Fonts: fixed broken support for legacy backend due to a mismatch with initial pre-build baked id.

imgui.cpp

@@ -8657,7 +8657,7 @@ void ImGui::UpdateCurrentFontSize()
     // - We may support it better later and remove this rounding.
     final_size = GetRoundedFontSize(final_size);
     final_size = ImMax(1.0f, final_size);
-    if (g.Font != NULL)
+    if (g.Font != NULL && (g.IO.BackendFlags & ImGuiBackendFlags_RendererHasTextures))
         g.Font->CurrentRasterizerDensity = g.FontRasterizerDensity;
     g.FontBaked = (g.Font != NULL) ? g.Font->GetFontBaked(final_size) : NULL;
     g.FontSize = final_size;

imgui.h

@@ -3467,7 +3467,7 @@ struct ImFontConfig
     float           GlyphExtraAdvanceX;     // 0        // Extra spacing (in pixels) between glyphs. Please contact us if you are using this.
     unsigned int    FontBuilderFlags;       // 0        // Settings for custom font builder. THIS IS BUILDER IMPLEMENTATION DEPENDENT. Leave as zero if unsure.
     float           RasterizerMultiply;     // 1.0f     // Linearly brighten (>1.0f) or darken (<1.0f) font output. Brightening small fonts may be a good workaround to make them more readable. This is a silly thing we may remove in the future.
-    float           RasterizerDensity;      // 1.0f     // DPI scale multiplier for rasterization. Not altering other font metrics: makes it easy to swap between e.g. a 100% and a 400% fonts for a zooming display, or handle Retina screen. IMPORTANT: If you change this it is expected that you increase/decrease font scale roughly to the inverse of this, otherwise quality may look lowered.
+    float           RasterizerDensity;      // 1.0f     // (Legacy: this only makes sense when ImGuiBackendFlags_RendererHasTextures is not supported). DPI scale multiplier for rasterization. Not altering other font metrics: makes it easy to swap between e.g. a 100% and a 400% fonts for a zooming display, or handle Retina screen. IMPORTANT: If you change this it is expected that you increase/decrease font scale roughly to the inverse of this, otherwise quality may look lowered.
     ImWchar         EllipsisChar;           // 0        // Explicitly specify Unicode codepoint of ellipsis character. When fonts are being merged first specified ellipsis will be used.
 
     // [Internal]

imgui_draw.cpp

@@ -3002,6 +3002,7 @@ ImFont* ImFontAtlas::AddFont(const ImFontConfig* font_cfg_in)
         font->FontId = FontNextUniqueID++;
         font->Flags = font_cfg_in->Flags;
         font->DefaultSize = font_cfg_in->SizePixels;
+        font->CurrentRasterizerDensity = font_cfg_in->RasterizerDensity;
         Fonts.push_back(font);
     }
     else