Add support for font loading and rendering

examples/win32_gdi/CMakeLists.txt

@@ -7,3 +7,9 @@ add_executable(win32_gdi WIN32 main.c)
 
 target_compile_options(win32_gdi PUBLIC)
 target_include_directories(win32_gdi PUBLIC .)
+
+add_custom_command(
+        TARGET win32_gdi POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy_directory
+        ${CMAKE_CURRENT_SOURCE_DIR}/resources
+        ${CMAKE_CURRENT_BINARY_DIR}/resources)

examples/win32_gdi/main.c

@@ -25,6 +25,7 @@ void CenterWindow(HWND hWnd);
 
 long lastMsgTime = 0;
 bool ui_debug_mode;
+HFONT fonts[1];
 
 #define RECTWIDTH(rc)   ((rc).right - (rc).left)
 #define RECTHEIGHT(rc)  ((rc).bottom - (rc).top)
@@ -116,7 +117,7 @@ LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
     case WM_PAINT:
     {
         Clay_RenderCommandArray renderCommands = ClayVideoDemo_CreateLayout(&demo_data);
-        Clay_Win32_Render(hwnd, renderCommands);
+        Clay_Win32_Render(hwnd, renderCommands, fonts);
         break;
     }
 
@@ -154,7 +155,10 @@ int APIENTRY WinMain(
     uint64_t clayRequiredMemory = Clay_MinMemorySize();
     Clay_Arena clayMemory = Clay_CreateArenaWithCapacityAndMemory(clayRequiredMemory, malloc(clayRequiredMemory));
     Clay_Initialize(clayMemory, (Clay_Dimensions){.width = 800, .height = 600}, (Clay_ErrorHandler){HandleClayErrors}); // This final argument is new since the video was published
-    Clay_SetMeasureTextFunction(Clay_Win32_MeasureText, NULL); 
+
+    // Initialize clay fonts and text drawing
+    fonts[FONT_ID_BODY_16] = Clay_Win32_SimpleCreateFont("resources/Roboto-Regular.ttf", "Roboto", -11, FW_NORMAL);
+    Clay_SetMeasureTextFunction(Clay_Win32_MeasureText, fonts);
 
     ZeroMemory(&wc, sizeof wc);
     wc.hInstance = hInstance;

renderers/win32_gdi/clay_renderer_gdi.c

@@ -5,7 +5,7 @@ HDC renderer_hdcMem = {0};
 HBITMAP renderer_hbmMem = {0};
 HANDLE renderer_hOld = {0};
 
-void Clay_Win32_Render(HWND hwnd, Clay_RenderCommandArray renderCommands)
+void Clay_Win32_Render(HWND hwnd, Clay_RenderCommandArray renderCommands, HFONT* fonts)
 {
     bool is_clipping = false;
     HRGN clipping_region = {0};
@@ -48,10 +48,17 @@ void Clay_Win32_Render(HWND hwnd, Clay_RenderCommandArray renderCommands)
             r.right = boundingBox.x + boundingBox.width + r.right;
             r.bottom = boundingBox.y + boundingBox.height + r.bottom;
 
+            uint16_t font_id = renderCommand->renderData.text.fontId;
+            HFONT hFont = fonts[font_id];
+            HFONT hPrevFont = SelectObject(renderer_hdcMem, hFont);
+
+            // Actually draw text
             DrawTextA(renderer_hdcMem, renderCommand->renderData.text.stringContents.chars,
                       renderCommand->renderData.text.stringContents.length,
                       &r, DT_TOP | DT_LEFT);
 
+            SelectObject(renderer_hdcMem, hPrevFont);
+
             break;
         }
         case CLAY_RENDER_COMMAND_TYPE_RECTANGLE:
@@ -216,6 +223,37 @@ static inline Clay_Dimensions Clay_Win32_MeasureText(Clay_StringSlice text, Clay
 {
     Clay_Dimensions textSize = {0};
 
+    if (userData != NULL)
+    {
+        HFONT* fonts = (HFONT*)userData;
+        HFONT hFont = fonts[config->fontId];
+
+        if (hFont != NULL)
+        {
+            HDC hScreenDC = GetDC(HWND_DESKTOP);
+            HDC hTempDC = CreateCompatibleDC(hScreenDC);
+
+            if (hTempDC != NULL)
+            {
+                HFONT hPrevFont = SelectObject(hTempDC, hFont);
+
+                SIZE size;
+                GetTextExtentPoint32(hTempDC, text.chars, text.length, &size);
+
+                textSize.width = size.cx;
+                textSize.height = size.cy;
+
+                SelectObject(hScreenDC, hPrevFont);
+                DeleteDC(hTempDC);
+
+                return textSize;
+            }
+
+            ReleaseDC(HWND_DESKTOP, hScreenDC);
+        }
+    }
+
+    // Fallback for system bitmap font
     float maxTextWidth = 0.0f;
     float lineTextWidth = 0;
     float textHeight = WIN32_FONT_HEIGHT;
@@ -238,4 +276,46 @@ static inline Clay_Dimensions Clay_Win32_MeasureText(Clay_StringSlice text, Clay
     textSize.height = textHeight;
 
     return textSize;
-}
+}
+
+HFONT Clay_Win32_SimpleCreateFont(const char* filePath, const char* family, int height, int weight)
+{
+    // Add the font resource to the application instance
+    int fontAdded = AddFontResourceEx(filePath, FR_PRIVATE, NULL);
+    if (fontAdded == 0) {
+        return NULL;
+    }
+
+    int fontHeight = height;
+
+    // If negative, treat height as Pt rather than pixels
+    if (height < 0) {
+        // Get the screen DPI
+        HDC hScreenDC = GetDC(HWND_DESKTOP);
+        int iScreenDPI = GetDeviceCaps(hScreenDC, LOGPIXELSY);
+        ReleaseDC(HWND_DESKTOP, hScreenDC);
+
+        // Convert font height from points to pixels
+        fontHeight = MulDiv(height, iScreenDPI, 72);
+    }
+
+    // Create the font using the calculated height and the font name
+    HFONT hFont = CreateFont(
+        fontHeight,             // Height 
+        0,                      // Width (0 means default width)
+        0,                      // Escapement angle
+        0,                      // Orientation angle
+        weight,                 // Font weight
+        FALSE,                  // Italic
+        FALSE,                  // Underline
+        FALSE,                  // Strikeout
+        ANSI_CHARSET,           // Character set
+        OUT_DEFAULT_PRECIS,     // Output precision
+        CLIP_DEFAULT_PRECIS,    // Clipping precision
+        DEFAULT_QUALITY,        // Font quality
+        DEFAULT_PITCH,          // Pitch and family
+        family                  // Font name
+    );
+
+    return hFont;
+}