////////////////////////////////////////////////////////////////////// // LibFile: partitions.scad // Cut objects with a plane, or partition them into interlocking pieces for easy printing of large objects. // Includes: // include // FileGroup: Basic Modeling // FileSummary: Cut objects with a plane or partition them into interlocking pieces. // FileFootnotes: STD=Included in std.scad ////////////////////////////////////////////////////////////////////// // Section: Planar Cutting // Function&Module: half_of() // Synopsis: Masks half of an object at a cut plane. // SynTags: Geom, VNF, Path, Region // Topics: Partitions, Masking // See Also: back_half(), front_half(), left_half(), right_half(), top_half(), bottom_half(), intersection() // // Usage: as module // half_of(v, [cp], [s], [planar]) CHILDREN; // Usage: as function // result = half_of(p,v,[cp]); // // Description: // Slices an object at a cut plane, and masks away everything that is on one side. The v parameter // is either a plane specification or a normal vector. The `s` parameter is needed for the module // version to control the size of the masking cube. If `s` is too large then the preview display // will flip around and display the wrong half, but if it is too small it won't fully mask your // model. When called as a function, you must supply a vnf, path or region in p. If planar is set // to true for the module version the operation is performed in 2D and UP and DOWN are treated as // equivalent to BACK and FWD respectively. // // Arguments: // p = path, region or VNF to slice. (Function version) // v = Normal of plane to slice at. Keeps everything on the side the normal points to. Default: [0,0,1] (UP) // cp = If given as a scalar, moves the cut plane along the normal by the given amount. If given as a point, specifies a point on the cut plane. Default: [0,0,0] // s = Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100 // planar = If true, perform a 2D operation. When planar, a `v` of `UP` or `DOWN` becomes equivalent of `BACK` and `FWD` respectively. (Module version). Default: false. // // Examples: // half_of(DOWN+BACK, cp=[0,-10,0]) cylinder(h=40, r1=10, r2=0, center=false); // half_of(DOWN+LEFT, s=200) sphere(d=150); // Example(2D): // half_of([1,1], planar=true) circle(d=50); module half_of(v=UP, cp, s=100, planar=false) { req_children($children); cp = is_vector(v,4)? assert(cp==undef, "Don't use cp with plane definition.") plane_normal(v) * v[3] : is_vector(cp)? cp : is_num(cp)? cp*unit(v) : [0,0,0]; v = is_vector(v,4)? plane_normal(v) : v; if (cp != [0,0,0]) { translate(cp) half_of(v=v, s=s, planar=planar) translate(-cp) children(); } else if (planar) { v = (v==UP)? BACK : (v==DOWN)? FWD : v; ang = atan2(v.y, v.x); difference() { children(); rotate(ang+90) { back(s/2) square(s, center=true); } } } else { difference() { children(); rot(from=UP, to=-v) { up(s/2) cube(s, center=true); } } } } function half_of(p, v=UP, cp) = is_vnf(p) ? assert(is_vector(v) && (len(v)==3 || len(v)==4),str("Must give 3-vector or plane specification",v)) assert(select(v,0,2)!=[0,0,0], "vector v must be nonzero") let( plane = is_vector(v,4) ? assert(cp==undef, "Don't use cp with plane definition.") v : is_undef(cp) ? [each v, 0] : is_num(cp) ? [each v, cp*(v*v)/norm(v)] : assert(is_vector(cp,3),"Centerpoint must be a 3-vector") [each v, cp*v] ) vnf_halfspace(plane, p) : is_path(p) || is_region(p) ? let( v = (v==UP)? BACK : (v==DOWN)? FWD : v, cp = is_undef(cp) ? [0,0] : is_num(cp) ? v*cp : assert(is_vector(cp,2) || (is_vector(cp,3) && cp.z==0),"Centerpoint must be 2-vector") cp ) assert(is_vector(v,2) || (is_vector(v,3) && v.z==0),"Must give 2-vector") assert(!all_zero(v), "Vector v must be nonzero") let( bounds = pointlist_bounds(move(-cp,p)), L = 2*max(flatten(bounds)), n = unit(v), u = [-n.y,n.x], box = [cp+u*L, cp+(v+u)*L, cp+(v-u)*L, cp-u*L] ) intersection(box,p) : assert(false, "Input must be a region, path or VNF"); /* This code cut 3d paths but leaves behind connecting line segments is_path(p) ? //assert(len(p[0]) == d, str("path must have dimension ", d)) let(z = [for(x=p) (x-cp)*v]) [ for(i=[0:len(p)-1]) each concat(z[i] >= 0 ? [p[i]] : [], // we assume a closed path here; // to make this correct for an open path, // just replace this by [] when i==len(p)-1: let(j=(i+1)%len(p)) // the remaining path may have flattened sections, but this cannot // create self-intersection or whiskers: z[i]*z[j] >= 0 ? [] : [(z[j]*p[i]-z[i]*p[j])/(z[j]-z[i])]) ] : */ // Function&Module: left_half() // Synopsis: Masks the right half of an object along the Y-Z plane, leaving the left half. // SynTags: Geom, VNF, Path, Region // Topics: Partitions, Masking // See Also: back_half(), front_half(), right_half(), top_half(), bottom_half(), half_of(), intersection() // // Usage: as module // left_half([s], [x]) CHILDREN; // left_half(planar=true, [s], [x]) CHILDREN; // Usage: as function // result = left_half(p, [x]); // // Description: // Slices an object at a vertical Y-Z cut plane, and masks away everything that is right of it. // The `s` parameter is needed for the module version to control the size of the masking cube. // If `s` is too large then the preview display will flip around and display the wrong half, // but if it is too small it won't fully mask your model. // // Arguments: // p = VNF, region or path to slice (function version) // s = Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100 // x = The X coordinate of the cut-plane. Default: 0 // planar = If true, perform a 2D operation. (Module version) Default: false. // Examples: // left_half() sphere(r=20); // left_half(x=-8) sphere(r=20); // Example(2D): // left_half(planar=true) circle(r=20); module left_half(s=100, x=0, planar=false) { req_children($children); dir = LEFT; difference() { children(); translate([x,0,0]-dir*s/2) { if (planar) { square(s, center=true); } else { cube(s, center=true); } } } } function left_half(p,x=0) = half_of(p, LEFT, [x,0,0]); // Function&Module: right_half() // SynTags: Geom, VNF, Path, Region // Synopsis: Masks the left half of an object along the Y-Z plane, leaving the right half. // Topics: Partitions, Masking // See Also: back_half(), front_half(), left_half(), top_half(), bottom_half(), half_of(), intersection() // // Usage: as module // right_half([s=], [x=]) CHILDREN; // right_half(planar=true, [s=], [x=]) CHILDREN; // Usage: as function // result = right_half(p, [x=]); // // Description: // Slices an object at a vertical Y-Z cut plane, and masks away everything that is left of it. // The `s` parameter is needed for the module version to control the size of the masking cube. // If `s` is too large then the preview display will flip around and display the wrong half, // but if it is too small it won't fully mask your model. // Arguments: // p = VNF, region or path to slice (function version) // s = Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100 // x = The X coordinate of the cut-plane. Default: 0 // planar = If true, perform a 2D operation. (Module version) Default: false. // Examples(FlatSpin,VPD=175): // right_half() sphere(r=20); // right_half(x=-5) sphere(r=20); // Example(2D): // right_half(planar=true) circle(r=20); module right_half(s=100, x=0, planar=false) { dir = RIGHT; difference() { children(); translate([x,0,0]-dir*s/2) { if (planar) { square(s, center=true); } else { cube(s, center=true); } } } } function right_half(p,x=0) = half_of(p, RIGHT, [x,0,0]); // Function&Module: front_half() // Synopsis: Masks the back half of an object along the X-Z plane, leaving the front half. // SynTags: