Adding text rendering flag to adjust spacing to fit horizontally

Now also works for multiline strings

Source/DiabloUI/ui_item.h

@@ -24,20 +24,21 @@ enum UiType : uint8_t {
 
 enum UiFlags : uint16_t {
 	// clang-format off
-	UIS_SMALL    = 1 << 0,
-	UIS_MED      = 1 << 1,
-	UIS_BIG      = 1 << 2,
-	UIS_HUGE     = 1 << 3,
-	UIS_CENTER   = 1 << 4,
-	UIS_RIGHT    = 1 << 5,
-	UIS_VCENTER  = 1 << 6,
-	UIS_SILVER   = 1 << 7,
-	UIS_GOLD     = 1 << 8,
-	UIS_RED      = 1 << 9,
-	UIS_BLUE     = 1 << 10,
-	UIS_BLACK    = 1 << 11,
-	UIS_DISABLED = 1 << 12,
-	UIS_HIDDEN   = 1 << 13,
+	UIS_SMALL       = 1 << 0,
+	UIS_MED         = 1 << 1,
+	UIS_BIG         = 1 << 2,
+	UIS_HUGE        = 1 << 3,
+	UIS_CENTER      = 1 << 4,
+	UIS_RIGHT       = 1 << 5,
+	UIS_VCENTER     = 1 << 6,
+	UIS_SILVER      = 1 << 7,
+	UIS_GOLD        = 1 << 8,
+	UIS_RED         = 1 << 9,
+	UIS_BLUE        = 1 << 10,
+	UIS_BLACK       = 1 << 11,
+	UIS_DISABLED    = 1 << 12,
+	UIS_HIDDEN      = 1 << 13,
+	UIS_FIT_SPACING = 1 << 14,
 	// clang-format on
 };
 

Source/control.cpp

@@ -1095,14 +1095,14 @@ static void PrintInfo(const CelOutputBuffer &out)
 	int yo = 0;
 	int lo = 1;
 	if (infostr[0] != '\0') {
-		DrawString(out, infostr, line, infoclr | UIS_CENTER, 2);
+		DrawString(out, infostr, line, infoclr | UIS_CENTER | UIS_FIT_SPACING, 2);
 		yo = 1;
 		lo = 0;
 	}
 
 	for (int i = 0; i < pnumlines; i++) {
 		line.y = PANEL_Y + LineOffsets[pnumlines - lo][i + yo];
-		DrawString(out, panelstr[i], line, infoclr | UIS_CENTER, 2);
+		DrawString(out, panelstr[i], line, infoclr | UIS_CENTER | UIS_FIT_SPACING, 2);
 	}
 }
 

Source/engine/render/text_render.cpp

@@ -194,12 +194,13 @@ void PrintChar(const CelOutputBuffer &out, int sx, int sy, int nCel, text_color
 	}
 }
 
-int GetLineWidth(const char *text, GameFontTables size, int spacing)
+int GetLineWidth(const char *text, GameFontTables size, int spacing, int *charactersInLine)
 {
 	int lineWidth = 0;
 
 	size_t textLength = strlen(text);
-	for (unsigned i = 0; i < textLength; i++) {
+	size_t i = 0;
+	for (; i < textLength; i++) {
 		if (text[i] == '\n')
 			break;
 
@@ -207,9 +208,23 @@ int GetLineWidth(const char *text, GameFontTables size, int spacing)
 		lineWidth += fontkern[size][frame] + spacing;
 	}
 
+	if (charactersInLine != nullptr)
+		*charactersInLine = i;
+
 	return lineWidth != 0 ? (lineWidth - spacing) : 0;
 }
 
+int AdjustSpacingToFitHorizontally(int &lineWidth, int maxSpacing, int charactersInLine, int availableWidth)
+{
+	if (lineWidth <= availableWidth || charactersInLine < 2)
+		return maxSpacing;
+
+	const int overhang = lineWidth - availableWidth;
+	const int spacingRedux = (overhang + charactersInLine - 2) / (charactersInLine - 1);
+	lineWidth -= spacingRedux * (charactersInLine - 1);
+	return maxSpacing - spacingRedux;
+}
+
 void WordWrapGameString(char *text, size_t width, size_t size, int spacing)
 {
 	const size_t textLength = strlen(text);
@@ -272,28 +287,44 @@ void DrawString(const CelOutputBuffer &out, const char *text, const SDL_Rect &re
 		color = COL_BLACK;
 
 	const int w = rect.w != 0 ? rect.w : out.w() - rect.x;
-	const int h = rect.h != 0 ? rect.h : out.h() - rect.x;
+	const int h = rect.h != 0 ? rect.h : out.h() - rect.y;
+
+	const size_t textLength = strlen(text);
+
+	int charactersInLine = 0;
+	int lineWidth = 0;
+	if ((flags & (UIS_CENTER | UIS_RIGHT | UIS_FIT_SPACING)) != 0)
+		lineWidth = GetLineWidth(text, size, spacing, &charactersInLine);
+
+	int maxSpacing = spacing;
+	if ((flags & UIS_FIT_SPACING) != 0)
+		spacing = AdjustSpacingToFitHorizontally(lineWidth, maxSpacing, charactersInLine, rect.w);
 
 	int sx = rect.x;
 	if ((flags & UIS_CENTER) != 0)
-		sx += (w - GetLineWidth(text, size, spacing)) / 2;
+		sx += (w - lineWidth) / 2;
 	else if ((flags & UIS_RIGHT) != 0)
-		sx += w - GetLineWidth(text, size, spacing);
+		sx += w - lineWidth;
 	int sy = rect.y;
 
 	int rightMargin = rect.x + w;
 	int bottomMargin = rect.y + h;
 
-	const size_t textLength = strlen(text);
 	for (unsigned i = 0; i < textLength; i++) {
 		uint8_t frame = fontframe[size][gbFontTransTbl[static_cast<uint8_t>(text[i])]];
-		int symbolWidth = fontkern[size][frame] + spacing;
-		if (text[i] == '\n' || sx + symbolWidth - spacing > rightMargin) {
+		int symbolWidth = fontkern[size][frame];
+		if (text[i] == '\n' || sx + symbolWidth > rightMargin) {
+			if ((flags & (UIS_CENTER | UIS_RIGHT | UIS_FIT_SPACING)) != 0)
+				lineWidth = GetLineWidth(&text[i + 1], size, spacing, &charactersInLine);
+
+			if ((flags & UIS_FIT_SPACING) != 0)
+				spacing = AdjustSpacingToFitHorizontally(lineWidth, maxSpacing, charactersInLine, rect.w);
+
 			sx = rect.x;
 			if ((flags & UIS_CENTER) != 0)
-				sx += (w - GetLineWidth(&text[i + 1], size)) / 2;
+				sx += (w - lineWidth) / 2;
 			else if ((flags & UIS_RIGHT) != 0)
-				sx += w - GetLineWidth(&text[i + 1], size, spacing);
+				sx += w - lineWidth;
 			sy += LineHeights[size];
 			if (sy > bottomMargin)
 				return;
@@ -302,7 +333,7 @@ void DrawString(const CelOutputBuffer &out, const char *text, const SDL_Rect &re
 			PrintChar(out, sx, sy, frame, color);
 		}
 		if (text[i] != '\n')
-			sx += symbolWidth;
+			sx += symbolWidth + spacing;
 	}
 	if (drawTextCursor) {
 		CelDrawTo(out, sx, sy, *pSPentSpn2Cels, PentSpn2Spin());

Source/engine/render/text_render.hpp

@@ -50,7 +50,16 @@ void FreeText();
  * @param col text_color color value
  */
 void PrintChar(const CelOutputBuffer &out, int sx, int sy, int nCel, text_color col);
-int GetLineWidth(const char *text, GameFontTables size = GameFontSmall, int spacing = 1);
+
+/**
+ * @brief Calculate pixel width of first line of text, respecting kerning
+ * @param text Text to check, will read until first eol or terminator
+ * @param size Font size to use
+ * @param spacing Extra spacing to add per character
+ * @param charactersInLine Receives characters read until newline or terminator
+ * @return Line width in pixels
+ */
+int GetLineWidth(const char *text, GameFontTables size = GameFontSmall, int spacing = 1, int *charactersInLine = nullptr);
 void WordWrapGameString(char *text, size_t width, size_t size = GameFontSmall, int spacing = 1);
 void DrawString(const CelOutputBuffer &out, const char *text, const SDL_Rect &rect, uint16_t flags = 0, int spacing = 1, bool drawTextCursor = false);
 int PentSpn2Spin();