This is intended as a means of rendering text pixel-perfectly at a fixed display size (size on screen) independent of the screen resolution. Ordinarily it is possible to render pixel-perfect text by calling QFont.Begin() / QFont.End(); however, this means working in a coordinate system corresponding to the current screen resolution. If the screen resolution changes, then the display size of the font will change accordingly which may not be desirable. Many games/applications prefer to use a fixed orthog coordinate system that is independent of screen resolution (e.g. 1000x1000) so that when the screen resolution changes, everything is still the same size on screen, it simply has higher definition - which is what this setting supports. One option is simply not to call QFont.Begin() / QFont.End(). This works; however, it becomes impossible to assure that glyphs are rendered pixel-perfectly. Instead they will be scaled in hardware. In most cases this looks fine; however, if you are a perfectionist, you may prefer to use this option to assure pixel perfection. Setting this option does two things: Rendering to a specified position is transformed Measurements are transformed So for example, suppose the screen resolution is 1024x768, but you wish to run orthog mode at 1000x1000. If you set: myFont.Options.TransformToViewport = new Viewport(0,0,1000,1000); Then, if you render at position 500,500: QFont.Begin(); myFont.Options.LockToPixel = true; myFont.Print("Hello",new Vector2(500,500)); QFont.End(); This will be printed pixel-pefectly at pixel position 512, 384. Additionally the font will be measured in terms of your 500x500 coordinate system. The only issue is that if you change the resolution, the size of your font will change. You can get around this by loading a font size that is proportional to the screen resolution. This makes sense: if you want a font to be rendered pixel-perfectly at a higher resolution, it will need to be a larger font. At present this needs to be doen manually. E.g: float fontScale = (float)Height / 800; compyFontSmall = new QFont("Data/comfy.ttf", 14 * fontScale);