Box around the plot is rather useful thing because it allows one to: see the plot boundaries, and better estimate points position since box contain another set of ticks. MathGL provide special function for drawing such box – box function. By default, it draw black or white box with ticks (color depend on transparency type, see Types of transparency). However, you can change the color of box, or add drawing of rectangles at rear faces of box. Also you can disable ticks drawing, but I don’t know why anybody will want it. The sample code, which demonstrate box features is:
int sample(mglGraph *gr) { gr->SubPlot(2,2,0); gr->Title("Box (default)"); gr->Rotate(50,60); gr->Box(); gr->SubPlot(2,2,1); gr->Title("colored"); gr->Rotate(50,60); gr->Box("r"); gr->SubPlot(2,2,2); gr->Title("with faces"); gr->Rotate(50,60); gr->Box("@"); gr->SubPlot(2,2,3); gr->Title("both"); gr->Rotate(50,60); gr->Box("@cm"); return 0; }