#1969 - Give graphics events the ability to override the standard process.

While graphics_rotate, graphics_resize, and graphics_composite events already exist, they don't have the ability to *override* the standard process.
This makes it a bit tricky when you want to replace the standard procedure with another (e.g. use jpegtran to perform lossless jpg rotation).
Solution:
- make a temp filename.
- tell the events to use it as the output file.
- if an event makes something, use it and skip the standard process.

1 files changed, 90 insertions, 68 deletions

diff --git a/modules/gallery/helpers/gallery_graphics.php b/modules/gallery/helpers/gallery_graphics.php
index e81d5468..b78bd9a7 100644
--- a/modules/gallery/helpers/gallery_graphics.php
+++ b/modules/gallery/helpers/gallery_graphics.php
@@ -29,21 +29,28 @@ class gallery_graphics_Core {
   static function rotate($input_file, $output_file, $options, $item=null) {
     graphics::init_toolkit();
 
-    module::event("graphics_rotate", $input_file, $output_file, $options, $item);
+    $temp_file = system::temp_filename("rotate_", pathinfo($output_file, PATHINFO_EXTENSION));
+    module::event("graphics_rotate", $input_file, $temp_file, $options, $item);
 
-    if (@filesize($input_file) == 0) {
-      throw new Exception("@todo EMPTY_INPUT_FILE");
-    }
+    if (@filesize($temp_file) > 0) {
+      // A graphics_rotate event made an image - move it to output_file and use it.
+      @rename($temp_file, $output_file);
+    } else {
+      // No events made an image - proceed with standard process.
+      if (@filesize($input_file) == 0) {
+        throw new Exception("@todo EMPTY_INPUT_FILE");
+      }
 
-    if (!isset($options["degrees"])) {
-      $options["degrees"] = 0;
-    }
+      if (!isset($options["degrees"])) {
+        $options["degrees"] = 0;
+      }
 
-    // Rotate the image.  This also implicitly converts its format if needed.
-    Image::factory($input_file)
-      ->quality(module::get_var("gallery", "image_quality"))
-      ->rotate($options["degrees"])
-      ->save($output_file);
+      // Rotate the image.  This also implicitly converts its format if needed.
+      Image::factory($input_file)
+        ->quality(module::get_var("gallery", "image_quality"))
+        ->rotate($options["degrees"])
+        ->save($output_file);
+    }
 
     module::event("graphics_rotate_completed", $input_file, $output_file, $options, $item);
   }
@@ -60,39 +67,46 @@ class gallery_graphics_Core {
   static function resize($input_file, $output_file, $options, $item=null) {
     graphics::init_toolkit();
 
-    module::event("graphics_resize", $input_file, $output_file, $options, $item);
+    $temp_file = system::temp_filename("resize_", pathinfo($output_file, PATHINFO_EXTENSION));
+    module::event("graphics_resize", $input_file, $temp_file, $options, $item);
 
-    if (@filesize($input_file) == 0) {
-      throw new Exception("@todo EMPTY_INPUT_FILE");
-    }
+    if (@filesize($temp_file) > 0) {
+      // A graphics_resize event made an image - move it to output_file and use it.
+      @rename($temp_file, $output_file);
+    } else {
+      // No events made an image - proceed with standard process.
+      if (@filesize($input_file) == 0) {
+        throw new Exception("@todo EMPTY_INPUT_FILE");
+      }
 
-    list ($input_width, $input_height, $input_mime, $input_extension) =
-      photo::get_file_metadata($input_file);
-    if ($input_width && $input_height &&
-        (empty($options["width"]) || empty($options["height"]) || empty($options["master"]) ||
-        (max($input_width, $input_height) <= min($options["width"], $options["height"])))) {
-      // Photo dimensions well-defined, but options not well-defined or would upscale the image.
-      // Do not resize.  Check mimes to see if we can copy the file or if we need to convert it.
-      // (checking mimes avoids needlessly converting jpg to jpeg, etc.)
-      $output_mime = legal_file::get_photo_types_by_extension(pathinfo($output_file, PATHINFO_EXTENSION));
-      if ($input_mime && $output_mime && ($input_mime == $output_mime)) {
-        // Mimes well-defined and identical - copy input to output
-        copy($input_file, $output_file);
+      list ($input_width, $input_height, $input_mime, $input_extension) =
+        photo::get_file_metadata($input_file);
+      if ($input_width && $input_height &&
+          (empty($options["width"]) || empty($options["height"]) || empty($options["master"]) ||
+          (max($input_width, $input_height) <= min($options["width"], $options["height"])))) {
+        // Photo dimensions well-defined, but options not well-defined or would upscale the image.
+        // Do not resize.  Check mimes to see if we can copy the file or if we need to convert it.
+        // (checking mimes avoids needlessly converting jpg to jpeg, etc.)
+        $output_mime = legal_file::get_photo_types_by_extension(pathinfo($output_file, PATHINFO_EXTENSION));
+        if ($input_mime && $output_mime && ($input_mime == $output_mime)) {
+          // Mimes well-defined and identical - copy input to output
+          copy($input_file, $output_file);
+        } else {
+          // Mimes not well-defined or not the same - convert input to output
+          $image = Image::factory($input_file)
+            ->quality(module::get_var("gallery", "image_quality"))
+            ->save($output_file);
+        }
       } else {
-        // Mimes not well-defined or not the same - convert input to output
+        // Resize the image.  This also implicitly converts its format if needed.
         $image = Image::factory($input_file)
-          ->quality(module::get_var("gallery", "image_quality"))
-          ->save($output_file);
-      }
-    } else {
-      // Resize the image.  This also implicitly converts its format if needed.
-      $image = Image::factory($input_file)
-        ->resize($options["width"], $options["height"], $options["master"])
-        ->quality(module::get_var("gallery", "image_quality"));
-      if (graphics::can("sharpen")) {
-        $image->sharpen(module::get_var("gallery", "image_sharpen"));
+          ->resize($options["width"], $options["height"], $options["master"])
+          ->quality(module::get_var("gallery", "image_quality"));
+        if (graphics::can("sharpen")) {
+          $image->sharpen(module::get_var("gallery", "image_sharpen"));
+        }
+        $image->save($output_file);
       }
-      $image->save($output_file);
     }
 
