Start of bidirectional code - implement SCI_SETBIDIRECTIONAL.

7 files changed, 65 insertions, 5 deletions

diff --git a/doc/ScintillaDoc.html b/doc/ScintillaDoc.html
index 90c5745e2..1e71bafbd 100644
--- a/doc/ScintillaDoc.html
+++ b/doc/ScintillaDoc.html
@@ -119,7 +119,7 @@
 
     <h1>Scintilla Documentation</h1>
 
-    <p>Last edited 11 August 2017 NH</p>
+    <p>Last edited 10 January 2018 NH</p>
 
     <p>There is <a class="jump" href="Design.html">an overview of the internal design of
     Scintilla</a>.<br />
@@ -3594,6 +3594,10 @@ struct Sci_TextToFind {
      <a class="message" href="#SCI_GETCODEPAGE">SCI_GETCODEPAGE &rarr; int</a><br />
      <a class="message" href="#SCI_SETIMEINTERACTION">SCI_SETIMEINTERACTION(int imeInteraction)</a><br />
      <a class="message" href="#SCI_GETIMEINTERACTION">SCI_GETIMEINTERACTION &rarr; int</a><br />
+<div  class="provisional">
+     <a class="message" href="#SCI_SETBIDIRECTIONAL"><span class="provisional">SCI_SETBIDIRECTIONAL(int bidirectional)</span></a><br />
+     <a class="message" href="#SCI_GETBIDIRECTIONAL">SCI_GETBIDIRECTIONAL &rarr; int</a><br />
+</div>
      <a class="message" href="#SCI_GRABFOCUS">SCI_GRABFOCUS</a><br />
      <a class="message" href="#SCI_SETFOCUS">SCI_SETFOCUS(bool focus)</a><br />
      <a class="message" href="#SCI_GETFOCUS">SCI_GETFOCUS &rarr; bool</a><br />
@@ -3718,6 +3722,27 @@ struct Sci_TextToFind {
      and the inline behaviour with <code>SCI_SETIMEINTERACTION(SC_IME_INLINE)</code>.
      Scintilla may ignore this call in some cases. For example, the inline behaviour might only be supported for some languages.</p>
 
+<div  class="provisional">
+    <a href="#ProvisionalMessages">These bidirectional features are not yet implemented and the API is provisional</a><br />
+    <p><b id="SCI_SETBIDIRECTIONAL">SCI_SETBIDIRECTIONAL(int bidirectional)</b><br />
+     <b id="SCI_GETBIDIRECTIONAL">SCI_GETBIDIRECTIONAL &rarr; int</b><br />
+     Some languages, like Arabic and Hebrew, are written from right to left instead of from left to right as English is.
+     Documents that use multiple languages may contain both directions and this is termed "bidirectional".
+     The default text direction may be right to left or left to right.
+     Scintilla only correctly displays bidirectional text on some platforms and there can be additional processing and storage
+     costs to this.
+     Currently, bidirectional text only works on Win32 using DirectWrite.
+     As some applications may not want to pay the costs, bidirectional support must be explicitly enabled by calling
+     <code>SCI_SETBIDIRECTIONAL(SC_BIDIRECTIONAL_L2R)</code> (1) which chooses left to right as the default direction or
+     <code>SCI_SETBIDIRECTIONAL(SC_BIDIRECTIONAL_R2L)</code> (2) for default right to left.
+     This should be done after setting the technology to <code>SC_TECHNOLOGY_DIRECTWRITE</code>,
+     <code>SC_TECHNOLOGY_DIRECTWRITERETAIN</code>, or
+     <code>SC_TECHNOLOGY_DIRECTWRITEDC</code>.</p>
+     <p>If the call succeeded <code>SCI_GETBIDIRECTIONAL</code> will return the same value otherwise
+     <code>SC_BIDIRECTIONAL_DISABLED</code> (0) is returned.
+     </p>
+</div>
+
     <p><b id="SCI_GRABFOCUS">SCI_GRABFOCUS</b><br />
      <b id="SCI_SETFOCUS">SCI_SETFOCUS(bool focus)</b><br />
      <b id="SCI_GETFOCUS">SCI_GETFOCUS &rarr; bool</b><br />
@@ -8073,8 +8098,6 @@ for line = lineStart to lineEnd do SCI_ENSUREVISIBLE(line) next
 
     <p>Provisional features are displayed in this document with <span class="provisional">a distinctive background colour</span>.</p>
 