Geom, VNF, Path, Region // Topics: Partitions, Masking // See Also: back_half(), left_half(), right_half(), top_half(), bottom_half(), half_of(), intersection() // // Usage: // front_half([s], [y]) CHILDREN; // front_half(planar=true, [s], [y]) CHILDREN; // Usage: as function // result = front_half(p, [y]); // // Description: // Slices an object at a vertical X-Z cut plane, and masks away everything that is behind it. // The `s` parameter is needed for the module version to control the size of the masking cube. // If `s` is too large then the preview display will flip around and display the wrong half, // but if it is too small it won't fully mask your model. // Arguments: // p = VNF, region or path to slice (function version) // s = Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100 // y = The Y coordinate of the cut-plane. Default: 0 // planar = If true, perform a 2D operation. (Module version) Default: false. // Examples(FlatSpin,VPD=175): // front_half() sphere(r=20); // front_half(y=5) sphere(r=20); // Example(2D): // front_half(planar=true) circle(r=20); module front_half(s=100, y=0, planar=false) { req_children($children); dir = FWD; difference() { children(); translate([0,y,0]-dir*s/2) { if (planar) { square(s, center=true); } else { cube(s, center=true); } } } } function front_half(p,y=0) = half_of(p, FRONT, [0,y,0]); // Function&Module: back_half() // Synopsis: Masks the front half of an object along the X-Z plane, leaving the back half. // SynTags: Geom, VNF, Path, Region // Topics: Partitions, Masking // See Also: front_half(), left_half(), right_half(), top_half(), bottom_half(), half_of(), intersection() // // Usage: // back_half([s], [y]) CHILDREN; // back_half(planar=true, [s], [y]) CHILDREN; // Usage: as function // result = back_half(p, [y]); // // Description: // Slices an object at a vertical X-Z cut plane, and masks away everything that is in front of it. // The `s` parameter is needed for the module version to control the size of the masking cube. // If `s` is too large then the preview display will flip around and display the wrong half, // but if it is too small it won't fully mask your model. // Arguments: // p = VNF, region or path to slice (function version) // s = Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100 // y = The Y coordinate of the cut-plane. Default: 0 // planar = If true, perform a 2D operation. (Module version) Default: false. // Examples: // back_half() sphere(r=20); // back_half(y=8) sphere(r=20); // Example(2D): // back_half(planar=true) circle(r=20); module back_half(s=100, y=0, planar=false) { req_children($children); dir = BACK; difference() { children(); translate([0,y,0]-dir*s/2) { if (planar) { square(s, center=true); } else { cube(s, center=true); } } } } function back_half(p,y=0) = half_of(p, BACK, [0,y,0]); // Function&Module: bottom_half() // Synopsis: Masks the top half of an object along the X-Y plane, leaving the bottom half. // SynTags: Geom, VNF, Path, Region // Topics: Partitions, Masking // See Also: back_half(), front_half(), left_half(), right_half(), top_half(), half_of(), intersection() // // Usage: // bottom_half([s], [z]) CHILDREN; // Usage: as function // result = bottom_half(p, [z]); // // Description: // Slices an object at a horizontal X-Y cut plane, and masks away everything that is above it. // The `s` parameter is needed for the module version to control the size of the masking cube. // If `s` is too large then the preview display will flip around and display the wrong half, // but if it is too small it won't fully mask your model. // Arguments: // p = VNF, region or path to slice (function version) // s = Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100 // z = The Z coordinate of the cut-plane. Default: 0 // Examples: // bottom_half() sphere(r=20); // bottom_half(z=-10) sphere(r=20); module bottom_half(s=100, z=0) { req_children($children); dir = DOWN; difference() { children(); translate([0,0,z]-dir*s/2) { cube(s, center=true); } } } function bottom_half(p,z=0) = half_of(p,BOTTOM,[0,0,z]); // Function&Module: top_half() // Synopsis: Masks the bottom half of an object along the X-Y plane, leaving the top half. // SynTags: Geom, VNF, Path, Region // Topics: Partitions, Masking // See Also: back_half(), front_half(), left_half(), right_half(), bottom_half(), half_of(), intersection() // // Usage: as module // top_half([s], [z]) CHILDREN; // Usage: as function // result = top_half(p, [z]); // // Description: // Slices an object at a horizontal X-Y cut plane, and masks away everything that is below it. // The `s` parameter is needed for the module version to control the size of the masking cube. // If `s` is too large then the preview display will flip around and display the wrong half, // but if it is too small it won't fully mask your model. // Arguments: // p = VNF, region or path to slice (function version) // s = Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100 // z = The Z coordinate of the cut-plane. Default: 0 // Examples(Spin,VPD=175): // top_half() sphere(r=20); // top_half(z=5) sphere(r=20); module top_half(s=100, z=0) { req_children($children); dir = UP; difference() { children(); translate([0,0,z]-dir*s/2) { cube(s, center=true); } } } function top_half(p,z=0) = half_of(p,UP,[0,0,z]); // Section: Partioning into Interlocking Pieces function _partition_subpath(type) = type=="flat"? [[0,0],[1,0]] : type=="sawtooth"? [[0,-0.5], [0.5,0.5], [1,-0.5]] : type=="sinewave"? [for (a=[0:5:360]) [a/360,sin(a)/2]] : type=="comb"? let(dx=0.5*sin(2)) [[0,0],[0+dx,0.5],[0.5-dx,0.5],[0.5+dx,-0.5],[1-dx,-0.5],[1,0]] : type=="finger"? let(dx=0.5*sin(20)) [[0,0],[0+dx,0.5],[0.5-dx,0.5],[0.5+dx,-0.5],[1-dx,-0.5],[1,0]] : type=="dovetail"? [[0,-0.5], [0.3,-0.5], [0.2,0.5], [0.8,0.5], [0.7,-0.5], [1,-0.5]] : type=="hammerhead"? [[0,-0.5], [0.35,-0.5], [0.35,0], [0.15,0], [0.15,0.5], [0.85,0.5], [0.85,0], [0.65,0], [0.65,-0.5],[1,-0.5]] : type=="jigsaw"? concat( arc(r=5/16, cp=[0,-3/16], start=270, angle=125), arc(r=5/16, cp=[1/2,3/16], start=215, angle=-250), arc(r=5/16, cp=[1,-3/16], start=145, angle=125) ) : assert(false, str("Unsupported cutpath type: ", type)); function _partition_cutpath(l, h, cutsize, cutpath, gap) = let( check = assert(is_finite(l)) assert(is_finite(h)) assert(is_finite(gap)) assert(is_finite(cutsize) || is_vector(cutsize,2)) assert(is_string(cutpath) || is_path(cutpath,2)), cutsize = is_vector(cutsize)? cutsize : [cutsize*2, cutsize], cutpath = is_path(cutpath)? cutpath : _partition_subpath(cutpath), reps = ceil(l/(cutsize.x+gap)), cplen = (cutsize.x+gap) * reps, path = deduplicate(concat( [[-l/2, cutpath[0].y*cutsize.y]], [for (i=[0:1:reps-1], pt=cutpath) v_mul(pt,cutsize)+[i*(cutsize.x+gap)+gap/2-cplen/2,0]], [[ l/2, cutpath[len(cutpath)-1].y*cutsize.y]] )), stidxs = [for (i = idx(path)) if (path[i].x < -l/2) i], enidxs = [for (i = idx(path)) if (path[i].x > +l/2) i], stidx = stidxs? last(stidxs) : 0, enidx = enidxs? enidxs[0] : -1, trunc = select(path, stidx, enidx) ) trunc; // Module: partition_mask() // Synopsis: Creates a mask to remove half an object with the remaining half suitable for reassembly. // SynTags: Geom // Topics: Partitions, Masking, Paths // See Also: partition_cut_mask(), partition() // Usage: // partition_mask(l, w, h, [cutsize], [cutpath], [gap], [inverse], [$slop=], [anchor=], [spin=], [orient=]) [ATTACHMENTS]; // Description: // Creates a mask that you can use to difference or intersect with an object to remove half of it, // leaving behind a side designed to allow assembly of the sub-parts. // Arguments: // l = The length of the cut