Release measured glyphs and reuse text data

FreeType glyphs created during measurement were never released, and rendering copied text and cached metrics unnecessarily. Release the surviving glyph on success and failure, and borrow data for the duration of each call.

Author: TheNicker

FreeTypeWrapper/Source/FreeTypeConnector.cpp

@@ -101,20 +101,20 @@ namespace FreeType
         using namespace std;
         using namespace LLUtils;
 
-        const auto textCreateParams = measureParams.createParams;
-        const BitFlags<TextCreateFlags> createFlags{ textCreateParams.flags };
-        const bool useMetaText = createFlags.test(TextCreateFlags::UseMetaText);
+        const auto& textCreateParams = measureParams.createParams;
+        const BitFlags<TextCreateFlags> createFlags{textCreateParams.flags};
+        const bool useMetaText       = createFlags.test(TextCreateFlags::UseMetaText);
         const bool lineEndFixedWidth = createFlags.test(TextCreateFlags::LineEndFixedWidth);
-        const bool usebidiText = createFlags.test(TextCreateFlags::Bidirectional);
+        const bool usebidiText       = createFlags.test(TextCreateFlags::Bidirectional);
 
-        const string_type text = textCreateParams.text;
-        const string_type& fontPath = textCreateParams.fontPath;
-        const uint16_t fontSize = textCreateParams.fontSize;
-        const uint32_t OutlineWidth = textCreateParams.outlineWidth;
-        FT_Render_Mode textRenderMOde = FreeTypeRenderer::GetRenderMode(textCreateParams.renderMode);
+        const string_type& text          = textCreateParams.text;
+        const string_type& fontPath      = textCreateParams.fontPath;
+        const uint16_t fontSize          = textCreateParams.fontSize;
+        const uint32_t OutlineWidth      = textCreateParams.outlineWidth;
+        FT_Render_Mode textRenderMOde    = FreeTypeRenderer::GetRenderMode(textCreateParams.renderMode);
         FT_Render_Mode outlineRenderMode = FreeTypeRenderer::GetRenderMode(textCreateParams.renderMode);
-        const bool renderOutline = OutlineWidth > 0;
-        mesureResult = {};
+        const bool renderOutline         = OutlineWidth > 0;
+        mesureResult                     = {};
         if (measureParams.createParams.text.empty() == false)
         {
 
@@ -201,6 +201,13 @@ namespace FreeType
                     if (FT_Error error = FT_Get_Glyph(face->glyph, &glyph))
                         LL_EXCEPTION(LLUtils::Exception::ErrorCode::RuntimeError, std::format("FreeType error {0}, {1}", error, GenerateFreeTypeErrorString("unable to render glyph",error)));
 
+                    // Bitmap conversion replaces the handle; release the surviving glyph even if measurement fails.
+                    struct GlyphCleanup
+                    {
+                        FT_Glyph& glyph;
+                        ~GlyphCleanup() { FT_Done_Glyph(glyph); }
+                    } cleanup{glyph};
+
                     if (glyph->format != FT_GLYPH_FORMAT_BITMAP)
                     {
                         if (FT_Error error = FT_Glyph_To_Bitmap(&glyph, textRenderMOde, nullptr, true); error != FT_Err_Ok)
@@ -288,16 +295,16 @@ namespace FreeType
             )
     {
         using namespace std;
-        const string_type text = textCreateParams.text;
-        const string_type& fontPath = textCreateParams.fontPath;
-        const uint16_t fontSize = textCreateParams.fontSize;
-        const uint32_t OutlineWidth = textCreateParams.outlineWidth;
-        const LLUtils::Color outlineColor = textCreateParams.outlineColor;
+        const string_type& text              = textCreateParams.text;
+        const string_type& fontPath          = textCreateParams.fontPath;
+        const uint16_t fontSize              = textCreateParams.fontSize;
+        const uint32_t OutlineWidth          = textCreateParams.outlineWidth;
+        const LLUtils::Color outlineColor    = textCreateParams.outlineColor;
         const LLUtils::Color backgroundColor = textCreateParams.backgroundColor;
 
