rounded_polygon() now copes with the degenrate case when tangents intersect to form a sharp corner with no arc.

Added an offset() function with some limitations.

CHANGELOG.md

@@ -3,6 +3,25 @@
 This changelog is generated by `changelog.py` using manually added semantic version tags to classify commits as breaking changes, additions or fixes.
 
 
+#### [v20.6.1](https://github.com/nophead/NopSCADlib/releases/tag/v20.6.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v20.6.0...v20.6.1 "diff with v20.6.0")
+*   2022-06-21 [`6a9af0a`](https://github.com/nophead/NopSCADlib/commit/6a9af0af8aef68978b8be248810d07c85150341b "show commit") [C.P.](# "Chris Palmer") Updates images
+
+*   2022-06-21 [`a6a0808`](https://github.com/nophead/NopSCADlib/commit/a6a08088d986dbcbc4d01c06e0475176ec8bc76f "show commit") [M.B.](# "Martin Budden") Fixed dimensions of E1515 extrusion.
+
+*   2022-06-21 [`bcf9fb3`](https://github.com/nophead/NopSCADlib/commit/bcf9fb38dfabaf93508a380b85b12e3b23f28cf8 "show commit") [M.B.](# "Martin Budden") Fixed typos.
+
+*   2022-06-21 [`06443a5`](https://github.com/nophead/NopSCADlib/commit/06443a558b407292a1e73f60c24cc90ec618d511 "show commit") [M.B.](# "Martin Budden") Standardised setting of imgsize in scripts.
+
+### [v20.6.0](https://github.com/nophead/NopSCADlib/releases/tag/v20.6.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v20.5.1...v20.6.0 "diff with v20.5.1")
+*   2022-06-14 [`18f3d43`](https://github.com/nophead/NopSCADlib/commit/18f3d43780d7e083fc3b21290db2049fb4364a46 "show commit") [C.P.](# "Chris Palmer") Added convexity parameter to `clip()`.
+
+#### [v20.5.1](https://github.com/nophead/NopSCADlib/releases/tag/v20.5.1 "show release") Fixes [...](https://github.com/nophead/NopSCADlib/compare/v20.5.0...v20.5.1 "diff with v20.5.0")
+*   2022-06-14 [`eda88cc`](https://github.com/nophead/NopSCADlib/commit/eda88cc8d75eb4c0cb59b368b4e2ad3db2115834 "show commit") [C.P.](# "Chris Palmer") Fixed `vero()` constructor documentation.
+Fixed missing space in veroboard vitamin description.
+
+*   2022-06-14 [`630268d`](https://github.com/nophead/NopSCADlib/commit/630268d71a0b478c28b6bde2a7c3ff9074c7a8fb "show commit") [C.P.](# "Chris Palmer") Changed `screw_knob()` facets to be suitable for 3D printing.
+Fixed `knob_height()` so it can take a screw as a type.
+
 ### [v20.5.0](https://github.com/nophead/NopSCADlib/releases/tag/v20.5.0 "show release") Additions [...](https://github.com/nophead/NopSCADlib/compare/v20.4.0...v20.5.0 "diff with v20.4.0")
 *   2022-05-31 [`cc5654d`](https://github.com/nophead/NopSCADlib/commit/cc5654d7d756287f5311e35104003f38a4a94475 "show commit") [C.](# "Chris") Added `usb_miniA()`.
 

readme.md

@@ -6608,6 +6608,8 @@ Because the tangents need to be calculated to find the length these can be calcu
 | Function | Description |
 |:--- |:--- |
 | `circle_tangent(p1, p2)` | Compute the clockwise tangent between two circles represented as [x,y,r] |
+| `line_intersection(l0, l1)` | Return the point where two 2D lines intersect or undef if they don't. |
+| `offset(points, offset)` | Offset a 2D polygon, breaks for concave shapes and negative offsets if the offset is more than half the smallest feature size. |
 | `rounded_polygon(points, _tangents = undef)` | Return the rounded polygon from the point list, can pass the tangent list to save it being calculated |
 | `rounded_polygon_arcs(points, tangents)` | Compute the arcs at the points, for each point [angle, rotate_angle, length] |
 | `rounded_polygon_length(points, tangents)` | Calculate the length given the point list and the list of tangents computed by `rounded_polygon_tangents` |
@@ -6883,7 +6885,7 @@ Original version by Doug Moen on the OpenSCAD forum
 | Module | Description |
 |:--- |:--- |
 | `box(xmin, ymin, zmin, xmax, ymax, zmax)` | Construct a box given its bounds |
-| `clip(xmin = -inf, ymin = -inf, zmin = -inf, xmax = inf, ymax = inf, zmax = inf)` | Clip child to specified boundaries |
+| `clip(xmin = -inf, ymin = -inf, zmin = -inf, xmax = inf, ymax = inf, zmax = inf, convexity = 1)` | Clip child to specified boundaries |
 
