DrawLine /Drawing

void DrawLine(vector2 p0, vector2 p1, uint color0, uint color1, float widthPx)

Draws a line connecting p0 and p1. If two different colors are set, the rasterizer will smoothly interpolate both colors along the surface.

uint green = ARGB(255,0,255,0);
uint blue  = ARGB(255,0,0,255);

// draw a line across the screen
DrawLine(vector2(0,0), GetScreenSize(), green, blue, 2.0f);