-        FT_Render_Mode textRenderMOde = FreeTypeRenderer::GetRenderMode(textCreateParams.renderMode);
+        FT_Render_Mode textRenderMOde    = FreeTypeRenderer::GetRenderMode(textCreateParams.renderMode);
         FT_Render_Mode outlineRenderMode = FreeTypeRenderer::GetRenderMode(textCreateParams.renderMode);
-        const bool renderOutline = OutlineWidth > 0;
+        const bool renderOutline         = OutlineWidth > 0;
 
         if (textRenderMOde == FT_Render_Mode::FT_RENDER_MODE_LCD && renderOutline == true)
             textRenderMOde = FT_Render_Mode::FT_RENDER_MODE_NORMAL;
@@ -311,17 +318,12 @@ namespace FreeType
 
         font->SetSize(fontSize, textCreateParams.DPIx, textCreateParams.DPIy);
 
-        TextMesureParams params;
-        params.createParams = textCreateParams;
-        
         TextMetrics metrics;
         if (in_metrics == nullptr)
-            MeasureText(params, metrics);
-        else
-            metrics = *in_metrics;
+            MeasureText({textCreateParams}, metrics);
 
-        
-        auto& mesaureResult = metrics;
+        // Cached measurements remain valid for this render; borrow them instead of copying their line data.
+        const auto& mesaureResult = in_metrics != nullptr ? *in_metrics : metrics;
 
         using namespace LLUtils;
         const uint32_t destPixelSize = sizeof(ColorF32);
@@ -366,12 +368,11 @@ namespace FreeType
         dest.pixelSizeInbytes = destPixelSize;
         dest.rowPitch = destRowPitch;
 
-        
-        int32_t penX = -mesaureResult.rect.LeftTop().x;
-        int32_t penY = -mesaureResult.rect.LeftTop().y;
+        const PointI32 origin = mesaureResult.rect.GetCorner(Corner::TopLeft);
+        int32_t penX          = -origin.x;
+        int32_t penY          = -origin.y;
 
-        
-        FT_Face face = font->GetFace();
+        FT_Face face             = font->GetFace();
         const auto descender = face->size->metrics.descender >> 6;
         const uint32_t rowHeight = mesaureResult.rowHeight;
 
@@ -392,7 +393,7 @@ namespace FreeType
             {
                 if (codepoint == L'\n')
                 {
-                    penX = static_cast<int>(-mesaureResult.rect.LeftTop().x);
+                    penX = static_cast<int>(-origin.x);
                     penY += rowHeight;
                     continue;
                 }
@@ -410,10 +411,10 @@ namespace FreeType
                 //Render outline
                 const auto advance = face->glyph->advance.x >> 6;
 
-                if (textCreateParams.maxWidthPx > 0 && penX + advance + mesaureResult.rect.LeftTop().x > static_cast<int>(textCreateParams.maxWidthPx))
+                if (textCreateParams.maxWidthPx > 0 && penX + advance + origin.x > static_cast<int>(textCreateParams.maxWidthPx))
                 {
                     penY += rowHeight;
-                    penX = static_cast<int>(-mesaureResult.rect.LeftTop().x);
+                    penX = static_cast<int>(-origin.x);
 
                 }
 
@@ -448,12 +449,13 @@ namespace FreeType
                 if (glyph->format != FT_GLYPH_FORMAT_BITMAP)
                 {
                     if (FT_Error error = FT_Glyph_To_Bitmap(&glyph, textRenderMOde, nullptr, true); error != FT_Err_Ok)
-                        LL_EXCEPTION(LLUtils::Exception::ErrorCode::RuntimeError, "FreeType error, unable to render glyph");
+                        LL_EXCEPTION(LLUtils::Exception::ErrorCode::RuntimeError,
+                                     "FreeType error, unable to render glyph");
                 }
 
                 FT_BitmapGlyph bitmapGlyph = reinterpret_cast<FT_BitmapGlyph>(glyph);
                 FreeTypeRenderer::BitmapProperties bitmapProperties = FreeTypeRenderer::GetBitmapGlyphProperties(bitmapGlyph->bitmap);
-                const auto textcolor = el.textColor != Color{ 0, 0, 0, 0 } ? el.textColor : params.createParams.textColor;
+                const auto textcolor = el.textColor != Color{ 0, 0, 0, 0 } ? el.textColor : textCreateParams.textColor;
 
                 LLUtils::Buffer rasterizedGlyph = FreeTypeRenderer::RenderGlyphToBuffer({ bitmapGlyph , backgroundColor, textcolor , bitmapProperties });