 ![clip](tests/png/clip.png)
 

scripts/changelog.py

@@ -157,7 +157,7 @@ if __name__ == '__main__':
                         break
                     j += 1
 
-                # Print verson info
+                # Print version info
                 print('%s [%s](%s "show release") %s %s' % ('#' * (level + 1), ver, url + '/releases/tag/' + ver, type, diff), file = file)
 
             # Print commits excluding merges

scripts/render.py

@@ -26,7 +26,7 @@ from set_config import *
 from exports import bom_to_parts
 import os
 import openscad
-from tests import do_cmd, update_image, colour_scheme, background
+from tests import do_cmd, update_image, colour_scheme, background, image_size
 from deps import mtime
 from colorama import init
 import json
@@ -95,7 +95,7 @@ def render(target, type):
             render = "--preview" if type == 'stl' or colour != pp1 else "--render"
             tmp_name = tmp_dir + '/' + part[:-4] + '.png'
             dummy_deps_name = tmp_dir + '/tmp.deps' # work around for OpenSCAD issue #3879
-            openscad.run("-o", tmp_name, png_maker_name, colour_scheme, "--projection=p", "--imgsize=4096,4096", cam, render, "--autocenter", "--viewall", "-d", dummy_deps_name)
+            openscad.run("-o", tmp_name, png_maker_name, colour_scheme, "--projection=p", image_size, cam, render, "--autocenter", "--viewall", "-d", dummy_deps_name)
             do_cmd(("magick "+ tmp_name + " -trim -resize 280x280 -background %s -gravity Center -extent 280x280 -bordercolor %s -border 10 %s"
                     % (background, background, tmp_name)).split())
             update_image(tmp_name, png_name)

scripts/set_config.py

@@ -57,13 +57,13 @@ def set_config(target, usage = None):
         sys.exit(1)
 
     if not targets:
-        print("Not a muli-configuration project (no config_<target>.scad files found)")
+        print("Not a multi-configuration project (no config_<target>.scad files found)")
         if usage:
             usage()
         sys.exit(1)
 
     if not target in targets:
-        print(target + " is not a configuration, avaliable configurations are: " + valid_targets_string())
+        print(target + " is not a configuration, available configurations are: " + valid_targets_string())
         if usage:
             usage()
         sys.exit(1)

scripts/tests.py

@@ -36,8 +36,7 @@ from blurb import *
 from colorama import Fore
 from tmpdir import *
 
-w = 4096
-h = w
+image_size = "--imgsize=4096,4096"
 threshold = 20  # Image comparison allowed number of different pixels
 fuzz = 5       # Image comparison allowed percentage error in pixel value
 
@@ -119,7 +118,7 @@ def tests(tests):
         libtest = True
         lib_blurb = scrape_blurb(scad_name)
         if not os.path.isfile(png_name):
-            openscad.run(scad_name, "-o", png_name, colour_scheme, "--projection=p", "--imgsize=%d,%d" % (w, h), "--camera=0,0,0,50,0,340,500", "--autocenter", "--viewall");
+            openscad.run(scad_name, "-o", png_name, colour_scheme, "--projection=p", image_size, "--camera=0,0,0,50,0,340,500", "--autocenter", "--viewall");
             do_cmd(["magick", png_name, "-trim", "-resize", "1280", "-bordercolor", background, "-border", "10", png_name])
     else:
         #
@@ -240,7 +239,7 @@ def tests(tests):
                 print(changed)
                 t = time.time()
                 tmp_name = tmp_dir + '/tmp.png'
-                openscad.run_list([scad_name, "-o", tmp_name] + options.list() + ["-D$bom=2", colour_scheme, "--projection=p", "--imgsize=%d,%d" % (w, h), "--camera=0,0,0,70,0,315,500", "--autocenter", "--viewall", "-d", dname]);
+                openscad.run_list([scad_name, "-o", tmp_name] + options.list() + ["-D$bom=2", colour_scheme, "--projection=p", image_size, "--camera=0,0,0,70,0,315,500", "--autocenter", "--viewall", "-d", dname]);
                 times.add_time(scad_name, t)
                 do_cmd(["magick", tmp_name, "-trim", "-resize", "1000x600", "-bordercolor", background, "-border", "10", tmp_name])
                 update_image(tmp_name, png_name)

