From f67c0738671b50c47e31c049959f77bcdc7a6eb6 Mon Sep 17 00:00:00 2001
From: nathan <nathan@dorkbox.com>
Date: Sun, 29 May 2016 21:42:02 +0200
Subject: [PATCH] Fixed scrolling in windows so that the screen is clipped (as
 per the specification)

---
 .../console/output/WindowsAnsiOutputStream.java | 17 ++++++++++-------
 src/dorkbox/console/util/windows/Kernel32.java  |  5 +++--
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/dorkbox/console/output/WindowsAnsiOutputStream.java b/src/dorkbox/console/output/WindowsAnsiOutputStream.java
index 81aeb65..03e2592 100644
--- a/src/dorkbox/console/output/WindowsAnsiOutputStream.java
+++ b/src/dorkbox/console/output/WindowsAnsiOutputStream.java
@@ -93,6 +93,9 @@ public final class WindowsAnsiOutputStream extends AnsiOutputStream {
     private volatile short savedX = (short) -1;
     private volatile short savedY = (short) -1;
 
+    // reused vars
+    private IntByReference written = new IntByReference();
+
     public
     WindowsAnsiOutputStream(final OutputStream os, int fileHandle) throws IOException {
         super(os);
@@ -166,7 +169,7 @@ public final class WindowsAnsiOutputStream extends AnsiOutputStream {
     protected
     void processEraseScreen(final int eraseOption) throws IOException {
         getConsoleInfo();
-        int[] written = new int[1];
+
         switch (eraseOption) {
             case ERASE_ALL:
                 COORD topLeft = new COORD();
@@ -198,7 +201,7 @@ public final class WindowsAnsiOutputStream extends AnsiOutputStream {
     protected
     void processEraseLine(final int eraseOption) throws IOException {
         getConsoleInfo();
-        int[] written = new int[1];
+
         switch (eraseOption) {
             case ERASE_ALL:
                 COORD currentRow = info.cursorPosition.asValue();
@@ -407,18 +410,18 @@ public final class WindowsAnsiOutputStream extends AnsiOutputStream {
         SMALL_RECT.ByReference scrollRect = new SMALL_RECT.ByReference();
         COORD.ByValue coordDest = new COORD.ByValue();
 
-        // the content that will be scrolled
-        scrollRect.top = (short) (0);
-        scrollRect.bottom = Short.MAX_VALUE;
+        // the content that will be scrolled (just what is visible in the window)
+        scrollRect.top = (short) (info.cursorPosition.y - info.window.height());
+        scrollRect.bottom = (short) (info.cursorPosition.y);
         scrollRect.left = (short) 0;
         scrollRect.right = (short) (info.size.x - 1);
 
         // The destination for the scroll rectangle is xxx row up/down.
         coordDest.x = (short) 0;
-        coordDest.y = (short) (-rowsToScroll);
+        coordDest.y = (short) (scrollRect.top - rowsToScroll);
 
         // fill the space with whatever color was already there with spaces
-        IntByReference attribs = new IntByReference();
+        IntByReference attribs = written;
         attribs.setValue(info.attributes);
 
         // The clipping rectangle is the same as the scrolling rectangle, so we pass NULL
diff --git a/src/dorkbox/console/util/windows/Kernel32.java b/src/dorkbox/console/util/windows/Kernel32.java
index 789ffc0..fb9040b 100644
--- a/src/dorkbox/console/util/windows/Kernel32.java
+++ b/src/dorkbox/console/util/windows/Kernel32.java
@@ -113,13 +113,13 @@ public class Kernel32 {
      * https://msdn.microsoft.com/en-us/library/ms682662%28VS.85%29.aspx
      */
     public static native
-    int FillConsoleOutputAttribute(HANDLE consoleOutput, short attribute, int length, COORD.ByValue writeCoord, int[] numberOfAttrsWritten);
+    int FillConsoleOutputAttribute(HANDLE consoleOutput, short attribute, int length, COORD.ByValue writeCoord, IntByReference numberOfAttrsWritten);
 
     /**
      * https://msdn.microsoft.com/en-us/library/ms682663%28VS.85%29.aspx
      */
     public static native
-    int FillConsoleOutputCharacterW(HANDLE consoleOutput, char character, int length, COORD.ByValue writeCoord, int[] numberOfCharsWritten);
+    int FillConsoleOutputCharacterW(HANDLE consoleOutput, char character, int length, COORD.ByValue writeCoord, IntByReference numberOfCharsWritten);
 
 
 
@@ -135,6 +135,7 @@ public class Kernel32 {
     public static native
     int SetConsoleMode(HANDLE handle, int mode);
 
+
     /**
      * https://msdn.microsoft.com/en-us/library/ms684961(v=VS.85).aspx
      */