Codechange: Move GetCharPosInString/GetCharAtPosition to gfx_layout.

These functions are related more to layouting than graphics.

src/gfx.cpp

@@ -895,39 +895,6 @@ Dimension GetStringListBoundingBox(std::span<const StringID> list, FontSize font
 	return d;
 }
 
-/**
- * Get the leading corner of a character in a single-line string relative
- * to the start of the string.
- * @param str String containing the character.
- * @param ch Pointer to the character in the string.
- * @param start_fontsize Font size to start the text with.
- * @return Upper left corner of the glyph associated with the character.
- */
-Point GetCharPosInString(std::string_view str, const char *ch, FontSize start_fontsize)
-{
-	/* Ensure "ch" is inside "str" or at the exact end. */
-	assert(ch >= str.data() && (ch - str.data()) <= static_cast<ptrdiff_t>(str.size()));
-	auto it_ch = str.begin() + (ch - str.data());
-
-	Layouter layout(str, INT32_MAX, start_fontsize);
-	return layout.GetCharPosition(it_ch);
-}
-
-/**
- * Get the character from a string that is drawn at a specific position.
- * @param str String to test.
- * @param x Position relative to the start of the string.
- * @param start_fontsize Font size to start the text with.
- * @return Index of the character position or -1 if there is no character at the position.
- */
-ptrdiff_t GetCharAtPosition(std::string_view str, int x, FontSize start_fontsize)
-{
-	if (x < 0) return -1;
-
-	Layouter layout(str, INT32_MAX, start_fontsize);
-	return layout.GetCharAtPosition(x, 0);
-}
-
 /**
  * Draw single character horizontally centered around (x,y)
  * @param c           Character (glyph) to draw