scripts/views.py

@@ -25,7 +25,7 @@
 from __future__ import print_function
 from set_config import *
 import openscad
-from tests import do_cmd, update_image, colour_scheme, background
+from tests import do_cmd, update_image, colour_scheme, background, image_size
 import time
 import times
 import options
@@ -223,7 +223,7 @@ def views(target, do_assemblies = None):
                                                 target_def = ['-D$target="%s"' % target] if target else []
                                                 cwd_def = ['-D$cwd="%s"' % os.getcwd().replace('\\', '/')]
                                                 view_def = ['--viewall', '--autocenter'] if not (zoomed & (1 << explode)) else ['--camera=0,0,0,55,0,25,140']
-                                                openscad.run_list(["-o", tmp_name, png_maker_name] + options.list() + target_def + cwd_def + view_def + ["-D$pose=1", "-D$explode=%d" % explode, colour_scheme, "--projection=p", "--imgsize=4096,4096", "-d", dname]);
+                                                openscad.run_list(["-o", tmp_name, png_maker_name] + options.list() + target_def + cwd_def + view_def + ["-D$pose=1", "-D$explode=%d" % explode, colour_scheme, "--projection=p", image_size, "-d", dname]);
                                                 times.add_time(png_name, t)
                                                 do_cmd(["magick", tmp_name, "-trim", "-resize", "1004x1004", "-bordercolor", background, "-border", "10", tmp_name])
                                                 update_image(tmp_name, png_name)

utils/core/clip.scad

@@ -41,8 +41,8 @@ module box(xmin, ymin, zmin, xmax, ymax, zmax) //! Construct a box given its bou
          [0,2,3,1]]  // left
     );
 
-module clip(xmin = -inf, ymin = -inf, zmin = -inf, xmax = inf, ymax = inf, zmax = inf) //! Clip child to specified boundaries
-    render() intersection() {
+module clip(xmin = -inf, ymin = -inf, zmin = -inf, xmax = inf, ymax = inf, zmax = inf, convexity = 1) //! Clip child to specified boundaries
+    render(convexity = convexity) intersection() {
         children();
 
         box(xmin, ymin, zmin, xmax, ymax, zmax);

utils/rounded_polygon.scad

@@ -33,7 +33,7 @@ function circle_tangent(p1, p2) = //! Compute the clockwise tangent between two
         dx = p2.x - p1.x,
         dy = p2.y - p1.y,
         d = sqrt(dx * dx + dy * dy),
-        theta = atan2(dy, dx) + acos((r1 - r2) / d),
+        theta = assert(d, str("points conicident ", p1)) atan2(dy, dx) + acos((r1 - r2) / d),
         v = [cos(theta), sin(theta)]
     )[ p1 + r1 * v, p2 + r2 * v ];
 
@@ -72,24 +72,52 @@ function rounded_polygon_length(points, tangents) = //! Calculate the length giv
         arcs = rounded_polygon_arcs(points, tangents)
     ) sumv( map( concat(tangents, arcs), function(e) e[2] ) );
 