axis. // w = The width of the part to be masked, back from the cut plane. // h = The height of the part to be masked. // cutsize = The width of the cut pattern to be used. // cutpath = The cutpath to use. Standard named paths are "flat", "sawtooth", "sinewave", "comb", "finger", "dovetail", "hammerhead", and "jigsaw". Alternatively, you can give a cutpath as a 2D path, where X is between 0 and 1, and Y is between -0.5 and 0.5. // gap = Empty gaps between cutpath iterations. Default: 0 // inverse = If true, create a cutpath that is meant to mate to a non-inverted cutpath. // spin = Rotate this many degrees around the Z axis. See [spin](attachments.scad#subsection-spin). Default: `0` // orient = Vector to rotate top towards. See [orient](attachments.scad#subsection-orient). Default: `UP` // $slop = The amount to shrink the mask by, to correct for printer-specific fitting. // Examples: // partition_mask(w=50, gap=0, cutpath="jigsaw"); // partition_mask(w=50, gap=30, cutpath="jigsaw"); // partition_mask(w=50, gap=30, cutpath="jigsaw", inverse=true); // partition_mask(w=50, gap=30, cutsize=15, cutpath="jigsaw"); // partition_mask(w=50, cutsize=[20,20], gap=30, cutpath="jigsaw"); // Examples(2D): // partition_mask(w=20, cutpath="sawtooth"); // partition_mask(w=20, cutpath="sinewave"); // partition_mask(w=20, cutpath="comb"); // partition_mask(w=20, cutpath="finger"); // partition_mask(w=20, cutpath="dovetail"); // partition_mask(w=20, cutpath="hammerhead"); // partition_mask(w=20, cutpath="jigsaw"); module partition_mask(l=100, w=100, h=100, cutsize=10, cutpath="jigsaw", gap=0, inverse=false, anchor=CENTER, spin=0, orient=UP) { cutsize = is_vector(cutsize)? point2d(cutsize) : [cutsize*2, cutsize]; path = _partition_cutpath(l, h, cutsize, cutpath, gap); midpath = select(path,1,-2); sizepath = concat([path[0]+[-get_slop(),0]], midpath, [last(path)+[get_slop(),0]], [[+(l/2+get_slop()), (w+get_slop())*(inverse?-1:1)], [-(l/2+get_slop()), (w+get_slop())*(inverse?-1:1)]]); bnds = pointlist_bounds(sizepath); fullpath = concat(path, [[last(path).x, w*(inverse?-1:1)], [path[0].x, w*(inverse?-1:1)]]); attachable(anchor,spin,orient, size=point3d(bnds[1]-bnds[0],h)) { linear_extrude(height=h, center=true, convexity=10) { intersection() { offset(delta=-get_slop()) polygon(fullpath); square([l, w*2], center=true); } } children(); } } // Module: partition_cut_mask() // Synopsis: Creates a mask to cut an object into two subparts that can be reassembled. // SynTags: Geom // Topics: Partitions, Masking, Paths // See Also: partition_mask(), partition() // Usage: // partition_cut_mask(l, w, h, [cutsize], [cutpath], [gap], [inverse], [$slop=], [anchor=], [spin=], [orient=]) [ATTACHMENTS]; // Description: // Creates a mask that you can use to difference with an object to cut it into two sub-parts that can be assembled. // The `$slop` value is important to get the proper fit and should probably be smaller than 0.2. The examples below // use larger values to make the mask easier to see. // Arguments: // l = The length of the cut axis. // w = The width of the part to be masked, back from the cut plane. // h = The height of the part to be masked. // cutsize = The width of the cut pattern to be used. // cutpath = The cutpath to use. Standard named paths are "flat", "sawtooth", "sinewave", "comb", "finger", "dovetail", "hammerhead", and "jigsaw". Alternatively, you can give a cutpath as a 2D path, where X is between 0 and 1, and Y is between -0.5 and 0.5. Default: "jigsaw" // gap = Empty gaps between cutpath iterations. Default: 0 // spin = Rotate this many degrees around the Z axis. See [spin](attachments.scad#subsection-spin). Default: `0` // orient = Vector to rotate top towards. See [orient](attachments.scad#subsection-orient). Default: `UP` // $slop = The width