Communicate max dimensions of profile images before upload

Summary:
Trying to set a large image as a project profile image, Phorge displays the "it is a mystery" placeholder image without errors or explanation.
Thus communicate the maximum file dimensions for transforming thumbnails, like Phorge already does for supported file format types.

Closes T15984

Test Plan:
* Go to http://phorge.localhost/project/picture/1/ and http://phorge.localhost/people/picture/1/ and set an image with 4096×4096px and an image with 4097×4097px and observe resulting image.
* Apply this patch, then go to http://phorge.localhost/project/picture/1/ and http://phorge.localhost/people/picture/1/ and see the additional "Maximum image dimensions: 4096×4096 pixels." in the "Upload New Picture" section, set an image with 4096×4096px and an image with 4097×4097px.
* Also test on http://phorge.localhost/phame/post/header/1/ and http://phorge.localhost/phame/blog/header/1/ but realize that these codepaths do not transform larger images, thus no problem. I remain clueless how to trigger PhameBlogProfilePictureController, DiffusionRepositoryProfilePictureController with similar code.

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: avivey, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Maniphest Tasks: T15984

Differential Revision: https://we.phorge.it/D25862

src/applications/files/transform/PhabricatorFileImageTransform.php

@@ -334,7 +334,8 @@ abstract class PhabricatorFileImageTransform extends PhabricatorFileTransform {
           'Unable to determine image width and height with getimagesize().'));
     }
 
-    $max_pixels = (4096 * 4096);
+    $max_pixels_array = $this->getMaxTransformDimensions();
+    $max_pixels = ($max_pixels_array[0] * $max_pixels_array[1]);
     $img_pixels = ($width * $height);
 
     if ($img_pixels > $max_pixels) {
@@ -365,6 +366,15 @@ abstract class PhabricatorFileImageTransform extends PhabricatorFileTransform {
     return $this->image;
   }
 
+  /**
+   * Get maximum supported image dimensions in pixels for transforming
+   *
+   * @return array<int> Maximum width and height
+   */
+  public function getMaxTransformDimensions() {
+    return array(4096, 4096);
+  }
+
   private function shouldUseImagemagick() {
     if (!PhabricatorEnv::getEnvConfig('files.enable-imagemagick')) {
       return false;

src/applications/people/controller/PhabricatorPeopleProfilePictureController.php

@@ -36,6 +36,15 @@ final class PhabricatorPeopleProfilePictureController
     $e_file = true;
     $errors = array();
 
+    // Get the image file transform.
+    $xform = PhabricatorFileTransform::getTransformByKey(
+      PhabricatorFileThumbnailTransform::TRANSFORM_PROFILE);
+
+    // Have an hard-limit to save our resources.
+    $max_image_dimensions = $xform->getMaxTransformDimensions();
+    $max_image_dimensions_message = pht('Maximum image dimensions: %s pixels.',
+      implode(mb_chr(215), $max_image_dimensions));
+
     if ($request->isFormPost()) {
       $phid = $request->getStr('phid');
       $is_default = false;
@@ -67,8 +76,6 @@ final class PhabricatorPeopleProfilePictureController
           $e_file = pht('Not Supported');
           $errors[] = $supported_formats_message;
         } else {
-          $xform = PhabricatorFileTransform::getTransformByKey(
-            PhabricatorFileThumbnailTransform::TRANSFORM_PROFILE);
           $xformed = $xform->executeTransform($file);
         }
       }
@@ -254,7 +261,8 @@ final class PhabricatorPeopleProfilePictureController
           ->setName('picture')
           ->setLabel(pht('Upload Picture'))
           ->setError($e_file)
-          ->setCaption($supported_formats_message))
+          ->setCaption($supported_formats_message.' '.
+            $max_image_dimensions_message))
       ->appendChild(
         id(new AphrontFormSubmitControl())
           ->addCancelButton($done_uri)

src/applications/project/controller/PhabricatorProjectEditPictureController.php

@@ -35,6 +35,15 @@ final class PhabricatorProjectEditPictureController
     $e_file = true;
     $errors = array();
 
+    // Get the image file transform.
+    $xform = PhabricatorFileTransform::getTransformByKey(
+      PhabricatorFileThumbnailTransform::TRANSFORM_PROFILE);
+
+    // Have an hard-limit to save our resources.
+    $max_image_dimensions = $xform->getMaxTransformDimensions();
+    $max_image_dimensions_message = pht('Maximum image dimensions: %s pixels.',
+      implode(mb_chr(215), $max_image_dimensions));
+
     if ($request->isFormPost()) {
       $phid = $request->getStr('phid');
       $is_default = false;
@@ -66,8 +75,6 @@ final class PhabricatorProjectEditPictureController
           $e_file = pht('Not Supported');
           $errors[] = $supported_formats_message;
         } else {
-          $xform = PhabricatorFileTransform::getTransformByKey(
-            PhabricatorFileThumbnailTransform::TRANSFORM_PROFILE);
           $xformed = $xform->executeTransform($file);
         }
       }
@@ -261,7 +268,8 @@ final class PhabricatorProjectEditPictureController
           ->setName('picture')
           ->setLabel(pht('Upload Picture'))
           ->setError($e_file)
-          ->setCaption($supported_formats_message))
+          ->setCaption($supported_formats_message.' '.
+            $max_image_dimensions_message))
       ->appendChild(
         id(new AphrontFormSubmitControl())
           ->addCancelButton($manage_uri)