+function line_intersection(l0, l1) = //! Return the point where two 2D lines intersect or undef if they don't.
+    assert(Len(l0) == 2 && Len(l1) == 2, "Two 2D vectors expected")
+    let(
+        p0 = l0[0], p1 = l0[1], p2 = l1[0], p3 = l1[1],
+        v1 = p1 - p0,
+        v2 = p3 - p2,
+        v3 = p0 - p2,
+        det = v1.x * v2.y - v2.x * v1.y,
+        s = det ? (-v1.y * v3.x + v1.x * v3.y) / det : inf,
+        t = det ? ( v2.x * v3.y - v2.y * v3.x) / det : inf
+    ) s >= 0 && s <= 1 && t >= 0 && t <= 1 ? p0 + t * v1 : undef;
+
 function rounded_polygon(points, _tangents = undef) = //! Return the rounded polygon from the point list, can pass the tangent list to save it being calculated
     let(
         len = len(points),
         tangents = _tangents ? _tangents : rounded_polygon_tangents(points),
         arcs = rounded_polygon_arcs(points, tangents)
-    ) [for(i = [0 : len - 1], last = (i - 1 + len) % len, R = points[i][2]) each [
-        vec2(tangents[last][1]),                        // End of last tangent
-        if(R)                                               // If rounded
-            let(r = abs(R),                                     // Get radius
-                n = r2sides4n(r),                               // Decide number of vertices
-                step = 360 / n,                                 // Angular step
-                arc = arcs[i],                                  // Get corner arc details
-                start = ceil(arc[1] / step + eps),              // Starting index
-                end = floor((arc[0] + arc[1]) / step - eps),    // Ending index
-                c = vec2(points[i])                             // Centre of arc
-            ) for(j = R > 0 ? [end : -1 : start] : [start : 1 : end], a = j * step) c + r * [cos(a), sin(a)], // Points on the arc
-        vec2(tangents[i][0])]                           // Start of next tangent
+    ) [for(i = [0 : len - 1], last = (i - 1 + len) % len)
+        let(
+            t0 = vec2(tangents[last]),
+            t1 = vec2(tangents[i]),
+            p = line_intersection(t0, t1),                              // Do the tangents cross?
+            R = points[i][2]
+        )
+        if(!is_undef(p))                                                // Tangents intersect, so just add the intersection point
+            p
+        else
+            each [                                                      // Else link the two tangent ends with an arc
+                t0[1],                                                  // End of last tangent
+                if(R)                                                   // If rounded
+                    let(r = abs(R),                                     // Get radius
+                        n = r2sides4n(r),                               // Decide number of vertices
+                        step = 360 / n,                                 // Angular step
+                        arc = arcs[i],                                  // Get corner arc details
+                        start = ceil(arc[1] / step + eps),              // Starting index
+                        end = floor((arc[0] + arc[1]) / step - eps),    // Ending index
+                        c = vec2(points[i])                             // Centre of arc
+                    ) for(j = R > 0 ? [end : -1 : start] : [start : 1 : end], a = j * step)
+                        c + r * [cos(a), sin(a)],                       // Points on the arc
+                if(R)
+                    t1[0],                                              // Start of next tangent
+            ]
        ];
 
+function offset(points, offset) =                                       //! Offset a 2D polygon, breaks for concave shapes and negative offsets if the offset is more than half the smallest feature size.
+    rounded_polygon([for(p = points) [p.x, p.y, offset]]);
+
 module rounded_polygon(points, _tangents = undef) //! Draw the rounded polygon from the point list, can pass the tangent list to save it being calculated
     polygon(rounded_polygon(points, _tangents), convexity = len(points));

utils/sweep.scad

@@ -127,8 +127,8 @@ function sweep_transforms(path, loop = false, twist = 0) =
                          i = i + 1,
                          rot = i < len ? rotate_from_to(tangents[i - 1], tangents[i]) * rot : undef) rot],
 
-        missmatch = loop ? calculate_twist(rotations[0], rotations[last]) : 0,
-        rotation = missmatch + twist
+        mismatch = loop ? calculate_twist(rotations[0], rotations[last]) : 0,
+        rotation = mismatch + twist
     )
     [for(i = [0 : last])
         let(za = rotation * lengths[i] / length)

vitamins/extrusions.scad

@@ -20,7 +20,7 @@
 // Extrusion
 //
 //                  W   H     d1     d2  sq    cw   cwi   t    st   f    recess
-E1515  = [ "E1515", 15, 15,  -2.5,    0, 5.7,  3.4,  5.7, 1.1, 1.1, 0.5, false ];
+E1515  = [ "E1515", 15, 15,  -3.3,    0, 5.5,  6.2,  9.5, 1.0, 0.9, 0.5, false ];
 E2020  = [ "E2020", 20, 20,  -4.2,   -3,   8,    6, 12.0,   2,   2, 1,   false ];
 E2020t = [ "E2020t",20, 20,  -5.0,   -3, 7.8,  6.2, 11.0, 1.8, 1.5, 1.5, [7.2, 0.5] ];
 E2040  = [ "E2040", 20, 40,  -4.2,   -3,   8,    6, 12.0,   2,   2, 1,   false ];