first import
This commit is contained in:
Bachir Soussi Chiadmi
182
sites/all/modules/imagecache_actions/image_overlay.inc
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182
sites/all/modules/imagecache_actions/image_overlay.inc
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<?php
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/**
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* @file extension to imageapi, provide an overlay action for blending two
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* layers, preserving transparency.
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*/
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// Not sure where this library will live between upgrade versions.
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// Be careful to not conflict with another copy of myself.
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if (! function_exists('image_overlay')) {
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/**
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* Place one image over another
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*
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* @param object $image
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* An image object.
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* @param object $overlay
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* An image object.
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* @param $x
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* Position of the overlay
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* @param $y
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* Position of the overlay
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* @param $alpha
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* Transparency of the overlay from 0-100. 0 is totally transparent. 100
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* (default) is totally opaque.
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* @param $reverse
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* BOOL flag to indicate the 'overlay' actually goes under the image. As
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* the imageapi callbacks modify the $image object by reference, this is needed
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* to replace the old image resource with the new one.
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* @return bool success
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*
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* @ingroup imageapi
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*/
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function image_overlay($image, &$layer, $x, $y, $alpha = 100, $reverse = FALSE) {
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if ($reverse) {
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$x = imagecache_actions_keyword_filter($x, $layer->info['width'], $image->info['width']);
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$y = imagecache_actions_keyword_filter($y, $layer->info['height'], $image->info['height']);
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}
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else {
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$x = imagecache_actions_keyword_filter($x, $image->info['width'], $layer->info['width']);
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$y = imagecache_actions_keyword_filter($y, $image->info['height'], $layer->info['height']);
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}
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return image_toolkit_invoke('overlay', $image, array($layer, $x, $y, $alpha, $reverse));
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}
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/**
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* Place one image over another
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* This modifies the passed image by reference
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*
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* This func is nominated for inclusion in imageapi package. Until then, we do
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* it ourselves.
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*
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* NOTE that the PHP libraries are not great at merging images SO we include a
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* library that does it pixel-by-pixel which is INCREDIBLY inefficient. If this
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* can be improved, in a way that supports all transparency, please let us know!
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*
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* A watermark is layer onto image, return the image. An underlay is image onto
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* layer, return the layer. Almost identical, but seeing as we work with
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* resource handles, the handle needs to be swapped before returning.
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*
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* @ingroup imageapi
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* @param $image
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* Base imageapi object.
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* @param $overlay
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* May be a filename or an imageAPI object
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* @param $x
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* Position of the overlay
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* @param $y
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* Position of the overlay
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* @param $alpha
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* Transparency of the overlay from 0-100. 0 is totally transparent. 100
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* (default) is totally opaque.
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* @param $reverse
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* BOOL flag to indicate the 'overlay' actually goes under the image. As
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* the imageapi callbacks modify the $image object by reference, this is needed
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* to replace the old image resource with the new one.
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* @return bool success
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*/
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function image_gd_overlay($image, $layer, $x, $y, $alpha = 100, $reverse = FALSE) {
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if (empty($layer->resource)) {
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trigger_error("Invalid input to " . __FUNCTION__ . " 'layer' is not a valid resource");
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#dpm($layer);
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return FALSE;
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}
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// If the given alpha is 100%, we can use imagecopy - which actually works,
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// Is more efficient, and seems to retain the overlays partial transparancy
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// Still does not work great for indexed gifs though?
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if ($reverse) {
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$upper = &$image;
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$lower = &$layer;
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}
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else {
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$upper = &$layer;
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$lower = &$image;
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}
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if ($alpha == 100 && ($upper->info['mime_type'] != 'image/gif')) {
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imagealphablending($lower->resource, TRUE);
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imagesavealpha($lower->resource, TRUE);
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imagealphablending($upper->resource, TRUE);
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imagesavealpha($upper->resource, TRUE);
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imagecopy($lower->resource, $upper->resource, $x, $y, 0, 0, $upper->info['width'], $upper->info['height']);
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imagedestroy($upper->resource);
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$image->resource = $lower->resource;
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$image->info = $lower->info;
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}
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else {
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// Else imagecopymerge fails and we have to use the slow library.
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module_load_include('inc', 'imagecache_actions', 'watermark');
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$watermark = new watermark();
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$result_img = $watermark->create_watermark($lower->resource, $upper->resource, $x, $y, $alpha);
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// Watermark creates a new image resource, so clean up both old images.
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imagedestroy($lower->resource);
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imagedestroy($upper->resource);
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$image->resource = $result_img;
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$image->info = $lower->info;
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}
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return TRUE;
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}
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/**
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* Improvements on this are welcomed!
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*
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* Please be aware of the limitations of imagemagick libraries out there - the
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* versions distributed on hosted servers (if any) are often several years
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* behind. Using the latest imagemagick release features will make this function
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* unusable in real deployments.
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*
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* @param $image
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* Base imageapi object.
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* @param $layer
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* May be a filename or an imageAPI object, gets placed on top
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* If using reverse, this is going to be the result we carry on working with.
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*/
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function image_imagemagick_overlay($image, $layer, $x = 0, $y = 0, $alpha = 100, $reverse = FALSE) {
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// In imagemagick terms:
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// - $image is the destination (the image being constructed)
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// - $layer is the source (the source of the current operation)
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// Add the layer image to the imagemagick command line.
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$image->ops[] = escapeshellarg($layer->source) . ' ';
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// Set its offset. Offset arguments require a sign in front.
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if ($x >= 0) {
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$x = "+$x";
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}
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if ($y >= 0) {
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$y = "+$y";
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}
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$image->ops[] = " -geometry $x$y";
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// And compose it with the destination.
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if ($alpha == 100) {
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// Lay one image over the other. The transparency channel of the upper
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// image and/or its dimensions (being smaller than the lower image) will
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// determine what remains visible of the lower image).
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//
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// Note: In explicitly setting a -compose operator we reset/overwrite any
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// previously set one (former versions could produce erroneous results
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// in combination with other effects before this one).
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if ($reverse) {
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$compose_operator = 'dst-over';
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}
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else {
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$compose_operator = 'src-over';
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}
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$image->ops[] = "-compose $compose_operator -composite ";
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}
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else {
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// Alpha is not 100, so this image effect turns into a blend operation.
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// The alpha determines what percentage of the upper image pixel will be
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// taken. From the lower image pixel, 100 - alpha percent will be taken.
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//
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// Note 1: I'm not sure if and how transparency of one or both images is
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// used in or after the blend operation.
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// Note 2: As of IM v6.5.3-4 (around june 2009) we can use:
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// -compose blend -define compose:args=30[,70]
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$image->ops[] = "-compose blend -define compose:args=$alpha -composite ";
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}
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return TRUE;
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}
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}
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