BFont: allow skipping fallbacks in GetHasGlyphs

Change-Id: I5a68008d25cce34596fb5ce6fb07259ae56c3a3d
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7829
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: Adrien Destugues <[email protected]>
Haiku-Format: Haiku-format Bot <[email protected]>

docs/user/interface/Font.dox

@@ -1740,12 +1740,18 @@
 /*!
 	\fn void BFont::GetHasGlyphs(const char charArray[], int32 numChars,
 		bool hasArray[]) const
-	\brief Fills out \a hasArray with whether or not each characters in
+	\brief Fills out \a hasArray with whether or not the font has a glyph
-		\a charArray has a glyph for the font.
+		for each character in \a charArray.
 
-	\c true is written in \a hasArray if the character has a glyph in the
+	\c true is written in \a hasArray if a glyph is found for the character,
-	current font and \c false is written in \a hasArray if the character
+	\c false otherwise.
-	does NOT have a glyph in the current font.
+
+	\remark After the introduction of fallback fonts for missing glyphs,
+	this is not exaclty what the name or the original desciption imply. As
+	the objective of this method is to know if a string can be presented
+	to the user without getting "no glyph" symbols, it will still write
+	\c true if the queried font does not provide a glyph for a character
+	but a fallback font does.
 
 	\param charArray The source character array.
 	\param numChars The number of characters to consider in \a charArray.
@@ -1755,6 +1761,25 @@
 */
 
 
+/*!
+	\fn void BFont::GetHasGlyphs(const char charArray[], int32 numChars,
+		bool hasArray[], bool useFallbacks) const
+	\brief Fills out \a hasArray with whether or not the font has a glyph
+		for each character in \a charArray.
+
+	\c true is written in \a hasArray if the character has a glyph in the
+	current font and \c false otherwise. Fallback fonts are also considered
+	in the search if \a useFallbacks is \c true.
+
+	\param charArray The source character array.
+	\param numChars The number of characters to consider in \a charArray.
+	\param hasArray The destination array of booleans.
+	\param useFallbacks Whether to consider fallback fonts in the answer.
+
+	\since Haiku R1
+*/
+
+
 /*!
 	\fn BFont& BFont::operator=(const BFont &font)
 	\brief Assignment overload method.

headers/os/interface/Font.h

@@ -275,6 +275,8 @@ public:
 			void				GetHasGlyphs(const char charArray[],
 									int32 numChars,
 									bool hasArray[]) const;
+			void				GetHasGlyphs(const char charArray[], int32 numChars,
+									bool hasArray[], bool useFallbacks) const;
 
 			BFont&				operator=(const BFont& font);
 			bool				operator==(const BFont& font) const;

src/kits/interface/Font.cpp

@@ -1345,6 +1345,14 @@ BFont::GetGlyphShapes(const char charArray[], int32 numChars,
 void
 BFont::GetHasGlyphs(const char charArray[], int32 numChars,
 	bool hasArray[]) const
+{
+	GetHasGlyphs(charArray, numChars, hasArray, true);
+}
+
+
+void
+BFont::GetHasGlyphs(const char charArray[], int32 numChars, bool hasArray[],
+	bool useFallbacks) const
 {
 	if (!charArray || numChars < 1 || !hasArray)
 		return;
@@ -1361,6 +1369,8 @@ BFont::GetHasGlyphs(const char charArray[], int32 numChars,
 	link.Attach<int32>(bytesInBuffer);
 	link.Attach(charArray, bytesInBuffer);
 
+	link.Attach<bool>(useFallbacks);
+
 	if (link.FlushWithReply(code) != B_OK || code != B_OK)
 		return;
 

src/servers/app/ServerApp.cpp

@@ -2487,6 +2487,7 @@ ServerApp::_DispatchMessage(int32 code, BPrivate::LinkReceiver& link)
 			// 3) int32 - numChars
 			// 4) int32 - numBytes
 			// 5) char - the char buffer with size numBytes
+			// 6) bool - whether to try fallback fonts
 
 			uint16 familyID, styleID;
 			link.Read<uint16>(&familyID);
@@ -2506,13 +2507,15 @@ ServerApp::_DispatchMessage(int32 code, BPrivate::LinkReceiver& link)
 
 			link.Read(charArray, numBytes);
 
+			bool useFallbacks;
+			link.Read<bool>(&useFallbacks);
+
 			ServerFont font;
 			status_t status = font.SetFamilyAndStyle(familyID, styleID,
 				fAppFontManager);
 
 			if (status == B_OK) {
-				status = font.GetHasGlyphs(charArray, numBytes, numChars,
+				status = font.GetHasGlyphs(charArray, numBytes, numChars, hasArray, useFallbacks);
-					hasArray);
 				if (status == B_OK) {
 					fLink.StartMessage(B_OK);
 					fLink.Attach(hasArray, numChars * sizeof(bool));

src/servers/app/ServerFont.cpp

@@ -692,8 +692,8 @@ ServerFont::IncludesUnicodeBlock(uint32 start, uint32 end, bool& hasBlock)
 
 
 status_t
-ServerFont::GetHasGlyphs(const char* string, int32 numBytes, int32 numChars,
+ServerFont::GetHasGlyphs(const char* string, int32 numBytes, int32 numChars, bool* hasArray,
-	bool* hasArray) const
+	bool useFallbacks) const
 {
 	if (string == NULL || numBytes <= 0 || numChars <= 0 || hasArray == NULL)
 		return B_BAD_DATA;
@@ -714,7 +714,7 @@ ServerFont::GetHasGlyphs(const char* string, int32 numBytes, int32 numChars,
 	while (charIndex < numChars && (charCode = UTF8ToCharCode(&string)) != 0) {
 		hasArray[charIndex] = entry->CanCreateGlyph(charCode);
 
-		if (hasArray[charIndex] == false) {
+		if (hasArray[charIndex] == false && useFallbacks) {
 			if (fallbacks.IsEmpty())
 				GlyphLayoutEngine::PopulateFallbacks(fallbacks, *this, false);
 

src/servers/app/ServerFont.h

@@ -123,7 +123,7 @@ class ServerFont {
 
 			status_t			GetHasGlyphs(const char charArray[],
 									int32 numBytes, int32 numChars,
-									bool hasArray[]) const;
+									bool hasArray[], bool useFallbacks) const;
 
 			status_t			GetEdges(const char charArray[], int32 numBytes,
 									int32 numChars, edge_info edgeArray[])