ImGui font rendering appears oversized on standard resolution displays

[juanchuletas]

Description

The current ImGui font setup loads a TTF font at a small fixed size and then applies FontGlobalScale to upscale it at runtime. This causes blurry text on all displays and produces inconsistent sizing across different screen types — the UI looks correct on a HiDPI OLED display but oversized on a standard 1080p laptop screen.

Root Cause

In GUI/imgui_layer.hpp, the font is loaded at 18.0f and then scaled by 1.8f globally:

io.Fonts->AddFontFromFileTTF("...Nunito-Regular.ttf", 18.0f);
io.FontGlobalScale = 1.8f;

FontGlobalScale stretches the already-rasterized font bitmap at render time. This is equivalent to zooming into a low-resolution texture — the result is blurry text. On a standard 1080p display with larger physical pixels, the upscaled text also appears disproportionately large.

Expected Behavior

Font should appear at a consistent, readable size across HiDPI and standard resolution displays, with crisp rendering on both.

Proposed Fix

Remove io.FontGlobalScale = 1.8f and load the font at the correct pixel size derived from the system DPI scale:

float xscale, yscale;
glfwGetWindowContentScale(m_window, &xscale, &yscale);
float fontSize = 16.0f * std::max(xscale, yscale);
io.Fonts->AddFontFromFileTTF("...Nunito-Regular.ttf", fontSize);
io.FontGlobalScale = 1.0f;

Files Affected

• GUI/imgui_layer.hpp — onAttach(), lines 191–204

Environment

• Works correctly on: HiDPI OLED display
• Broken on: standard 1080p laptop display