prevent auto format from scrolling (issue #1533)

app/src/processing/app/Editor.java

@@ -1671,6 +1671,10 @@ public abstract class Editor extends JFrame implements RunnerListener {
       final String formattedText = createFormatter().format(source);
       // save current (rough) selection point
       int selectionEnd = getSelectionStop();
+      
+//      boolean wasVisible = 
+//        textarea.getSelectionStopLine() >= textarea.getFirstLine() && 
+//        textarea.getSelectionStopLine() < textarea.getLastLine();
 
       // make sure the caret would be past the end of the text
       if (formattedText.length() < selectionEnd - 1) {
@@ -1682,8 +1686,24 @@ public abstract class Editor extends JFrame implements RunnerListener {
       } else {
         // replace with new bootiful text
         // selectionEnd hopefully at least in the neighborhood
+        int scrollPos = textarea.getScrollPosition();
         setText(formattedText);
         setSelection(selectionEnd, selectionEnd);
+        
+        // Put the scrollbar position back, otherwise it jumps on each format.
+        // Since we're not doing a good job of maintaining position anyway, 
+        // a more complicated workaround here is fairly pointless.
+        // http://code.google.com/p/processing/issues/detail?id=1533
+        if (scrollPos != textarea.getScrollPosition()) {
+//          boolean wouldBeVisible = 
+//            scrollPos >= textarea.getFirstLine() && 
+//            scrollPos < textarea.getLastLine();
+//
+//          // if it was visible, and now it's not, then allow the scroll
+//          if (!(wasVisible && !wouldBeVisible)) {   
+          textarea.setScrollPosition(scrollPos);
+//          }
+        }
         getSketch().setModified(true);
         // mark as finished
         statusNotice("Auto Format finished.");

app/src/processing/app/syntax/JEditTextArea.java

@@ -369,6 +369,14 @@ public class JEditTextArea extends JComponent
     painter.repaint();
   }
   
+  
+  /** 
+   * Convenience for checking what's on-screen. [fry] 
+   */
+  public final int getLastLine() {
+    return getFirstLine() + getVisibleLines();
+  }
+  
 
   /**
    * Returns the number of lines visible in this text area.

todo.txt

@@ -46,10 +46,14 @@ X   http://code.google.com/p/processing/issues/detail?id=1520
 X prevent inertia scrolling on OS X from making editor jumpy
 X Suggest possible import statements for common Java classes
 X   http://code.google.com/p/processing/issues/detail?id=1550
+X   for others like collections and Date, show warning and option to add?
+X   along with warning that it's not supported
 X processing-java throws java.lang.ArrayIndexOutOfBoundsException: -1
 X   http://code.google.com/p/processing/issues/detail?id=1548
 X Library manager leaves temporary folders in sketchbook folder
 X   http://code.google.com/p/processing/issues/detail?id=1527
+X "Auto format" should not scroll current line to first line
+X   http://code.google.com/p/processing/issues/detail?id=1533
 
 manindra
 M bug that was causing the Debugger to point to wrong break point line numbers
@@ -75,8 +79,6 @@ o   if sketch was open, then restart by dragging the .pde to p5.app
 https://processing-js.lighthouseapp.com/
 
 _ add Iterator as an import?
-_ for others like collections and Date, show warning and option to add?
-_   along with warning that it's not supported
 
 _ remove sketch.properties when moving back to the default?
 _   or can we not do this, because the next mode needs this?