UI: Fix over scroll issue with line number widget

Author: chrisws

ChangeLog

@@ -7,6 +7,7 @@
 	Fix keyboard handling for non-us keymaps
 	Fix Ctrl+Home editor keystroke handler
 	Fix crash with online command if site is down
+	Fix over scroll issue with line number widget
 	Implemented editor F2 command to display online help
 
 2015-10-20

src/platform/sdl/editor.cpp

@@ -13,12 +13,21 @@
 #include "ui/textedit.h"
 #include "platform/sdl/syswm.h"
 
-void onlineHelp(const char *nodeId) {
-  if (nodeId != NULL) {
-    char path[100];
+void onlineHelp(TextEditInput *widget) {
+  char path[100];
+  const char *nodeId = widget->getNodeId();
+  if (nodeId != NULL && nodeId[0] != '0') {
     sprintf(path, "http://smallbasic.sf.net/?q=node/%s", nodeId);
-    browseFile(path);
+  } else {
+    char *selection = widget->getWordBeforeCursor();
+    if (selection != NULL) {
+      sprintf(path, "http://smallbasic.sf.net/?q=search/node/%s", selection);
+      free(selection);
+    } else {
+      sprintf(path, "http://smallbasic.sf.net");
+    }
   }
+  browseFile(path);
 }
 
 void System::editSource(strlib::String &loadPath) {
@@ -141,7 +150,7 @@ void System::editSource(strlib::String &loadPath) {
         break;
       case SB_KEY_F(2):
         redraw = false;
-        onlineHelp(widget->getNodeId());
+        onlineHelp(editWidget);
         break;
       case SB_KEY_F(5):
         saveFile(editWidget, loadPath);

src/ui/textedit.cpp

@@ -1285,13 +1285,25 @@ void TextEditInput::gotoNextMarker() {
   }
 }
 
-void TextEditInput::lineNavigate(bool lineDown) {
-  if (lineDown) {
+void TextEditInput::lineNavigate(bool arrowDown) {
+  if (arrowDown) {
+    // starting from the cursor position (relative to the screen),
+    // count the number of rows to the bottom of the document.
+    int rowCount = _cursorLine - _scroll;
     for (int i = _state.cursor; i < _buf._len; i++) {
-      if (_buf._buffer[i] == '\n' && i + 1 < _buf._len) {
-        _state.cursor = i + 1;
-        _scroll += 1;
-        break;
+      if (_buf._buffer[i] == '\n') {
+        rowCount++;
+      }
+    }
+    int pageRows = (_height / _charHeight) - 1;
+    if (rowCount >= pageRows) {
+      // rows exist below end of page to pull up
+      for (int i = _state.cursor; i < _buf._len; i++) {
+        if (_buf._buffer[i] == '\n' && i + 1 < _buf._len) {
+          _state.cursor = i + 1;
+          _scroll += 1;
+          break;
+        }
       }
     }
   } else if (_scroll > 0) {