Changes between Version 1 and Version 2 of BossaExampleFour

Timestamp:

Jul 31, 2008, 2:19:00 PM (16 years ago)

Author:

davea

Comment:

--

BossaExampleFour

@@ -23 +23 @@
 Using the administrative interface, create an application named "bossa_example4".
 Create a directory '''~/projects/test/html/user/example4_images'''.
-Put some images (.png or .jpg) there; a good source is
+Put some images (.png or .jpg) there; some sample images are in
 http://isaac.ssl.berkeley.edu/test/example4_images/
 
@@ -32 +32 @@
 }}}
 
-==
+== Opaque data ==
+
+The application uses the following opaque data:
+
+ * Jobs
+{{{
+path: the name of image file
+}}}
+ * Instances
+{{{
+features: an array of structures, each containing:
+
+x: the X coordinate of the center
+y: the Y coordinate of the center
+type: the feature type (Tooth, Skull, Other)
+comment: the user-supplied comment
+}}}
+
+== Callback functions ==
+
+The '''job_show()''' function displays the image and overlays
+existing annotations.
+Each one is shown as a box with an "info" button
+(which pops up the type and comment)
+and a "delete" button linked to the edit page.
+
+The image is an input item in a form linked to the edit page,
+so that clicks on the image produce a new annotation.
+Javascript is used to require that a feature type be selected
+in order for the annotation to be accepted.
+
+The "Done" button is linked to '''bossa_job_finished.php'''.
+
+== The edit handler ==
+
+The edit handler is invoked with the following GET arguments:
+
+ * '''bji''': the ID of the instance
+ * '''action''': "add", "delete", or "" (to display the image)
+ * '''pic_x''' and '''pic_y''' (if action is "add")
+
+The code is as follows.
+The first two functions add and delete annotations;
+each one ends by redirecting to the same page with no "action" argument;
+this will redisplay the image with the new set of annotations.
+{{{
+     7  function handle_add($job, $inst) {
+     8      $f = null;
+     9      $f->x = get_int('pic_x');
+    10      $f->y = get_int('pic_y');
+    11      $f->type = get_str('type');
+    12      $c = get_str('comment', true);
+    13      if (strstr($c, "(optional)")) $c = "";
+    14      $f->comment = $c;
+    15      $output = $inst->get_opaque_data();
+    16      $output->features[] = $f;
+    17      $inst->set_opaque_data($output);
+    18      header("location: bossa_example4.php?bji=$inst->id");
+    19  }
+    20
+    21  function handle_delete($job, $inst, $index) {
+    22      $output = $inst->get_opaque_data();
+    23      $features = $output->features;
+    24      array_splice($features, $index, 1);
+    25      $output->features = $features;
+    26      $inst->set_opaque_data($output);
+    27      header("location: bossa_example4.php?bji=$inst->id");
+    28  }
+}}}
+
+The main part of the script is as follows.
+First, we get the instance ID and call a Bossa API function
+to get the job, instance, and user:
+{{{
+    30  $bji = get_int("bji");
+    31  if (!bossa_lookup_job($bji, $job, $inst, $u)) {
+    32      error_page("No such instance");
+    33  }
+}}}
+Then we verify that this instance belongs to the logged-in user:
+{{{
+    34  $user = get_logged_in_user();
+    35  if ($u->id != $user->id) {
+    36      error_page("Not your job");
+    37  }
+}}}
+Then we perform the operation (or show the image with existing annotations):
+{{{
+    39  $action = get_str("action", true);
+    40  switch ($action) {
+    41  case "add":
+    42      handle_add($job, $inst);
+    43      break;
+    44  case "delete":
+    45      $index = get_int("index");
+    46      handle_delete($job, $inst, $index);
+    47      break;
+    48  default:
+    49      job_show($job, $inst, $user);
+    50      break;
+    51  }
+    52
+    53  ?>
+}}}