     module::event("graphics_resize_completed", $input_file, $output_file, $options, $item);
@@ -118,35 +132,43 @@ class gallery_graphics_Core {
     try {
       graphics::init_toolkit();
 
-      module::event("graphics_composite", $input_file, $output_file, $options, $item);
-
-      list ($width, $height) = photo::get_file_metadata($input_file);
-      list ($w_width, $w_height) = photo::get_file_metadata($options["file"]);
-
-      $pad = isset($options["padding"]) ? $options["padding"] : 10;
-      $top = $pad;
-      $left = $pad;
-      $y_center = max($height / 2 - $w_height / 2, $pad);
-      $x_center = max($width / 2 - $w_width / 2, $pad);
-      $bottom = max($height - $w_height - $pad, $pad);
-      $right = max($width - $w_width - $pad, $pad);
-
-      switch ($options["position"]) {
-      case "northwest": $x = $left;     $y = $top;       break;
-      case "north":     $x = $x_center; $y = $top;       break;
-      case "northeast": $x = $right;    $y = $top;       break;
-      case "west":      $x = $left;     $y = $y_center;  break;
-      case "center":    $x = $x_center; $y = $y_center;  break;
-      case "east":      $x = $right;    $y = $y_center;  break;
-      case "southwest": $x = $left;     $y = $bottom;    break;
-      case "south":     $x = $x_center; $y = $bottom;    break;
-      case "southeast": $x = $right;    $y = $bottom;    break;
-      }
+      $temp_file = system::temp_filename("composite_", pathinfo($output_file, PATHINFO_EXTENSION));
+      module::event("graphics_composite", $input_file, $temp_file, $options, $item);
 
-      Image::factory($input_file)
-        ->composite($options["file"], $x, $y, $options["transparency"])
-        ->quality(module::get_var("gallery", "image_quality"))
-        ->save($output_file);
+      if (@filesize($temp_file) > 0) {
+        // A graphics_composite event made an image - move it to output_file and use it.
+        @rename($temp_file, $output_file);
+      } else {
+        // No events made an image - proceed with standard process.
+
+        list ($width, $height) = photo::get_file_metadata($input_file);
+        list ($w_width, $w_height) = photo::get_file_metadata($options["file"]);
+
+        $pad = isset($options["padding"]) ? $options["padding"] : 10;
+        $top = $pad;
+        $left = $pad;
+        $y_center = max($height / 2 - $w_height / 2, $pad);
+        $x_center = max($width / 2 - $w_width / 2, $pad);
+        $bottom = max($height - $w_height - $pad, $pad);
+        $right = max($width - $w_width - $pad, $pad);
+
+        switch ($options["position"]) {
+        case "northwest": $x = $left;     $y = $top;       break;
+        case "north":     $x = $x_center; $y = $top;       break;
+        case "northeast": $x = $right;    $y = $top;       break;
+        case "west":      $x = $left;     $y = $y_center;  break;
+        case "center":    $x = $x_center; $y = $y_center;  break;
+        case "east":      $x = $right;    $y = $y_center;  break;
+        case "southwest": $x = $left;     $y = $bottom;    break;
+        case "south":     $x = $x_center; $y = $bottom;    break;
+        case "southeast": $x = $right;    $y = $bottom;    break;
+        }
+
+        Image::factory($input_file)
+          ->composite($options["file"], $x, $y, $options["transparency"])
+          ->quality(module::get_var("gallery", "image_quality"))
+          ->save($output_file);
+      }
 
       module::event("graphics_composite_completed", $input_file, $output_file, $options, $item);
     } catch (ErrorException $e) {