Implemented endAtLastLine attribute which allows option of scrolling one

page below last document line.

5 files changed, 48 insertions, 6 deletions

diff --git a/doc/ScintillaDoc.html b/doc/ScintillaDoc.html
index 8b1e6dca5..55f397b8b 100644
--- a/doc/ScintillaDoc.html
+++ b/doc/ScintillaDoc.html
@@ -286,6 +286,10 @@ SCI_SETHSCROLLBAR(bool visible)
 SCI_GETHSCROLLBAR
 SCI_GETXOFFSET
 SCI_SETXOFFSET(int xoffset)
+SCI_SETSCROLLWIDTH(int pixelWidth)
+SCI_GETSCROLLWIDTH
+SCI_SETENDATLASTLINE(bool endAtLastLine)
+SCI_GETENDATLASTLINE
 </pre>
     <p>
       SCI_SETCARETPOLICY can be set to a combination of the flags CARET_SLOP
@@ -307,6 +311,14 @@ SCI_SETXOFFSET(int xoffset)
     <p>
       The xoffset is the horizontal scroll position in pixels.
     </p>
+    <p>
+      SCI_SETSCROLLWIDTH sets the document width assumed for scrolling.
+    </p>
+    <p>
+      SCI_SETENDATLASTLINE sets the scroll range so that maximum 
+      scroll position has the last line at the bottom of the view (default). 
+      Setting this to false allows scrolling one page below the last line.
+    </p>
     <h3>
        Searching
     </h3>
diff --git a/include/Scintilla.h b/include/Scintilla.h
index e5ccd6f11..b4fa06359 100644
--- a/include/Scintilla.h
+++ b/include/Scintilla.h
@@ -362,6 +362,8 @@ typedef sptr_t (*SciFnDirect)(sptr_t ptr, unsigned int iMessage, uptr_t wParam,
 #define SCI_SETSCROLLWIDTH 2274
 #define SCI_GETSCROLLWIDTH 2275
 #define SCI_TEXTWIDTH 2276
+#define SCI_SETENDATLASTLINE 2277
+#define SCI_GETENDATLASTLINE 2278
 #define SCI_LINEDOWN 2300
 #define SCI_LINEDOWNEXTEND 2301
 #define SCI_LINEUP 2302
diff --git a/include/Scintilla.iface b/include/Scintilla.iface
index 99afef5c0..8a4849025 100644
--- a/include/Scintilla.iface
+++ b/include/Scintilla.iface
@@ -943,6 +943,15 @@ get int GetScrollWidth=2275(,)
 # Does not handle tab or control characters.
 fun int TextWidth=2276(int style, string text)
 
+# Sets the scroll range so that maximum scroll position has 
+# the last line at the bottom of the view (default). 
+# Setting this to false allows scrolling one page below the last line.
+set void SetEndAtLastLine=2277(bool endAtLastLine,)
+
+# Retrieve whether the maximum scroll position has the last 
+# line at the bottom of the view. 
+get int GetEndAtLastLine=2278(,)
+
 ## Start of key messages
 # Move caret down one line.
 fun void LineDown=2300(,)
diff --git a/src/Editor.cxx b/src/Editor.cxx
index db5fe54b5..133e62b40 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -327,6 +327,7 @@ Editor::Editor() {
 	xCaretMargin = 50;
 	horizontalScrollBarVisible = true;
 	scrollWidth = 2000;
+	endAtLastLine = true;
 
 	pixmapLine = Surface::Allocate();
 	pixmapSelMargin = Surface::Allocate();
@@ -452,11 +453,17 @@ int Editor::LinesToScroll() {
 int Editor::MaxScrollPos() {
 	//Platform::DebugPrintf("Lines %d screen = %d maxScroll = %d\n",
 	//LinesTotal(), LinesOnScreen(), LinesTotal() - LinesOnScreen() + 1);
-	int retVal = cs.LinesDisplayed() - LinesOnScreen();
-	if (retVal < 0)
+	int retVal = cs.LinesDisplayed();
+	if (endAtLastLine) {
+		retVal -= LinesOnScreen();
+	} else {
+		retVal--;
+	}
+	if (retVal < 0) {
 		return 0;
-	else
+	} else {
 		return retVal;
+	}
 }
 
 static inline bool IsControlCharacter(char ch) {
@@ -2184,9 +2191,9 @@ void Editor::ReconfigureScrollBars() {}
 void Editor::SetScrollBars() {
 	RefreshStyleData();
 
-	int nMax = cs.LinesDisplayed();
-	int nPage = nMax - MaxScrollPos() + 1;
-	bool modified = ModifyScrollBars(nMax, nPage);
+	int nMax = MaxScrollPos();
+	int nPage = LinesOnScreen();
+	bool modified = ModifyScrollBars(nMax + nPage - 1, nPage);
 
 	// TODO: ensure always showing as many lines as possible
 	// May not be, if, for example, window made larger
@@ -4717,6 +4724,17 @@ sptr_t Editor::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam) {
 		PLATFORM_ASSERT(lParam);
 		return TextWidth(wParam, reinterpret_cast<char *>(lParam));
 
+	case SCI_SETENDATLASTLINE:
+		PLATFORM_ASSERT((wParam == 0) || (wParam ==1));
+		if (endAtLastLine != (wParam != 0)) {
+			endAtLastLine = wParam != 0;
+			SetScrollBars();
+		}
+		break;
+
+	case SCI_GETENDATLASTLINE:
+		return endAtLastLine;
+
 	case SCI_GETCOLUMN:
 		return pdoc->GetColumn(wParam);
 
diff --git a/src/Editor.h b/src/Editor.h
index 353e4ee9f..a86008456 100644
--- a/src/Editor.h
+++ b/src/Editor.h
@@ -201,6 +201,7 @@ protected:	// ScintillaBase subclass needs access to much of Editor
 	int xCaretMargin;	///< Ensure this many pixels visible on both sides of caret
 	bool horizontalScrollBarVisible;
 	int scrollWidth;
+	bool endAtLastLine;
 
 	Surface *pixmapLine;
 	Surface *pixmapSelMargin;