Feature #3027559 Extend "sticky caret" feature from Jason Oster.

Additional mode SC_CARETSTICKY_WHITESPACE implemented.

5 files changed, 49 insertions, 18 deletions

diff --git a/doc/ScintillaDoc.html b/doc/ScintillaDoc.html
index cd4939a55..41c3a5d43 100644
--- a/doc/ScintillaDoc.html
+++ b/doc/ScintillaDoc.html
@@ -2526,7 +2526,7 @@ struct Sci_TextToFind {
     <a class="message" href="#SCI_SETCONTROLCHARSYMBOL">SCI_SETCONTROLCHARSYMBOL(int
     symbol)</a><br />
      <a class="message" href="#SCI_GETCONTROLCHARSYMBOL">SCI_GETCONTROLCHARSYMBOL</a><br />
-     <a class="message" href="#SCI_SETCARETSTICKY">SCI_SETCARETSTICKY(bool useCaretStickyBehaviour)</a><br />
+     <a class="message" href="#SCI_SETCARETSTICKY">SCI_SETCARETSTICKY(int useCaretStickyBehaviour)</a><br />
      <a class="message" href="#SCI_GETCARETSTICKY">SCI_GETCARETSTICKY</a><br />
      <a class="message" href="#SCI_TOGGLECARETSTICKY">SCI_TOGGLECARETSTICKY</a><br />
     </code>
@@ -2631,12 +2631,25 @@ struct Sci_TextToFind {
     You can read back the current symbol with the <code>SCI_GETCONTROLCHARSYMBOL</code> message.
     The default symbol value is 0.</p>
 
-    <p><b id="SCI_SETCARETSTICKY">SCI_SETCARETSTICKY(bool useCaretStickyBehaviour)</b><br />
+    <p><b id="SCI_SETCARETSTICKY">SCI_SETCARETSTICKY(int useCaretStickyBehaviour)</b><br />
     <b id="SCI_GETCARETSTICKY">SCI_GETCARETSTICKY</b><br />
     <b id="SCI_TOGGLECARETSTICKY">SCI_TOGGLECARETSTICKY</b><br />
-    These messages set, get or toggle the caretSticky flag which controls when the last position
-     of the caret on the line is saved. When set to true, the position is not saved when you type
-     a character, a tab, paste the clipboard content or press backspace.</p>
+    These messages set, get or toggle the caretSticky setting which controls when the last position
+    of the caret on the line is saved.</p>
+
+    <p>When set to <code>SC_CARETSTICKY_OFF</code> (0), the sticky flag is off; all text changes
+    (and all caret position changes) will remember the
+    caret's new horizontal position when moving to different lines. This is the default.</p>
+
+    <p>When set to <code>SC_CARETSTICKY_ON</code> (1), the sticky flag is on, and the only thing which will cause the editor to remember the
+    horizontal caret position is moving the caret with mouse or keyboard (left/right arrow keys, home/end keys, etc). </p>
+
+    <p>When set to <code>SC_CARETSTICKY_WHITESPACE</code> (2), the caret acts like mode 0 (sticky off) except under one
+    special case; when space or tab characters are inserted. (Including pasting <b>only space/tabs</b> -- undo, redo,
+    etc. do not exhibit this behavior..).</p>
+
+    <p><code>SCI_TOGGLECARETSTICKY</code> switches from <code>SC_CARETSTICKY_ON</code> and <code>SC_CARETSTICKY_WHITESPACE</code>
+    to <code>SC_CARETSTICKY_OFF</code> and from <code>SC_CARETSTICKY_OFF</code> to <code>SC_CARETSTICKY_ON</code>.</p>
 
     <h2 id="Margins">Margins</h2>
 
diff --git a/include/Scintilla.h b/include/Scintilla.h
index b91c78c2a..efb536742 100644
--- a/include/Scintilla.h
+++ b/include/Scintilla.h
@@ -669,6 +669,9 @@ typedef sptr_t (*SciFnDirect)(sptr_t ptr, unsigned int iMessage, uptr_t wParam,
 #define SCI_FINDCOLUMN 2456
 #define SCI_GETCARETSTICKY 2457
 #define SCI_SETCARETSTICKY 2458
+#define SC_CARETSTICKY_OFF 0
+#define SC_CARETSTICKY_ON 1
+#define SC_CARETSTICKY_WHITESPACE 2
 #define SCI_TOGGLECARETSTICKY 2459
 #define SCI_SETPASTECONVERTENDINGS 2467
 #define SCI_GETPASTECONVERTENDINGS 2468
diff --git a/include/Scintilla.iface b/include/Scintilla.iface
index d7c850840..f40530fda 100644
--- a/include/Scintilla.iface
+++ b/include/Scintilla.iface
@@ -1780,10 +1780,15 @@ fun int EncodedFromUTF8=2449(string utf8, stringresult encoded)
 fun int FindColumn=2456(int line, int column)
 
 # Can the caret preferred x position only be changed by explicit movement commands?
-get bool GetCaretSticky=2457(,)
+get int GetCaretSticky=2457(,)
 
