiItalic');
$draw->setFontSize( 30 );
/* Create text */
$image->annotateImage($draw, 10, 45, 0, 'The quick brown fox jumps over the lazy dog');
/* Give image a format */
$image->setImageFormat('png');
/* Output the image with headers */
header('Content-type: image/png');
echo $image;
Source: http://php.net/manual/en/imagick.annotateimage.php
There is great default library called GD which should do the job.
Well my idea how to make what you need:
1. Create maybe several background images for your certifications.
2. Load the image with PHP GD library
3. Write text and save the file, or render it on the fly if there will be less traffic.
http://us1.php.net/manual/en/function.imagefttext.php
<?php
// Create a 300x100 image
$im = imagecreatetruecolor(300, 100);
$red = imagecolorallocate($im, 0xFF, 0x00, 0x00);
$black = imagecolorallocate($im, 0x00, 0x00, 0x00);
// Make the background red
imagefilledrectangle($im, 0, 0, 299, 99, $red);
// Path to our ttf font file
$font_file = './arial.ttf';
// Draw the text 'PHP Manual' using font size 13
imagefttext($im, 13, 0, 105, 55, $black, $font_file, 'PHP Manual');
// Output image to the browser
header('Content-Type: image/png');
imagepng($im);
imagedestroy($im);
?>
I have a website I am building that takes data (the person's name) from a form and posts it into a customized "note" in a table on the next page. I want the user to then be able to save their "note" as an image with their customized name on it. Is there a way to save a SPECIFIC HTML TABLE as a PNG? Maybe take a screenshot of a specific coordinate on a web page?
If not is there a way to render posted PHP content from the form in an HTML canvas?
Any help would be great. I'm in a little over my head right now.
While you can render HTML using a variety of tools, you can't be sure that those tools will render the HTML the same way your browser renders it.
If your end goal is to generate an image with text on it, then let's solve that problem instead of trying to make the solution you suggested work.
Have a look at PHP's imagettftext() function. It contains an Example #1 which creates a small, simple image from text that can be stored in any variable ... including a form variable.
By using this example, and adding a few other of PHP's GD functions, you can make a decent replica of a table, and make sure it looks exactly the way you want it, rather than the way html2ps or some other tool renders it.
<?php
// Set the content-type
header('Content-Type: image/png');
// Create the image
$im = imagecreatetruecolor(400, 30);
// Create some colors
$white = imagecolorallocate($im, 255, 255, 255);
$grey = imagecolorallocate($im, 128, 128, 128);
$black = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 399, 29, $white);
// The text to draw
$text = isset($_POST['name']) ? $_POST['name'] : "name";
// Replace path by your own font path
$font = 'arial.ttf';
// Add some shadow to the text
imagettftext($im, 20, 0, 11, 21, $grey, $font, $text);
// Add the text
imagettftext($im, 20, 0, 10, 20, $black, $font, $text);
// Using imagepng() results in clearer text compared with imagejpeg()
imagepng($im);
imagedestroy($im);
?>
Here's sample output generated by the above script:
Note that you'll need to provide arial.ttf per the instructions at the link above.
If things don't work, look for errors both on-screen and in your web server's error log FIRST, before following up here. It's possible that PHP's GD module is not installed on your web server. If this is the case, you should check with your server administrator to make sure what you need is available to you.
You can try this JS library on client side.
workable solution
use fpdf to create pdf from html (table)
use imagemagick to convert pdf to png
You can also use Xvfb. It's a linux package. It stands for "X-window Virtual Frame Buffer" (if you were wondering why on earth it had such an esoteric name).
What that will do, is load a page, execute any JavaScript and apply the different stylings from CSS, all in the frame-buffer of the server. Then you can save the image.
Xvfb will probably not be available on most shared-hosting services, however, if that doesn't matter, then it would be a viable solution.
You can use something like html2ps
I am framing ads with a curved border.
Here is a sample ad: http://imageshack.us/f/20/4e5f5fe94b327new60seciq.png/
I am trying to replicate what would be done in Photoshop, place one on top of the other. Here is the code I'm using:
// create destination canvas
$dest_img = imagecreatetruecolor(176, 75);
// Make the background transparent
$black = imagecolorallocate($dest_img, 0, 0, 0);
imagecolortransparent($dest_img, $black);
imageAlphaBlending($dest_img, false);
imageSaveAlpha($dest_img, true);
// copy ad into destination
imagecopy($dest_img, $ad_image, 0, 0, 0, 0, 176, 75);
// copy frame onto first half of image
imagecopy($dest_img, $curve_image, 0, 0, 0, 0, 88, 75);
What is happening is that the last copy to take place (the frame) is taking priority and instead of seeing the ad, im getting a transparent block. Here is a blown up image of what GD is doing:
http://imageshack.us/f/684/unled1to.png/
I'm hoping there is a simple solution to get the lower layer to remain visible - if not I think I will have to write a function and go pixel by pixel and compare...
if (bottom_px == trans && top_px == trans) {
dest_px = trans;
}
else {
dest_px = top_px;
}
Set imagealphablending to true. From the manual, emphasis added:
In blending mode, the alpha channel component of the color supplied to all drawing function, such as imagesetpixel() determines how much of the underlying color should be allowed to shine through. As a result, gd automatically blends the existing color at that point with the drawing color, and stores the result in the image. The resulting pixel is opaque. In non-blending mode, the drawing color is copied literally with its alpha channel information, replacing the destination pixel. Blending mode is not available when drawing on palette images.
Also, you are not actually coloring the background transparent. You are just telling that $black is transparent. Instead, use imagefill with imagecolorallocatealpha:
imagefill($dest_img, 0, 0, imagecolorallocatealpha($dest_img, 0, 0, 0, 127));
Using PHP: How can I create an image to display an email address (to help reduce spam)?
Meaning, if I want to display "joe#example.com" on my web page, since crawlers can easily find that text - I want to display the email address as an image that says "joe#example.com".
How do I do that? I want the font to be:
color: #20c
font: 11px normal tahoma
A simple search that you could easily do....
However: (color, font and string not the ones you specified)
header("Content-type: image/png");
$im = #imagecreate(110, 20)
or die("Cannot Initialize new GD image stream");
$background_color = imagecolorallocate($im, 0, 0, 0);
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 1, 5, 5, "A Simple Text String", $text_color);
imagepng($im);
imagedestroy($im);
Relevant function definitions:
php.net/imagecreate
php.net/imagestring
Use these:
header, to tell the browser to expect an image instead of HTML (PHP's default). The image function doc pages have more information about this.
imagettfbbox, to find out the required size for the image
imagecreatetruecolor, to create the image resource
imagecolorallocate, to allocate a color for the text
imagettftext, to draw the text (read the example, it's almost all you need)
imagepng, to output the image to the browser
You should use gd image processing library.
If you are only doing this for one address you should not be doing this dynamically everytime the page loads for performance reasons. If this is the case you can find amny email obfuscator online such as this one:
http://digitalcolony.com/lab/maskemail/maskemail.aspx