note 117021 added to ref.image

I was after a technique to produce an image by using the image resources available to PHP and to have access to the image's binary data directly in PHP WITHOUT saving to a temporary file. My purpose of this was to produce a directory of images with small image thumbnails (16x16) next to the filenames. Instead of having countless tiny images saved, I wanted to print out the image data into the <img> HTML tag (inline) using the data URI scheme. I found no such code or suggestion for this, and I've done some digging around at likely approaches and finally came up with a solution. There may or may not be a better way of doing this, but this way works for me. The guts of the approach started here with the example of registering a class as a stream wrapper: http://php.net/manual/en/stream.streamwrapper.example-1.php - this way we have access to, and can over-ride, the behaviour of "file" I/O with a custom wrapper. <?php // first, we define our class for the stream wrapper class VariableStream { var $position; var $varname; function stream_open($path, $mode, $options, &$opened_path) { $url = parse_url($path); $this->varname = $url['host']; $this->position = 0; return TRUE; } function stream_write($data) { $left = substr(@$GLOBALS[$this->varname], 0, $this->position); $right = substr(@$GLOBALS[$this->varname], $this->position+strlen($data)); $GLOBALS[$this->varname] = $left.$data.$right; $this->position+= strlen($data); return strlen($data); } function stream_eof() { return $this->position>=strlen($GLOBALS[$this->varname]); } } // register the class as a stream wrapper ("var://asdf") stream_wrapper_register('var', 'VariableStream'); // create a really simple dynamically-generated image // in my case, I used imagecreatefromjpeg to create 16x16 thumbnails $im = imagecreatetruecolor(130, 36); imagefill($im, 0, 0, 0xAAAAAA); imagestring($im, 5, 10, 10, 'Hello world!', 0x0000FF); // and output it to our wrapper! imagepng($im, 'var://asdf/'); // $asdf now contains our image binary! imagedestroy($im); // free memory $asdf = base64_encode($asdf); // base64 encode our data for... printf("<img alt=\"\" src=\"data:image/png;base64,%s\"/>", $asdf); ?> The class 'VariableStream' lacks ability to seek, ftell, and read for the sake of simple code for my purpose. More complete code for I/O operations can be found in the example document I references above. You could also then use fopen using the wrapper and variable name to access it like a file again. This technique can be applied to other functions that don't allow direct access to the data generated to files or sockets. Hope this helps! ---- Server IP: 72.52.91.14 Probable Submitter: 82.25.3.36 ---- Manual Page -- http://php.net/manual/en/ref.image.php Edit -- https://master.php.net/note/edit/117021 Del: integrated -- https://master.php.net/note/delete/117021/integrated Del: useless -- https://master.php.net/note/delete/117021/useless Del: bad code -- https://master.php.net/note/delete/117021/bad+code Del: spam -- https://master.php.net/note/delete/117021/spam Del: non-english -- https://master.php.net/note/delete/117021/non-english Del: in docs -- https://master.php.net/note/delete/117021/in+docs Del: other reasons-- https://master.php.net/note/delete/117021 Reject -- https://master.php.net/note/reject/117021 Search -- https://master.php.net/manage/user-notes.php