(svn r22627) -Codechange: Rename PrepareTextRefStackUsage() to StartTextRefStackUsage() to make it more obvious that you must call StopTextRefStackUsage() at some point. Also extent the documentation.

src/build_vehicle_gui.cpp

@@ -740,7 +740,7 @@ static uint ShowAdditionalText(int left, int right, int y, EngineID engine)
 
 	/* STR_BLACK_STRING is used to start the string with {BLACK} */
 	SetDParam(0, GetGRFStringID(GetEngineGRFID(engine), 0xD000 + callback));
-	PrepareTextRefStackUsage(0);
+	StartTextRefStackUsage(0);
 	uint result = DrawStringMultiLine(left, right, y, INT32_MAX, STR_BLACK_STRING);
 	StopTextRefStackUsage();
 	return result;

src/industry_gui.cpp

@@ -74,7 +74,7 @@ static void GetCargoSuffix(uint cargo, CargoSuffixType cst, const Industry *ind,
 	if (HasBit(indspec->callback_mask, CBM_IND_CARGO_SUFFIX)) {
 		uint16 callback = GetIndustryCallback(CBID_INDUSTRY_CARGO_SUFFIX, 0, (cst << 8) | cargo, const_cast<Industry *>(ind), ind_type, (cst != CST_FUND) ? ind->location.tile : INVALID_TILE);
 		if (GB(callback, 0, 8) != 0xFF) {
-			PrepareTextRefStackUsage(6);
+			StartTextRefStackUsage(6);
 			GetString(suffix, GetGRFStringID(indspec->grf_prop.grffile->grfid, 0xD000 + callback), suffix_last);
 			StopTextRefStackUsage();
 		}
@@ -458,7 +458,7 @@ public:
 					if (callback_res != CALLBACK_FAILED) {  // Did it fail?
 						str = GetGRFStringID(indsp->grf_prop.grffile->grfid, 0xD000 + callback_res);  // No. here's the new string
 						if (str != STR_UNDEFINED) {
-							PrepareTextRefStackUsage(6);
+							StartTextRefStackUsage(6);
 							DrawStringMultiLine(left, right, y, bottom, str);
 							StopTextRefStackUsage();
 						}
@@ -788,7 +788,7 @@ public:
 				if (message != STR_NULL && message != STR_UNDEFINED) {
 					y += WD_PAR_VSEP_WIDE;
 
-					PrepareTextRefStackUsage(6);
+					StartTextRefStackUsage(6);
 					/* Use all the available space left from where we stand up to the
 					 * end of the window. We ALSO enlarge the window if needed, so we
 					 * can 'go' wild with the bottom of the window. */

src/newgrf_industries.cpp

@@ -551,7 +551,7 @@ CommandCost CheckIfCallBackAllowsCreation(TileIndex tile, IndustryType type, uin
 
 	/* Copy some parameters from the registers to the error message text ref. stack */
 	SwitchToErrorRefStack();
-	PrepareTextRefStackUsage(4);
+	StartTextRefStackUsage(4);
 	SwitchToNormalRefStack();
 
 	switch (result) {

src/newgrf_industrytiles.cpp

@@ -310,7 +310,7 @@ CommandCost PerformIndustryTileSlopeCheck(TileIndex ind_base_tile, TileIndex ind
 
 	/* Copy some parameters from the registers to the error message text ref. stack */
 	SwitchToErrorRefStack();
-	PrepareTextRefStackUsage(4);
+	StartTextRefStackUsage(4);
 	SwitchToNormalRefStack();
 
 	switch (callback_res) {

src/newgrf_text.cpp

@@ -955,10 +955,22 @@ void RestoreTextRefStackBackup(struct TextRefStack *backup)
 }
 
 /**
- * Prepare the TTDP compatible string code parsing
+ * Start using the TTDP compatible string code parsing.
+ *
+ * On start a number of values is copied on the #TextRefStack.
+ * You can then use #GetString() and the normal string drawing functions,
+ * and they will use the #TextRefStack for NewGRF string codes.
+ *
+ * However, when you want to draw a string multiple times using the same stack,
+ * you have to call #RewindTextRefStack() between draws.
+ *
+ * After you are done with drawing, you must disable usage of the #TextRefStack
+ * by calling #StopTextRefStackUsage(), so NewGRF string codes operate on the
+ * normal string parameters again.
+ *
  * @param numEntries number of entries to copy from the registers
  */
-void PrepareTextRefStackUsage(byte numEntries)
+void StartTextRefStackUsage(byte numEntries)
 {
 	extern TemporaryStorageArray<int32, 0x110> _temp_store;
 

src/newgrf_text.h

@@ -34,7 +34,7 @@ void CleanUpGRFText(struct GRFText *grftext);
 
 bool CheckGrfLangID(byte lang_id, byte grf_version);
 
-void PrepareTextRefStackUsage(byte numEntries);
+void StartTextRefStackUsage(byte numEntries);
 void StopTextRefStackUsage();
 void SwitchToNormalRefStack();
 void SwitchToErrorRefStack();

src/object_gui.cpp

@@ -236,7 +236,7 @@ public:
 					if (callback_res != CALLBACK_FAILED) {
 						StringID message = GetGRFStringID(spec->grf_prop.grffile->grfid, 0xD000 + callback_res);
 						if (message != STR_NULL && message != STR_UNDEFINED) {
-							PrepareTextRefStackUsage(6);
+							StartTextRefStackUsage(6);
 							/* Use all the available space left from where we stand up to the
 							 * end of the window. We ALSO enlarge the window if needed, so we
 							 * can 'go' wild with the bottom of the window. */