-    <p>There are currently no provisional messages or values.</p>
-
     <p>Some developers may want to only use features that are stable and have graduated from
     provisional status. To avoid using provisional messages compile with the symbol
     <code>SCI_DISABLE_PROVISIONAL</code> defined.</p>
diff --git a/include/Scintilla.h b/include/Scintilla.h
index 25649302e..74ec5b91a 100644
--- a/include/Scintilla.h
+++ b/include/Scintilla.h
@@ -1103,6 +1103,13 @@ typedef sptr_t (*SciFnDirect)(sptr_t ptr, unsigned int iMessage, uptr_t wParam,
 #define SCN_AUTOCCOMPLETED 2030
 #define SCN_MARGINRIGHTCLICK 2031
 #define SCN_AUTOCSELECTIONCHANGE 2032
+#ifndef SCI_DISABLE_PROVISIONAL
+#define SC_BIDIRECTIONAL_DISABLED 0
+#define SC_BIDIRECTIONAL_L2R 1
+#define SC_BIDIRECTIONAL_R2L 2
+#define SCI_GETBIDIRECTIONAL 2708
+#define SCI_SETBIDIRECTIONAL 2709
+#endif
 /* --Autogenerated -- end of section automatically generated from Scintilla.iface */
 
 /* These structures are defined to be exactly the same shape as the Win32
diff --git a/include/Scintilla.iface b/include/Scintilla.iface
index 04de613a5..bb00ed634 100644
--- a/include/Scintilla.iface
+++ b/include/Scintilla.iface
@@ -4861,10 +4861,19 @@ evt void AutoCCompleted=2030(string text, int position, int ch, CompletionMethod
 evt void MarginRightClick=2031(int modifiers, int position, int margin)
 evt void AutoCSelectionChange=2032(int listType, string text, int position)
 
-# There are no provisional APIs currently.
-
 cat Provisional
 
+enu Bidirectional=SC_BIDIRECTIONAL_
+val SC_BIDIRECTIONAL_DISABLED=0
+val SC_BIDIRECTIONAL_L2R=1
+val SC_BIDIRECTIONAL_R2L=2
+
+# Retrieve bidirectional text display state.
+get int GetBidirectional=2708(,)
+
+# Set bidirectional text display state.
+set void SetBidirectional=2709(int bidirectional,)
+
 cat Deprecated
 
 # Divide each styling byte into lexical class bits (default: 5) and indicator
diff --git a/src/EditModel.cxx b/src/EditModel.cxx
index 7dfd90e37..0e00bcfe0 100644
--- a/src/EditModel.cxx
+++ b/src/EditModel.cxx
@@ -63,6 +63,7 @@ EditModel::EditModel() {
 	highlightGuideColumn = 0;
 	primarySelection = true;
 	imeInteraction = imeWindowed;
+	bidirectional = Bidirectional::bidiDisabled;
 	foldFlags = 0;
 	foldDisplayTextStyle = SC_FOLDDISPLAYTEXT_HIDDEN;
 	hotspot = Range(Sci::invalidPosition);
diff --git a/src/EditModel.h b/src/EditModel.h
index 773309d45..6e4919bd5 100644
--- a/src/EditModel.h
+++ b/src/EditModel.h
@@ -38,6 +38,8 @@ public:
 
 	enum IMEInteraction { imeWindowed, imeInline } imeInteraction;
 
+	enum class Bidirectional { bidiDisabled, bidiL2R, bidiR2L  } bidirectional;
+
 	int foldFlags;
 	int foldDisplayTextStyle;
 	ContractionState cs;
diff --git a/src/Editor.cxx b/src/Editor.cxx
index d45a8684c..36af34685 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -6736,6 +6736,13 @@ sptr_t Editor::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam) {
 	case SCI_GETIMEINTERACTION:
 		return imeInteraction;
 
+	case SCI_SETBIDIRECTIONAL:
+		// SCI_SETBIDIRECTIONAL is implemented on platform subclasses if they support bidirectional text.
+		break;
+
+	case SCI_GETBIDIRECTIONAL:
+		return static_cast<sptr_t>(bidirectional);
+
 		// Marker definition and setting
 	case SCI_MARKERDEFINE:
 		if (wParam <= MARKER_MAX) {
diff --git a/win32/ScintillaWin.cxx b/win32/ScintillaWin.cxx
index 2d2fc266c..45b091546 100644
--- a/win32/ScintillaWin.cxx
+++ b/win32/ScintillaWin.cxx
@@ -1744,6 +1744,17 @@ sptr_t ScintillaWin::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam
 			}
 			break;
 
+		case SCI_SETBIDIRECTIONAL:
+			if (technology == SC_TECHNOLOGY_DEFAULT) {
+				bidirectional = EditModel::Bidirectional::bidiDisabled;
+			} else if ((wParam >= SC_BIDIRECTIONAL_DISABLED) && (wParam <= SC_BIDIRECTIONAL_R2L)) {
+				bidirectional = static_cast<EditModel::Bidirectional>(wParam);
+			}
+			// Invalidate all cached information including layout.
+			DropGraphics(true);
+			InvalidateStyleRedraw();
+			break;
+
 #ifdef SCI_LEXER
 		case SCI_LOADLEXERLIBRARY:
 			LexerManager::GetInstance()->Load(reinterpret_cast<const char *>(lParam));