 # Stop the caret preferred x position changing when the user types.
-set void SetCaretSticky=2458(bool useCaretStickyBehaviour,)
+set void SetCaretSticky=2458(int useCaretStickyBehaviour,)
+
+enu CaretSticky=SC_CARETSTICKY_
+val SC_CARETSTICKY_OFF=0
+val SC_CARETSTICKY_ON=1
+val SC_CARETSTICKY_WHITESPACE=2
 
 # Switch between sticky and non-sticky: meant to be bound to a key.
 fun void ToggleCaretSticky=2459(,)
diff --git a/src/Editor.cxx b/src/Editor.cxx
index ecac75118..6119944c3 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -94,6 +94,15 @@ static inline bool IsControlCharacter(int ch) {
 	return ch >= 0 && ch < ' ';
 }
 
+static inline bool IsAllSpacesOrTabs(char *s, unsigned int len) {
+	for (unsigned int i = 0; i < len; i++) {
+		// This is safe because IsSpaceOrTab() will return false for null terminators
+		if (!IsSpaceOrTab(s[i]))
+			return false;
+	}
+	return true;
+}
+
 Editor::Editor() {
 	ctrlID = 0;
 
@@ -148,7 +157,7 @@ Editor::Editor() {
 	lineWidthMaxSeen = 0;
 	verticalScrollBarVisible = true;
 	endAtLastLine = true;
-	caretSticky = false;
+	caretSticky = SC_CARETSTICKY_OFF;
 	multipleSelection = false;
 	additionalSelectionTyping = false;
 	multiPasteMode = SC_MULTIPASTE_ONCE;
@@ -3813,7 +3822,8 @@ void Editor::AddCharUTF(char *s, unsigned int len, bool treatAsDBCS) {
 	EnsureCaretVisible();
 	// Avoid blinking during rapid typing:
 	ShowCaretAtCurrentPosition();
-	if (!caretSticky) {
+	if ((caretSticky == SC_CARETSTICKY_OFF) ||
+		((caretSticky == SC_CARETSTICKY_WHITESPACE) && !IsAllSpacesOrTabs(s, len))) {
 		SetLastXChosen();
 	}
 
@@ -5072,21 +5082,21 @@ int Editor::KeyCommand(unsigned int iMessage) {
 		break;
 	case SCI_DELETEBACK:
 		DelCharBack(true);
-		if (!caretSticky) {
+		if ((caretSticky == SC_CARETSTICKY_OFF) || (caretSticky == SC_CARETSTICKY_WHITESPACE)) {
 			SetLastXChosen();
 		}
 		EnsureCaretVisible();
 		break;
 	case SCI_DELETEBACKNOTLINE:
 		DelCharBack(false);
-		if (!caretSticky) {
+		if ((caretSticky == SC_CARETSTICKY_OFF) || (caretSticky == SC_CARETSTICKY_WHITESPACE)) {
 			SetLastXChosen();
 		}
 		EnsureCaretVisible();
 		break;
 	case SCI_TAB:
 		Indent(true);
-		if (!caretSticky) {
+		if (caretSticky == SC_CARETSTICKY_OFF) {
 			SetLastXChosen();
 		}
 		EnsureCaretVisible();
@@ -5094,7 +5104,7 @@ int Editor::KeyCommand(unsigned int iMessage) {
 		break;
 	case SCI_BACKTAB:
 		Indent(false);
-		if (!caretSticky) {
+		if ((caretSticky == SC_CARETSTICKY_OFF) || (caretSticky == SC_CARETSTICKY_WHITESPACE)) {
 			SetLastXChosen();
 		}
 		EnsureCaretVisible();
@@ -6720,7 +6730,7 @@ sptr_t Editor::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam) {
 
 	case SCI_PASTE:
 		Paste();
-		if (!caretSticky) {
+		if ((caretSticky == SC_CARETSTICKY_OFF) || (caretSticky == SC_CARETSTICKY_WHITESPACE)) {
 			SetLastXChosen();
 		}
 		EnsureCaretVisible();
@@ -7475,9 +7485,9 @@ sptr_t Editor::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam) {
 		return endAtLastLine;
 
 	case SCI_SETCARETSTICKY:
-		PLATFORM_ASSERT((wParam == 0) || (wParam == 1));
-		if (caretSticky != (wParam != 0)) {
-			caretSticky = wParam != 0;
+		PLATFORM_ASSERT((wParam >= SC_CARETSTICKY_OFF) && (wParam <= SC_CARETSTICKY_WHITESPACE));
+		if ((wParam >= SC_CARETSTICKY_OFF) && (wParam <= SC_CARETSTICKY_WHITESPACE)) {
+			caretSticky = wParam;
 		}
 		break;
 
diff --git a/src/Editor.h b/src/Editor.h
index 54411fad5..e7aa2e6ce 100644
--- a/src/Editor.h
+++ b/src/Editor.h
@@ -159,7 +159,7 @@ protected:	// ScintillaBase subclass needs access to much of Editor
 	int lineWidthMaxSeen;
 	bool verticalScrollBarVisible;
 	bool endAtLastLine;
-	bool caretSticky;
+	int caretSticky;
 	bool multipleSelection;
 	bool additionalSelectionTyping;
 	int multiPasteMode;