set uiScale on non-glfw backends

Author: nmwsharp

src/render/mock_opengl/mock_gl_engine.cpp

@@ -1562,6 +1562,9 @@ void MockGLEngine::initialize() {
   GLFrameBuffer* glScreenBuffer = new GLFrameBuffer(view::bufferWidth, view::bufferHeight, true);
   displayBuffer.reset(glScreenBuffer);
 
+  if(options::uiScale < 0) { // only set from system if the value is -1, meaning not set yet
+    options::uiScale = 1.;
+  }
 
   // normally we get initial values for the buffer size from the window framework,
   // with the mock backend we we need to manually set them to some sane value

src/render/opengl/gl_engine_egl.cpp

@@ -254,6 +254,10 @@ void GLEngineEGL::initialize() {
               << "EGL version: " << majorVer << "." << minorVer << std::endl;
   }
 
+  if(options::uiScale < 0) { // only set from system if the value is -1, meaning not set yet
+    options::uiScale = 1.;
+  }
+
   { // Manually create the screen frame buffer
     // NOTE: important difference here, we manually create both the framebuffer and and its render buffer, since
     // headless EGL means we are not getting them from a window