Implement get_string_width function (#509)

* Implement get_string_width function

  uint16_t get_string_width(const char* buffer);

* Use readCodePoint to parse the string

* Fix formatting issue

* reverting back changes with readCodePoint

* Remove unicode.h

* Addressed review comments

* Added const definition

Co-authored-by: Duncan <duncans_pumpkin@hotmail.co.uk>

src/openloco/graphics/gfx.cpp

@@ -182,12 +182,87 @@ namespace openloco::gfx
      * @param buffer @<esi>
      * @return width @<cx>
      */
-    uint16_t get_string_width(const char* buffer)
+    uint16_t getStringWidth(const char* buffer)
     {
-        registers regs;
-        regs.esi = (uintptr_t)buffer;
-        call(0x495685, regs);
-        return regs.cx;
+        uint16_t width = 0;
+        const uint8_t* str = reinterpret_cast<const uint8_t*>(buffer);
+        int16_t fontSpriteBase = _currentFontSpriteBase;
+
+        while (*str != (uint8_t)0)
+        {
+            const uint8_t chr = *str;
+            str++;
+
+            if (chr >= 32)
+            {
+                width += _characterWidths[chr - 32 + fontSpriteBase];
+                continue;
+            }
+
+            switch (chr)
+            {
+                case control_codes::move_x:
+                    width = *str;
+                    str++;
+                    break;
+
+                case control_codes::adjust_palette:
+                case 3:
+                case 4:
+                    str++;
+                    break;
+
+                case control_codes::newline:
+                case control_codes::newline_smaller:
+                    continue;
+
+                case control_codes::font_small:
+                    fontSpriteBase = font::small;
+                    break;
+
+                case control_codes::font_large:
+                    fontSpriteBase = font::large;
+                    break;
+
+                case control_codes::font_bold:
+                    fontSpriteBase = font::medium_bold;
+                    break;
+
+                case control_codes::font_regular:
+                    fontSpriteBase = font::medium_normal;
+                    break;
+
+                case control_codes::outline:
+                case control_codes::outline_off:
+                case control_codes::window_colour_1:
+                case control_codes::window_colour_2:
+                case control_codes::window_colour_3:
+                case 0x10:
+                    break;
+
+                case control_codes::inline_sprite_str:
+                {
+                    const uint32_t image = reinterpret_cast<const uint32_t*>(str)[0];
+                    const uint32_t imageId = image & 0x7FFFF;
+                    str += 4;
+                    width += _g1Elements[imageId].width;
+                    break;
+                }
+
+                default:
+                    if (chr <= 0x16)
+                    {
+                        str += 2;
+                    }
+                    else
+                    {
+                        str += 4;
+                    }
+                    break;
+            }
+        }
+
+        return width;
     }
 
     static void setTextColours(palette_index_t pal1, palette_index_t pal2, palette_index_t pal3)

src/openloco/graphics/gfx.h

@@ -74,7 +74,7 @@ namespace openloco::gfx
     void clear_single(drawpixelinfo_t& dpi, uint8_t paletteId);
 
     int16_t clip_string(int16_t width, char* string);
-    uint16_t get_string_width(const char* buffer);
+    uint16_t getStringWidth(const char* buffer);
 
     gfx::point_t draw_string(drawpixelinfo_t* context, int16_t x, int16_t y, uint8_t colour, void* str);
 

src/openloco/ui/WindowManager.cpp

@@ -200,6 +200,18 @@ namespace openloco::ui::WindowManager
                 return 0;
             });
 
+        register_hook(
+            0x00495685,
+            [](registers& regs) FORCE_ALIGN_ARG_POINTER -> uint8_t {
+                registers backup = regs;
+                const char* buffer = (const char*)regs.esi;
+                uint16_t width = gfx::getStringWidth(buffer);
+                regs = backup;
+                regs.cx = width;
+
+                return 0;
+            });
+
         register_hook(
             0x00499B7E,
             [](registers& regs) FORCE_ALIGN_ARG_POINTER -> uint8_t {

src/openloco/windows/textinputwnd.cpp

@@ -413,8 +413,8 @@ namespace openloco::ui::textinput
         std::string cursorStr = _buffer.substr(0, cursor_position);
 
         _currentFontSpriteBase = font::medium_bold;
-        auto stringWidth = gfx::get_string_width(_buffer.data());
-        auto cursorX = gfx::get_string_width(cursorStr.data());
+        auto stringWidth = gfx::getStringWidth(_buffer.data());
+        auto cursorX = gfx::getStringWidth(cursorStr.data());
 
         int x = _xOffset + cursorX;
 
@@ -440,8 +440,8 @@ namespace openloco::ui::textinput
         std::string cursorStr = _buffer.substr(0, cursor_position);
 
         _currentFontSpriteBase = font::medium_bold;
-        auto stringWidth = gfx::get_string_width(_buffer.data());
-        auto cursorX = gfx::get_string_width(cursorStr.data());
+        auto stringWidth = gfx::getStringWidth(_buffer.data());
+        auto cursorX = gfx::getStringWidth(cursorStr.data());
 
         auto midX = containerWidth / 2;