of the cut mask, to correct for printer-specific fitting. // Examples: // partition_cut_mask(gap=0, cutpath="dovetail"); // partition_cut_mask(gap=30, cutpath="dovetail"); // partition_cut_mask(gap=30, cutsize=15, cutpath="dovetail"); // partition_cut_mask(gap=30, cutsize=[20,20], cutpath="dovetail"); // Examples(2DMed): // partition_cut_mask(cutpath="sawtooth",$slop=0.5); // partition_cut_mask(cutpath="sinewave",$slop=0.5); // partition_cut_mask(cutpath="comb",$slop=0.5); // partition_cut_mask(cutpath="finger",$slop=0.5); // partition_cut_mask(cutpath="dovetail",$slop=1); // partition_cut_mask(cutpath="hammerhead",$slop=1); // partition_cut_mask(cutpath="jigsaw",$slop=0.5); module partition_cut_mask(l=100, h=100, cutsize=10, cutpath="jigsaw", gap=0, anchor=CENTER, spin=0, orient=UP) { cutsize = is_vector(cutsize)? cutsize : [cutsize*2, cutsize]; path = _partition_cutpath(l, h, cutsize, cutpath, gap); attachable(anchor,spin,orient, size=[l,cutsize.y,h]) { linear_extrude(height=h, center=true, convexity=10) { stroke(path, width=max(0.1, get_slop()*2)); } children(); } } // Module: partition() // Synopsis: Cuts an object in two with matched joining edges, then separates the parts. // SynTags: Geom, VNF, Path, Region // Topics: Partitions, Masking, Paths // See Also: partition_cut_mask(), partition_mask() // Usage: // partition(size, [spread], [cutsize], [cutpath], [gap], [spin], [$slop=]) CHILDREN; // Description: // Partitions an object into two parts, spread apart a small distance, with matched joining edges. // Arguments: // size = The [X,Y,Z] size of the object to partition. // spread = The distance to spread the two parts by. // cutsize = The width of the cut pattern to be used. // cutpath = The cutpath to use. Standard named paths are "flat", "sawtooth", "sinewave", "comb", "finger", "dovetail", "hammerhead", and "jigsaw". Alternatively, you can give a cutpath as a 2D path, where X is between 0 and 1, and Y is between -0.5 and 0.5. // gap = Empty gaps between cutpath iterations. Default: 0 // spin = Rotate this many degrees around the Z axis. See [spin](attachments.scad#subsection-spin). Default: `0` // --- // $slop = Extra gap to leave to correct for printer-specific fitting. // Examples(Med): // partition(spread=12, cutpath="dovetail") cylinder(h=50, d=80, center=false); // partition(spread=12, gap=30, cutpath="dovetail") cylinder(h=50, d=80, center=false); // partition(spread=20, gap=20, cutsize=15, cutpath="dovetail") cylinder(h=50, d=80, center=false); // partition(spread=25, gap=15, cutsize=[20,20], cutpath="dovetail") cylinder(h=50, d=80, center=false); // Examples(2DMed): // partition(cutpath="sawtooth") cylinder(h=50, d=80, center=false); // partition(cutpath="sinewave") cylinder(h=50, d=80, center=false); // partition(cutpath="comb") cylinder(h=50, d=80, center=false); // partition(cutpath="finger") cylinder(h=50, d=80, center=false); // partition(spread=12, cutpath="dovetail") cylinder(h=50, d=80, center=false); // partition(spread=12, cutpath="hammerhead") cylinder(h=50, d=80, center=false); // partition(cutpath="jigsaw") cylinder(h=50, d=80, center=false); module partition(size=100, spread=10, cutsize=10, cutpath="jigsaw", gap=0, spin=0) { req_children($children); size = is_vector(size)? size : [size,size,size]; cutsize = is_vector(cutsize)? cutsize : [cutsize*2, cutsize]; rsize = v_abs(rot(spin,p=size)); vec = rot(spin,p=BACK)*spread/2; move(vec) { intersection() { children(); partition_mask(l=rsize.x, w=rsize.y, h=rsize.z, cutsize=cutsize, cutpath=cutpath, gap=gap, spin=spin); } } move(-vec) { intersection() { children(); partition_mask(l=rsize.x, w=rsize.y, h=rsize.z, cutsize=cutsize, cutpath=cutpath, gap=gap, inverse=true, spin=spin); } } } // vim: expandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap