Handle infite maximum line widths more safely

Include/RmlUi/Core/ElementText.h

@@ -57,7 +57,7 @@ public:
 	/// line.size()!
 	/// @param[out] line_width The width (in pixels) of the generated line.
 	/// @param[in] line_begin The index of the first character to be rendered in the line.
-	/// @param[in] maximum_line_width The width (in pixels) of space allowed for the line, or -1 for unlimited space.
+	/// @param[in] maximum_line_width The width (in pixels) of space allowed for the line, or infinite for unlimited space.
 	/// @param[in] right_spacing_width The width (in pixels) of the spacing (consisting of margins, padding, etc.) that must be remaining on the right
 	/// of the line if the last of the text is rendered onto this line.
 	/// @param[in] trim_whitespace_prefix If we're collapsing whitespace, true to remove all prefixing whitespace, or false to collapse it down to a
@@ -89,7 +89,7 @@ public:
 	using LineList = Vector<Line>;
 
 	// Returns the current list of lines.
-	const LineList &GetLines() const { return lines; }
+	const LineList& GetLines() const { return lines; }
 
 protected:
 	void OnRender() override;

Source/Core/ElementText.cpp

@@ -42,6 +42,7 @@
 #include "ElementDefinition.h"
 #include "ElementStyle.h"
 #include "TransformState.h"
+#include <limits>
 
 namespace Rml {
 
@@ -49,6 +50,17 @@ static bool BuildToken(String& token, const char*& token_begin, const char* stri
 	bool break_at_endline, Style::TextTransform text_transformation, bool decode_escape_characters);
 static bool LastToken(const char* token_begin, const char* string_end, bool collapse_white_space, bool break_at_endline);
 
+static int RoundDownToIntegerClamped(float value)
+{
+	constexpr int clamp = (1 << std::numeric_limits<float>::digits);
+	constexpr float clamp_f = float{clamp};
+	if (value >= clamp_f)
+		return clamp;
+	if (value <= -clamp_f)
+		return -clamp;
+	return static_cast<int>(value);
+}
+
 void LogMissingFontFace(Element* element)
 {
 	const String font_family_property = element->GetProperty<String>("font-family");
@@ -184,8 +196,7 @@ bool ElementText::GenerateLine(String& line, int& line_length, float& line_width
 	bool trim_whitespace_prefix, bool decode_escape_characters, bool allow_empty)
 {
 	RMLUI_ZoneScoped;
-	RMLUI_ASSERT(
-		maximum_line_width >= 0.f); // TODO: Check all callers for conformance, check break at line condition below. Possibly check for FLT_MAX.
+	RMLUI_ASSERT(maximum_line_width >= 0.f);
 
 	FontFaceHandle font_face_handle = GetFontFaceHandle();
 
@@ -204,13 +215,13 @@ bool ElementText::GenerateLine(String& line, int& line_length, float& line_width
 	// Determine how we are processing white-space while formatting the text.
 	using namespace Style;
 	const auto& computed = GetComputedValues();
-	WhiteSpace white_space_property = computed.white_space();
-	bool collapse_white_space =
-		white_space_property == WhiteSpace::Normal || white_space_property == WhiteSpace::Nowrap || white_space_property == WhiteSpace::Preline;
-	bool break_at_line = (maximum_line_width >= 0) &&
+	const WhiteSpace white_space_property = computed.white_space();
+	const bool collapse_white_space =
+		(white_space_property == WhiteSpace::Normal || white_space_property == WhiteSpace::Nowrap || white_space_property == WhiteSpace::Preline);
+	const bool break_at_line =
 		(white_space_property == WhiteSpace::Normal || white_space_property == WhiteSpace::Prewrap || white_space_property == WhiteSpace::Preline);
-	bool break_at_endline =
-		white_space_property == WhiteSpace::Pre || white_space_property == WhiteSpace::Prewrap || white_space_property == WhiteSpace::Preline;
+	const bool break_at_endline =
+		(white_space_property == WhiteSpace::Pre || white_space_property == WhiteSpace::Prewrap || white_space_property == WhiteSpace::Preline);
 
 	const TextShapingContext text_shaping_context{computed.language(), computed.direction(), computed.font_kerning(), computed.letter_spacing()};
 	TextTransform text_transform_property = computed.text_transform();
@@ -241,14 +252,14 @@ bool ElementText::GenerateLine(String& line, int& line_length, float& line_width
 		if (break_at_line)
 		{
 			const bool is_last_token = LastToken(next_token_begin, string_end, collapse_white_space, break_at_endline);
-			int max_token_width = int(maximum_line_width - (is_last_token ? line_width + right_spacing_width : line_width));
+			int max_token_width = RoundDownToIntegerClamped(maximum_line_width - (is_last_token ? line_width + right_spacing_width : line_width));
 
 			if (token_width > max_token_width)
 			{
 				if (word_break == WordBreak::BreakAll || (word_break == WordBreak::BreakWord && line.empty()))
 				{
 					// Try to break up the word
-					max_token_width = int(maximum_line_width - line_width);
+					max_token_width = RoundDownToIntegerClamped(maximum_line_width - line_width);
 					const int token_max_size = int(next_token_begin - token_begin);
 					const char* partial_string_end = token_begin + token_max_size;
 

Source/Core/Elements/WidgetTextInput.cpp

@@ -1263,7 +1263,8 @@ Vector2f WidgetTextInput::FormatText(float height_constraint)
 	// Keep generating lines until all the text content is placed.
 	do
 	{
-		if (available_width <= 0.f)
+		const float maximum_line_width = available_width - cursor_size.x;
+		if (maximum_line_width <= 0.f)
 		{
 			lines.push_back(Line{});
 			break;
@@ -1275,8 +1276,7 @@ Vector2f WidgetTextInput::FormatText(float height_constraint)
 		String line_content;
 
 		// Generate the next line.
-		last_line =
-			text_element->GenerateLine(line_content, line.size, line_width, line_begin, available_width - cursor_size.x, 0, false, false, false);
+		last_line = text_element->GenerateLine(line_content, line.size, line_width, line_begin, maximum_line_width, 0, false, false, false);
 
 		// Check if the editable length needs to be truncated to dodge a trailing endline.
 		line.editable_length = (int)line_content.size();